Multilayer AlN/AlGaN/GaN/AlGaN heterostructures with quantum wells for high-power field-effect transistors grown by ammonia MBE

High-power field-effect transistors (FETs) are among the main applications of heterostructures based on group III metal nitrides, which in most cases implement the classical GaN/AlGaN structure with a single junction. An alternative approach based on the use of double heterostructures with imporved two-dimensional electron gas (2DEG) confinement offers a number of advantages, but such structures are usually characterized by a lower carrier mobility and density (in GaN layers of reduced thickness) as compared to the values in the single-junction structures. Optimization of the heterostructure design and ammonia MBE growth conditions allowed us to obtain multilayer AlN/AlGaN/GaN/AlGaN heterostructures with quantum wells, which are characterized by a 2DEG carrier mobility of 1100-1300 cm(2)/(V s) and a sheet electron density of (1.1-1.3) x 10(13) cm(-2). Experimental FETs based on the obtained multilayer heterostructures in a static regime exhibit working current densities up to 0.6 A/mm at a transconductance of up to 150 mS/mm and a breakdown voltage above 100 V.