Sequential Lateral Solidification of PECVD and Sputter Deposited a-Si Films

Abstract

ABSTRACTWe have investigated sequential lateral solidification (SLS) of amorphous Si films that have been prepared via PECVD and sputter deposition methods. The focus of the work was on identifying and analyzing the energy density and per-pulse translation distance parameter space that permits SLS of these films. Experimental details include the use of a two-axisprojection irradiation system to image a straight-slit beamlet pattern onto the sample, and analyzing the resulting microstructures by SEM and optical microscopy of Secco-etched samples. High-temperature-deposited LPCVD films were also examined to enable further comparative analysis. We conclude from these results that there are no major differences in both the SLS process characteristics and the resulting microstructure among the investigated films (provided that the films are dehydrogenated in the case of PECVD a-Si). Based on the controlled super-lateral growth (C-SLG) model of the SLS process, we attribute these findings to the fact that the SLS method involves—as one of its essential features—complete melting of the Si film at fluences that are sufficient to thoroughly melt crystalline Si films, during which all pre-irradiation phase and microstructural details are erased.