InZnO 기반 투명산화물 트랜지스터의 전기적 특성변화에 대한 연구

Abstract

Thin film transistors (TFTs) for flat panel display using transparent oxide semiconductors (TOS) have much attentions due to high reliability, mobility as well as excellent transparency. It is reported that the stability of transparent oxide TFT is superior to that of a-Si based TFT and overall uniformity is better than low temperature poly silicon (LTPS) TFT, which can keep an amorphous phase. In other to improve the TFT device performance, several oxide semiconductors as an active channel layer, such as In-Ga-Zn-O, In-Zn-O, Zn-In-Sn-O, Zn-Sn-O, and In-Al-Zn-O have been usually suggested. Suppression of the charge carrier in semiconducting oxide (<～1018 cm-3) in other to improve the stability of TFTs by binding with oxygen group Ⅲ and Ⅳ elements (e.g., Ga, Y, Si, Sn, Ti, Zr and Hf) are considered to control. Due to several advantages i.e., good conductivity, high optical transparency and low deposition temperature, Indium-Zinc oxide (IZO) based oxide was selected for an active layer candidate material for high performance semiconducting and electrode layers in TFT. Also, to investigate the doping effect, we selected tungsten oxide (WO3), yttrium oxide (Y2O3) and tantalum oxide (Ta2O5) materials to control the carrier concentration of IZO film and studied the effect of Ar/O2 gas ratio on structural, electrical and optical proerties of IZO based films. To evaluate WInZnO, YInZnO and TaInZnO films as a semiconducting channel layer, the device performance of TFTs were characterized.