Schottky contact diameter effect on the electrical properties and interface states of Ti/Au/p-AlGaAs/GaAs/Au/Ni/Au Be-doped p-type MBE Schottky diodes

Schottky diodes based on Be-doped p-type AlGaAs were grown by molecular beam epitaxy and their current–voltage ( I – V ) and capacitance–voltage ( C – V ) characteristics measured. The Schottky and Ohmic contacts are Ti/Au and Au/Ni/Au, respectively. The effect of the Schottky contact diameter on I – V and C – V characteristics was studied. To elucidate this effect, the Schottky diode figures of merits and interface states are extracted from I – V and C – V characteristics, respectively. It was found that interface states density increases with increasing Schottky contact diameter then saturates beyond 400 µ m. The frequency dependence of the C – V characteristics was also related to these interface states. The results of this present study can help choosing the right Schottky contact dimensions.