In situ measurements and growth kinetics of silicon carbide chemical vapor deposition from methyltrichlorosilane

Abstract

The growth kinetics of silicon carbide (SiC) by chemical vapor deposition (CVD) from methyltrichlorosilane (MTS : CH 3SiCl 3) was investigated by in situ measurements of growth rates, which were converted from the deposited weight by thermogravimetry, as a function of temperature and partial pressure of MTS ( P MTS). The growth rates were limited by surface reactions at lower temperatures and by vapor mass transfer at higher temperatures. The limiting kinetic processes changed at a critical temperature of about 1300°C independent of P MTS variation. Although these results are supported by the stagnant gas layer model, it is impossible to explain the P MTS dependence of the activation energy by this model. The calculated growth rates from the two-sites competitive adsorption model under equilibrium partial pressures fit the experimental growth rates as a function of P MTS. The heat of adsorptions was 32.3 kcal/mol for SiCl 3 and 26.8 kcal/mol for CH 3. Considering the adsorption coverage of CH 3 on Si sites and SiCl 3 on C sites, it was concluded that the growth rates of SiC were controlled by the amount of CH 3 adsorbed on Si sites.