Comparison of GaN HEMTs on Diamond and SiC Substrates

The performance of AlGaN/GaN high-electron-mobility transistors (HEMTs) on diamond and SiC substrates is examined. We demonstrate GaN-on-diamond transistors with periphery
WG
= 250 mum, exhibiting
ft
= 27.4 GHz and yielding a power density of 2.79 W/mm at 10 GHz. Additionally, the temperature rise in similar devices on diamond and SiC substrates is reported. To the best of our knowledge, these represent the highest frequency of operation and first-reported thermal and
X
-band power measurements of GaN-on-diamond HEMTs.