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Structural and phase composition features of carbon
films grown by DC PECVD process
A.A. Zolotukhin, A.P. Volkov, A.O. Ustinov, A.N. Obraztsov,
Physics Department of Moscow State University
Introduction In this work we present the results of in-situ and ex-situ Raman
spectroscopic examination of CVD diamond films deposited in a DC discharge plasma. Despite a considerable interest in the CVD technology and the wide use of Raman spectroscopy for the characterisation of diamond CVD films, only a few experiments were described in the literature that were devoted to the Raman in-situ diagnostics of diamond films. The in-situ Raman measurements can be used for determining the temperature of films, because conventional optical pyrometry is hindered by intense emission from the plasma region. Position of Raman lines may also change as a result of the mechanical stresses developed in the material application of an external load.
Scheme of Experimental Setup
High voltage DCpower supply
Cu-vapor laser
H2CH4
Rotary pumpMass-flowcontrollers
Monochromator
Stainless steelwater-cooled
reactor
Optical windowsTungsten
ring cathode
Substrate
Scheme of a setup for in-situ monitoring of the Raman spectra.
COMPOSITION AND SURFACE MORPHOLOGY STUDIES
800 1000 1200 1400 1600 1800
Ram
an In
tens
ity, [
arb.
un.]
Raman Shift, [cm-1]
RS of typical polycrystalline diamond
SEM Image of typical diamond polycrystalline CVD film
1000 1200 1400 1600 1800
R
aman
Inte
nsity
, [ar
b.un
.]
Raman Shift, [cm-1]
RS of nanocrystalline diamond
AFM image of typical diamond nanocrystalline CVD film
1000 1200 1400 1600 1800
3R
am
an Inte
nsity, [a
rb.u
n.]
2
1
Raman Shift, [cm-1]
Raman spectra measured in situ in the course of carbon deposition: (1) amorphous carbon film; (2) diamond film composed of nanocrystals;
(3) diamond film composed of a well crystallites.
In-situ Raman spectroscopy of CVD diamond films
1200 1300 1400 1500
3
2
1
Ra
ma
n I
nte
nsity,
[arb
.un
.]
Raman Shift, [cm-1]
Raman spectra of diamond films measured in-situ at various time instants after the begining of deposition: (1) 15; (2) 30; (3) 45 min;
1100 1200 1300 1400 1500
3
2
1
Ram
an In
tens
ity, [
arb.
un.]
Raman Shift, [cm-1]
0 200 400 600 800 1000 12001300
1310
1320
1330
Ra
ma
n S
hift
, [c
m-1]
Temperature, [oC]
Raman spectra of diamond films measured in-situ at various substrate
temperatures: (1)25; (2)1000; (3) 1200°C.
Position of the “diamond” Raman line (1332cm-1) versus the film
temperature: (points) this experiment; (dashed line) the plot measured on
a diamond single crystal
C. Johnson, A. Crosley, P.R. Chalker, et al., Diamond and
Related Mat., 1 (1992) 450.
the experiment
1200 1300 1400 1500
5432
1
Ram
an In
tens
ity, [
arb.
un.]
Raman Shift, [cm-1]-100 0 100 200 300
1300
1320
1340
1360
1380
1400
1420
543
21
Ra
ma
n S
hift
, [c
m-1]
Pressure, [kbar]
Raman spectra of a diamond film measured in-situ at various time instants after the begining of its etching in a hydrogen plasma:
(1) 15; (2)30; (3)45; (4)60; (5)90 min.
Position of the “diamond” Raman line (1332 cm-1) versus the pressure:(dashed line) the plot measured
on a diamond single crystal; (points) polycrystalline diamond film measured in-situ
in the course of etching in a hydrogen plasma.
M. Hanfland and K.Syassen., J. Appl. Phys., 1985, vol.57,
p. 2752.
the experiment
Conclusions
The CVD method was used for fabrication of different thin film carbon materials. Their structural, morphology, phase composition properties were studied by a number of experimental methods including Raman, SEM, STM, AFM, TEM, HRTEM.
The original in-situ Raman spectrometer was elaborated and a set of experiments performed to study specificity of the diamond CVD growth in plasma activated by DC discharge.