A review of β-Ga_2O_3 single crystal defects, their effects on device performance and their formation mechanism  

作　　者：Bo Fu Zhitai Jia Wenxiang Mu Yanru Yin Jian Zhang Xutang Tao 

机构地区：[1]State Key Laboratory of Crystal Materials & Key Laboratory of Functional Crystal Materials and Device, Shandong University

出　　处：《Journal of Semiconductors》2019年第1期45-55,共11页半导体学报（英文版）

基　　金：the Financial support from the National key Research and Development Program of China(Nso.2018YFB0406502,2016YFB1102201);the National Natural Science Foundation of China(Grant No.51321091);the key Research and Development Program of Shandong Province(No.2018CXGC0410);the Young Scholars Program of Shandong University(No.2015WLJH36);the 111 Project 2.0(No.BP2018013)

摘　　要：As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.

关 键 词：β-Ga2O3 CRYSTAL DEFECTS device performance FORMATION mechanism 

分 类 号：TN303[电子电信—物理电子学]