KINETICS OF SILICIDE-INDUCED CRYSTALLIZATION OF POLYCRYSTALLINE THIN-FILM TRANSISTORS FABRICATED FROM AMORPHOUS CHEMICAL-VAPOR-DEPOSITION SILICON

Self-aligned, n-channel, polycrystalline silicon thin-him transistors with 15 mu m channels were fabricated by recrystallizing amorphous sil icon for 6 h at 500 degrees C. A thin nickel silicide at the source an d drain was used to seed the crystallization. The channel mobility was initially 87 cm(2)/V s, and improved to 170 cm2/V s after hydrogenati ng the devices. The recrystallization velocity in the channel was meas ured optically and electrically, and found to be 3.5 x 10(-8) cm/s; th is value exceeds by two orders of magnitude the solid-phase epitaxial regrowth rate of amorphous silicon. This observation, together with th e low activation energy of 0.3 eV measured for the silicide-assisted r egrowth velocity as compared to 2.76 eV for epitaxial regrowth, sugges t that the channel recrystallization is assisted by Ni diffusing to th e recrystallization front. (C) 1998 American Institute of Physics.