Author Proof Chapter 9 Characterization of Local...

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Chapter 9Characterization of Local Structuresin Plasma Deposited Semiconductors by X-rayAbsorption Spectroscopy

M. Alper Sahiner

Abstract Extended X-ray-Absorption Fine-Structure Spectroscopy (EXAFS) has1

been used to investigate the subtle local structural variations in plasma deposited2

semiconductors. Grazing incidence geometry EXAFS is a very effective tool to study3

the surface layers. Since EXAFS is an element specific sensitive local structural4

probe, it is advantageous to commonly used structural characterization techniques5

where there is no long-range crystalline order in material. EXAFS can provide cru-6

cial information deposition or post-deposition induced crystallographic structural7

modifications. The information extracted from EXAFS can be used as an impor-8

tant feedback for the thin film growth mechanisms. In this chapter the fundamental9

principles of EXAFS will be introduced. The data reduction and analyses with the10

structural model calculations will be discussed. The application of the EXAFS in11

plasma deposited silicon wafers and plasma-plume deposited high-k dielectric thin12

films will be presented.13

9.1 Introduction14

The continuous down scaling of the semiconductor devices creates challenging mate-15

rials related problems for the semiconductor researchers. Highly sensitive structural16

characterization techniques are crucial in searching for materials based solutions to17

these problems. One of most challenging tasks in semiconductor industry is to keep18

the dopant levels very high in ever shrinking the p and n-type dopant areas of the19

complementary metal oxide semiconductor (CMOS) devices. The dopant atom con-20

centrations usually exceed the solid solubility limits of silicon or germanium and21

post deposition annealing processes are applied to prevent the dopant clustering and22

increase electrical activation. In addition to conventional beamline ion implantation23

M. A. Sahiner (B)

Department of Physics, Seton Hall University, South Orange, NJ 07079, USAe-mail: [email protected]

M. Bonitz et al. (eds.), Complex Plasmas, Springer Series on Atomic, 1Optical, and Plasma Physics 82, DOI: 10.1007/978-3-319-05437-7_9,© Springer International Publishing Switzerland 2014

314158_1_En_9_Chapter � TYPESET DISK LE � CP Disp.:28/2/2014 Pages: 22 Layout: T1-Standard

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methods, alternative plasma based deposition techniques have recently been used24

to increase the dopant levels and electrically active charge carriers in ultra-shallow25

junctions. Plasma immersion ion implantation (PIII) technology is shown to be one26

of the effective techniques in this field [1] and can provide a better conformal doping27

on 3D structures [2]. An increase of retained dose after annealing has been reported28

for arsenic implantation using plasma sources [3, 4]. These PIII prepared samples29

were fabricated using AsH3/H2, <2kV bias in a sub 30 m Torr pressure. After the30

deposition the samples were laser annealed using a pulsed laser by varying the laser31

power, the total annealing time and the number of laser pulses. EXAFS studies on32

these samples revealed interesting local structural response to variations in the post33

deposition annealing conditions.34

In another example pulsed laser deposited (PLD) high-k dielectric thin films were35

studied by EXAFS in order to investigate the present non-equilibrium structural phase36

present in the deposited thin films. In pulsed laser deposition, the solid target material37

is evaporated by laser pulses of a high-energy KrF excimer laser, ionized and ejected38

as a plasma plume. The plasma plume expands outwards and deposits the target39

material on a substrate. The plasma properties of the plume determine the quality of40

the thin films deposited on the substrate. These plasma plume properties include ion41

density, ion flow speed, electron temperature, and plume peaking parameter [5]. Hf42

based oxide thin films were prepared by PLD and subtle variations in the deposition43

parameter such as substrate temperature and the thickness of the films were probed44

by EXAFS giving a detailed picture of the non-equilibrium crystal phases in the thin45

films.46

9.2 EXAFS47

Extended X-ray absorption fine structure spectroscopy (EXAFS) is a local struc-48

tural probe utilizing the measurement of energy dependence of X-ray absorption49

coefficient μ(E) of the selected main absorbing atom in the material. EXAFS is ele-50

ment specific, that is, by tuning the incoming X-ray energy, through the use of the51

beamline’s double crystal Si monochromator, to the absorption edge of any specific52

element in the material local structure around that particular atom can be probed. An53

incident X-ray is absorbed by a main absorbing atom when the energy of the X-ray54

is transferred to a core-level electron which is ejected from the atom. Any excess55

energy from the incident X-ray is given to the ejected photoelectron. The energy56

dependent X-ray absorption coefficient is modulated due to interference between the57

outgoing photoelectron waves and the backscattered waves from the near neighbor58

atoms. Figure 9.1 is a schematic diagram showing to the X-ray absorption process,59

atomic potentials and the EXAFS data for a main absorber atom A surrounded by60

near-neighbor B atoms. Therefore, the absorption coefficient intrinsically contains61

full local structural information around the main absorbing atoms. If the scatter-62

ing properties (scattering amplitude, phase shift, and mean free path) of the neighbor63

atom are known or calculated through simulations, then EXAFS can provide detailed64


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9 Characterization of Local Structures in Plasma Deposited Semiconductors 3

Energy

Abs

orpt

ion

Coe

ffici

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EXAFS FunctionAtomic Absorption Background

EXAFS

Abs

orpt

ion

Edg

e

Backscattered electron waves

Outgoing electron waves

Fig. 9.1 A schematic diagram for EXAFS process and acquired EXAFS data

information on the near neighbor distances, coordination numbers, crystal symme-65

try, and the structural disorder around the main absorbing atom. Since the scattering66

is from the first couple of near neighbor atoms EXAFS can provide information on67

non-periodic structures even on amorphous materials. EXAFS studies on subtle local68

structural modifications, such as Hf based high-k thin films in this work, is most pow-69

erful when EXAFS data is supported by using computer generated models of similar70

atom clusters and the corresponding scattering simulations of EXAFS functions.71

9.2.1 EXAFS Experimental Set-up72

In Fig. 9.2, a schematic diagram for a typical EXAFS experiment is shown. Highly73

collimated, X-ray white beam through the synchrotron source is passed through a74

monochromator in order to tune the incoming X-ray energies about the absorption75

edge of the selected atoms. The incoming X-ray intensity (I0) is measured by a76

ionization chamber and then the sample is irradiated and either the intensity of the77

outgoing X-rays (I) or the fluorescent radiation intensity (If) is measured either by78

another ionization chamber or a fluorescence (Lytle) detector.79


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Fluorescence Detector (If)

