High-performance low-temperature poly-Si TFTs and circuits

High-performance low-temperature poly-Si TFTs (Thin Film Transistors) and b asic digital and analog circuits have been developed to open up the possibi lity of integrating systems on glass substrates. The TFTs were fabricated o n a glass substrate, using excimer laser annealing. The threshold voltage w as 0.86 V and the field effect mobility was 168 cm(2)/Vs for an n-channel T FT, while the threshold voltage was -0.9 V and the mobility was 129 cm(2)/V s for a p-channel TFT. The maximum scanning frequency for the 4-mu m-gate b i-directional shift register, which needs no additional TFTs for changing t he shift-direction, was 47 MHz at 5-V supply. The unity-gain frequency of a CMOS TFT operational amplifier, used to build analog circuits, was 1.4 MHz at supply voltages of +/-8 V.