Lateral Grain Growth of Amorphous Silicon Films With Wide Thickness Range by Blue Laser Annealing and Application to High Performance Poly-Si TFTs

We report high performance p-type poly-Si thin-film transistors (TFTs) achieved by lateral grain growth of amorphous silicon (a-Si) by using a continuous-wave blue diode laser of wavelength 445 nm. The blue laser beam is efficiently absorbed into the a-Si film, such that full melting and lateral crystallization is achieved in all thicknesses investigated, 50-200 nm. TFTs fabricated with 75-, 100-, and 125-nm-thick poly-Si films laterally grown by the blue laser annealing exhibited field-effect mobility of 108 ± 7, 104 ± 9, and 134 ± 12 cm
²
/V · s, and subthreshold swing of 210±51, 191±16, and 193±53 mV/decade, respectively, and high ON/OFF current ratio of ~10
⁸
.