利用大氣常壓電漿輔助化學氣相沉積和中性粒子束系統雙重氣體處理應用於高效能銦鎵鋅氧薄膜電晶體研究

Abstract

傳統非晶矽薄膜電晶體存在較高的臨界電壓，低場效遷移率、較大的操作電壓與次臨界擺幅等缺點，為了改善傳統非晶矽薄膜電晶體(a-Si)低場效遷移率的問題，以非晶銦鎵鋅氧薄膜電晶體取代，其具備較好的場效遷移率(>10 cm2/V．S)，較大的開關電流比(>106)，較小的次臨界擺幅和較穩定的電性，目前已被廣泛研究，並且應用在下世代主動式陣列顯示器，可製造透明且隢性的顯示器。 在這篇論文中，我們使用大氣常壓電漿化學氣相沉積(AP-PECVD)來沉積銦鎵鋅氧主動層和中性粒子束系統後處理於銦鎵鋅主動層。大氣常壓電漿系統不用在真空系統下運作，因此可以降低成本，並且利用在大面積的製造上，中性粒子束系統在常溫下運作，且隔絕電漿中對元件造成缺陷的UV-rays、Chatge Bulid-up，使元件電特性更提升。 藉由在沉積銦鎵鋅氧薄膜電晶體時混入氫氣當沉積氣體和中性束氧粒子雙氣體處理，使元件得到高場效遷移率、高開關電流比、更小的次臨界擺幅，成功改善非晶銦鎵鋅氧薄膜電晶體電特性。

Conventional a-Si TFTs have higher subthreshold swing (SS),low field-effect mobility and higher turn on voltage these disadvantage. In order to improve these problems , we replace a-Si TFTs with amorphous In-Ga-Zn-O (IGZO) thin film transistors. The a-IGZO TFTs have attracted attention that due to its better field-effect mobility (>10 cm2/V．S), larger Ion/Ioff ratio (>106), smaller subthreshold swing (SS) and better stability. Furthermore, the a-IGZO TFTs have been studied extensively for their perspective in next generation active-matrix displays and can be applied to fabricate the full transparent TFT on flexible substrate. In this investigation, we used atmospheric-pressure PECVD (AP-PECVD) to deposit our IGZO active layer and post-oxidation by Neutral Beam System(NBS). With AP-PECVD, we could deposit IGZO thin film without vacuum system, thus, it could lower our cost and applied to large area manufacturing. With NBS , we could isolate UV-rays radiation, charge build-up which could deteriorate the device that could promote the electric characteristic. We improved the a-IGZO TFT with dual treatment of in-situ hydrogen incorporation by AP-PECVD and post-oxidation by NBS, thus, we will get higher field-effect mobility,