Backside Process Considerations for Fabricating Millimeter-Wave
GaN HEMT MMICs
Keywords: Backside process, Via-hole, GaN HEMT, Millimeter-wave, MMIC
We describe a backside process for fabricating millimeter-wave GaN HEMT MMICs having a 0.1-_m length gate covered with a very thin SiN passivation layer, a thin epitaxial layer and airbridges. In particular, we discuss backside process issues regarding thin wafer support, SiC via-hole etching and wafer dicing. Finally, we demonstrate a W-band GaN low-noise amplifier with a record gain of 23 dB at 76.5 GHz and a noise figure of 3.8 dB at 80 GHz.