The effects of growth parameters on the electrical properties in InAlN/AlN/GaN high-electron-mobility transistors (HEMTs)

The electrical properties in the InAlN/AlN/GaN high electron mobility transistor grown by metal-organic vapor deposition (MOCVD) with different growth parameters were investigated in this study. We observed that two-dimensional electron gas (2DEG) channel was influenced by thickness of AlN spacer layer and a stable stage prior to the growth of AlN spacer layer. The TEM images showed the generation of dislocations at interface between AlN/GaN and InAlN/AlN with the thicker AlN spacer layer. These dislocations acted as electron scattering center and degraded the electron mobility in the 2DEG channel. Besides, a too long stable stage also appeared degradation in the electron mobility due to the etching effect of H₂ gas. By optimizing growth parameters, the highest electron mobility of 890 cm²/V.s.