Hard amorphous silicon carbonitride coatings produced by plasma enhanced chemical vapour deposition

Abstract

Hard amorphous silicon carbonitride coatings for wear resistance have been produced by d.c. plasma‐enhanced chemical vapour deposition on pure iron at 573 K. Compared with most plasma assisted processes work was conducted under a relatively high pressure of 130 Pa. The advantages of this technique are an amorphous film structure, high deposition rates (up to 2 μm/min), high hardness and simple equipment. Hexamethyldisilazan (HMDSN) was used as precursor and argon, hydrogen, nitrogen and ammonia as process gases. The dependence of the coatings on the process parameters (process gas and d.c. power) was investigated. The characterization of the samples was carried out mainly by Fourier transform infrared spectrometry (FTIR), electron probe microanalysis (EPMA) and hardness measurement. Samples show clearly the infrared spectra absorption bands characteristic of SiC and Si3N4, with traces of hydrogen bonding. The material structure shows a strong dependence on the process gas and the d.c. power. However, for argon and hydrogen were deposited carbon‐rich SiC films with low nitrogen content. Nitridic films with low carbon content were deposited using nitrogen and especially ammonia. The hardness of the produced coatings was about 10 ‐ 55 GPa.

Silicon Carbonitride Films Produced by Remote Hydrogen Microwave Plasma CVD Using a (Dimethylamino)dimethylsilane Precursor

“…[36] Relatively large density values found for a-Si:C:N:H films account for their highly crosslinked structure. The refractive index values (Table 1) are comparable with those reported for a-Si:C:N:H films produced by DP-CVD from hexamethyldisilazane [1,5] and a SiH 4 /CH 4 /N 2 mixture. [9] The mechanical properties of the a-Si:C:N:H films are most attractive for practical application.…”

“…[18] Both amorphous and polycrystalline Si:C:N films were effectively produced by CVD techniques using various organosilicons as single-source precursors. These methods include fabrication of the Si:C:N films by: thermal CVD from ethylcyclosilazanes, [19] Ar ion beam-induced CVD from hexamethyldisilazane, [20] direct plasma (DP)-CVD from hexamethyldisilazane, [1,5,8] 1-dimethylsilyl-2,2-dimethylhydrazine, [21] dimethylbis(2,2-dimethylhydrazino)silane, [21] remote helium plasma CVD from hexamethyldisilazane, [22±25] and remote hydrogen-nitrogen plasma CVD from 1,1,3,3-tetramethyldisilazane, [26±28] and tris(dimethylamino)silane. [29] The last technique, RP-CVD, in which plasma is generated in a non-film forming and chemically reactive gas (e.g., H 2 , N 2 , or H 2 /N 2 mixture), is extremely beneficial since it offers well-controlled deposition conditions, free from film damaging effects such as charged-particle bombardment or highenergy ultraviolet irradiation, [30] which are inherently present in DP-CVD.…”

Remote Hydrogen Microwave Plasma CVD of Silicon Carbonitride Films from a Tetramethyldisilazane Source. Part 1: Characterization of the Process and Structure of the Films

“…[2][3][4] Of the various methods used for the fabrication of Si:C:N films, the CVD techniques using organosilicon single-source precursors appeared to be very effective. The Si:C:N films were formed by; thermal CVD from ethylcyclosilazane, [5] hot-wire CVD from hexamethyldisilazane, [6] direct plasma (DP)CVD from hexamethyldisilazane, [7][8][9][10][11] bis(trimethylsilyl)carbodiimide, [10][11][12] and bis(dimethylamino)dimethylsilane, [13] RPCVD from hexamethyldisilazane, [14][15][16][17] 1-dimethylsilyl-2,2-dimethylhydrazine, [18,19] dimethylbis(2,2-dimethylhydrazino)silane, [18,19] 1,1,3,3-tetramethyldisilazane, [20,21] tris(dimethylamino)silane, [22] and (dimethylamino)dimethylsilane. [23] Among these CVD techniques the latter, RPCVD (also termed indirect or downstream plasma CVD) was found to be particularly useful for the fabrication of defect-free and morphologically uniform Si:C:N thin-film materials.…”

Remote Hydrogen Microwave Plasma CVD of Silicon Carbonitride Films From a Tetramethyldisilazane Source. Part 2: Compositional and Structural Dependencies of Film Properties

“…[32] A decrease in the density with rising ratio C/Si was also noted for the Si:C:N films produced by DPCVD from HMDSN. [7] The increase in q and n values noted with increasing ratios N/Si (Fig. 2b) and N/C (Fig.…”

“…This is due to the previously mentioned loosening of the network structure due to incorporation of the NH species into Si:C:N films, which takes place in nitrogen RPCVD. [30] For comparison, the density and refractive index values reported for Si:C:N films produced by the direct plasma (DP)CVD from a hexamethyldisilazane (HMDSN)/hydrogen mixture at T S = 250-350°C and a diethylsilane/ammonia mixture at T S = 150-300°C, are q = 1.95-2.27 g cm -3 , n = 1.9-2.1, [7] and q =1.8-2.1 g cm -3 , n = 1.7-1.8, [33] respectively. Figure 2 shows the density and refractive index of the films deposited at various substrate temperatures as functions of the Auger electron spectroscopy (AES) atomic concentration ratios C/Si (Fig.…”