Kinetics of silicon epitaxy using SiH₄ in a rapid thermal chemical vapor deposition reactor

Abstract

The equilibrium hydrogen surface coverage on Si(100) during silicon epitaxy using SiH4 has been measured in a rapid thermal chemical vapor deposition reactor. The hydrogen coverage could be "frozen out" completely on the surface by a rapid cool-down and pump-down of the reactor up to temperatures of ≅575°C; at temperatures above 575°C only partial "freeze-out" is achieved. Surface hydrogen was titrated in situ using the reactor as a thermal desorption spectrometer. Epitaxial silicon films were grown in the temperature range 450-700°C and the film growth kinetics was correlated with the equilibrium hydrogen coverage. The growth mechanism changes from the low-temperature regime, where the surface is hydrogen covered, to the high-temperature regime, where the surface is essentially clean.