I0

Ionization Chamber Ionization Chamber

I

Synchrotron X-ray Source

Double-crystal Monochromator

Fig. 9.2 Schematic experimental set-up for an EXAFS experiment

LytleDetector,

If

Sample

I0

I

Fig. 9.3 Lytle detector in background measure If . A large sample (5 cm × 5 cm) is mounted on afan motor wired to a variac so it can spin and avoid swamping the detector with Bragg peaks

Some of the EXAFS experiments for this work, were performed at the National80

Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) on81

beamline X23A2, operated by the National Institute of Standards and Technology82

(NIST). The Hf L3 absorption edge (9561 eV) or As-K edge (11867 eV) were used83

in the EXAFS data acquisition in the fluorescence detection mode with a 0.5◦ angle84

of X-ray incidence. Figure 9.3 below is a photograph of the EXAFS experimental85

set-up at X23A2 for these measurements.86

9.2.2 EXAFS Data Analysis87

The absorption coefficient as a function of energy is then calculated as shown in88

Fig. 9.4. The spectrum shown in Fig. 9.4 is a typical X-ray absorption spectrum. The89

spectrum plotted in red is the isolated atomic absorption background and the blue90


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close to the critical angle of silicon.

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Energy (eV)

11800 12000 12200 12400 12600

Abs

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Coe

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1

2

3

4

5

6

Atomic absorption background

Fig. 9.4 A typical EXAFS spectrum (blue) and the atomic absorption background (red). (will bemodified)

k (Å-1)

0 2 4 6 8 10 12 14

Å-1

-0.10

-0.05

0.00

0.05

0.10 EXAFS (k)

R (Å)

0 2 4 6 8 10

(R)

(Å-3)

0.0

0.5

1.0

1.5

2.0 Fourier TransformedEXAFS (R)

(a) (b)

Fig. 9.5 a EXAFS function χ(k) b Magnitude of the Fourier transform of χ(k)

line plot is the EXAFS spectra exhibiting the oscillatory behavior due to scattering91

from near-neighbor atoms.92

After the atomic absorption background is subtracted, the spectra is plotted inphotoelectron wave number, k, using,

E − E0 = (hk/2π)2

2m⇒ k =

√2m (E − E0)

(h/2π)2

where, E0 is the absorption threshold energy, m is the electron mass, h is the Planck’s93

constant. This function is called the EXAFS function χ(k). A typical χ(k) and its94

Fourier Transform is shown in Fig. 9.5.95

χ(k) is simply a summation of the scattering contributions (damped sine waves)from all the possible photoelectron scattering paths between the main absorbing atomand its near-neighbors [6, 7].


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χ (k) =∑

j

χ j (k) = N j f j (k)

k R2j

e−2R j /λ(k)e−2k2σ 2j sin

[2k R j + δ j (k)

]

where, j is the indices for the paths; N j is coordination number; R j is the near-96

neighbor distance; f j scattering amplitude; δ j is the scattering phase; σ is the Debye-97

Waller factor indicating the structural disorder; and λ is the electron mean-free path.98

In Fig. 9.5b the magnitude of the Fourier transformed χ(k) is exhibited. The FT data99

leads to a pseudo radial distribution function around the main absorbing atom. The FT100

data does not reflect the actual distances of the near-neighbor atoms because of the FT101

contains extraneous information such as scattering phases and amplitudes. However,102

if the scattering amplitudes and phases are known then the corresponding the all the103

scattering contributions to can be calculated and the theoretical χ(k) can be obtained.104

To be able to extract reliable information on the details of local structure of a system,105

detailed EXAFS fitting should be applied based on the calculated theoretical models,106

χ j (k). These χ j (k)’s are then fed into EXAFS fitting routines in order to compute107

the local structural parameters of the unknown from its experimental EXAFS data.108

Previous similar work on EXAFS characterization of complicated systems like109

layered superconductors [8–10] and similar EXAFS modeling and analysis work on110

the dopant-related electrically inactive structures in semiconductors [11–16] proved111

that with careful theoretical modeling and the EXAFS data analysis and interpretation112

could lead to crucial information about the subtle structural modifications under113

pressure, ion implantation and post annealing [17–19].114

9.3 Local Structural Information in Arsenic Ultra Shallow115

Junctions by EXAFS116

The understanding of the behavior of arsenic in highly doped near surface silicon117

layers is of crucial importance for the formation of n-type Ultra Shallow Junctions in118

current and future very-large-scale integration (VLSI) technology. This is of peculiar119

relevance when studying novel implantation and annealing methods. Past theoretical120

as well as experimental investigations have suggested that the increase of As concen-121

trations, and therefore the vicinity of the dopant atoms, leads to a drastic increase of122

electrically inactive defects giving only marginal effects on reducing sheet resistance123

[11]. Monoclinic SiAs clusters, as well as various arsenic-vacancy aggregates con-124

tribute to the deactivation of the arsenic. Giubertoni et al. [11] correlated the results of125

electrical activation measurements with EXAFS measurements. Specifically, a quan-126

titative interpretation of the EXAFS spectra has been carried out in order to correlate127

the local atomic order of arsenic to the electrical characteristics as determined by Hall128

Effect measurement. Moreover, the percentage of substitutional dopant produced by129

the different annealing processes has been obtained through least squares fits of the130

EXAFS spectra with simulations of relaxed structures of AsnV defects obtained131

by density functional theory (DFT) calculations. The results confirm EXAFS as a132


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powerful technique, not only able to correlate atomic structures with macroscopic133

electrical behaviors, but also to give quantitative information about the defect popu-134

lations even for ultra-shallow As distributions. For these experiments, EXAFS mea-135

surements have been performed at room temperature at the BM08 GILDA beamline136

of the European Synchrotron Radiation Facility in grazing incidence and fluores-137

cence acquisition with a side-looking 13 element GeHP detector. The sample was138

positioned horizontally [20]. As K-edge spectra have been acquired in the energy139

range 11600–12700 eV with variable energy step (0.5 eV in the proximity of the140

edge, 5 eV at the periphery of the scan) at an incidence angle above the critical for141

total reflection (about 0.18◦ measured from the sample surface) for all samples. The142

critical angle for total reflection for Si varies between 0.154◦ and 0.140◦ for energies143

in the range 11600 and 12700 eV respectively. The chosen angle of incidence allows144

the sampling of the whole dopant distribution with almost uniform weight across the145

implant. A 100 keV As implant (fluence 1×1015cm−2) laser (melting) annealed with146

supposed electrical activation close to 100 % was used as a reference for the EXAFS147

analyses. Theoretical EXAFS functions were calculated using University of Wash-148

ington’s multiple scattering EXAFS calculation code FEFF8.4 [21]. The structural149

parameters, which were obtained by the DFT calculations, were used in calculat-150

ing these EXAFS models. The theoretical EXAFS standards for possible cluster151

structures and monoclinic SiAs precipitates were used in least-squares EXAFS fits152

to the Fourier Transformed (FT) data. Experimental EXAFS functions, χ(k)’s, are153

extracted by subtracting atomic absorption background using the AUTOBK code154

[22]. The χ(k)’s are then Fourier Transformed (FT) using a Gaussian window for155

