Change in bonding properties of amorphous hydrogenated silicon-carbide layers prepared with different gases as carbon sources

Abstract

Amorphous hydrogenated silicon-carbide films (a-SiC:H) were deposited in a standard rf glow discharge. Various gases as carbon sources, in addition to silane (SiH4), were used, namely methane (CH4), disilylmethane (DSM), trisilylmethane (TSM), and tetrasilylmethane (TetraSM). All our films show low hydrogen contents (NH≤2.5×1022 cm−3 for EG≤2.4 eV, determined by elastic recoil detection analysis) and low Urbach energies (E0≤70 meV for EG≤2.0 eV, determined by photothermal deflection spectroscopy). Infrared spectroscopy reveals that the more Si—C bonds are offered in the gas phase by using different carbon sources as feedstock, the more Si—C bonds are incorporated into the a-SiC:H solid. Furthermore, the number of CH3 groups decreases with the increasing number of Si—C bonds. The ratio of the hydrogen to the carbon content suggests less CH3 groups to be present in our films, compared to films of other authors.

Compositional and structural properties of hydrogenated amorphous silicon-carbon films prepared by ultra-high-vacuum plasma-enhanced chemical vapour deposition with different carbon sources

“…This band increases as a function of carbon content in the films. The result is in agreement with the behaviour in optical properties (energy gap and refractive index) and mass density as a function Several determinations of the ACH and AS,H constants between the oscillator density and the integrated IR absorption intensities of the CH, and SiH, vibrational modes have been performed (Brodsky, Cardona and Cuomo 1977, Freeman and Paul 1978, Fang et al 1980, Maley et al 1989, Langford et al 1992. Through nuclear magnetic resonance (NMR) measurements on a-Sil -,C,: H films deposited with different plasma techniques and having different carbon contents (Petrich, Gleason and Reimer 1987), i L was determined that the A S~H constant for a-Si : H films is also valid for a-Si 1 -%C, : H. There is no increase in the effective charge in a-Sil -xCx: H which would change the matrix elements of Si-H vibrations (Daey Ouwens et al 1993, Daey Ouwens 1994.…”

Dependence of chemical composition and bonding of amorphous SiC on deposition temperature and the choice of substrate

“…Comparatively, single source precursor MS, containing directly bonded Si and C atoms, has the advantage of a simpler and the possibility of a more efficient chemical vapour deposition process. The incorporation of H 2 during the deposition can either widen or narrow the optical energy gap of deposited SiC films [17][18][19]. The composition and chemical bonds of a-SiC prepared from MS had been reported [15,16], however, the employed deposition method was plasma enhanced chemical vapour deposition (PECVD) rather than standard low-pressure chemical vapour deposition (LPCVD).…”

Synthesis and Molecular Structure of Silylated Ethenes and Acetylenes

“…179.2 (2) range. The C = C triple bond length is significantly shorther as compared to that of related com pounds [7,31].…”

“…The first route starts from bis(trichlorosilyl)acetylene (2 ), which is read ily accessible on a large as well as on a laboratory scale [17][18][19]. The compound can be reduced to disilylacetylene using phase transfer techniques …”

“…Polysilylmethanes [1][2][3][4][5][6] and polysilylbenzenes [7][8][9] have received considerable interest as p re cursors for chemical vapour deposition (CVD) of silicon/carbon alloys [1][2][3] and for the synthesis of various silicon/carbon polymers [9], By varying their stoichiometry these compounds can be used as single source feedstock gases for layers with tailor-made composition. In a new approach to the epitaxial deposition of silicon carbide, halogencontaining feedstock gases are expected to show improved properties owing to a greater reversi bility of the deposition process.…”