Electrical characterization of phosphorus-doped n-type homoepitaxial diamond layers by Schottky barrier diodes

Temperature-dependent current–voltage (I–V), capacitance–voltage (C–V) measurements, and frequency-dependent C–V measurements have been carried out to investigate electrical properties of phosphorus (P)-doped n-type homoepitaxial diamond layers. We have fabricated lateral dot-and-plane (with ring-shaped-gap) Schottky barrier diodes. Frequency-dependent capacitance measurements revealed the existence of a deep donor level. C–V measurements deduced that the net donor concentration was 6.2×1017 cm−3 and the corresponding built-in potential was 4.0 eV, when the P concentration was 8.3×1017 cm−3. Phosphorus electrical activity was 0.75 in the P-doped diamond layer. The carrier thermal activation energy (the donor level) was evaluated to be 0.6 eV from the relation between the net donor concentration and the carrier concentration.