Si-C-N thin films were deposited on silicon substrates by plasma-enhanced chemical vapor deposition (PECVD) using hexamethyldisilazane as the main precursor. An influence of substrate temperature (TS) on film properties was analyzed. It was established that the deposited films were x-ray amorphous. The growth of the films slows down with increasing substrate temperature. The distribution of Si–C, Si–N and
C–N bonds were almost independent of TS, whereas the number of С–Н, Si–H and N–H bonds essentially decreased when substrate temperature increased. The nanohardness and elastic modulus increased with TS due to a reduction of the weak hydrogen bonds

Dub, S.M.

Ivashchenko, V.I.

Kozak, A.O.

Pohrebniak, Oleksandr Dmytrovych

Porada, O.K.

Погребняк, Александр Дмитриевич

Погребняк, Олександр Дмитрович

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  
NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 4 No 1, 01NTF09(3pp) (2015) 
 
 
2304-1862/2015/4(1)01NTF09(3) 01NTF09-1  2015 Sumy State University 
Hard Si-C-N Chemical Vapor Deposited Films 
 
O.K. Porada1, A.O. Kozak1, V.I. Ivashchenko1, S.M Dub2, A.D. Pogrebnjak3 
 
1 Institute for Problems of Materials Sciences, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03142 Kyiv, Ukraine 
2 Institute for Superhard materials, NAS of Ukraine, 2, Avtozavodskaya Str., 03142 Kyiv, Ukraine 
3 Sumy State University, 2 Rymsky-Korsakov Str. 40007 Sumy, Ukraine 
 
 (Received 30 June 2015; published online 29 August 2015) 
 
Si-C-N thin films were deposited on silicon substrates by plasma-enhanced chemical vapor deposition 
(PECVD) using hexamethyldisilazane as the main precursor. An influence of substrate temperature (TS) on 
film properties was analyzed. It was established that the deposited films were x-ray amorphous. The 
growth of the films slows down with increasing substrate temperature. The distribution of Si–C, Si–N and 
C–N bonds were almost independent of TS, whereas the number of С–Н, Si–H and N–H bonds essentially 
decreased when substrate temperature increased. The nanohardness and elastic modulus increased with 
TS due to a reduction of the weak hydrogen bonds.  
 
 
Keywords: Sі–C–N films, PECVD, hexamethyldisilazane, substrate temperature, nanohardness. 
  
PACS numbers: 81.15.Gh, 73.61.Jc, 62.20.Qp 
 
 
1. INTRODUCTION 
 
The investigation of Si-C-N films shows that nano-
hardness (H) can change from 6 to 40 GPa depending 
on deposition procedure [1-7]. Amorphous hydrogenat-
ed Si-C-N films that are deposited using photo-CVD 
(Photo-chemical vapor deposition), PECVD (Plasma-
enhanced chemical vapor deposition), ECR-CVD (Elec-
tron cyclotron resonance - chemical vapor deposition) 
[1,3] demonstrate the lowest values of nanohardness 6-
11 GPa [2,4,5]. The highest values of nanohardness are 
reached for the films prepared by high-temperatures 
(more than 1000 °C) CVD (Chemical Vapor Deposition) 
(27–38 GPa) [1,3] and PVD (Physical Vapor Deposition) 
(25–40 GPa) [8]. The films usually have the amorphous 
structure, while the nanocrystalline or polycrystalline 
films are prepared at extreme deposition parameters 
(for en example, at high deposition temperatures > 
1000 °C). In the literature, the values of nanohardness 
(H) and elastic modulus (E) of the Si-C-N films are of-
ten reported in the range of 18-25 GPa and 110-200 
GPa, respectively [2-7]. The influence of the main pa-
rameters of PECVD on the structural and mechanical 
properties of Si-C-N films was studied by us earlier. In 
particular, the influence of discharge power [9], nitro-
gen flow rate [10], substrate bias voltage [11], substrate 
temperature [12] and vacuum annealing [13] on film 
characteristics were analyzed. The maximum values of 
nanohardness and elastic modulus were 25 GPa and 
200 GPa, respectively [9-12].  
In this work we continue the investigation of Si-C-N 
films to reach larger values of the hardness of the Si-C-
N films preserving their amorphous structure. The lat-
ter is very important, because amorphous films are 
more resistant to oxidation than nanocrystalline ones. 
We increased substrate temperature to 700 °C as com-
pared to the maximum TS = 400 °C used in Ref. [12]. 
The deposited films were characterized by X-Ray dif-
fraction, FTIR spectroscopy and nanoindentation.  
 
