Dual-gate a—Si:H thin film transistors

Dual-gate accumulation mode thin film transistors have been fabricated for the first time in a-Si:H on bulk glass substrates. The devices display exceptionally high performance, as compared to previously reported single-gate a-Si:H transistors. For a channel length of 10 µm and width of 168 µm, drain currents in the range of 5-10 µA were obtained for gate biases of 15 V in both of the two conducting channels induced in the a-Si:H layer. The drain current of the TFT operating in the dual-gate mode was found to be larger than the arithmetic sum of the drain currents through the two individual channels obtained from single-mode operation. A significant difference in dc stability between the two channels was observed. The use of the dual-gate TFT as a diagnostic structure for studying interface properties and contact effects has been demonstrated.