Improved Stability of Atomic Layer Deposited ZnO Thin Film Transistor by Intercycle Oxidation

ETRI Journal

关键词: negative bias stress;    thin film transistor;    ZnO;   

Others  :  1186414
DOI  :  10.4218/etrij.12.0211.0186

【 摘 要 】

By inserting H2O treatment steps during atomic layer deposition of a ZnO layer, the turn-on voltage shift from negative bias stress (NBS) under illumination was reduced considerably compared to that of a device that has a continuously grown ZnO layer without any treatment steps. Meanwhile, treatment steps without introducing reactive gases, and simply staying under a low working pressure, aggravated the instability under illuminated NBS due to an increase of oxygen vacancy concentration in the ZnO layer. From the experiment results, additional oxidation of the ZnO channel layer is proven to be effective in improving the stability against illuminated NBS.

   

【 参考文献 】

• [1]J.K. Jeong et al., "Origin of Threshold Voltage Instability in Indium-Gallium-Zinc Oxide Thin Film Transistors," Appl. Phys. Lett., vol. 93, no. 12, 2008, pp. 123508.1-3
• [2]S. Yang et al., "Improvement in the Photon-Induced Bias Stability of Al-Sn-Zn-In-O Thin Film Transistors by Adopting AlOx Passivation Layer," Appl. Phys. Lett., vol. 96, no. 21, 2010, pp. 213511.1-3.
• [3]S.H.K. Park et al., "Channel Protection Layer Effect on the Performance of Oxide TFTs," ETRI J., vol. 31, no. 6, June 2009, pp. 653-659.
• [4]H. Omura et al., "First-Principles Study of Native Point Defects in Crystalline Indium Gallium Zinc Oxide," J. Appl. Phys., vol. 105, no. 9, 2009, pp. 093712.1-8.
• [5]T. Kamiya, K. Nomura, and H. Hosono, "Electronic Structure of the Amorphous Oxide Semiconductor a-InGaZnO4-x:Tauc-Lorentz Optical Model and Origins of Subgap States," Phys. Status Solidi A, vol. 206, no. 5, 2008, pp. 860-867.
• [6]T. Kamiya et al., "Electronic Structure of Oxygen Deficient Amorphous Oxide Semiconductor a-InGaZnO4-x: Optical Analyses and First-Principle Calculations," Phys. Status Solidi C, vol. 5, no. 9, 2008, pp. 3098-3100.
• [7]B. Ryu et al., "O-Vacancy as the Origin of Negative Bias Illumination Stress Instability in Amorphous In-Ga-Zn-O Thin Film Transistors," Appl. Phys. Lett., vol. 97, no. 2, 2010, pp. 022108.1-3
• [8]J.H. Shin et al., "Light Effects on the Bias Stability of Transparent ZnO Thin Film Transistors," ETRI J., vol. 31, no. 1, Feb. 2009, pp. 62-64
• [9]S.H.K. Park et al., "Transparent and Photo-Stable ZnO Thin-Film Transistors to Drive an Active Matrix Organic-Light-Emitting-Diode Display Panel," Adv. Mater., vol. 21, no. 6, 2009, pp. 678-682.
• [10]H. Oh et al., "Photon-Accelerated Negative Bias Instability Involving Subgap States Creation in Amorphous In-Ga-Zn-O Thin Film Transistor," Appl. Phys. Lett., vol. 97, no. 18, 2010, pp. 183502.1-3.
• [11]H. Oh et al., "Enhanced Bias Illumination Stability of Oxide Thin Film Transistor through Insertion of Ultrathin Positive Charge Barrier into Active Material," Appl. Phys. Lett., vol. 99, no. 2, 2011, pp. 022105.1-3.
• [12]H. Oh et al., "Transition of Dominant Instability Mechanism Depending on Negative Gate Bias under Illumination in Amorphous In-Ga-Zn-O Thin Film Transistor," Appl. Phys. Lett., vol. 98, no. 3, 2011, pp. 033504.1-3.