[2.0–10.0 Å−1] k-range with a k2 weighting in order to fully account the contribution156

from the larger k region. EXAFS fits were performed assuming the co-presence of157

all the AsnV(n = 1–4) clusters, SiAs-precipitates and the substitutional-As (arsenic158

atoms surrounded by silicon atoms in silicon crystal) in the samples.159

9.3.1 DFT Calculations160

Geometry optimizations were carried out for four systems containing a Si vacancy161

surrounded by 1–4 As substitutional defects using the CASTEP plane wave density162

functional code [23]. Initial state structures of AsnV (V = vacancy, n = 1–4) were163

prepared as follows. A bulk Si crystal (Fd3̄m), in which the cell origin was translated164

by 0.5 a to place a Si atom at its center was first relaxed using the GGA PW-165

91 exchange-correlation functional [24] to less than 0.01 eV/atom. The planewave166

basis cutoff energy was 320 eV and a Monkhorst-Pack k-point grid with 0.037 Å−1167

spacing was used for all energy minimizations. The relaxed Si crystal was modified168

to contain a Si vacancy defect at the cell center and 1–4 As substitutional defects in169

the first coordination shell around the vacancy (Fig. 9.6). For each defect state the170

fractional coordinates were optimized using the same functional and convergence171

criteria as used for bulk Si. The cubic lattice parameters obtained for relaxed bulk Si172

were used for initial state structures for each of the As-substitutional defect states.173


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Fig. 9.6 Unit cell schematic showing Si (yellow), As substitution sites (purple) and Si vacancy(white)

Geometry optimizations of the defect states were done using fixed lattice parameters174

but flexible internal fractional coordinates. Fixing the lattice parameters to relaxed175

bulk values permits geometry optimization of the defect environment while retaining176

cubic bulk symmetry in the neighboring cells and bulk crystal lattice.177

DFT geometry optimizations yielded a Si bulk lattice constant of 5.382 Å, 0.9 %178

smaller than the experimental value. DFT geometry optimizations of high atom179

density crystals, particularly Si, are recognized to yield slightly smaller lattice con-180

stants than experimental results although the fractional coordinates are reliable [25].181

The lattice parameters and fractional displacements (in x, y and z directions) of182

the atoms in the first coordination shell around the vacancy for optimized AsnV183

are shown in Table 9.1. In all cases, the vacancy neighbor shell atoms are displaced184

toward the vacancy on the order of 0.2–0.35 Å for As and 0.1–0.2 Å for Si. Although185

other vacancy-substitution defects are possible, we modeled those systems which186

are expected to exhibit the most stable states. Both the stability and diffusion char-187

acteristics of these defect states impact their presence in the lattice, particularly after188

implantation annealing.189

9.3.2 Electrical Data and EXAFS Results190

The sheet resistance (Rs) values measured on all thermally treated samples are191

reported in Table 9.2.192

Samples 2 and 3 showed similar values: 679 and 723 �/sq, respectively. Due193

to the similar junction depth (xj) observed by secondary ion mass spectrometry194

(SIMS), the Rs difference is expected to be due to a different level of electrical195

activation. In fact, the measured active carrier dose is 2.9 × 1014 and 2.7 × 1014196

cm−2 for samples 2 and 3, respectively. When the implanted fluence is increased197


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Table 9.1 Fractional atomic displacements for geometry optimized AsnV (n = 1–4) states

State a (Å) Fractional displacement toward vacancy

Bulk Si 5.382 – – – –(As) (Si) (Si) (Si)

x 0.0137 0.0051(6) 0.00516 0.00612AsV 5.382 y 0.0140 0.0059(5) 0.00524 0.00523

z 0.0140 0.0052(4) 0.00595 0.00523(As) (As) (Si) (Si)

x 0.01377 0.01377 0.01083 0.01083As2V 5.382 y 0.01377 0.01377 0.01083 0.01083

z 0.01451 0.01454 0.00512 0.00512(As) (As) (As) (Si)

x 0.01400 0.01266 0.03578 0.01459As3V 5.382 y 0.01433 0.01266 0.01373 0.00793

z 0.01250 0.01378 0.03607 0.01488(As) (As) (As) (As)

x 0.01768 0.01768 0.01768 0.01768As4V 5.382 y 0.01768 0.01768 0.01768 0.01768

z 0.01768 0.01768 0.01768 0.01768

Table 9.2 Samples description and Hall effect results

Sample Implanted Annealing Etching Rs Mobility Carrier Retained ActiveID dose (�/sq) (cm2/Vs) dose dose fraction

(cm−2) (cm−2) (cm−2) (%)

1 1 × 1015 As implanted – – – – 9.6 × 1014 –2 1 × 1015 LA 1150 ◦C – 679 31.7 2.9 × 1014 9.9 × 1014 29.53 1 × 1015 LA 1300 ◦C – 723 32 2.7 × 1014 1.0 × 1015 27.34 3 × 1015 LA 1300 ◦C – 782 (95) (9.15 × 1013) (2.7 × 1015) (3.4)5 1 × 1015 RTP 1050 ◦C – 490 64.6 2.0 × 1014 7.0 × 1014 28.26 1 × 1015 LA 1150 ◦C + – 450.5 60.8 2.2 × 1014 6.6 × 1014 33.6

RTP 1050 ◦C5 etch 1 × 1015 RTP 1050 ◦C Yes 817.9 73.4 1.0 × 1014 3.1 × 1014 33.26 etch 1 × 1015 LA 1150 ◦C + Yes 698.0 68.7 1.30 × 1014 3.1 × 1014 41.9

RTP 1050◦C

RTP Rapid thermal processing, LA Lase annealing

to 3 × 1015 cm−2 the Rs value also appears to increase to 782 �/sq and the active198

carrier dose is just 9.1 × 1013 cm−2, indicating poorer electrical activation. Due to199

the accuracy of the SIMS results, the ratio of the Hall Effect measured active dose to200

the SIMS determined dose gives a relatively reliable measure of the active fraction201

of dopant in the junction: this value, reported in Table 9.1, is nearly one third for202

the 1 × 1015 cm−2 samples, whereas it falls to ∼3 % for the 3 × 1015 cm−2 sample.203

