Infrared semiconductor laser irradiation used for crystallization of silicon thin films

We report the rapid thermal crystallization of silicon films using infrared semiconductor laser. Carbon films were used on silicon films to absorb the laser light. Uniform crystalline regions were achieved by a line shape laser beam with a length of 20 μm. Polycrystalline silicon thin film transistors were fabricated in crystallized regions. The effective electron carrier mobility and threshold voltage were achieved to be 130 cm2/Vs and 0.4 V, respectively, when the crystalline volume ratio of the silicon films was 0.95.

► Rapid 976-nm semiconductor laser heating was developed for about 20 μs.
► 40-nm-thick amorphous silicon films were successfully crystallized.
► A crystalline volume ratio of 0.95 was achieved by the heating for 25 μs.
► Polycrystalline thin film transistors were fabricated in the crystallized films.
► The carrier mobility and threshold voltage were achieved to be 130 cm2/Vs and 0.4 V.