 
 
2. EXPERIMENTAL DETALIES 
 
Si-C-N thin films were deposited with using high-
frequency plasma-chemical equipment on base of 
“VUP-5” (Ukraine). The main discharge was excited by 
high-frequency (HF) generator (40.68MHz). Hexame-
thyldisilazane (HMDS, (СH3)6Si2NHN) was used as a 
main precursor. The HMDS vapor, produced in a ther-
mostated bubbler heated to 40 °C, was transported into 
the reaction chamber by hydrogen. Substrate bias was 
produced by a HF generator (5.27 MHz). The films were 
deposited on polished Si(001) substrates. 
The films were deposited at different substrate 
temperatures TS = 300, 400, 500, 650 and 700°C and at 
fixed other deposition parameters: substrate bias -
250 V, gas mixture pressure in the reactor 0.2 Torr, 
discharge power PW = 0.2 W/cm3, flow rate of hydrogen 
through the thermostated bubbler with HMDS  
FH+HMDS = 12 sccm, nitrogen flow rate FN2 = 1 sccm. 
Deposition time was 60 min.  
X-ray diffraction (XRD) investigations of the films 
were carried out by using a diffractometer “DRON-3M” 
(Ukraine). The chemical bonding was studied by Fouri-
er traform infrared spectroscopy (FTIR) with the help 
of a spectrometer “FSM 1202” LLC “Infraspek” 
Nanoindentation was carried out with the help of a 
device G200 equipped with the Berkovich indenter. 
Nanohardness (H) and elastic modulus (E) were deter-
mined using the Oliver and Pharr procedure [14]. The 
thickness of the films was estimated by an optical pro-
filometer "Micron - alpha" (Ukraine). The film thick-
ness approximated 0.8 m, and slightly decreased with 
increasing TS.  
 
3. RESULTS AND DISCUSSION 
 
The XRD analysis showed that there are no any 
crystallites in the deposited films (not shown here). It 
follows that they are X-Ray amorphous.  
Fig. 1 shows the substrate temperature influence on 
the deposition rate of Si-C-N films. The increase of TS up 
to 400°C leads to noticeable increase in deposition rate, 
 O.K. PORADA, A.O. KOZAK, V.I. IVASHCHENKO, ET AL. PROC. NAP 4, 01NTF09 (2015) 
 
 
01NTF09-2 
which can be connected with additional thermal stimula-
tion of chemical reactions on the surface of the substrate. 
A further increase of TS leads to decreasing deposition 
rate due to the predominance of the densification process 
due to hydrogen effusion from films and sputtering the 
weakly bonded units from the film surface.  
In Fig. 2 we present the dependences of nanohard-
ness and elastic modulus of the films deposited at dif-
ferent TS as functions of indenter penetration (L). It is 
clearly seen that the elastic modulus is more sensitive 
to substrate than nanohardness: E reaches the maxi-
mum values at the indentation depth ~ 25 nm, and 
then   decreases with further increasing L.  
 
 
Fig. 1 – Dependence of Si-C-N film deposition rate (V) on sub-
strate temperature (TS). 
 
 
 
Fig. 2 – Nanohardness (H) and elastic modulus (E) as func-
tions of indenter penetration (L). 
 
In Fig. 3 we show the value of H and E of the depos-
ited films as functions of TS. These values were deter-
mined as the maximum values in the dependences 
shown in Fig. 2. From Fig. 3 it is clearly seen that H 
and E increases with TS.  
The analysis of the properties of Si-C-N films [9-13] 
shows that the mechanical characteristics are very sen-
sitive to substrate temperature.  On the other hand, the 
mechanical properties depend on the chemical bonding. 
In this work, we investigate the character of chemical 
bonding of the deposited films using the FITIR spec-
troscopy. 
 
