The performance and stability of hafnium-indium-zinc-oxide (HIZO) thin-film transistors (TFTs) are evaluated with respect to the relative content in In and Zn cations. While devices that incorporate an active layer with an In-rich composition exhibit higher field-effect mobility values, they undergo larger negative shifts in Vth upon negative-bias illumination stress (NBIS). Density-of-states analyses suggest that a higher In/Zn ratio in the semiconductor results in larger defect states in the vicinity of the semiconductor/gate-insulator interface. Accordingly, these defect states may act as carrier traps that accelerate the degradation of HIZO TFTs upon NBIS.
Bibliographical noteFunding Information:
Manuscript received May 17, 2011; revised June 12, 2011; accepted June 22, 2011. Date of publication August 17, 2011; date of current version August 24, 2011. This work was supported in part by KOSEF under NRL Program 2011-0000375 and in part by the BK21 Project. The review of this letter was arranged by Editor W. T. Ng.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering