Study of AlGaN/GaN High-Electron-Mobility Transistors on Si Substrate with Thick Copper-Metallized Interconnects for Ka-Band Applications

Herein, the AlGaN/GaN high-electron-mobility transistors (HEMTs) on silicon substrates using thick copper-metallized interconnects with Pt diffusion barrier layer for Ka-band application are reported. High output power density of 6.6 W mm⁻¹ with power-added efficiency (PAE) of 45.6% at 28 GHz is achieved for the 4 × 50 μm device in continuous-wave (CW) mode. No obvious change in the drain–source current (I _DS) is observed for the device under 40 V high-voltage stress for 100 h and the device shows good thermal stability when annealed at 300 °C for 30 min. It demonstrates that the AlGaN/GaN HEMTs on silicon substrate with thick copper-metallized interconnects can enhance the device performance with good reliability for future 5 G applications.