Phosphorus doping and sharp profiles in silicon and silicon-germanium epitaxy by rapid thermal chemical vapor deposition

In situ phosphous doping of silicon epitaxy from 700 to 1000 degrees C by l ow pressure rapid thermal chemical vapor deposition in a cold wall system, using dichlorosilane as the silicon source, has been investigated. At a hig h phosphine flow rate, the growth rate of silicon decreases dramatically (b y similar to 60%) and the phosphorus incorporation level saturates. A signi ficant persistence effect of phosphorus after turning off phosphine is obse rved. However, a sharper transition and higher doping level are observed in Si1-xFex layers grown at 625 degrees C. Improvement of the phosphous profi le in silicon to similar to 13 nm/decade is demonstrated by reactor cleanin g and ex situ etching of the wafer surface during a growth interruption aft er phosphorus-doped epitaxy. Despite the growth interruption, an in situ 80 0 degrees C bake at 10 Torr in hydrogen before regrowth can give an oxygen- and carbon-free interface without excessive dopant diffusion. (C) 2000 The Electrochemical Society. S0013-4651(99)11-104-2. All rights reserved.