Device characteristics of AlGaN/GaN MIS–HEMTs with high-k HfxZr1−xO2 (x = 0.66, 0.47, 0.15) insulator layer

• We studied the AlGaN/GaN MIS–HEMTs with HfxZr1−xO2 high-k films as gate dielectrics.
• Sputtered high-k HfxZr1−xO2 with a bandgap of 5.2–5.71 eV was produced.
• By increasing the Zr content of HfZrO, the VTH shifted from −1.8 V to −1.1 V.
• The highest Hf content of HfxZr1−xO2 reduced the gate leakage current.

This study investigates the characteristics of AlGaN/GaN MIS–HEMTs with HfxZr1−xO2 (x = 0.66, 0.47, and 0.15) high-k films as gate dielectrics. Sputtered HfxZr1−xO2 with a dielectric constant of 20–30 and a bandgap of 5.2–5.71 eV was produced. By increasing the Zr content of HfZrO2, the VTH shifted from −1.8 V to −1.1 V. The highest Hf content at this study reduced the gate leakage by approximately one order of magnitude below that of those Zr-dominated HFETs. The maximum IDS currents were 474 mA/mm, 542 mA/mm, and 330 mA/mm for Hf content of 66%, 47%, 15% at VGS = 3 V, respectively.