Analyses of hetero-interface trapping properties in AlGaN/GaN high electron mobility transistor heterostructures grown on silicon with thick buffer layers

We report on the analyses of trapping properties of metal-organic chemical vapor deposition grown AlGaN/GaN high-electron-mobility transistor (HEMT) heterostructures on silicon with increasing buffer thickness (T-buff). An exact exponential dependence of AlGaN/GaN hetero-interface trap time constants with gate bias was observed in the vicinity of threshold voltage. A low hetero-interface state density (D-it) value of similar to 2.5 x 10(10) cm(-2) eV(-1) was achieved for heterostructures grown by using thick T-buff similar to 5 mu m against a D-it value of similar to 1 x 10(11) cm(-2) eV(-1) for a similar heterostructures grown with thin T-buff similar to 1.25 mu m. Further, the high resolution x-ray rocking curve and Van der Pauw-Hall measurements also confirmed that increasing the T-buff improves the AlGaN/GaN HEMT heterostructures with reduced edge dislocation densities and enhanced carrier transport properties. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4733359]