Thermal properties of hydrogenated amorphous silicon prepared by high-density plasma chemical vapor deposition

The properties of hydrogenated amorphous silicon (a-Si:H) deposited by plasma enhanced chemical vapor deposition (PECVD) have been widely investigated. In this paper, a-Si:H films were prepared by high-density plasma chemical vapor deposition (HDP-CVD) with high power density of 3.18 W/cm2 and high deposition rate of 2.6 nm/s. The correlation between the characteristics of Si–Hn bonds and annealing temperature was investigated. Furthermore, the variation of the film stress against temperature that correlates to the hydrogen desorption at different stages during thermal annealing has also been studied in this work. The FTIR spectra show that Si–Hn bond almost disappeared when annealed above 400 °C, and the film started to condense. On the other hand, thermal desorption spectra (TDS) resulted in the Si–Hn bond breaking at during about 300–600 °C and the behavior of H2 desorption remaining the same as the stress variation.