材料科学
光电子学
原子层沉积
高-κ电介质
电介质
栅极电介质
高电子迁移率晶体管
宽禁带半导体
氧化物
无定形固体
氮化镓
晶体管
纳米技术
图层(电子)
电压
电气工程
化学
有机化学
工程类
冶金
作者
Wei‐Chih Cheng,Jiaqi He,Minghao He,Zepeng Qiao,Yang Jiang,Fangzhou Du,Xiang Wang,Haimin Hong,Qing Wang,Hongyu Yu
摘要
The high-k nature of HfO2 makes it a competitive gate oxide for various GaN-based power devices, but the high trap densities at the HfO2/GaN interface have hindered the application. This work was specifically carried out to explore the interface between GaN and ozone-based atomic-layer-deposited HfO2 gate oxide. Furthermore, the GaN surface is preoxidized before gate oxide deposition to prepare an oxygen-rich HfO2/GaN interface. On the preoxidized GaN surface, a sharper HfO2/GaN interface and amorphous HfO2 bulk form during the subsequent deposition, translating to improved electric performance in metal–insulator–semiconductor (MIS) devices. The ozone-based HfO2 shows a high breakdown electric field (∼7 MV/cm) and a high dielectric constant (∼28). Furthermore, the MIS high electron mobility transistors' negligible VTH hysteresis and parallel conductance measurements reflect the ultralow trap densities of the HfO2/GaN interface (<1012 cm−2 eV−1). Therefore, the proposed HfO2 gate oxide scheme offers a promising solution for developing GaN MIS devices.
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