Electrical characterization of homoepitaxial diamond p–n junction

Electrical properties of homoepitaxial diamond p–n⁺ junction of boron (B)-doped p-type layer and phosphorus-doped n-type layer on Ib (111) diamond single crystal have been characterized. Current–voltage characteristics show a clear rectifying property with rectification ratio of over 10⁵ at ± 10 V. From capacitance–voltage characteristics, it is found that a spatial distribution of space-charge density N_i of the p–n⁺ junction is not uniform and N_i at a middle region of the space-charge layer formed at zero bias voltage is higher than that of other region of the space-charge layer. This peculiar characteristic can be explained by superposition of two effects; one is the deep dopant effect due to B atoms in the p-type layer, which makes to reduce N_i at around the edge of the space-charge layer formed at zero bias voltage. The other is the compensation of B acceptors by impurity atoms diffusing during the p–n⁺ interface and incorporating during the growth of p-type layer, which makes to reduce N_i at the vicinity of the p–n⁺ interface.