Effect of temperature on the performance of ScAlN/GaN high-electron mobility transistor

We have studied the operation of the ScAlN/GaN high-electron mobility transistor (HEMT) at high temperatures up to 700 K (423 °C). A maximum drain current density of ∼2 A/mm and an on-resistance of ∼1.5 Ω·mm was measured at room temperature (RT). The epi-structure exhibited a very high two-dimensional electron gas (2DEG) density of 6 × 1013 cm−2 at RT using Hall measurement. The Sc0.15Al0.85N barrier, nearly lattice matched to the GaN channel, showed a drain current reduction of ∼50% at 700 K. The decrease in 2DEG mobility, which leads to an increase in sheet resistance, is mostly responsible for this reduction in drain current. However, an excellent electrostatic control was achieved at 700 K with the drain current value exceeding 1 A/mm, which is 2 times higher compared to that of AlGaN/GaN HEMTs reported previously. These results indicate that ScAlN/GaN HEMTs are a promising candidate for high-temperature and high-power electronic applications.