[8a-A13-1~13] 6.3 Oxide electronics

11:45 AM - 12:00 PM JST(2:45 AM - 3:00 AM UTC)

[8a-A13-11] The origin of performance degradation in ultra-thin a-IGZO TFTs

〇Masatake Tsuji¹, Hanjun Cho¹, Shigenori Ueda², Hideo Hosono^1,2 (1.Science Tokyo, 2.NIMS)

Keywords:

TFT,amorphous oxide semiconductor,point defect

Scaling down the channel thickness t_ch of a-IGZO TFTs below 10 nm causes severe degradation in field-effect mobility (μ_FE) and operational instability. In this study, we propose that this degradation originates from oxygen-related defect pairs—the coexistence of donor-type oxygen vacancies (V_O) and acceptor-type interstitial oxygen (O_i)—that are kinetically frozen during deposition. Furthermore, we demonstrate that positive bias stress (PBS) instability can be suppressed and μ_FE can be restored by implementing two strategies: defect deactivation and the removal of the defective surface layer, respectively.