Electrical measurements on p+-p--p+ homoepitaxial diamond capacitors

Conductance versus voltage and capacitance versus voltage (C-V) characteristics are investigated for p(+)-p(-)-p(+) capacitors over a temperature range of 40-300 K, where the p(+) layer is heavily doped homoepitaxial diamond and has impurity-band conduction and the p(-) layer is slightly doped with valence-band conduction. Above 200 K, the capacitors behave like a semiconductor-insulator-semiconductor diode with interface barrier height of about 0.07 eV. The C-V curve agrees closely with the standard theory of semiconductor-insulator-semiconductor structure and shows formation of the deletion layer at the p(+) layer on the interface. The Cole-Cole plot of conductance versus susceptance reveals that there is a virtual trap level in the p(-) layer which is located about 0.06 eV above the valence band. (C) 2000 American Institute of Physics. [S0003-6951(00)01334-6].