THE STUDY OF SELECTIVITY IN SILICON SELECTIVE EPITAXIAL-GROWTH

Selective epitaxial silicon layers have been grown in a rapid thermal processing reactor, using dichlorosilane (DCS) diluted in H-2, either at millibar low pressure or at a reduced DCS flow. The selective epita xial growth (SEG) occurs under conditions of near thermodynamic equili brium. Thus equilibrium partial pressures of the predominant species i n the Si-H-Cl system have been calculated to give an insight into the experimental results. The ratio of HCl species relative to silicon con taining species in the gas phase, P(HCl)/P(Si), determines reaction sy stem selectivity, while the product of system supersaturation and P(Si )/P(HCl) ratio indicates system growth capability.