Oxide Charge Engineering of Atomic Layer Deposited AlOxNy/Al2O3 Gate Dielectrics: A Path to Enhancement Mode GaN Devices

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• 作者：M. A. Negara ; M. Kitano ; R. D. Long ; P. C. McIntyre
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 17, 2016
• 年：2016
• 卷：8
• 期：32
• 页码：21089-21094
• 全文大小：437K
• 年卷期：0
• ISSN：1944-8252

文摘

Nitrogen incorporation to produce negative fixed charge in Al₂O₃ gate insulator layers is investigated as a path to achieve enhancement mode GaN device operation. A uniform distribution of nitrogen across the resulting AlO_xN_y films is obtained using N₂ plasma enhanced atomic layer deposition (ALD). The flat band voltage (V_fb) increases to a significantly more positive value with increasing nitrogen concentration. Insertion of a 2 nm thick Al₂O₃ interlayer greatly decreases the trap density of the insulator/GaN interface, and reduces the voltage hysteresis and frequency dispersion of gate capacitance compared to single-layer AlO_xN_y gate insulators in GaN MOSCAPs.