Generation of ultra high-power thermal plasma jet and its application to crystallization of amorphous silicon films

摘要

We have successfully generated ultra high-power thermal plasma jet (Super TPJ: s-TPJ) by increasing the Ar gas supply pressure to 0.4MPa and the flow rate to 18 L/min. DC arc discharge was stably performed under a supply power of 4.6kW. The peak power density of s-TPJ reached 64.1kW/cm(2) and enabled us to melt and recrystallize amorphous silicon (a-Si) films on quartz substrates with a scanning speed as high as 8000mm/s. Under ultra high-speed scanning faster than 3000mm/s, we observed granular crystal growth (GCG) competing with conventional high-speed lateral crystallization (HSLC). When further high speed scanning was performed, we observed a significant increase in grain density, which suggests spontaneous nucleation in undercooled molten Si as the origin of GCG. When we crystallized an isolated pattern of 6 x 6 mu m(2) under GCG conditions, single crystalline growth was successfully achieved. (C) 2017 The Japan Society of Applied Physics