Investigation of interface traps in β-(AlGa)2O3/Ga2O3 heterostructures by dynamic capacitance dispersion technique

In this work, interface traps in β-(AlGa)2O3/Ga2O3 modulation-doped field effect transistor (MODFET) were investigated qualitatively and quantitatively by means of dynamic capacitance dispersion technique. The fabricated β-(AlGa)2O3/Ga2O3 MODFET showed drain current modulation demonstrating the transistor behavior. The existence of two-dimensional electron gas was confirmed by the plateau region in the capacitance–voltage (C–V) characteristics. The difference in capacitance profile dispersion at multifrequency C–V measurement suggested the loss mechanism due to trapping and de-trapping effects of carriers. An interface analysis of β-(AlGa)2O3/Ga2O3 heterostructures estimated the interface states with density of trap states and time constants of 0.56×1012–5.92×1012 cm−2 eV−1 and 59–27 μs, respectively.