Local-Degradation-Induced Threshold Voltage Shift in Turned-OFF Amorphous InGaZnO Thin Film Transistors Under AC Drain Bias Stress
| Autor: | Mi Seon Seo, Keum Dong Jung, Daeun Lee, Kim Tae Young, Jong-Ho Lee, Hyuck-In Kwon, Jong-In Kim, Je-Hun Lee, In-Tak Cho, Mun Soo Park, Chan-Yong Jeong |
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| Rok vydání: | 2015 |
| Předmět: |
Stretched exponential function
Materials science Condensed matter physics business.industry Electrical engineering Capacitance Electronic Optical and Magnetic Materials Threshold voltage Amorphous solid Stress (mechanics) Duty cycle Thin-film transistor Electrical and Electronic Engineering business Quantum tunnelling |
| Zdroj: | IEEE Electron Device Letters. 36:579-581 |
| ISSN: | 1558-0563 0741-3106 |
| DOI: | 10.1109/led.2015.2424966 |
| Popis: | Local degradation caused by drain bias ( $V_{\mathrm {\mathbf {DS}}}$ ) stressing is recently considered as a key issue in amorphous InGaZnO (a-IGZO) thin film transistors (TFTs). In this letter, we investigate the instability of turned-OFF a-IGZO TFTs under ac $V_{\mathrm {\mathbf {DS}}}$ stressing. The negative threshold voltage shift, which was well fitted by a stretched exponential function, was accelerated with increasing duty cycle despite the same effective stress time. A capacitance measurement reveals that a higher duty cycle induced more donor states near the drain, implying that the stretched-exponential time dependence cannot be fully explained by trapping mechanism. Temperature-dependent $\tau $ followed the Arrhenius relation, whereas $\beta $ showed unusual temperature dependence in contrast to that under dc $V_{\mathrm {\mathbf {DS}}}$ stressing. These findings suggest an additional origin such as a stress release effect under an ac $V_{\mathrm {\mathbf {DS}}}$ stress other than hopping/tunneling mechanism. |
| Databáze: | OpenAIRE |
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