Generation-recombination noise in GaN/AlGaN heterostructure field effect transistors

Local levels with a large activation energy E/sub a//spl sim/0.8-1.0 eV have been observed in low-frequency noise measurements of GaN/AlGaN heterostructure field effect transistors (HFETs and MOS-HFETs) grown on 4N-SiC substrates. The noise might come from the thin (30 nm) AlGaN barrier layer. The estimates of the level parameters based on this assumption resulted in reasonable values of capture cross section /spl sigma//sub n//spl ap/(10/sup -12/-10/sup -13/) cm/sup 2/ and trap concentration N/sub t//spl ap/5-10/sup 16/ cm/sup -3/.