Effect of incident kinetic energy on a-Si:H structure: A molecular dynamics simulation study

This paper utilized molecular dynamics simulation to investigate the influences of the incident kinetic energy on the structure of hydrogenated amorphous silicon (a-Si:H) thin films. The SiH₃ radical impinged on the Si (001) surface with substrate temperature of 500 K in the incident kinetic energy range from 0.04 to 5.81 eV. The results showed that high incident kinetic energy could smooth the surface, promote the densification of internal structure, and increase the adsorption rate of SiH₃ radical and the crystalline volume fraction. The SiH_x and dangling bonds, which are the key factors that affecting the film quality, have been further analyzed, the results reflected that the increase of the incident kinetic energy will increase the content of SiH combination pattern and decrease the dangling bonds in the films, thus improving the quality of the thin films. There is a critical value, 0.64 eV, 1.45 eV or 4.04 eV, of this variation rate. Steep variation trends is corresponding to the incident kinetic energy less than this critical value, and variation trends is gentle for that above it.