AlGaN/GaN High Electron Mobility Transistors and Diodes Fabricated on Large Area Silicon on poly-SiC (SopSiC) Substrates for Lower Cost and Higher Yield

The dc and rf performance of AlGaN/GaN High Electron Mobility Transistors (HEMTs) grown by Molecular Beam Epitaxy on Si-on-poly-SiC (SopSiC) substrates is reported. The HEMT structure incorporated a 7 period GaN/AlN superlattice between the AlGaN barrier and GaN channel for improved carrier confinement. The knee voltage of devices with 2 μm gatedrain spacing was 2.12 V and increased to 3 V at 8 μm spacing. The maximum frequency of oscillation, fMAX, was ~40 GHz for devices with 0.5 μm gate length and 2 μm gate-drain spacing. Parameter extraction from the measured rf characteristics showed a maximum intrinsic transconductance of 143 mS.mm.