A SIMPLIFIED MODEL DESCRIBING ENHANCED GROWTH-RATES DURING VAPOR-PHASE SELECTIVE EPITAXY

Nonuniform and enhanced growth rates due to gas-phase diffusion are ca lculated for vapor phase selective epitaxy. By solving Laplace's equat ion above a partially masked growth substrate, the effects of gas phas e diffusion on vapor phase selective epitaxy are considered. Surface f eatures having a single dielectric masking stripe or series of periodi cally spaced masking stripes are analyzed. Closed form expressions are given for reactant concentrations and enhanced growth rates away from the edge of a large single masking stripe, and similar calculations a re made for the case of repetitive masking stripes. These calculations compare favorably with low pressure organometallic vapor phase select ive epitaxy of GaAs and InAs on SiO2 masked GaAs, substrates.