Enhancing electrical properties of LiNbO3/AlGaN/GaN transistors by using ZnO buffers

• Published in: Journal of applied physics 2013-07, Vol.114 (2)
• Main Authors: Hao, Lanzhong, Li, Yanrong, Zhu, Jun, Wu, Zhipeng, Deng, Jie, Zeng, Huizhong, Zhang, Jihua, Liu, Xingzhao, Zhang, Wanli
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4811820

LiNbO3 (LN) ferroelectric films were deposited on the ZnO buffered AlGaN/GaN templates by pulse laser deposition technique. The microstructures of the buffer layers and LN films were characterized by reflective high energy electron diffraction, atomic force microscope, and X-ray diffraction, respectively. With the help of Cu/Si3N4 double-layer masks, LN/ZnO/AlGaN/GaN transistors were fabricated and the electrical properties were studied. Normally off characteristics were exhibited for the fabricated transistors with LN gate layers. Due to the modifications of the 5-nm-thick ZnO layer to the interface, the electrical properties of the transistor were enhanced greatly. The maximum transconductance increased from 27 to 46 mS/mm, and the maximum drain current increased from 97 to 204 mA/mm. The operation mechanisms of the devices were proposed by the numerical calculations of the electronic band structure and charge distribution.