Plasma‐Enhanced Chemical Vapor Deposition of Silicon Epitaxial Layers

Abstract

Silicon epitaxial layers are conventionally deposited by atmospheric or reduced pressure chemical vapor deposition (CVD) at temperatures of 1050°–1200°C. This relatively high processing temperature limits the minimum thickness and conductivity of epitaxial films deposited on substrates containing heavily doped regions near the surface because of solid‐state outdiffusion and autodoping. In order to minimize outdiffusion and autodoping, the epitaxial process step needs to be carried out at lower temperatures. Plasma‐enhanced CVD (PECVD) is a technique capable of depositing silicon epitaxial layers at relatively low temperatures (700°–800°C) and with reasonable deposition rates (200–2000 Å/min). This article discusses the PECVD process and its application to the low temperature deposition of silicon epitaxial films.