改善聚乙烯醇製作軟性薄膜電晶體之遲滯現象

Abstract

本論文研究是以探討InGaZnO4半導體薄膜於軟性不□鋼基板上的彎曲特性，並嘗試以機械應力的角度來探討薄膜與薄膜間的交互作用；我們發現在基板可彎曲的限度內，使用低楊氏係數PVA製程介電層的薄膜電晶體遠比舊有的二氧化矽薄膜穩定，在臨限電壓的位移上從2.4 V降至 0.1 V，其載子遷移率均可達7.8 cm2V-1s-1，已達到薄膜電晶體應用之要求。而在使用PVA製程的薄膜電晶體，電性上產生明顯的遲滯現象臨限電壓位移，藉由添加二氧化矽粉末於溶液中，大幅降低臨限電壓位移從3.9 V 降至0 V，其載子傳輸效率為 9.7 cm2V-1s-1，保有穩定TFT特性表現。

In this thesis, the electrical characteristics of amorphous InGaZnO4 thin film transistor (TFT) on stainless steel substrate were evaluated under flat and bending conditions. Our investigation based on the interaction between films at each layers of TFT under mechanical stress. The low Young’s modulus materials, such as poly vinyl alcohol (PVA), are more stable than the traditional silicon dioxide thin film under bending. The displacement of threshold voltage decreases substantially from 2.4 V to 0.1 V by using PVA as insulator. Furthermore, the hysteresis on the threshold voltage of TFT can be improved by using silicon dioxide (SiO2) nano-particles in PVA. The threshold voltage shift is greatly reduced from 3.9 V to 0 V. The field effect mobility is 9.7 cm2 V-1 s-1. The electrical characteristic of IGZO TFTs using SiO2/PVA as insulator keeps a stable feature even they are built on stainless steel.