Electrical properties of B-related acceptor in B-doped homoepitaxial diamond layers grown by microwave plasma CVD

Abstract

Electrical properties of B-related acceptor associated with B doping have been studied by current–voltage ( I– V) measurements, frequency-dependent capacitance–voltage ( C– V) measurements, Hall effect measurements and secondary ion mass spectroscopy measurements in B-doped homoepitaxial diamond layers grown by microwave plasma CVD. Lateral dot-and-plane (with ring-shaped gap) Schottky barrier diodes using Au/Ni and Au/Pt/Ti were fabricated. These diodes have been considered to be nearly ideal Schottky junctions, in which the ideality factor n was 1.04 at 300 K. Frequency-dependent measurements on these Schottky barrier diodes have shown that capacitance is reduced at a high-frequency, most probably due to the inability of a deep center to maintain an equilibrium ionization state under a high-frequency modulation. We have shown the relation between doped B concentration, net acceptor concentration and hole concentration at 300 K. B electrical activity, which means ratio of net acceptor concentration to B concentration, was found to be almost unity in the B concentration range from 5×10 16 to 6×10 17 cm −3. It was considered that the background (or compensating) donor concentration is quite low in comparison with the net acceptor concentration in B-doped homoepitaxial diamond layer in this work.