Electron microscope study of intrinsic and extrinsic stacking faults, and twins in SOS at the early stage of epitaxial growth

Abstract

Fine structures of the Si films on (1 1 02) sapphire have been studied by a lattice resolution TEM. The Si was deposited by the pyrolysis of silane in H 2 at 1000°C at a growth rate of 0.1μm/min. The samples for TEM were prepared by peeling off the Si films from the substrates after HF treatment. A film having a mean thickness of 500 Å was composed of (100) and {110} domains. The volume fraction of the {110} domains was more than 50% and about constant as a function of growth time. The {110} domains contained much higher density of microtwins than the (100) domains. These microtwins had various thicknesses including one atomic layer (intrinsic stacking faults) and two atomic layers (extrinsic stacking faults). The density of the intrinsic stacking faults was higher than those of extrinsic stacking faults and other twins. The {110} and (100) islands were nucleated independently and the microtwins were also present in the islands smaller than 500 Å in diameter.