EXAFS was thus used to investigate the amount of As in substitional position and204

to understand defects behind the relatively large fractions of inactive dopant. Only205

AsnV clusters and SiAs precipitates were incorporated in the EXAFS fits together206


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R (Å)

0 1 2 3 4 5 6

Mag

nitu

de o

f the

Fou

rier

tran

sfor

m o

f k2

(k)

(Å-2

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

FT dataLSQ Fit

1E15/cm2As-implanted

Reference

3E15cm-2LA1150 oC

1E15cm-2LA1150 oC

3E15cm-2 LA1300 oC

Fig. 9.7 Fourier transformed EXAFS data and the corresponding fits for laser annealed samples.The reference sample and the As-implanted sample (data only) were also plotted for comparisonpurposes of the second shell structures

with the substitutional arsenic. As discussed before, AsnV complexes are not the207

only possible As clusters according theoretical studies but most likely ones due to208

lower formation energies. Not only the formation energies but also the diffusion209

characteristics of different clusters have important effects on the presence of these210

structures after post implantation annealing [26, 27]. For AsnV clusters, the local211

structural parameters obtained from geometry optimization calculations were used212

in modeling of the EXAFS functions that were used in the least squares fits. For the213

monoclinic-SiAs, EXAFS modeling the structural parameters from literature was214

used [28] and for the substitutional-As form, EXAFS model was calculated with215

arsenic core atom replacing one of the Si atom in a silicon crystal.216

Figure 9.7 shows the FT data of the EXAFS function for the laser annealed samples217

measured above critical angle and the corresponding EXAFS fits except for the218


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Table 9.3 Active As fraction from Hall effect measurements and fraction of the As complexesobtained from least squares EXAFS fits

Sample Active fraction X-ray Substitional AsV As2V As3V As4V SiAs(%) inc. angle As

2 29.5 Above 0.31 0.10 0.00 0.39 0.14 0.073 27.3 Above 0.26 0.12 0.02 0.53 0.05 0.004 3.4 Above 0.05 0.16 0.05 0.38 0.15 0.215 28.2 Above 0.24 0.06 0.08 0.14 0.18 0.14

Below 0.13 0.08 0.16 0.17 0.29 0.176 33.6 Above 0.36 0.09 0.12 0.15 0.14 0.14

Below 0.14 0.13 0.17 0.18 0.20 0.185 etch 33.2 Above 0.57 0.04 0.07 0.04 0.20 0.086 etch 41.9 Above 0.58 0.00 0.10 0.08 0.13 0.12Reference – Above 0.59 0.00 0.24 0.00 0.17 0.00

Table 9.4 Coordination numbers, near-neighbor distances and Debye-Waller factors from fits

Sample ID X-ray inc. angle First shell Second shellN R(Å) σ(Å2) N* R(Å) σ(Å2)

2 Above 3.7(2) 2.38(2) 0.002(1) 10.8(4) 3.85(2) 0.04(1)3 Above 3.6(2) 2.37(2) 0.002(1) 11.3(3) 3.87(2) 0.03(1)4 Above 3.3(2) 2.36(2) 0.004(2) 9.9(4) 3.88(2) 0.05(3)5 Above 3.7(3) 2.38(2) 0.003(2) 10.6(3) 3.86(2) 0.04(2)

Below 3.4(3) 2.35(1) 0.003(2) 10.3(4) 3.87(1) 0.03(2)6 Above 3.6(3) 2.38(2) 0.002(1) 10.6(3) 3.85(2) 0.02(2)

Below 3.5(2) 2.36(1) 0.003(1) 10.2(4) 3.88(2) 0.04(2)5 etch Above 3.8(2) 2.39(2) 0.002(1) 11.5(2) 3.85(1) 0.03(2)6 etch Above 3.8(2) 2.39(2) 0.002(1) 11.4(2) 3.85(1) 0.03(2)Reference Above 3.9(1) 2.40(1) 0.002(1) 11.6(2) 3.84(1) 0.02(1)

as-implanted sample, which exhibits no long range order beyond the first shell as219

expected for a high dose amorphizing implant.220

The final weighting (fraction) of the different structures was determined from221

the fit results and it is listed in Table 9.3. The arsenic coordination numbers, near-222

neighbor distances, and Debye-Waller factors are listed in Table 9.4.223

Generally the agreement between the active dose obtained from electrical mea-224

surement and the fraction of substitutional As obtained with the EXAFS fit results is225

very good as seen from Table 9.3. The results of the electrical measurements indicate226

that the application of only laser annealing does not increase activation levels higher227

than ∼30 %: EXAFS results for the substitutional As fraction for samples 2 and 3228

are 33 and 26 %, respectively, confirming the findings from combining Hall Effect229

and SIMS characterization. Increasing the As implant dose (sample 3 compared with230

sample 4) sharply reduces the activated As fraction. Similarly EXAFS determined231

substitutional As fraction is significantly lower (5 %) for the 3 × 1015 As implant232

sample. Furthermore, when electrical activation is lower, the coordination number233


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Table 9.5 Matrix of analyzed PIII samples; all samples were produced on the same wafer labeledS2

Sample ID C08: C09: C10: C11:N laser pulses N × 3 laser pulses N × 10 laser pulses N × 30 laser pulse

R1: low laser power S2R1C08 S2R1C09 S2R1C10 S2R1C11R6: high laser power S2R6C08 S2R6C09 S2R6C10 S2R6C11

decreases for both first and second shell. The bond length slightly decreases in the234

first shell whereas increases in the second one: this behavior is consistent with AsnV235

structures as already reported by Allain et al. [17] and D’Acapito et al. [29]. The latter236

obtained bond length values systematically slightly higher than the ones reported in237

Table 9.4 and from Allain et al. [17], but within the experimental error. Regarding the238

fractions of the As complexes, the low dose samples do not have relevant presence239

of SiAs precipitates but most As is in AsV and As3V defects. The latter prevails as240

main deactivating defect even on the more thermodynamically stable As4V, proba-241

bly because of kinetics constraints and because entropy does not favor the formation242

of large complexes in line with what suggested by Mueller et al. [30]. When the As243

dose is increased (sample 4), the fractions of dopant in As4V and SiAs complexes244

increase as expected being the concentration higher.245

9.3.3 Arsenic PIII Structures by EXAFS246

Arsenic implants were fabricated by plasma ion immersion implantation (PIII) using247

