Amorphous titanium silicide phase formation by surface microroughness on Si(100)

The formation of amorphous Ti-silicide phase on two different kinds of Si(100) substrates was investigated. Two different substrates, the off-axis Si(100) which was cut with 4 degrees to the (100) plane and the on-axis Si(100) which was cut with less than 0.5 degrees were prepared. The Si(100) substrates were examined with atomic force microscope (AFM) to verify the atomic scale microroughnesses of the initial Si substrates after HF clean removing the native oxide. The on-axis Si(100) substrate exhibited much rougher surface morphology than that of the off-axis Si(100). The atomic scale microroughness of two different Si(100) substrates such as atomic steps and pits were investegated by high resolution transmission electron microscopy (HRTEM). Ti thin films were deposited in an e-beam evaporator after HF clean and the amorphous Ti-silicide layers were formed by annealing. The amorphous layer thicknesses on the on axis Si(100) exhbited thicker than those of the off-axis Si(100) and this difference of amorphous Ti-silicide layer thicknesses was considered to be related with atomic scale microroughnesses of Si surface.