 
 
Fig. 3 – Nanohardness (H) and elastic modulus (E) as func-
tions of substrate temperature (TS) . 
 
The FTIR absorption spectra of the Si-C-N films de-
posited at various substrate temperatures are present-
ed in Fig 4a. The absorption bands were identified on 
the basis of published data [17-24]. In the FTIR spec-
tra, the dominant absorption broad band in the range 
of 600–1300 cm−1 and four absorption bands in the 
range 1300–3500 cm−1 are observed. The preliminary 
analysis shows that the dominant absorption band can 
be interpreted as vibrations of Si-C (610–877 cm−1) [24], 
Si-N (950–1000 cm−1) [23] and Si-O (1000–1030 cm−1) 
[18] bonds. Absorption bands in the range of 1300–3500 
cm−1 can be attributed to vibrations of C-C bonds at 
1555 cm−1, C-N [18] and/or Si-H [20] bonds at 2130 
cm−1, as well as vibrations of hydrogen bonds C-H [21] 
and N-H [19,20] at 2877 cm−1 and 3375 cm−1, respec-
tively. It is easy to see that the intensity of hydrogen 
bonds in the range of 1550-3500 cm-1 gradually de-
creases with increasing substrate temperature, while 
the change in the main absorption band at 600-
1300 cm–1 is barely visible. In order to analyze the con-
tributions of different vibrations to this band and their 
evolution with substrate temperature we present the 
main absorption band as a superposition of three 
Gaussians. Fig. 4b shows the results of decomposition of 
the FTIR spectra in the range of the main absorption 
band into Gaussian components. The chosen area is rep-
resented by three components, and, for ease perception, it 
is inversed relatively to the horizontal axis. Given the 
band identifications [10], the Gaussian components can be 
assigned to vibrations of Si-C [24], Si-N in Si3N4 [16] and 
Si-O [25] bonds (cf. Fig 4b). The total area of the Gaussian 
peaks is practically independent of substrate temperature.  
It is seen that Si-C bonds are predominant. Also, besides 
the mentioned vibrations, the following vibrations related 
to hydrogen bonds can contribute to the main absorption 
band: vibrations of (SiH2)n bonds with peak at 915cm–1, 
Si–H bonds at 978cm–1 and a-SiC–H and С–Hn bonds at 
990 cm–1 [16[. Unfortunately, the analysis of hydrogen 
bonds within the main absorption band is practically im-
possible owing to the presence of the intensive vibrations 
of Si-C, Si-N and Si-O bonds in this absorption region. 
Nevertheless, we can assume that the reduction of 
Gaussian peak at 975 cm–1 with increasing of substrate  
 HARD SI-C-N CHEMICAL VAPOR DEPOSITED FILMS PROC. NAP 4, 01NTF09 (2015) 
 
 
01NTF09-3 
 
Fig. 4 – FTIR absorption spectra of the films deposited at different substrate temperatures Ts = 300-700 ° C (a). Results of the 
decomposition of the main absorption band by three Gaussian components (b). 
 
temperature is due to hydrogen effusion. We note a 
tendency to reducing the intensity of the vibrations of 
hydrogen bonds at 2130, 2877 and 3375 cm-1 with in-
creasing TS. In our PECVD technologies, hydrogen is a 
plasma gas, and therefore its content is very high in 
the films deposited at low TS. A moderate substrate 
temperature (less than 500 °C) leads to formation of 
hydrogenated structure of the Si-C-N films that is 
characterized by the presence of Si-H, C-H and N-H 
bonds. The hydrogenated structure promotes the for-
mation of the pores that leads to decreasing film densi-
ty, and to the deterioration of mechanical properties. 
So, the films deposited at low TS will exhibit low hard-
ness due to the hydrogenated porous structure. At 
higher substrate temperatures, the formation of hydro-
gen bonds slows down, which leads to the formation of 
the denser structures, and in turn, to strengthening of 
the films. 
 
