Heterogeneously-Integrated Gallium Nitride and Indium Phosphide Devices for Ka-Band Amplifiers

Heterogeneously-integrated millimeter-wave (mm-wave) amplifiers are fabricated on a common silicon interposer using two compound semiconductor device technologies, demonstrating the potential for high-frequency RFICs consisting of multiple device technologies. An Indium Phosphide (InP) heterojunction bipolar transistor (HBT) and Gallium Nitride (GaN) High-Electron-Mobility Transistor (HEMT) are integrated into a high-resistivity silicon substrate with a 4-metal back-end-of-the-line (BEOL) to support high-quality factor (Q) passives for matching networks. The 21–32 GHz InP amplifier offers more than 10 dB gain and 22.5 dBm saturated output power (Psat). The 26–31 GHz GaN amplifier offers more than 6 dB gain and has an output power exceeding 25 dBm. Both circuits are extremely compact, occupying an area of less than 1.0 mm-sq with pads.