Channel to Channel Thermal Coupling of Double-Channel GaN-based HEMTs

A systematic thermal analysis of the channel-to-channel coupling in AlGaN/GaN double-channel HEMTs (DCHEMTs) has been conducted. Device temperature was extracted by electrical method to verify the established finite element thermal model. The impact of spacing and power distribution of the two channels on device temperature and vertical thermal distribution was revealed. The peak temperature of DC-HEMTs decreases with the increased channel spacing and the decreased power ratio, while the peak temperature nearly always appears in the 1st channel. Diamond heat spreader was applied on the device surface to cool the DC-HEMTs and a completely different thermal distribution has been observed. For different channel spacings, the device achieves the lowest peak temperature accompanied a more uniform temperature distribution across the two channels when the power ratio is 1/1. The different thermal modulation mechanisms for DC-HEMTs with and without diamond heat spreader for various spacings and power ratios have been discussed, which is of great significant for the performance optimization of double-channel devices