Growth of Polycrystalline Silicon Grains

Abstract

The relationship between the surface morphology of Si after in situ annealing carried out after a-Si deposition by low pressure chemical vapor deposition (LPCVD) and the preferred crystal orientation is examined. Dome-shaped grains are produced with <311> preferred orientations, and scrambling grains are produced at the boundaries between the <311> and <110> preferred orientations. Here, the scrambling grains are defined as some connected dome-shaped grains. The in situ annealing results in crystallization of the surface amorphous layer on the original <311> textured films. The <311> orientation factor is significantly increased after annealing. Taking into account the reciprocal reaction during the in situ annealing between the polycrystalline Si (poly-Si) grains formed on the a-Si surface and the poly-Si grown from the interface between the a-Si and the SiO2 substrate, the origin of the scrambling grains is discussed.