Nitrogen-Polar Polarization-Doped Field-Effect Transistor Based on Al_0.8Ga_0.2N/AlN on SiC With Drain Current Over 100 mA/mm

This letter reports the demonstration of N-polar Al _0.8 Ga _0.2 N/AlN continuously-graded-channel polarization-doped field-effect transistors (PolFETs) on SiC. A PolFET with a source to drain distance of $12~\mu \text{m}$ exhibited a maximum drain current of 62.8 mA/mm and an ON/OFF current ratio of $1.1\times 10^{{4}}$ . The maximum drain current was stable between 20 °C and 250 °C operating temperatures. With the addition of 30-nm-thick Al ₂ O ₃ gate insulator the maximum drain current increased to 126 mA/mm.