Gadolinium gallium oxide/gallium oxide insulators on GaAs and In0.53Ga0.47As n+ MOS capacitors: The interface state model and beyond

The electrical characteristics of n+ GaAs and In0.53Ga0.47As MOS capacitors with a dielectric stack of Ga2O3/Gd0.25Ga0.15O0.6 have been examined in detail and compared to the interface state model. The deviations from the model are assessed and the limitations of different interface state density extraction techniques are highlighted. The results of a model which accounts for many of the electrical characteristics of the InGaAs material by including states within the oxide and at the interface are reported. A hypothesis that may explain the difference between the GaAs and InGaAs characteristics and the similarities between the properties of many different oxides on InGaAs is discussed, leading to suggestions on how the oxide quality may be improved.