Hydrogen Content in a-SiC:H Films Prepared by Plasma Decomposition of Silane and Methane or Ethylene

Abstract

The hydrogen content in a-SiC:H films prepared by the plasma decomposition of gas mixtures of silane and methane or ethylene was measured by 1H(15N, αγ)12C nuclear reaction (NR) and infrared absorption spectroscopy (IR). The contents observed by both methods can be made to agree well for most of the films by putting the average value of the inverse absorption cross section for the CH n (n=1, 2 and 3) stretching mode over all values of n as A s=1.0×1021 cm-2. In some films prepared from silane and ethylene mixtures, the hydrogen content given by NR was higher than that by IR. Hydrogen release from films with a hydrogen content of over 30 atm.% was observed during NR analysis. The mechanism of the hydrogen release is discussed by comparing the IR spectra before and after ion bombardment.

Mass and bond density measurements for PECVD a-SiCx:H thin films using Fourier transform-infrared spectroscopy

“…3, we find K CH ′ ranges from 1.8-4.2× 10 21 /cm 2 . These values are consistent with but slightly on the higher side of K CH values previously reported in the literature for a-C:H [36][37][38][39], DLC [39,[41][42][43], and a-SiC:H [28][29][30][31][32]44] films. In these studies, values of 2 × 10 20 to 3.8 × 10 21 /cm 2 have been reported for K CH with the lower values typically being reported for low density, polymeric like a-C:H and higher values being reported for high density, diamond like a-C:H (DLC) films (see Table 3).…”

“…The ability to qualitatively fingerprint and quantitatively measure the concentration of various chemical bonds by this technique has further led to the use of FTIR spectroscopy in numerous practical applications ranging from monitoring greenhouse gas emissions to quality control in manufacturing processes [1][2][3][4]. Within the semiconductor micro/nano-electronics industry, FTIR has also been utilized for quantitative measurements of a variety of materials of interest to the industry including: a-Si:H [5][6][7][8][9][10][11][12][13], a-SiO 2 [14][15][16][17][18][19], a-SiN x :H [20][21][22][23][24][25][26][27], a-SiC x :H [28][29][30][31][32][33][34][35][36], and a-C:H [37][38][39][40][41][42][43][44][45]. In these studies, FTIR has been utilized to determine the concentration of both terminal hydrogen bonding (Si-H, C-H, O-H, N-H) …”

Optical and mechanical properties of plasma-beam-deposited amorphous hydrogenated carbon

“…Dischler and co-workers 22 assumed about 10 years ago that all sp y CH x bonding types have the same proportionality constant. This assumption is adapted by most authors, e.g., Buuron et al 7 and Fujimoto et al 36 However, about 5 years ago Tanaka et al 33 already argued that there should be different proportionality constants for each bonding type as is also the case for a-Si:H. 37 They measured and calculated the constants for the sp 3 CH x bonds, using the relative intensity differences obtained by Fox and Martin 38 for the various bonds in gas phase measurements. Recently, Jacob and Unger 39 proposed a constant value for all different bonds which is only dependent on the hydrogen-to-carbon ratio in the deposited film; but, in the end they also conclude that it is more likely that for each bond itself a proportionality con-stant exists.…”

FTIR analysis of a-SiC:H films grown by plasma enhanced CVD

“…Therefore, quantitative measurement of hydrogen content is important. Infrared spectroscopy can be used to determine the content of chemical bonds, including hydrogen bonds [11][12][13][14][15][16], based on the integrated absorption intensity of stretching mode bonds. Si-H n (n ¼ 1; 2), C-H 2, C-H 3 and Si-C bonds are observed as peaks at 2000-2200, 2890, 2960 and 790 cm À1 , respectively [14,[17][18][19][20].…”

“…The absorption cross-section and film thickness are also required for this calculation, obtained from Ref. [11][12][13][14][15][16] and measured experimentally, respectively.…”