Rational Hydrogenation for Enhanced Mobility and High Reliability on ZnO-based Thin Film Transistors: From Simulation to Experiment

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• 作者：Lei Xu ; Qian Chen ; Lei Liao ; Xingqiang Liu ; Ting-Chang Chang ; Kuan-Chang Chang ; Tsung-Ming Tsai ; Changzhong Jiang ; Jinlan Wang ; Jinchai Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 2, 2016
• 年：2016
• 卷：8
• 期：8
• 页码：5408-5415
• 全文大小：503K
• ISSN：1944-8252

文摘

Hydrogenation is one of the effective methods for improving the performance of ZnO thin film transistors (TFTs), which originate from the fact that hydrogen (H) acts as a defect passivator and a shallow n-type dopant in ZnO materials. However, passivation accompanied by an excessive H doping of the channel region of a ZnO TFT is undesirable because high carrier density leads to negative threshold voltages. Herein, we report that Mg/H codoping could overcome the trade-off between performance and reliability in the ZnO TFTs. The theoretical calculation suggests that the incorporation of Mg in hydrogenated ZnO decrease the formation energy of interstitial H and increase formation energy of O-vacancy (V_O). The experimental results demonstrate that the existence of the diluted Mg in hydrogenated ZnO TFTs could be sufficient to boost up mobility from 10 to 32.2 cm²/(V s) at a low carrier density (∼2.0 × 10¹⁸ cm^–3), which can be attributed to the decreased electron effective mass by surface band bending. The all results verified that the Mg/H codoping can significantly passivate the V_O to improve device reliability and enhance mobility. Thus, this finding clearly points the way to realize high-performance metal oxide TFTs for low-cost, large-volume, flexible electronics.