Influence of AlN interfacial layer on electrical properties of high-Al-content Al_(0.45)Ga_(0.55)N/GaN HEMT structure

摘要

Unintentionally doped high-Al-content Al_(0.45)Ga_(0.55)N/GaN high electron mobility transistor (HEMT) structures with and without AlN interfacial layer were grown by metal-organic chemical vapor deposition (MOCVD) on two-inch sapphire substrates. The effects of AlN interfacial layer on the electrical properties were investigated. At 300 K, high two-dimensional electron gas (2DEG) density of 1.66 x 10~(13) cm~(-2) and high electron mobility of 1346 cm~2 V~(-1) s~(-1) were obtained for the high Al content HEMT structure with a 1 nm AlN interfacial layer, consistent with the low average sheet resistance of 287 Ω/sq. The comparison of HEMT wafers with and without AlN interfacial layer shows that high Al content AlGaN/AlN/GaN heterostructures are potential in improving the electrical properties of HEMT structures and the device performances.