A set of multisectoral boron-doped diamond plates cut from a 10-ct high pressure high temperature single crystal was thoroughly studied. The plates' morphologies were examined by atomic-force microscopy, it showed the average roughness of 5-10 nm. For electrical measurements, ohmic and rectifying platinum contacts were deposited by magnetron sputtering. Schottky diodes arrays were investigated by admittance spectroscopy; current-voltage (I-V) and capacitance-voltage (C-V) characteristics were obtained and analysed. Frequency dispersion of C-V characteristics was registered. Blue (111) and white (100) faces of samples showed a drastic difference in I-V and C-V behaviour. Mathematical processing of the obtained data was performed and the depth distributions of apparent charge carriers were obtained for all diodes. The registered concentration for the white sector is in the range (1-3)•10 17 cm −3 , and for the blue sector it is one order more. Charge carrier distribution over the sample surface was obtained and it showed a fine correlation with sectors' colour and growth direction with appropriate discussion.

To improve the performance characteristics of power and high-frequency electronics, wide bandgap semiconductors are now widely used. This paper presents consideration of features arising during exploration of electronic characteristics of wide bandgap materials. We use the admittance spectroscopy method for analyzing free carrier concentration and boron-impurity activation energy in semiconductor diamond. The special aspect that should be taken into account while studying wide bandgap materials is incomplete ionization of impurity. In this work we adjust the experimental conditions, basing on the previous experience, in particular reduce signal/noise ratio and reckon with heat capacity of the samples and substrate. As a result we obtained high quality conductance spectra and activation energy of boron impurity in low-doped diamond.

A single-crystal diamond doped with boron was studied in this work. For electrical measurements an array of Schottky contacts and a large Ohmic contact were fabricated. The capacitance-voltage (C-V) characteristics of the sample were obtained experimentally in wide temperature range and modeled. At high temperature (445 K) the slope of the C-V characteristics does not depend on the test signal frequency. The calculated concentration of free charge carriers is the same for all frequencies within the experimental error and approximately corresponds to the total boron concentration. At low temperatures (235 K), there is a significant difference in capacitances measured at different frequencies, the calculated concentration varies from 5·1017 cm-3 to 5·1015 cm-3 in the available frequency range. The reasons for the frequency dispersion of capacitance-voltage characteristics of boron-doped diamond diodes are discussed.