非晶態氧化銦鎵鋅薄膜電晶體其幾何結構對表面能態影響的整合

Abstract

目前氧化物薄膜電晶體所使用的四種元件結構類似於非晶矽薄膜電晶體。其中值得注意的地方為不同的元件結構會對元件的電性產生明顯的改變，例如臨界電壓及次臨界擺幅等等。因此對於設計元件結構來說，考慮幾何結構對其元件電性上的影響是很重要的。 本研究採用逆交錯型(inverted-staggered)和逆共面型(inverted-coplanar)結構去調查及模型化表面能態對於非晶態氧化銦鎵鋅薄膜電晶體的影響。逆交錯型結構有者較少的表面能態及較低的接觸電阻，因此表現出更好的元件電性和穩定性。基於實驗的結果，逆交錯型表現出較高的載子移動率及較好的電壓應力下的穩定度，因此適合作為高性能非晶態氧化銦鎵鋅薄膜電晶體的元件結構。

For oxide based TFTs, the device structures are employed for four types which similar to a-Si TFTs. Noteworthy, the different structures result in distinct electrical properties including threshold voltage (Vth), sub-threshold swing (S) and so forth. Therefore, the geometry effect is important for designing device structures that varies the electrical performances seriously. In this study, we investigate and model the influence of surface state effects of a-IGZO TFTs by adopting the inverted-staggered and inverted-coplanar structures. The inverted-staggered TFTs with less surface states and lower contact resistance show improved electrical and stable performances compared to inverted-coplanar TFTs. Based on our results, the inverted-staggered structure with higher mobility and better stability under voltage stressing is suitable as high-performance a-IGZO TFTs.