Split-Channel Dual-Gate High Voltage Thin Film Transistors

High-voltage thin film transistors (HVTFTs) have potential applications for driving high-voltage devices. Drain offset is a typical HVTFT structure but degrades ON-current. In this study, a-IGZO split-channel dual-gate HVTFTs are explored to achieve both high-voltage and high breakdown voltage. It is found that the dual-gate structure without split-channel improves the ON-current of offset-drain thin film transistors (TFTs) but degrades the breakdown voltage. Experiment results show that high ON-current induced thermal breakdown is the main reason limiting the breakdown voltage of dual-gate HVTFTs. The split-channel structure is introduced to enhance the heat dissipation and thus dual-gate HVTFTs with higher breakdown voltage were obtained. Split-channel dual-gate HVTFTs were fabricated with a breakdown voltage of 464 V, ON-current of
$61.60~\mu \text{A}$
, threshold voltage of −1.0 V, and subthreshold swing of 0.38 V/dec. This study demonstrates that split-channel dual-gate HVTFTs are a promising candidate for high-voltage and high ON-current TFT.