Observation of Si-2p Level Shift in Hydrogenated Amorphous Silicon by X-Ray Photoelectron Spectroscopy

The XPS spectra of hydrogenated amorphous silicon (a-Si: H) and amorphous silicon without hydrogen (a-Si) are studied in the Si-2p core level region as functions of in-situ heat treatments. The Si-2p binding energy in a-Si: H does not change until 400°C heating and shifts to the lower energy side by 0.15 eV after 500°C heat treatment where most of hydrogen incorporated evolves, while the Si-2p binding energy in a-Si without hydrogen remains unchanged by heat treatment up to 600°C, The results suggest that incorporated hydrogen affects not only Si atoms directly bonded to hydrogen but also the remote Si atoms in the Si–Si network.