An Experimental Study on Laser Annealing of Thin Silicon Layers

A laser annealing technique directed toward producing single crystalline silicon on substrates is studied. In this paper the laser-induced melting of thin silicon films is studied experimentally. Direct heating of thin silicon layers on substrates is shown to produce a variety of different silicon melting patterns. A systematic study of these phase change phenomena has been performed. The important parameters are: (1) the laser beam power, (2) the laser beam intensity distribution, and (3) the speed of the translating silicon layer. Unstable silicon phase boundaries break up to form regions where solid and melt silicon coexist. Complicated silicon phase boundary patterns are shown. The experimental results showed the occurrence of organized patterns of alternating solid and liquid silicon stripes for two-dimensional heating distributions. Finally, temperature fields for the experimental operating conditions are calculated using an enthalpy model.