Density of States in Amorphous In-Ga-Zn-O Thin-Film Transistor under Negative Bias Illumination Stress

作者：Ueoka Yoshihiro^*; Ishikawa Yasuaki; Bermundo Juan Paolo; Yamazaki Haruka; Urakawa Satoshi; Fujii Mami; Horita Masahiro; Uraoka Yukiharu

来源：ECS Journal of Solid State Science and Technology, 2014, 3(9): Q3001-Q3004.

DOI：10.1149/2.001409jss

Amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors on glass substrates were fabricated, and the density of state (DOS) in TFTs after a negative bias stress (NBS) and negative bias illumination stress (NBIS) was investigated. For a NBIS of -20 V, the threshold voltage (Vth) shifted toward the negative direction but an increase of shallow states expected as positively ionized oxygen vacancies (V-o(+) or V-o(++)) were not observed in the DOS curves. On the other hand, for NBIS of -30 V, changes in the DOS near the conduction band edge before and after applying a bias stress were observed. This suggests that V-o(+) or V-o(++) was generated by NBIS but accumulation of holes at the a-IGZO/SiO2 interface mainly caused the Vth shifts.

• 出版日期2014