In-situ X-ray diffraction analysis of the crystallisation of a-SI:H films deposited by the expanding thermal plasma technique

The solid phase crystallization (SPC) kinetics of expanding thermal plasma (ETP) grown a-Si:H films on glass substrates was studied by means of in-situ X-ray diffraction (XRD). The Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was used for the analysis of the SPC kinetics revealing random nucleation and 3D growth of the crystallites. The activation energy of the SPC process was found to be 2.9 eV, which is lower compared to other deposition techniques. This indicates a more stable SPC process which is more tolerant to temperature variations. Post-SPC characterization using electron backscatter diffraction showed indications of good crystal quality with average grain sizes of ~0.7-0.9 μm. Indications of homogeneous nucleation with no preferred nucleation sites were observed.