200W discrete GaN HEMT power device in a 7×7mm CMC package

This paper presents the development of high power AlGaN/GaN HEMTs on GaN/SiC epi-materials in MACOM Technology Solutions. Instead using state-of-the art via-hole technology popular in the GaN HEMT industry to have the common-source on the device bottom, our source-contact is designed on the device top-surface for enhancing its surface thermal dissipation as well as achieving variable input and output inductance. The effects of various layout design and fabrication processes on the device performance as well as thermal resistance were studied. It showed that the gate-gate pitch was scaled up from 29 to 42 mum for optimal device performance with increasing the unit gate width from 125 to 200 mum. A similar thermal resistance of 1.38degC/W was observed for these two designs. A 25 mm total gate-periphery single chip packaged in a 7times3.5 mm CMC package showed 120 W (4.8 W/mm) P
_1dB
and 130 W (5.2 W/mm) P
_2dB
CW output at 2 GHz, 10.5 dB liner gain and 58% drain efficiency with a drain bias of 36 V. A single chip with a 7times7 mm larger package is in processing with an expected power of 200 W CW at 1.85 GHz and 14 dB liner gain.