4. CONCLUSIONS 
 
1. Amorphous Si-C-N films with the thickness of 
0.6 - 0.80 m were deposited on silicon substrates by 
PECVD using the liquid precursor - hexamethyldisi-
lazane. 
2. An increase of substrate temperature (above 400 ° 
C) slows down film growth.  
3. The nanohardness and elastic modulus of amor-
phous Si-C-N films increase from 13 to 33 GPa and 
from 120 to 360 GPa, respectively, when substrate 
temperature increases from 300 to 700 °C 
4. The observed increase in the mechanical charac-
teristics of amorphous Si-C-N films can be explained by 
decreasing the number of hydrogen bonds Si-H, C-H, 
N-H, since the number of  Si-C and Si -N bonds is prac-
tically independent of substrate temperature. 
5. The deposited high temperature amorphous Si-
C-N films  can be recommended as wear resistant coat-
ings in MEMS. 
 
 
REFERENCES 
 
1. A. Bendeddouche, R. Berjoane, et al., J. Appl. Phys. 81, 
6147 (1997). 
2. Y. Awad, M.A. El et al., Surf. Coat. Technol. 204, 539 
(2009). 
3. A. Bendeddouche, R. Berjoan, et al., Surf. Coat. Technol. 
111, 184 (1999). 
4. Z. Shi, Y. Wang et al., Appl. Surf. Sci. 259, 1328 (2011). 
5. Z. Shi, Y. Wang et al., J. Alloy. Compnd. 552, 111 (2013). 
6. S. Peter, M. Günther, et al. Vacuum 90, 155 (2013). 
7. H.C. Lo, J.J. Wu, et al., Diam. Rel. Mater. 10, 1916 (2001). 
8. J. Vlček, M. Kormunda, et al., Surf. Coat. Tech. 160, 74 
(2002). 
9. L.A. Іvaschenko, V.І. Іvaschenko, et al., Nanostructured 
Materials Science 4, 42 (2011) [in Ukrainian]. 
10. V.I. Ivashchenko, A.O. Kozak et al., Thin Solid Films 569, 57 
(2014). 
11. O.K. Porada, Nanostructured Materials Science 3-4 32, (2014) 
[in Ukrainian]. 
12. A.O. Kozak, V.I. Ivashchenko, et al., J. Nano- Electron. 
Phys. 6, 04047(2014). 
13. O.K. Porada, V.I. Ivashchenko, Nanostructured Materials 
Science, 2, 32 (2010) [in Ukrainian]. 
14. W.C. Oliver, G.M. Pharr, J. Mater. Res. 7, 1564 (1992). 
15. I. Maissel, R. Glang, Handbook of Thin Film Technology 
(In 2v.- New York: McGRAW HILL HODK COMPAN 2, 
765, 1970). 
16. Y. Awad, M.A. El Khahani, et al., J. Appl. Phys. 107, 
033517 (2010). 
17. A. Bendeddouche, R. Berjoan, et al., Surf. Coat. Technol. 
111, 184 (1999).  
18. J. Huran, A. Valovič, et al., J. Electr. Eng. 63, 333 (2012). 
19. D. Kuo, D. Yang, Thin Solid Films 374, 92 (2000). 
20. Z. Shi, Y. Wang et al., Appl. Surf. Sci. 258, 1328 (2011). 
21. B.P. Swain, N.M. Hwang, Appl. Surf. Sci. 254, 5319 (2008). 
22. X.-С. Xiao, Yа-W. Li, et al., Appl. Surf. Sci. 156, 155 
(2000). 
23. M. Xu, S. Xu, et al., J. Non-Cryst. Solids 352, 5463 (2006). 
24. X.B. Yan, B. Tay, et al., Electrochem. Comm. 8, 737 (2006). 
25. X.C. Wu, R.Q. Cai, et al., Appl. Surf. Sci. 185, 262 (2002). 
 
