Numerical simulation of two-dimensional electron gas characteristics of a novel (InxAl1−xN/AlN)MQWs/GaN high electron mobility transistor

The high electron mobility transistor (HEMT) structure employing novel InxAl1−xN/AlN multiple-quantum-wells (MQWs) as barrier layer is presented. The two-dimensional electron gas (2DEG) characteristics of (InxAl1−xN/AlN)MQWs/GaN heterojunction have been investigated by solving coupled Schrödinger and Poisson equations self-consistently. The influence of AlN thickness, InxAl1−xN thickness, In content and pair number of (InxAl1−xN/AlN)MQWs on sheet carrier density is investigated. AlN thickness dependence of carriers in barrier layer to total carriers in HEMT and In0.18Al0.82N conduction band diagrams are discussed. The sheet carrier density of (In0.18Al0.82N/AlN)MQWs/GaN heterojunction is larger than that of (AlxGa1−xN/GaN)SLs/GaN heterojunction and achieves to as large as 3.59 × 1013 cm−2 with AlN thickness of 1.4 nm, barrier thickness of 15 nm and pair number of 5. The calculation shows that (In0.18Al0.82N/AlN)MQWs provide high barrier which confines the 2DEG effectively.