AsH3/H2, <2kV bias in a sub 30 m Torr pressure [2]. The samples were subsequently248

laser annealed using a pulsed laser to a range of laser powers and varying the total249

annealing time by varying the number of pulses. A single 300 mm (100) Si wafer250

(labeled ‘S2’) was processed adjusting the doping parameters to implant a nominal251

Arsenic dose of ∼1 × 1015 at/cm2. On the wafer a pattern of differently annealed252

areas of ∼1 × 3 cm2 was created by the laser thermal treatment using different laser253

energy per area [J/cm2]. Varying two main parameters of the laser annealing, namely254

laser power and the number of laser pulses, two series of samples were generated,255

one annealed using low laser energy (R1) and the other using high laser energy (R6).256

Within each series the number of pulses was varied to investigate whether this affects257

the annealing. Table 9.5 shows the matrix of analyzed samples.258

Fourier transformed EXAFS data collected for selected PIII samples are displayed259

in Fig. 9.8. They agree very well with the findings obtained by SIMS and XPS in260

terms of As concentrations in the oxide and silicon: clear amplitudes corresponding261

to As having Oxygen as nearest neighbor (labeled as ‘As-O’) for all samples of series262

R1 (except for sample R1C11) indicate a significant amount of As in SiO2.263

The standard XA4 (80 % As in SiO2) is plotted for comparison. The FT data show264

that the As-Si peaks are slightly shifted towards larger near-neighbor distances in265

the R1 samples indicating a change in the As local environment compared with the266


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Fig. 9.8 Fourier transform of the EXAFS collected for selected PIII samples and standards XA4(∼80 % of As in SiO2) and MR24 (substitutional As in Si). The labeled peaks indicate the amplitudescorresponding to the first coordination shells of As-O and As-Si structures

reference samples. It is interesting to note that the As-O peaks on the other hand agree267

very well with the corresponding amplitudes of the standard suggesting that it is the268

part of As in Si (at the Si interface) which is (chemically) different. However, this is269

not surprising as the As concentrations in the PIII samples are more than one order270

of magnitude larger than the ones in the standard making it reasonable that the As271

in that case is part of a different chemical complex. As before sample R1C11 shows272

different EXAFS than all other samples: in agreement with XPS (oxide thickness)273

and SIMS (oxide thickness and profile) the EXAFS shows no detectable As-O signal,274

suggesting that all (most) As is in Si. The remaining part of As found in the oxide275

layer by SIMS has to be considered below the detection limit of EXAFS analysis for276

this sample, because the weak As-O signal is covered by the much stronger signal277

corresponding to As-Si. (The same is obviously true for the EXAFS collected for278

the samples of series R6 where the As-O to As-Si signal ratio is even smaller.)279

Finally, none of the samples of series R1 show any detectable higher local order,280

i.e. crystallinity, like in the standard MR24 suggesting that the annealing was able to281

redistribute part of the As (diffusion into Si, redistribution within As rich oxide layer)282

but was not sufficient to significantly heal the crystal damage (within the EXAFS283

detection limit).284

From a technological point of view, when aiming for ultra-shallow As distributions285

with very high retained doses, we can conclude that a combination of PIII and laser286

annealing with carefully optimized laser parameters seems a very promising approach287

as revealed from structural EXAFS analyses [2].288

9.4 Local Structural Information in High-k Dielectrics289

by EXAFS290

Although, the use of high-k dielectrics in the SiO2 in the gate dielectric region of the291

complementary metal oxide (CMOS) devices have already started in industry in 2007,292

some of the materials related issues described by Wilk [31] such as the determination293

of the stable crystal phases of the formed oxides under high processing temperatures294


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14 M. A. Sahiner

still remain to be solved. Since the possible inclusion of Ge in future CMOS devices295

due to promising results in increasing the channel mobility, characterization of Hf-296

based oxides on germanium are attracting interests of researchers [32, 33]. In both297

cases (silicon and germanium substrates) the detailed local structural information298

around the Hf atom has crucial value in terms of further process development using299

these exciting new structures.300

In search of the replacement of SiO2 at the gate dielectric region of the CMOS301

devices, Hf based oxides are the leading candidates. The local structural modifica-302

tions around the Hf atom and a reliable method of monitoring the local structural303

modifications as response to synthesis conditions are crucial in studying these mate-304

rials. One of the key questions to be addressed in studying the Hf based oxides is305

determining the stabilized crystal structure formed under various synthesis condi-306

tions. Previously, crystal phase transformations due to post deposition treatments in307

Hf based oxide thin films [34] or Zr content Hf1−xZrxO2 nanocrystals [35] have308

been reported.309

EXAFS analyses were used in order to study the thin films of Hf based oxides310

deposited on silicon and germanium by pulsed laser deposition technique [36]. It311

has been observed that the HfO2 crystal structure is highly dependent on parame-312

ters of the synthesis such as substrate temperature during the deposition and Zr313

concentration in Hf1−xZrxO2(x = 0.0–1.0). The local structural modifications due314

to substrate temperature variations during the deposition and the Zr inclusion and315

the local structure of HfO2 thin films on germanium were probed by X-ray absorp-316

tion fine-structure spectroscopy (EXAFS) [36]. Specifically, pulsed laser deposition317

(PLD) technique has been used in the deposition of the thin films with systematic318

variations of substrate temperature, Zr content of the targets and substrate selection.319

Non-equilibrium processes between plasma plume produced by the high energy KrF320

laser pulses on the solid HfZrO targets and the single crystal silicon or germanium321

substrate is shown to lead to non-equiblirum crystal phases in these high-k dielectric322

thin films [37].323

The local structural information acquired from extended X-ray absorption spec-324

troscopy (EXAFS) is correlated with the thin film growth conditions. The response325

of the local structure around Hf and Zr atoms to growth parameters was investi-326

gated by EXAFS experiments performed at the National Synchrotron Light Source327

of Brookhaven National Laboratory. The competing crystal phases of oxides of Hf328

were identified and the intricate relation between the stabilized phase and the para-329

meters as: the substrate temperature; Hf to Zr ratio; have been revealed. Specifically,330

HfO2 thin films on Si(100) exhibit a tetragonal to monoclinic phase transformation331

upon increase in the substrate temperature during deposition whereas, HfO2 PLD332

films on Ge(100) substrates remain in tetragonal symmetry regardless of the substrate333

temperature [36].334

Previous studies in determining the crystal symmetry of the HfO2 with respect335

to thin film layer thickness and annealing conditions revealed existence of non-336

equilibrium phases (tetragonal) of HfO2 [34] under certain annealing conditions.337