 
(a) (b) 


Hard Si-C-N Chemical Vapor Deposited Films

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 4 No 1, 01NTF09(3pp) (2015)   2304-1862/2015/4(1)01NTF09(3) 01NTF09-1  2015 Sumy State University Hard Si-C-N Chemical Vapor Deposited Films  O.K. Porada1, A.O. Kozak1, V.I. Ivashchenko1, S.M Dub2, A.D. Pogrebnjak3  1 Institute for Problems of Materials Sciences, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03142 Kyiv, Ukraine 2 Institute for Superhard materials, NAS of Ukraine, 2, Avtozavodskaya Str., 03142 Kyiv, Ukraine 3 Sumy State University, 2 Rymsky-Korsakov Str. 40007 Sumy, Ukraine   (Received 30 June 2015; published online 29 August 2015)  Si-C-N thin films were deposited on silicon substrates by plasma-enhanced chemical vapor deposition (PECVD) using hexamethyldisilazane as the main precursor. An influence of substrate temperature (TS) on film properties was analyzed. It was established that the deposited films were x-ray amorphous. The growth of the films slows down with increasing substrate temperature. The distribution of Si–C, Si–N and C–N bonds were almost independent of TS, whereas the number of С–Н, Si–H and N–H bonds essentially decreased when substrate temperature increased. The nanohardness and elastic modulus increased with TS due to a reduction of the weak hydrogen bonds.    Keywords: Sі–C–N films, PECVD, hexamethyldisilazane, substrate temperature, nanohardness.   PACS numbers: 81.15.Gh, 73.61.Jc, 62.20.Qp   1. INTRODUCTION  The investigation of Si-C-N films shows that nano-hardness (H) can change from 6 to 40 GPa depending on deposition procedure [1-7]. Amorphous hydrogenat-ed Si-C-N films that are deposited using photo-CVD (Photo-chemical vapor deposition), PECVD (Plasma-enhanced chemical vapor deposition), ECR-CVD (Elec-tron cyclotron resonance - chemical vapor deposition) [1,3] demonstrate the lowest values of nanohardness 6-11 GPa [2,4,5]. The highest values of nanohardness are reached for the films prepared by high-temperatures (more than 1000 °C) CVD (Chemical Vapor Deposition) (27–38 GPa) [1,3] and PVD (Physical Vapor Deposition) (25–40 GPa) [8]. The films usually have the amorphous structure, while the nanocrystalline or polycrystalline films are prepared at extreme deposition parameters (for en example, at high deposition temperatures > 1000 °C). In the literature, the values of nanohardness (H) and elastic modulus (E) of the Si-C-N films are of-ten reported in the range of 18-25 GPa and 110-200 GPa, respectively [2-7]. The influence of the main pa-rameters of PECVD on the structural and mechanical properties of Si-C-N films was studied by us earlier. In particular, the influence of discharge power [9], nitro-gen flow rate [10], substrate bias voltage [11], substrate temperature [12] and vacuum annealing [13] on film characteristics were analyzed. The maximum values of nanohardness and elastic modulus were 25 GPa and 200 GPa, respectively [9-12].  In this work we continue the investigation of Si-C-N films to reach larger values of the hardness of the Si-C-N films preserving their amorphous structure. The lat-ter is very important, because amorphous films are more resistant to oxidation than nanocrystalline ones. We increased substrate temperature to 700 °C as com-pared to the maximum TS = 400 °C used in Ref. [12]. The deposited films were characterized by X-Ray dif-fraction, FTIR spectroscopy and nanoindentation.     2. EXPERIMENTAL DETALIES  Si-C-N thin films were deposited with using high-frequency plasma-chemical equipment on base of “VUP-5” (Ukraine). The main discharge was excited by high-frequency (HF) generator (40.68MHz). Hexame-thyldisilazane (HMDS, (СH3)6Si2NHN) was used as a main precursor. The HMDS vapor, produced in a ther-mostated bubbler heated to 40 °C, was transported into the reaction chamber by hydrogen. Substrate bias was produced by a HF generator (5.27 MHz). The films were deposited on polished Si(001) substrates. The films were deposited at different substrate temperatures TS = 300, 400, 500, 650 and 700°C and at fixed other deposition parameters: substrate bias -250 V, gas mixture pressure in the reactor 0.2 Torr, discharge power PW = 0.2 W/cm3, flow rate of hydrogen through the thermostated bubbler with HMDS  FH+HMDS = 12 sccm, nitrogen flow rate FN2 = 1 sccm. Deposition time was 60 min.  