不同双栅极设计对a-Si:H TFT特性影响

Effect of different dual gate design on A-Si:H TFT electrical characteristics

本实验于原有的单底栅a-Si TFT产品结构下,通过增加不同的顶栅极设计方式(不同a-Si覆盖比例、不同沟道几何形貌、不同沟道W/L比例)来研究双栅极设计对a-Si TFT特性的影响。实验结果显示双栅极a-Si TFT比现行单底栅a-Si TFT可以提升I_(on)7%、降低SS 3%、同时对I_(off)以及TFT稳定性影响不明显,显示双栅极a-Si TFT设计结构具有在不提高成本以及不变更工艺流程下,达到整体提升TFT特性的效果。顶栅极TFT特性不如底栅极,推测为a-Si/PVX界面不佳使得电子导通困难导致,未来可以借由改善a-Si/PVX界面工艺提升顶栅极TFT特性。

Different TFT geometry design （top gate area coverage ratio, different channel shape and various W/I. value） on dual gate a-Si TFT characteristics were investigated. Dual gate a-Si TFT shows better TFT characteristics than single bottom gate a-Si TFT with higher Ion 7 %, lower SS 3 and comparable Ioff and stress stability. Dual gate TFT structure is an economic way to improve a-Si TFT characteristic without production cost up and additional process flow modification. The character- istics of top gate TFT is worse than bottom gate TFT due to a worse a-Si/PVX interface than GI/a Si interface and may be improved by modifying a-Si/PVX process.