Specifically, 1.4, 1.8, and 4.0 nm thick HfO2 films on 1.0 nm SiO2 interfacial layers338

on Si(100) substrates were subjected to different annealing treatments. Figure 9.9339


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R (Å)

0 1 2 3 4 5 6

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2(k

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-2 )

0.0

0.4

0.8

1.2

1.6

2.0

2.4

2.8

3.2

1.4 nm PDA

1.8 nm PDA

4.0 nm PDA

R (Å)

0 1 2 3 4 5 60.0

0.4

0.8

1.2

1.6

2.0

2.4

2.8

3.2

1.4 nm PDA+RTA

4.0 nm PDA+RTA

1.8 nm PDA+RTA

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Fig. 9.9 HfO2 thin films on Si(100) and the second shell EXAFS fits. PDA Post deposition anneal-ing, RTA Rapid thermal annealing

Table 9.6 Fraction ofdifferent crystal phases inHfO2 thin films

FractionMonoclinic Tetragonal Orthorhombic

1.4 nm PDA 0.00 0.96 0.041.8 nm PDA 0.00 0.99 0.014.0 nm PDA 0.67 0.33 0.001.4 nm PDA + RTA 0.57 0.43 0.001.8 nm PDA + RTA 0.60 0.40 0.004.0 nm PDA + RTA 0.96 0.04 0.00

shows the FT data and corresponding second shell fits and Table 9.6 lists the fraction340

of the different phases present in these films [34].341

During the pulsed laser deposition process the thin films of Hf1−xZrxO2(x = 0,342

0.10, 0.25, 0.50, 0.75), were deposited on 2 inch p-type Si(100) and wafers using a343

KrF excimer laser with a wavelength of 248 nm. The surface oxide on the substrate344

wafers were removed by a 1:10 of solution of HF + H2O and rinsed using deionized345

water solution before the deposition. The partial O2pressure was kept at 100 mTorr346

during the deposition to prevent oxygen deficiency in the thin films. The laser energy347

density was set to 1.1 J/cm2 and laser pulse frequency was at 10 Hz. The substrate348

temperature was varied between 100 and 800 ◦C. The target to substrate distance was349

set to 5 cm in all the depositions. The orientation/quality of the films was checked350

by X-ray diffraction. The thickness of the films varied between 15–20 nm as verified351

with a thin film reflectometry system with a resolution of 0.1 nm.352

Hf L3-edge X-ray absorption fine structure spectroscopy (EXAFS) experiments353

were performed at the National Institute of Standards and Technology’s (NIST)354

beamline (X23A2) at National Synchrotron Light Source (NSLS) at Brookhaven355


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HfO2/Si(100) PLD at Different

Substrate Temperatures and XAFS Fits

R (Å)

0 1 2 3 4 5 6

Mag

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f k2

(k)

(Å-2 )

0.0

0.5

1.0

1.5

2.0

2.5

800 oC

700 oC

600 oC

500 oC

400 oC

300 oC

200 oC

100 oC

Fig. 9.10 The Fourier-transformed EXAFS data and the least-square EXAFS fits to the data forthe PLD deposited HfO2/Si(100) films at substrate temperatures of 100–800 ◦C

National Laboratory (BNL). EXAFS data were acquired in the fluorescence detection356

mode and the X-ray angle of incidence was set to 3◦ during the measurements.357

All the EXAFS measurements were performed at the Hf L3 absorption edge and358

the atomic absorption background were subtracted by AUTOBK code [22]. EXAFS359

functions χ(k)’s are Fourier Transformed (FT) using a Gaussian window for ( 2.0–360

12.5 Å−1) k-range with a k2 weighting in order to fully account the larger k region.361

University of Washington’s multiple scattering code FEFF8.4 [21], has been used for362

the EXAFS calculations of the theoretical standards to be used in least-square EXAFS363

fits to the data. The theoretical standards for all the possible crystal phases of HfO2364

were created using lattice parameters and fractional coordinates from literature [38].365

These were monoclinic, tetragonal, cubic and orthorhombic structures. The stable366

structure for HfO2 at the room temperature is the monoclinic phase [35]. For the least367

square fits of the Fourier Transformed (FT) HfO2 EXAFS data all of these phases are368

used for the identification of the final crystal phases present in the thin films. The first369

shell is dominated by the Hf-O near-neighbors and the second shell mostly involves370

Hf-Hf scattering in the EXAFS functions for all the different crystal symmetries. The371

second shell is more sensitive to modifications on the local structure around Hf atom.372


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Figure 9.10 shows the FT data for HfO2/Si(100) PLD films deposited at different373

substrate temperatures and the EXAFS fits to the data.374

The FT data in the second shell (2.2–3.5 Å) indicate a difference for the two375

lowest substrate temperature deposition samples (100 and 200 ◦C) and the samples,376

which were deposited at 300 ◦C or higher substrate temperatures. The differences377

are attributed to the slight modifications of the crystal symmetry of Hf atoms. In378

order to probe these subtle changes all the calculated possible phases of the HfO2379

are used. The double peak structure in the second shell (smaller peak around 2.8 Å380

and a slightly larger peak around 3.1 Å) is a signature of the HfO2 monoclinic phase381

[34]. The EXAFS fits results for the near-neighbor distances (R) and the coordination382

numbers (N) are tabulated in Table 9.7. The fit region is set to the second shell and383

the multiple scattering paths were negligible. The uncertainties in the near neighbor384

distances, and the coordination numbers are ±0.02 Å and ±0.1, respectively. The385

fraction of the two found phases (tetragonal and monoclinic) and the near neighbor386

distances and coordination numbers around the Hf atom are also listed in Table 9.7.387

For the films deposited at 100 and 200 ◦C substrate temperature the crystal sym-388

metry around the Hf atom is tetragonal when the substrate temperature is raised to389

300 ◦C the monoclinic structure starts to appear and when higher substrate temper-390

atures are used the HfO2 structure settles in pure monoclinic phase as indicated in391

