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 (P
sat
). 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.