MODELING SILICON EPITAXIAL-GROWTH WITH SIH2CL2

Silicon epitaxial growth with SiH2Cl2 was modeled using measured SiH2C l2 adsorption kinetics and H-2, HCl, and SiCl2 desorption kinetics fro m studies on Si(111) 7 x 7 surfaces. The predicted growth rates were c ompared with growth rates measured recently by Regolini et al. as a fu nction of surface temperature between 923 and 1523 K. The agreement be tween the predicted and measured growth rates was very good. At lower temperatures between 923 and 1173 K, the silicon growth rates varied e xponentially with temperature. The calculations revealed that HCl deso rption is rate-limiting in this growth regime controlled by the availa bility of free surface sites. At temperatures above 1173 K, the silico n growth rates were proportional to the SiH2Cl2 pressure. This higher temperature region is controlled by the incident reactant flux and the reactive sticking coefficient of SiH2Cl2. The agreement between the c alculations and measurements indicates that silicon epitaxial growth r ates during low pressure chemical vapor deposition can be interpreted in terms of gas kinetic theory and adsorption and desorption surface k inetics.