THERMAL SPREADING PERFORMANCE OF GaN-ON-DIAMOND SUBSTRATE HEMTS WITH LOCALIZED JOULE HEATING

Diamond is the new substrate of choice for high power/frequency AlGaN/GaN high electron mobility transistors (HEMTs). Due to its high thermal conductivity, diamond presents improvements in removing concentrated heat from the electron channel, a necessity for reliable performance of these devices. Previous thermal performance comparison studies of GaN-on-SiC and GaN-on-diamond devices are limited to devices with often large and identical heat source regions due to modeling and experimental limitations. Analytical procedure presented in this study overcome these limitations and provide a more comprehensive thermal spreading performance analysis of GaN-on-SiC and GaN-on-diamond HEMTs with localized Joule heating. Important thermal spreading factors such as thermal boundary resistance, GaN buffer layer thickness, and multifinger arrangements are also investigated in this study.