Hang Hu1, Shi-Jin Ding1, HF Lim1, Chunxiang Zhu1, M.F. Li1, 2,

S.J.Kim1, XF Yu1, JH Chen1, YF Yong1, Byung Jin Cho1, D.S.H.

Chan1, Subhash C Rustagi2, MB Yu2, CH Tung2, Anyan Du2, Doan

My2, PD Foo2, Albert Chin3, Dim-Lee Kwong4

1SNDL, Dept. of ECE, National Univ. of Singapore, Singapore, 2Institute of Microelectronics, Singapore,

3Dept. of Electronics Eng., National Chiao Tung Univ., Taiwan4Dept. of Electrical & Computer Eng., Univ. of Texas, Austin, TX 78712, USA

High Performance ALD HfOHigh Performance ALD HfO22-Al-Al22OO33 Laminate MIM Laminate MIM

Capacitors for RF and Mixed Signal IC ApplicationsCapacitors for RF and Mixed Signal IC Applications

Silicon Nano Device Laboratory / Dept of ECE

Outline of Presentation

Motivation

Experiment

Results and Discussion

I. RF characterization

II. DC properties

III. Reliability and lifetime

IV. High-κ MIM capacitors comparison

Conclusions

Year of Production 2003 2004 2005 2006 2007 2010 2013 2016

Analog capacitor

Density (fF/µm2) 3 3 4 4 4 7 10 15

Voltage linearity (ppm/V2)

100

Leakage (fA[pF•V] 7

RF bypass capacitor

Density (fF/µm2) 8 9 10 11 12 17 20 23

Voltage linearity (ppm/V)

1000

The International Technology Roadmap for Semiconductors, 2002 Edition

Mixed signal MIM capacitor requirement

Motivation

SiO2 and Si3N4 MIM capacitors usually provide low

capacitance density of ~1 fF/μm2.

High-k dielectrics needs to be used for future MIM

application according to ITRS roadmap.

HfO2 is a promising high-k material for MIM

capacitor. However fast oxygen diffusion.

Al2O3 have the advantage of large band gap, low

oxygen diffusivity, however only middle k value.

Motivation

4 4 μμm SiOm SiO22 deposition on Si substrate for isolation deposition on Si substrate for isolation

Bottom Bottom electrodeelectrode deposition deposition (Ta/TaN) (Ta/TaN)

Transmission line formationTransmission line formation

Dielectric depositionDielectric deposition by atomic layer deposition (ALD) by atomic layer deposition (ALD)

TEM photo of 13 nm laminate film

Experiment

Al2O3 (1nm)/HfO2 (5nm) laminate

Al2O3 as electrode contacting layers

13, 31, and 43 nm used in our work

Post deposition anneal (420Post deposition anneal (420ooC)C)

Contact hole etchingContact hole etching

TopTop metal deposition metal deposition (TaN/Al) and patterning (TaN/Al) and patterning

MIM structure Dummy device

Final Device structure for characterization

Experiment

C1

Port1 Port2RSLS2

R1 R2C2

RP

C

LS1

Cox1 Cox2

Capacitor modeling in RF regime

Equivalent circuit diagram for MIM capacitor

modeling in RF regime

I. RF capacitor model

S11

1.0

-2.0

-1.0

-0.5

0.5 2.0

1.0

0

S21

S11

1.0

-2.0-1.0

-0.5

0.5 2.01.0

0

S21

I. S-parameter simulation

Measured and simulated S-parameters for laminate

MIM capacitors by IC-CAP using SPICE3 simulator.

Measured Simulated

S11

1.0

-2.0-1.0

-0.5

0.5 2.0

1.0

0

S21

13 nm 31 nm 43 nm

0.0 5.0G 10.0G 15.0G 20.0G-300p

-200p

-100p

0

100p

200p

Sin

gle

en

ded

eff

ecti

ve c

apac

itan

ce

Frequency (GHz)

13 nm 31 nm 43 nm

Capacitive

Inductive

I. High frequency response

High frequency response of laminate MIM

capacitors from 50 MHz to 20 GHz

1k 100k 10M 1G 100G0

2

4

6

8

10

12

14

RF analysis up to 20 GHz

Cap

acit

ance

den

sity

(fF

/m

2 )

Frequency (Hz)

13 nm 31 nm 43 nm

Low frequency 1 MHz

I. Cap. versus frequency

The frequency dependence of capacitance density

of laminate capacitors (k ~19).

-2 -1 0 1 2

10-9

10-8

10-7

J (A

/cm

2 )

DC Voltage (V)

13nm 43nm

II. J-V characteristics

Typical J-V characteristics of laminate MIM capacitors

0.0 0.5 1.0 1.5 2.00.1

1

JT

/ J

RT

Voltage (V)

50C 75C 100C 125C

Leakage obtained at different temperatures for 13

nm MIM capacitor (normalized to JRT: leakage

measured at room temperature)

II. J-V characteristics

0.0 0.5 1.0 1.5 2.0

10-13

10-12

10-11

10-10

0.5 1.0 1.5-20

-18

-16

-14

-12

Ln (

J)

E1/2 (MV/cm)1/2

Schottky mechanism

J/E

(A

/V*c

m)

E1/2 (MV/cm)1/2

Poole-Frenkel mechanism

13 nm

Conduction mechanisms of 13 nm laminate MIM

capacitor, showing Pool-Frankel conduction at

high field.