X-ray diffraction (XRD) investigations of the films were carried out by using a diffractometer “DRON-3M” (Ukraine). The chemical bonding was studied by Fouri-er traform infrared spectroscopy (FTIR) with the help of a spectrometer “FSM 1202” LLC “Infraspek” Nanoindentation was carried out with the help of a device G200 equipped with the Berkovich indenter. Nanohardness (H) and elastic modulus (E) were deter-mined using the Oliver and Pharr procedure [14]. The thickness of the films was estimated by an optical pro-filometer "Micron - alpha" (Ukraine). The film thick-ness approximated 0.8 m, and slightly decreased with increasing TS.   3. RESULTS AND DISCUSSION  The XRD analysis showed that there are no any crystallites in the deposited films (not shown here). It follows that they are X-Ray amorphous.  Fig. 1 shows the substrate temperature influence on the deposition rate of Si-C-N films. The increase of TS up to 400°C leads to noticeable increase in deposition rate,  O.K. PORADA, A.O. KOZAK, V.I. IVASHCHENKO, ET AL. PROC. NAP 4, 01NTF09 (2015)   01NTF09-2 which can be connected with additional thermal stimula-tion of chemical reactions on the surface of the substrate. A further increase of TS leads to decreasing deposition rate due to the predominance of the densification process due to hydrogen effusion from films and sputtering the weakly bonded units from the film surface.  In Fig. 2 we present the dependences of nanohard-ness and elastic modulus of the films deposited at dif-ferent TS as functions of indenter penetration (L). It is clearly seen that the elastic modulus is more sensitive to substrate than nanohardness: E reaches the maxi-mum values at the indentation depth ~ 25 nm, and then   decreases with further increasing L.    Fig. 1 – Dependence of Si-C-N film deposition rate (V) on sub-strate temperature (TS).    Fig. 2 – Nanohardness (H) and elastic modulus (E) as func-tions of indenter penetration (L).  In Fig. 3 we show the value of H and E of the depos-ited films as functions of TS. These values were deter-mined as the maximum values in the dependences shown in Fig. 2. From Fig. 3 it is clearly seen that H and E increases with TS.  The analysis of the properties of Si-C-N films [9-13] shows that the mechanical characteristics are very sen-sitive to substrate temperature.  On the other hand, the mechanical properties depend on the chemical bonding. In this work, we investigate the character of chemical bonding of the deposited films using the FITIR spec-troscopy.    Fig. 3 – Nanohardness (H) and elastic modulus (E) as func-tions of substrate temperature (TS) .  The FTIR absorption spectra of the Si-C-N films de-posited at various substrate temperatures are present-ed in Fig 4a. The absorption bands were identified on the basis of published data [17-24]. In the FTIR spec-tra, the dominant absorption broad band in the range of 600–1300 cm−1 and four absorption bands in the range 1300–3500 cm−1 are observed. The preliminary analysis shows that the dominant absorption band can be interpreted as vibrations of Si-C (610–877 cm−1) [24], Si-N (950–1000 cm−1) [23] and Si-O (1000–1030 cm−1) [18] bonds. Absorption bands in the range of 1300–3500 cm−1 can be attributed to vibrations of C-C bonds at 1555 cm−1, C-N [18] and/or Si-H [20] bonds at 2130 cm−1, as well as vibrations of hydrogen bonds C-H [21] and N-H [19,20] at 2877 cm−1 and 3375 cm−1, respec-tively. It is easy to see that the intensity of hydrogen bonds in the range of 1550-3500 cm-1 gradually de-creases with increasing substrate temperature, while the change in the main absorption band at 600-1300 cm–1 is barely visible. In order to analyze the con-tributions of different vibrations to this band and their evolution with substrate temperature we present the main absorption band as a superposition of three Gaussians. Fig. 4b shows the results of decomposition of the FTIR spectra in the range of the main absorption band into Gaussian components. The chosen area is rep-resented by three components, and, for ease perception, it is inversed relatively to the horizontal axis. Given the band identifications [10], the Gaussian components can be assigned to vibrations of Si-C [24], Si-N in Si3N4 [16] and Si-O [25] bonds (cf. Fig 4b). The total area of the Gaussian peaks is practically independent of substrate temperature.  