High-voltage poly-Si TFTs with multichannel structure

High-voltage (>100-V) and large-transconductance poly-Si thin-film transistors (TFTs) have been fabricated on quartz substrates by the use of laser-recrystallized multiple-strip poly-Si films as semiconductors in the channel regions. The TFTs have an offset gate structure between the source and the gate (L_OFF,1), and between the gate and the drain (L_OFF,2). With the nonsymmetric offset gate structure at L_OFF,1=3 μm and L_OFF,2=15 μm, the TFTs have a large transconductance of 520 μS and exhibit low-threshold n-channel enhancement-mode characteristics. Simultaneously, a very large ON/OFF current ratio (above 10⁷) and a low leakage current of 2×10^-10 A occur at the high drain voltage of V _D=100 V. The breakdown voltage V_BD of the TFT depends strongly on L_OFF,2, so V_BD can increase with increasing L_OFF,2 to 110 V at L_OFF,2=10 μm, 130 V at L_OFF,2 =15 μm, and 170 V at L_OFF,2=20 μm