InGaZnO4 非晶透明導電薄膜的物性研究與以其製備的薄膜電晶體特性

Abstract

本論文研究的是InGaZnO 透明半導體薄膜的各種物理性質，並嘗試實際作出以InGaZnO 為通道的透明薄膜電晶體元件出來；我們發現在所探討的溫度範圍內(室溫∼300℃)，以脈衝雷射蒸鍍燒結的純相InGaZnO 靶材所得的薄膜，均為非晶相。且在可見光範圍內，透光率可達80％以上，改變蒸鍍時腔內氧氣壓力時，對所得InGaZnO 薄膜的電阻率和載子濃度有很大的影響。一般而言，氧壓越大載子濃度越小，而電阻率越大，值得一提的是，在150℃-300℃下蒸鍍的薄膜，其載子遷移率均可達20 以上，此值比非晶矽高出20倍以上，而且已達薄膜電晶體應用之要求。最後由光激發光和電阻對溫度變化的分析中，這類非晶薄膜並非典型的半導體；其載子傳輸行為則介於二維至三維的強侷限範圍跳躍的傳導機制。

In this thesis, we study the physical characteristics of amorphous InGaZnO thin film fabricated by pulsed laser deposition. The target used is a sintered stoichiometric InGaZnO bulk disk and the substrates used were glass substrates maintaining at temperature ranging from ambient to 300℃. All films obtained in the current study are amorphous , as revealed by x-ray diffraction measurements. Nonetheless, all film display a carrier mobility greater than 20 and have over 80％ of transparency in the visible light range. The oxygen partial pressure present during deposition appears to have significant effects on both film resistivity and carrier concentration. However, it seems that the mobility is immune from variation of deposition temperature and oxygen partial pressure. The photoluminescence and temperature dependent resistance analyses reveal that the amorphous films are probably not semiconductor in nature, instead the carrier transport is more likely governed by two- dimensional to three-dimensional variable range hopping mechanism.