Sun Yue, Kang Xuanwu, Zheng Yingkui, Wei Ke, Li Pengfei, Wang Wenbo, Liu Xinyu, Zhang Guoqi
Shenzhen Institute of Wide-bandgap Semiconductors, Shenzhen 518000, China.
Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
Nanomaterials (Basel). 2020 Apr 1;10(4):657. doi: 10.3390/nano10040657.
The optimization of mesa etch for a quasi-vertical gallium nitride (GaN) Schottky barrier diode (SBD) by inductively coupled plasma (ICP) etching was comprehensively investigated in this work, including selection of the etching mask, ICP power, radio frequency (RF) power, ratio of mixed gas, flow rate, and chamber pressure, etc. In particular, the microtrench at the bottom corner of the mesa sidewall was eliminated by a combination of ICP dry etching and tetramethylammonium hydroxide (TMAH) wet treatment. Finally, a highly anisotropic profile of the mesa sidewall was realized by using the optimized etch recipe, and a quasi-vertical GaN SBD was demonstrated, achieving a low reverse current density of 10 A/cm at -10 V.
本工作全面研究了通过电感耦合等离子体（ICP）蚀刻对准垂直氮化镓（GaN）肖特基势垒二极管（SBD）的台面蚀刻进行优化，包括蚀刻掩膜的选择、ICP功率、射频（RF）功率、混合气体比例、流速和腔室压力等。特别地，通过ICP干法蚀刻和四甲基氢氧化铵（TMAH）湿法处理相结合的方式消除了台面侧壁底角处的微沟槽。最后，通过使用优化的蚀刻工艺实现了台面侧壁的高度各向异性轮廓，并展示了一个准垂直GaN SBD，在-10 V时实现了10 μA/cm²的低反向电流密度。
