Formation of (111) nanotwin lamellae hillocks in polycrystalline silicon thin films caused by deposition of silicon dioxide layer

Plasma-enhanced chemical vapor deposition was used to deposit layers of tetraethylorthosilicate at different temperatures. In the case of low-temperature deposition (300 degrees C), the deposited film surface was smooth and the major surface defects of the polycrystalline silicon (poly-silicon) film surface were grooves of grain boundaries. In contrast, in the case of high-temperature deposition (500 degrees C), the deposited silicon oxide surface exhibited hillocks, and these hillocks were derived from the top end of inclined silicon (111) where protruding nanotwin lamellae penetrated the poly-silicon thin film. The observed hillocks stemming from nanotwin lamellae could have been formed by compressive stress during high-temperature silicon dioxide deposition. (c) 2006 American Institute of Physics.