銅製程對非晶矽氧化銦鎵鋅薄膜電晶體特性影響之研究

Abstract

在這份研究裡，將探討銅製程對非晶矽氧化銦鎵鋅(a-IGZO)薄膜電晶(TFTs)特性的影響。我們藉由比較電極為鈦/鋁/鈦結構的薄膜電晶體和電極為銅/鈦結構的薄膜電晶體特性，觀察到銅/鈦結構的薄膜電晶體特性會產生惡化，以及偏壓加壓下的不穩定性會增加。藉由二次離子質譜分析儀得知此現象是因為銅進入元件的通道層。為了探討銅的濃度對非晶矽氧化銦鎵鋅薄膜電晶體特性影響的關係，我們將鈦/鋁/鈦結構的薄膜電晶體浸泡在硫酸銅溶液中，以觀察對元件影響的程度，及其內部缺陷的變化。本研究充分證明銅對薄膜電晶體的影響，足為使用銅製程製作a-IGZO TFTs的重要參考。

In this work, the influence of copper process on amorphous type Indium Gallium Zinc Oxide (a-IGZO) thin film transistor’s (TFTs) transfer curve is studied. By comparing the TFTs characteristics with Ti/Al/Ti source/ drain and Cu/Ti source/drain, we observed that the performance of Cu/Ti structure would become worse than that with Ti/Al/Ti structure. Furthermore, the bias stress induced instability would become more obvious. It is attributed to the presence of the copper in the channel region of the device, which is verified by Secondary Ion Mass Spectrometry (SIMS) analysis. In order to check the influence of Cu, a verification experiment is conducted by dipping Ti/Al/Ti structure devices into the solution of CuSO4. With this experiment, we can observe the influence of Cu with different concentration on change of density of states (DOS). This study substantially proves the influence of copper on the characteristics of TFT, which is an important reference for the fabrication of a-IGZO TFT using Cu process.