摘要
采用拉曼热测量技术结合有限元热仿真模型,分析比较新型铜/石墨复合物法兰封装与传统铜钼法兰封装的GaN器件的结温与热阻,发现前者的整体热阻比铜钼法兰器件的整体热阻低18.7%,器件内部各层材料的温度分布显示铜/石墨复合物法兰在器件中的热阻占比相比铜钼法兰在器件中的热阻占比低13%,这证明使用高热导率铜/石墨复合物法兰封装提高GaN器件热扩散性能的有效性.通过对两种GaN器件热阻占比的测量与分析,发现除了封装法兰以外,热阻占比最高的是GaN外延与衬底材料之间的界面热阻,降低界面热阻是进一步提高器件热性能的关键.同时,详细阐述了使用拉曼光热技术测量GaN器件结温和热阻的原理和过程,展示了拉曼光热技术作为一种GaN器件热特性表征方法的有效性.
The electrical performance and the long-term reliability of GaN-based high electron mobility transistors(HEMTs) are greatly affected by the Joule self-heating effect under high power density operation condition.Measurement of the junction temperature and analysis of the thermal resistance of the constituent layers including the packaging material are critically important for thermal design and reliability assessment of GaNbased HEMTs. In this paper, Raman thermometry combined with the finite element thermal simulation is used to compare the junction temperature and the thermal resistance of a GaN HEMT mounted on a novel Cu/graphite composite flange with those of a conventional Cu Mo flanged device. The results show that the junction temperature of the Cu/graphite flanged device is 15% lower than that of the Cu Mo flanged device at a power dissipation of 1.43 W/mm, while the overall device thermal resistance is 18.7% lower in the Cu/graphite flanged device. In addition, the temperature distributions of each layer along the cross-plane direction are analyzed for the two devices;the thermal resistance ratio of the Cu/graphite flange is 40% of the overall device thermal resistance, while the Cu Mo flange account for 53% of the overall thermal resistance of the device. This proves the effectiveness and benefit of using the Cu/graphite composite material package of high thermal conductivity to improve the heat dissipation of GaN HEMTs. By tuning the mass fraction of the graphite, it is possible to further increase the thermal conductivity of the Cu/graphite composite flange and to further reduce the device thermal resistance. It is observed in the Raman thermal measurement that the highest thermal resistance after flanging is the interfacial thermal resistance between the GaN epitaxial layer and the Si C substrate(~50 m2·K/GW). For obtaining the better thermal characteristics of the GaN HEMT, it is crucial to reduce the GaN/Si C interfacial thermal resistance through interface engineering during the epitaxial growth.
作者
刘康
孙华锐
Liu Kang;Sun Hua-Rui(School of Science,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China;Key Laboratory of Micro-Nano Optoelectronic Information System of Ministry of Industry and Information Technology,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第2期284-291,共8页
Acta Physica Sinica
基金
国家自然科学基金青年科学基金(批准号:61604049)
深圳市海外高层次人才技术创新项目(批准号:KQJSCX20170726104440871)
深圳市引进人才启动经费资助的课题~~
关键词
GAN高电子迁移率晶体管
热阻
铜/石墨法兰
拉曼热测量
GaN high electron mobility transistor
thermal resistance
Cu/graphite flange
Raman thermometry
