Interface properties of anodically oxidized GaAs MIS capacitors

The interface properties Of anodically oxidized GaAs MIS capacitors have been investigated by means of a computer controlled measuring set-up. DLTS, C(t) and C(U) measurements have been performed, The measurement of CLF anil CHF at the same bond-bending allows a reliable determination of the interface state density. The distribution of interface states shows a minimum which can occur at different energies in the band gap. Additionally, from CHF (U) the interface charge has been calculated which allowed a distinction between donor and acceptor typo interface states. The results of DLTS and (C(t) measurements are influenced by the width of the filling pulses. This effect is interpreted an n carrier drift into the insulating layer.