GaN HEMT可靠性光学测试技术研究进展

Research Progresses on Optical Measurement Technologies of GaN HEMT Reliability

氮化镓(GaN)高电子迁移率晶体管(HEMT)具有高工作电压、大功率密度、高截止频率等特点,被广泛应用于微波射频领域。然而GaN材料内部的结构缺陷降低了GaN HEMT的可靠性,因此研究器件的结构缺陷对于提升其可靠性具有重要意义。综述了电致发光(EL)、光致发光(PL)、阴极荧光(CL)、显微拉曼光谱和红外(IR)热成像五种光学测试技术的基本原理和实验系统,以及近年来国内外利用相关光学测试技术分析GaN HEMT可靠性的研究进展。分析了五种光学测试技术的优势和局限性,与电学测试技术相比,光学测试技术可以确定缺陷的类型及空间位置。不同测试技术的相互补充将为GaN HEMT可靠性研究提供更加系统化的方案。

GaN high electron mobility transistors(HEMTs)are widely used in microwave and radio frequency fields due to their crucial properties including high operating voltage,high power density and high cut-off frequency.However,structural defects existing inside the GaN material decrease the reliability of GaN HEMTs.Therefore,it is important to study the structural defects in devices to improve the device reliability.The basic principles and experimental systems of electroluminescence(EL),photoluminescence(PL),cathodoluminescence(CL),micro-Raman spectroscopy and infrared(IR)thermography are introduced,and the recent research progresses on GaN HEMT reliability analysis using these optical measurement technologies are also reviewed.Moreover,the advantages and limitations of these optical measurement technologies are summarized.Compared with electrical measurement technologies,the optical ones can recognize types and locations of the defects.The combination of different measurement technologies will provide more systematic schemes for researches on the GaN HEMT reliability.