Table 9.7. This indicates that the HfO2 tetragonal phase can be stabilized on Si(100)392

by setting the substrate temperature at the deposition below 300 ◦C.393

Figure 9.11 shows the FT EXAFS data for the Hf0.9Zr0.1O2/Si(100) PLD thin394

films. For this series PLD films were prepared using a mixture of HfO2 and ZrO2395

powder and in a fine mesh and using the resulting mixture as the target material for396

the deposition. As can be observed from the evolution of the second shell peaks the397

settling of the monoclinic phase is delayed up to 500 ◦C when 10 % Zr is incorporated398

into the target material.399

In Fig. 9.12, overlays of FT data for Hf1−xZrxO2/Si(100){x = 0, 0.10, 0.25, 0.50,400

0.75} deposited at 200 and 500 ◦C are plotted side by side. For the 200 ◦C substrate401

temperature deposition, the increase in the Zr content does not change the structures402

of the second shell and the symmetry is tetragonal for all x ranges.403

However, at 500 ◦C the Zr effects are seen. HfO2 monoclinic structure is observ-404

able in the second shell up to x = 0.10 but the structure gradually shifts away mono-405

clinic for x ≥ 0.25.406

Figure 9.13 is an overlay of the FT data for HfO2/Ge(100) films deposited at407

substrate temperature between 100 and 400 ◦C and HfO2/Si(100) films deposited408

at 100, 200, and 400 ◦C for comparison purposes.409

All the films on Ge(100) exhibits a very similar structure to those on Si(100) for410

the two lowest substrate temperatures of deposition i.e., 100 and 200 ◦C. As dis-411

cussed previously, the HfO2/Si(100) structure is exhibits tetragonal symmetry for412

100 and 200 ◦C and settles down in monoclinic structure for temperatures higher413

than 200 ◦C. In contrast HfO2/Ge(100), remains in tetragonal symmetry for all tem-414

perature ranges up to 500 ◦C. An overlay of the FT data of HfO2/Si(100) at 400 ◦C415

is plotted just to show the difference between the settled monoclinic phase for films416

on silicon and the sustained tetragonal phases on germanium. Debernardi et al. [39]417


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Table 9.7 2nd shell EXAFS fit results to Fourier transformed data of HfO2/Si(100)

2nd shell fits for HfO2 on siliconMonoclinic (P21/c) Tetragonal (P42/nmc)

Sample ID R(Å) NHf−Hf Fraction R(Å) NHf−Hf Fraction

HfO2/Si(100) @100 ◦C 3.36 6.3 0.03 3.61 10.9 0.97HfO2/Si(100) @200 ◦C 3.38 6.2 0.05 3.59 10.3 0.95HfO2/Si(100) @300 ◦C 3.37 6.5 0.65 3.56 9.8 0.35HfO2/Si(100) @400 ◦C 3.35 6.5 0.88 3.53 9.5 0.12HfO2/Si(100) @500 ◦C 3.40 6.2 0.94 3.52 9.6 0.06HfO2/Si(100) @600 ◦C 3.41 6.7 1.00 0.00HfO2/Si(100) @700 ◦C 3.41 6.6 1.00 0.00HfO2/Si(100) @800 ◦C 3.43 6.8 1.00 0.00

R is the near-neighbor distance and the N is the coordination number around Hf atom

Hf0.9Zr0.1O2/Si(100) PLD at Different

Substrate Temperatures

R (Å)

0 1 2 3 4 5 6

Mag

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m o

f k2

(k)

(Å-2 )

0.0

0.5

1.0

1.5

2.0

2.5

3.0

800 oC

700 oC

600 oC

500 oC

400 oC

300 oC

200 oC

Fig. 9.11 The Fourier transformed EXAFS data for the PLD deposited Hf0.9Zr0.1O2/Si(100) filmsat substrate temperatures of 200–800 ◦C


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Hf1-xZrxO2/Si(100) PLD 200oC

R (Å)

0 1 2 3 4 5 6

Mag

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1.5

2.0

2.5

3.0

x=0.0

x=0.10

x=0.25

x=0.50

x=0.75

Hf1-xZrxO2/Si(100) PLD 500oC

R (Å)

1 2 3 4 5 6

x=0.0

x=0.10

x=0.25

x=0.50

x=0.75

Fig. 9.12 The Fourier transformed EXAFS data for the PLD deposited Hf1−xZrxO2/Si(100)

{x = 0.0–0.75} at T = 200 ◦C and T = 500 ◦C

have suggested epitaxial tetragonal structure of HfO2/Ge(100) by depending on418

their theoretical calculations. They based their arguments on the better lattice match419

between the tetragonal phase of HfO2 and the Ge but failed to observe it experi-420

mentally by X-ray diffraction. To our knowledge, our work is the first experimental421

evidence of tetragonal growth of HfO2 on Ge(100). The EXAFS fit results for Ge422

substrate films are tabulated in Table 9.8 confirm the tetragonal symmetry in these423

films.424

9.5 Summary425

Extended X-ray absorption fine structure spectroscopy has been used to investigate426

the subtle local structural modifications and thin-film formation process caused by427

the variations in the plasma process parameters in semiconducting materials. AQ1428

The effectiveness of the EXAFS in non-destructively probing microstructural429

variations were shown in two materials related challenges in semiconductor materi-430

als. The first example was on the dopant clustering and deactivation problem in high431

dose plasma immersion ion implants (arsenic). The second example was on the non-432

equilibrium crystal phase identificationson the high-k dielectric thin films prepared by433


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HfO2/Si(100) or HfO2/Ge(100) PLD

R (Å)

0 1 2 3 4 5 6

Mag

nitu

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Fou

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m o

f k2

(k)

(Å-2 )

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Ge @100oC

Ge @500oC

Ge @400oC

Ge @200oC

Si @400oC

Si @200oC

Si @100oC

Fig. 9.13 The Fourier transformed EXAFS data for the PLD deposited HfO2/Ge(100) at T = 100,200, 400, and 500 ◦C. FT Data for HfO2/Si(100) films at T = 100, 200, and 400 ◦C are overlayedfor comparison

Table 9.8 2nd shell EXAFS fit results to Fourier transformed data of HfO2/Ge(100)

2nd shell fits for HfO2 on germanium-tetragonal (P42/nmc)Sample ID R (Å) NHf−Hf

HfO2/Ge(100) @100 ◦C 3.58 10.2HfO2/Ge(100) @200 ◦C 3.57 10.5HfO2/Ge(100) @400 ◦C 3.63 10.8HfO2/Ge(100) @500 ◦C 3.62 10.4

R is the near-neighbor distance and the N is the coordination number around Hf atom

the pulsed laser deposition (through plasma plume of the target materials). Through434

these examples EXAFS has been shown to be a very effective non-destructive local435

X-ray technique in studying the physics of the complex plasma processes.436

Acknowledgments This work was supported by Research Corporation Award # CC6405 and NSF437

