Four-terminal (4T) polycrystalline silicon (poly-Si) thin-film transistors (TFTs) having both front and back gates were fabricated to investigate the effect of the internal tensile strain induced by continuous-wave (CW) laser lateral crystallization (CLC) on the carrier mobility. The tensile strain values at the surfaces and back interfaces were estimated to be approximately 0.3% and over 0.4%, respectively. In both front and back channel operations, the successful operation of a variable threshold voltage (Vth) scheme was confirmed. Front and back channel effective electron mobilities of 4T CLC poly-Si TFTs were evaluated under bias conditions so as not to form an inversion layer on the Vth-control gate side. Because of the larger tensile strain at the back interface, the back channel effective electron mobility was 1.2 times larger than the front channel effective mobility.
ASJC Scopus subject areas
- Physics and Astronomy(all)