Electrical Properties of Diamond Platinum Vertical Schottky Barrier Diodes

Electrical and photoelectrical properties of Pt vertical Schottky barrier diodes prepared on thick lightly-doped CVD diamond grown on heavily-doped IIb HPHT substrates were studied. The films were p-type, with the concentration of residual boron acceptors in the mid-1014 cm-3. The Schottky barrier heights determination from photocurrent spectra measurements revealed the presence of two barrier values of 1.45 eV and 2 eV. The former dominated the temperature dependence of the forward current, the latter determined the voltage cut-off in C-V measurements. The results are explained by difference in oxygen termination conditions. The higher barrier is attributed to oxygen-related states at the terminated surface, the lower barrier is associated with native defects.