Growth Characteristics of Alpha-Silicon Carbide

Abstract

The equilibrium partial pressures of various vapor species in the system silicon‐carbon‐hydrogen were computed for conditions under which epitaxial normalSiC deposition has been achieved. It was found that in the temperature range 1300°–1700°C the tendency to form solid silicon carbide decreases with increasing temperature and with increasing silicon to carbon atom ratio. The limiting conditions under which single crystalline deposits of α‐normalSiC could be experimentally obtained were those within which normalSiC was computed to be the only thermodynamically stable solid phase. At 1650° single‐phase silicon carbide condenses at normalSi/C ratios ranging from 0.2 to 0.89. The computed results were in good agreement with experiments.

Growth Characteristics of Alpha-Silicon Carbide

“…The observed temperature dependence of the growth rate in this region, however, is not in good agreement with that expected for a process under diffusion control. This result is not surprising because the etching rate of SiC increases as does the rate of homogeneous n ucleation and heterogeneous nucleation of silicon on the reactor wall (5) with increasing temperature; furthermore, the efficiency of Sill4 and C3Hs in forming SiC decreases with increasing temperature (2). It should be pointed out that the values of reactant concentrations at which either single crystal or polycrystalline growth takes place (Fig.…”

“…Growth of SiC from the vapor phase using Sill4 and C3Hs (and other reagents) has been reported (1). This and subsequent studies (2) have considered the dependence of growth rate on temperature and the effects of varying the Si/C ratio. In all instances SiC was grown on SiC.…”

A Model of Silicon Carbide Chemical Vapor Deposition

“…To obtain the correct stoichiometry (one silicon for every carbon deposited) we have written the surface reactions so that carbon species deposit only on sites occupied by silicon, St(s), and silicon deposits only on sites occupied by carbon, C(s). This restriction clearly does not permit formation of either pure silicon or carbon phases; however, experiments (6,16,28) indicate that only SiC is formed when the C/St ratio is 1.00. Note that, although there is no bulk species defined as "SIC," silicon carbide is deposited with the correct density by depositing bulk silicon, St(b), and bulk carbon, C(b), with effective densities determined by their mass fraction in silicon carbide.…”

“…Chemical reactions occurring in both the gas phase and on heated surfaces are significant components of all these processes. The chemistry of the deposition process has been examined by several investigators through the calculation of gas-and solid-phase equilibria (13)(14)(15)(16). Stinespring and Wormhoudt have also studied the kinetics of gas-phase silane (Sill4) and propane (C:~Hs) decomposition, shedding considerable light upon the deposition process and pointing out the importance of gas-phase *Electrochemical Society Active Member.…”

Synthesis of SIC(β) ultrafine particles from Si, SiO, or SiO2 powder and CH4

“…The free energies, enthalpies, and entropies of formation of each were taken from the JANAF Thennochemical Tables (1971). The ealculation results for the three reaction systems are relatively similar and are shown in temperature range of 1,000 K to 2,300 K. Therefore, only the polymorph should be considered in the polytypes of Sic (Guo et al, 1995;Kingon et al, 1983;Harris et al, 1971). The thermodynamic analysis results indicate that the highest potential for Sic formation lies in the temperature range of 1,000 to 2,300 K. The other species which should be considered in this temperature range are H(g), H,(g), C(s>, C,H(g), C,H,(g), Si(g), SiC,(g), and Si,C(g) in the Si-CH,-Ar system; H(g), H,(g), C(s), C,H(g), C,H,(g), CNg), Si(g), SiO,(s), Sic& and Si,C(g) in the SiO-CH,-Ar system; and H(g), H,(g), C(s), CO(g), Si(g), SiO(g), SiOJs), SiC,(g) and Si,C(g) in the Si0,-CH,-Ar system, depending on the molar ratios of Si/CH,, SiO/CH, and SiO,/CH,, respectively.…”