Growth of Selective Silicon Epitaxy Using Disilane and Chlorine on Heavily Implanted Substrates: II. Role of Implanted Arsenic

Abstract

In this report, we present results on the low thermal budget deposition of selective silicon epitaxy on heavily arsenic implanted substrates using and in an ultrahigh vacuum rapid thermal chemical vapor deposition reactor. The selectivity of silicon to as well as the silicon growth kinetics, epitaxial quality, and dopant incorporation for varying substrate implant dose conditions and varying levels of chlorine during processing were investigated. We demonstrate that an increase in the arsenic implant dose can reduce the silicon growth by means of an inherent incubation time for deposition occurring in a chlorinated ambient. The extent to which the silicon growth suppression occurs, however, can be lessened by specific changes in the system conditions, and therefore, growth reductions due to arsenic can be minimized. In addition to changes in the silicon growth kinetics, arsenic implanted substrates have demonstrated a tendency to degrade the surface morphology and enhance the density of defects within the deposited silicon epitaxial films. Furthermore, by depositing the silicon film immediately following implantation and prior to any high temperature anneal, movement of arsenic into the deposited silicon layers has been observed at growth temperatures as low as 800°C. Therefore, the incorporation of arsenic into the deposited epitaxial films has been found to be controllable such that abrupt profiles or intentional diffuse structures can be achieved by variation of the process sequence and the annealing conditions. © 1999 The Electrochemical Society. All rights reserved.