II. Conduction mechanism

-2 -1 0 1 2

0.000

0.005

0.010

0.015

d

C/C

o 13nm = 1990ppm/V2; = 211ppm/V

DC Voltage (V)

Measured @1MHz

31nm = 405ppm/V2; = -95ppm/V 43nm = 207ppm/V2; = -65ppm/V

Quadratic (α) and linear (β) VCCs of laminate MIM

capacitors with thicknesses of 13, 31 and 43 nm

II. CV characteristics

4 6 8 10 12 14102

103

104

Capacitance density (fF/m2)

(p

pm

/V2 )

Thickness dependence of quadratic VCC (α) for

laminate MIM capacitors. The implication is

significant for the scaling of the high-k dielectrics.

II. CV characteristics

10k 100k 1M102

103

104

p

pm

/V2 )

Frequency (kHz)

13nm 31nm 43nm

Frequency dependence of quadratic VCC α for

laminate MIM capacitors

II. CV characteristics

0 1000 2000 3000 4000

0.88

0.90

0.92

0.94

0.96

0.98

1.00

1.02

0 1000 2000 3000 4000

1.0

1.1

1.2

1.3

1.4

/ 0

Stress Time (sec)

/ o

Stress Time (sec)

10kHz 100kHz 1MHz

Stressed @4V

Quadratic VCC as a function of stress time.

The inset shows time dependence of linear VCC .

II. CV characteristics

-350

-300

-250

2100

2200

2300

2400

0

5

10

15

20

25

30

35

Remeasured after stress stop (1hr)

Stress time @4V (1500sec)

Stress time (0sec)

(ppm/V2)

(ppm/V)

J @4V (ppmA/cm2)

Time dependence on VCCs and leakage, under

stress condition. The recovery of leakage and VCCs

may further prolong lifetime under AC condition.

II. CV characteristics

0 30 60 90 120 150 180

0

10000

20000

30000

No

rmal

ized

Cap

acit

ance

(p

pm

)

Temperature (oC)

13 nm 182 ppm/oC

31 nm 196 ppm/oC

43 nm 199 ppm/oC

TCC values for laminate MIM capacitors

with three different thicknesses

II. TCC properties

10 100 1000

1.2x10-5

1.6x10-5

2x10-5

J (A

/cm

2)

Stress time (sec)

Area=1E-4 cm2As-stressed

After 10hurs

Stressed @4V

Stress time dependence of leakage for a fresh

device up to 2000s. The device was re-stressed and

re-measured after interrupting stress for 10 hours.

III. Constant voltage stress

Life time projection of 13 nm laminate capacitor, using

50% failure time criteria, the extrapolated voltage for

10 years lifetime is 3.3 V.

III. Lifetime projection

0

20

40

60

80

100

101 102 103

Time (sec)

Cum

ulat

ive

Failu

re (%

)

Stressed @-6V Stressed @-5.8V Stressed @-5.5V

Area=1E-4cm2

0.0 1.3 2.6 3.9 5.2 6.5 7.8

0 1 2 3 4 5 6

100

102

104

106

108

1010

E (MV/cm)

Tim

e to

50%

Fai

lure

(se

c)Voltage (V)

10 years Area=1x10-4cm2

Reference [1] [2] [3] [4] [5] This work

Dielectric HfO2 (ALD) Ta2O5

AlTaOx

(PVD)Ta2O5 (CVD)

Tb doped HfO2 (PVD)

Hf/Al laminate

(ALD)

Capacitance density (fF/µm2)

13 9.2 10 9 13.3 12.8

Leakage (A/cm2)

5.7×10-7@2V 2×10-8@1.5V 4.6×10-6@1V — 1×10-7@2V 7.45×10-9@2V

VCC607 ppm/V

853 ppm/V2 2060 ppm/V 3580 ppm/V2

2818 ppm/V2 2050 ppm/V475 ppm/V2

332 ppm/V 2667 ppm/V2

211 ppm/V 1990 ppm/V2

TCC (ppm/oC) — ~200 255 — 123 198

[1]. XF Yu et al. EDL. Vol. 24, 2003. [2]. Tsuyoshi. I et al. IEDM 2002, p.940. [3]. C. H. Huang, et al. MTT-S. 2003.[4]. Y. L. Tu. et al VLSI symp. 2003, p.79. [5]. S.J. Kim et al. VLSI symp. 2003, p.77.

IV. High-κ MIM cap. comparison

Laminate capacitor is among one of the best for RF

capacitor application.

Conclusions

High performance HfOHigh performance HfO22/Al/Al22OO33 laminate MIM capacitors laminate MIM capacitors

have been demonstrated for the first time.have been demonstrated for the first time.

The ALDThe ALD laminate MIM capacitors exhibit high C laminate MIM capacitors exhibit high C

density, superior dielectric stability up to 20 GHz, density, superior dielectric stability up to 20 GHz,

low leakage current, and promising reliability.low leakage current, and promising reliability.

For 13For 13 nm nm laminate laminate MIM capacitor MIM capacitor

C density C density ~12.8~12.8 fF/ fF/μμmm22 up to 20 Gup to 20 GHzHz

~ 2~ 21111 ppm/V ppm/V,,

Leakage ~ Leakage ~ 7.45 n7.45 nA/cmA/cm22 at at 2 V2 V

Meets Meets all requirements for RF bypassall requirements for RF bypass ccapacitorapacitor

Acknowledgment

This work was supported by Institute of

Microelectronics (Singapore) under Grant

R-263-000-233-490 and the National

University of Singapore under Grant R-263-

000-221-112.