Fabrication of polycrystalline silicon thin films from a-SiO_x via the inverted aluminum-induced layer exchange process

A novel fabrication method of polycrystalline silicon (poly-Si) films by aluminum-induced crystallization of amorphous silicon suboxide (a-SiO_0.2) material via the inverted aluminum-induced layer exchange (ALILE) mechanism on glass substrates is presented. The presence of oxygen in the system prevented the formation of columnar crystalline Si precipitates (hillocks) in the bottom layer of the structure even at a process temperature of 550 °C. At the same time, this layer, consisting of Al, Si, and O atoms, contained nanocrystalline Si inclusions and a layer of initial a-SiO_x with a thickness of about 60 nm, which was called the “a-SiO_x residual layer”. The poly-Si formed had a preferred (1 1 1) crystal orientation and an average crystallite size of 4.5 µm.