High mobility quaternary AlGaScN/GaN heterostructures grown by metalorganic chemical vapor deposition

Quaternary AlGaScN may mitigate ongoing growth challenges with metalorganic chemical vapor deposition (MOCVD)-grown AlScN, namely, compositional inhomogeneities, interface quality, and high impurity levels. However, there are very few reports on epitaxial AlGaScN with no MOCVD data. In this work, MOCVD growth experiments of AlGaScN/GaN high electron mobility transistor (HEMT) structures were performed. AlGaScN/GaN samples demonstrated abrupt interfaces and smooth surfaces. The quaternary barrier structures consistently exhibited high mobilities and low sheet resistances compared to equivalent ternary AlScN-based structures. Electron mobilities of up to 1731 cm2 V−1 s−1 were achieved at a sheet charge of 1.7 × 1013 cm−2, with a sheet resistance of 212 Ω/□. These results indicate significant potential for AlGaScN barrier HEMTs grown by MOCVD.