It is seen that Si-C bonds are predominant. Also, besides the mentioned vibrations, the following vibrations related to hydrogen bonds can contribute to the main absorption band: vibrations of (SiH2)n bonds with peak at 915cm–1, Si–H bonds at 978cm–1 and a-SiC–H and С–Hn bonds at 990 cm–1 [16[. Unfortunately, the analysis of hydrogen bonds within the main absorption band is practically im-possible owing to the presence of the intensive vibrations of Si-C, Si-N and Si-O bonds in this absorption region. Nevertheless, we can assume that the reduction of Gaussian peak at 975 cm–1 with increasing of substrate   HARD SI-C-N CHEMICAL VAPOR DEPOSITED FILMS PROC. NAP 4, 01NTF09 (2015)   01NTF09-3  Fig. 4 – FTIR absorption spectra of the films deposited at different substrate temperatures Ts = 300-700 ° C (a). Results of the decomposition of the main absorption band by three Gaussian components (b).  temperature is due to hydrogen effusion. We note a tendency to reducing the intensity of the vibrations of hydrogen bonds at 2130, 2877 and 3375 cm-1 with in-creasing TS. In our PECVD technologies, hydrogen is a plasma gas, and therefore its content is very high in the films deposited at low TS. A moderate substrate temperature (less than 500 °C) leads to formation of hydrogenated structure of the Si-C-N films that is characterized by the presence of Si-H, C-H and N-H bonds. The hydrogenated structure promotes the for-mation of the pores that leads to decreasing film densi-ty, and to the deterioration of mechanical properties. So, the films deposited at low TS will exhibit low hard-ness due to the hydrogenated porous structure. At higher substrate temperatures, the formation of hydro-gen bonds slows down, which leads to the formation of the denser structures, and in turn, to strengthening of the films.  4. CONCLUSIONS  1. Amorphous Si-C-N films with the thickness of 0.6 - 0.80 m were deposited on silicon substrates by PECVD using the liquid precursor - hexamethyldisi-lazane. 2. An increase of substrate temperature (above 400 ° C) slows down film growth.  3. The nanohardness and elastic modulus of amor-phous Si-C-N films increase from 13 to 33 GPa and from 120 to 360 GPa, respectively, when substrate temperature increases from 300 to 700 °C 4. The observed increase in the mechanical charac-teristics of amorphous Si-C-N films can be explained by decreasing the number of hydrogen bonds Si-H, C-H, N-H, since the number of  Si-C and Si -N bonds is prac-tically independent of substrate temperature. 5. The deposited high temperature amorphous Si-C-N films  can be recommended as wear resistant coat-ings in MEMS.   REFERENCES  1. A. Bendeddouche, R. Berjoane, et al., J. Appl. Phys. 81, 6147 (1997). 2. Y. Awad, M.A. El et al., Surf. Coat. Technol. 204, 539 (2009). 3. A. Bendeddouche, R. Berjoan, et al., Surf. Coat. Technol. 111, 184 (1999). 4. Z. Shi, Y. Wang et al., Appl. Surf. Sci. 259, 1328 (2011). 5. Z. Shi, Y. Wang et al., J. Alloy. Compnd. 552, 111 (2013). 6. S. Peter, M. Günther, et al. Vacuum 90, 155 (2013). 7. H.C. Lo, J.J. Wu, et al., Diam. Rel. Mater. 10, 1916 (2001). 8. J. Vlček, M. Kormunda, et al., Surf. Coat. Tech. 160, 74 (2002). 9. L.A. Іvaschenko, V.І. Іvaschenko, et al., Nanostructured Materials Science 4, 42 (2011) [in Ukrainian]. 10. V.I. Ivashchenko, A.O. Kozak et al., Thin Solid Films 569, 57 (2014). 11. O.K. Porada, Nanostructured Materials Science 3-4 32, (2014) [in Ukrainian]. 12. A.O. Kozak, V.I. Ivashchenko, et al., J. Nano- Electron. Phys. 6, 04047(2014). 13. O.K. Porada, V.I. Ivashchenko, Nanostructured Materials Science, 2, 32 (2010) [in Ukrainian]. 14. W.C. 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Hard Si-C-N Chemical Vapor Deposited Films

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