Stress in silicon films deposited heteroepitaxially on insulating substrates with particular reference to corundum

Abstract

The stresses in a thin silicon film deposited epitaxially on to a corundum substrate, arising from the differences in thermal expansion, are considered theoretically and the results are found to be in agreement with published experimental data. It is shown that the stress problem in such films cannot be overcome in the context of the two-layer system, though some alleviation can be obtained by the application of stringent dimensional conditions. Theoretical considerations show that the use of a third layer of material as a backing for the corundum substrate can reduce the stress at the silicon-corundum interface to zero and that at the silicon surface to a negligibly small value.