|학술대회||2012년 가을 (11/07 ~ 11/09, 라카이샌드파인 리조트)|
|발표분야||F. 광기능/디스플레이 재료(Optical Funtional and Display Materials)|
|제목||The influence of hafnium doping on bias stability in zinc-tin oxide thin film transistors|
|초록|| Thin-film transistors(TFTs) based on oxide semiconductors have been investigated as promising alternatives for conventional amorphous and polycrystalline silicon TFTs. Oxide TFTs have several advantages, such as low temperature processing, transparency and high field-effect mobility. Lots of oxide semiconductors for example ZnO, SnO2, In2O3, InZnO, ZnSnO, and InGaZnO etc. have been extensively researched. Particularly, zinc-tin oxide(ZTO) is suitable for channel layer of oxide TFTs with a high mobility that Sn in ZTO can improve the carrier transport by overlapping orbital. However, when bias stress and high temperature is applied, electrical characteristics would be changed. In order to solve these instability problems, Hf was considered as a dopant which could play a role as a stabilizer that suppress charge carrier by binding with oxygen.
In this study, we fabricated staggered bottom-gate structure ZTO-TFT and patterned channel layer using shadow mask. Indium tin oxide(ITO) was used as the source and drain electrodes. ZTO(40 nm thick) and ITO(300 nm thick) were deposited by DC magnetron sputtering. Then, we compare the performance of ZTO-TFTs and hafnium doped ZTO-TFTs. The amount of dopants is 0, 0.5, 1.0 and 2.0 at. %. The devices were annealed at 200, 400 and 600 ℃ for 1 hour and the performances were measured using HP 4145B semiconductor analyzer. The results showed that performances of ZTO-TFTs were improved by hafnium doping on ZTO-TFTs and also high stability ZTO-TFTs were obtained from negative bias temperature instability test. And as the atomic ratio of hafnium increased, the stability of ZTO-TFTs was improved.
|저자||강유진, 한동석, 문대용, 박재형, 이상호, 신소라, 박종완|
|키워드||ZTO TFT; Hafnium doping; Oxide semiconductors|