DMI 0420952, and SEMATECH.438


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References439

1. D. Gupta, Int. J. Adv. Technol. 2(4), 507–529 (2011)440

2. F. Meirer et al., AIP Conf. Proc. 1496, 183 (2012)441

3. S. Qin et al., IEEE Trans. Plasma Sci. 37(10), 2082 (2009)442

4. S.B. Felch et al., Surf. Coat. Tech. 156, 229 (2002)443

5. J. Haverkamp, R.M. Mayo, M.A. Bourham et al., Plasma plume characteristics and properties444

of pulsed laser deposited diamond-like carbon films. J. Appl. Phys. 93, 3627 (2003)445

6. D.C. Koningsberger, R. Prins (eds.), X-ray absorption: principles, applications, techniques of446

EXAFS, SEXAFS, and XANES, in chemical analysis 92 (John Wiley, NJ, 1988)447

7. G. Bunker (ed.), Introduction to XAFS: a practical guide to X-ray absorption fine structure448

spectroscopy (Cambridge University Press, Cambridge, 2010)449

8. A. Sahiner, D. Crozier, D.T. Jiang, R. Ingalls, Phys. Rev. B 59, 3902 (1999).450

9. A. Sahiner, M. Croft, S. Guha, I. Perez, Z. Zhang, M. Greenblatt, P.A. Metcalf, H. Jahns, G.451

Liang, Phys. Rev. B 51, 5879 (1995)452

10. A. Sahiner, M. Croft, S. Guha, Z. Zhang, M. Greenblatt, I. Perez, P.A. Metcalf, H. Jahns, G.453

Liang, Phys. Rev. B 53, 9745 (1996)454

11. D. Giubertoni, G. Pepponi, S. Gennaro, M. Bersani, M.A. Sahiner, S.P. Kelty, R. Doherty, M.A.455

Foad, M. Kah, K.J. Kirkby, J.C. Woicik, P. Pianetta, J. Appl. Phys. 104, 103716 (2008)456

12. M.A. Sahiner, S.W. Novak, J.C. Woicik, Y. Takamura, P.B. Griffin, J.D. Plummer, MRS Proc.457

717, C3.6.1 (2003)458

13. M.A. Sahiner, D.F. Downey, S.W. Novak, J. Liu, V. Krishnamoorthy, IEEE Trans. Ion Implant.459

Technol. 432, 600 (2000)460

14. M.A. Sahiner, D.F. Downey, S.W. Novak, J.C. Woicik, D.A. Arena, Microelectron. J. (Elsevier)461

36, 3 (2005)462

15. M.A. Sahiner, P. Ansari, M.S. Carroll, C.A. King, Y.S. Suh, R.A. Levy, T. Buyuklimanli, M.463

Croft, MRS Proc. 864, E7.8.1 (2005)464

16. M.A. Sahiner, S.W. Novak, J.C. Woicik, J. Liu, V. Krishnamoorty, MRS Proc. 669, J5.8.1465

(2001)466

17. J.L. Allain, A. Bourret, J.R. Regnard, A. Armigliato, Appl. Phys. Lett. 61, 264 (1992)467

18. A. Armigliato, F. Romanato, A. Drigo, A. Carnera, C. Brizard, J.R. Regnard, J.L. Allain, Phys.468

Rev. B 52, 1859 (1995)469

19. C. Revenant-Brizard, J.R. Regnard, S. Solmi, A. Armigliato, S. Valmorri, C. Cellini, F.470

Romanato, J. Appl. Phys. 79, 9037 (1996)471

20. G. Pepponi, D. Giubertoni, S. Gennaro, M. Bersani, M. Anderle, R. Grisenti, M. Werner, J.A.472

van den Berg, Ion Implantation Technology, Marseille, France, p. 117, 2006, ed. by K.J. Kirkby473

et al., American Institute of Physics474

21. A.L. Ankudinov, B. Ravel, J.J. Rehr, S.D. Conradson, Phys. Rev. B 58, 7565 (1998)475

22. M. Newville, P. Livins, Y. Yacoby, J.J. Rehr, E.A. Stern, Phys. Rev. B 47, 14126 (1993)476

23. M.D. Segall, P.J.D. Lindan, M.J. Probert, C.J. Pickard, P.J. Hasnip, S.J. Clark, M.C. Payne, J.477

Phys. Cond. Matt. 14, 2717 (2002)478

24. J.P. Perdew, Y. Wang, Phys. Rev. B 45, 13244 (1992)479

25. C. Skylaris, P.D. Haynes, J. Chem. Phys. 127, 164712 (2007)480

26. M. Ramamoorthy, S.T. Pantelides, Phys. Rev. Lett. 76(25), 4753 (1996)481

27. D.C. Mueller, E. Alonso, W. Fichtner, Phys. Rev. B 68, 045208 (2003)482

28. T. Wadsten, Acta Chem. Scand. 19, 1232 (1965)483

29. F. d’Acapito, S. Milita, A. Satta, L. Colombo, J. Appl. Phys. 102, 043524 (2007)484

30. D.C. Mueller, E. Alonso, W. Fichtner, Phys. Rev. B 68, 045208 (2003)485

31. W.R.M. Wilk, J.M. Anthony, J. Appl. Phys. 89, 5243 (2001)486

32. C. Beer et al., Appl. Phys. Lett. 91, 263512 (2008)487

33. Y.J. Yang, W.S. Ho, C.F. Huang, S.T. Chang, C.W. Liu, Appl. Phys. Lett. 91, 102103 (2007)488

34. P. Lysaght, J.C. Woicik, M.A. Sahiner, B.-H. Lee, R. Jammy, Appl. Phys. Lett. 91, 122910489

(2007)490


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35. J. Tang, J. Fabbri, R.D. Robinson, Y. Zhu, I.P. Herman, M.L. Steigerwald, L.E. Brus, Chem.491

Mater. 16, 1336 (2004)492

36. M. Alper Sahiner, J.C. Woicik, T. Kurp, J. Serfass, M. Aranguren, Mater. Sci. Semicond.493

Process. 11, 245 (2008)494

37. M.A. Sahiner, J.C. Woicik, P. Gao, P. McKeown, M.C. Croft, M. Gartman, B. Benapfla, Thin495

Solid Films 515, 6548 (2007)496

38. X. Zhao, D. Vanderbilt, Phys. Rev. B 65, 233106 (2002)497

39. A. Debernardi, C. Wiemer, M. Fanciulli, Phys. Rev. B 76, 155405 (2007)498


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