Rapid thermal annealing of amorphous silicon thin films grown by electron cyclotron resonance chemical vapor deposition

Hydrogenated amorphous silicon (a-Si:H) thin films were deposited on pre-oxidized Si wafers by electron cyclotron resonance chemical vapor deposition (ECRCVD). The rapid thermal annealing (RTA) treatments were applied to the as-grown samples in nitrogen atmosphere, and the temperature range for the RTA process is from 450 to 950 degrees C. The crystallization and grain growth behaviors of the annealed films were investigated by Raman spectroscopy and X-ray diffraction (XRD). The onset temperature for the crystallization and grain growth is around 625 similar to 650 degrees C. The crystalline fraction of annealed a-Si: H films can reach similar to 80%, and a grain size up to 17 nm could be obtained from the RTA treatment at 700 degrees C. We found that the crystallization continues when the grain growth has stopped.