Two-step degradation of a-InGaZnO thin film transistors under DC bias stress. (February 2019)

• Record Type: Journal Article
• Authors: Hu, Chun-Feng; Teng, Tong; Qu, Xin-Ping
• Is Part Of: Solid-state electronics. Volume 152(2019)
• Page Start: 4
• Page End: 10
• Publication Date: 2019-02
• Subjects: IGZO TFTs -- PBTI -- Two–step degradation -- H2O molecule -- Donor-like states creation -- Electron trapping; Semiconductors -- Periodicals; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.sse.2018.11.005
• Languages: English
• ISSNs: 0038-1101

Abstract

Highlights: A unified explanation is proposed to consistently explain the two-step degradation of a-IGZO TFTs under DC PBTI stress without or with different stress Vds . For PBTI stress without stress Vds, the initial negative Vth shift is believed to be induced by donor-like defect states corresponding to H2 O molecule and intrinsic defects. For PBTI stress with stress Vds, the negative shift is believed to be induced by donor-like defect states corresponding to oxygen vacancies. The gate-bias-induced electron trapping mechanism is responsible for the positive Vth shift. Abstract: A unified explanation is proposed to consistently explain the two-step degradation of amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) under DC positive bias temperature instability (PBTI) stress without or with different drain stress voltages ( Vds ). For PBTI stress without stress Vds, this initial negative Vth shift is believed to be induced by donor-like defect states corresponding to H2 O molecule and intrinsic defects, while for PBTI stress with stress Vds, the negative shift is believed to be induced by donor-like defect states corresponding to oxygen vacancies. The gate-bias-induced electron trapping mechanism is responsible for positive Vth shift. These transitions from negative to positive Vth shift are resulted from the competition between the donor-like states creation and electron trapping.