Determination of boron in natural semiconducting diamond by prompt particle nuclear microanalysis and Schottky barrier differential-capacitance measurements

Capacitance-voltage characteristics have been obtained for Schottky barrier diodes, formed on polished surfaces of natural p-type semiconducting diamond, before and after illumination with radiation capable of neutralizing ionized donors in the depletion layer. Plots of 1/C² versus V for the two cases have yielded values for both the acceptor concentration N_A and the donor concentration N_D. Comparison of these data with those obtained from Hall effect measurements indicate that the latter overestimate the value of N_A-N_D by almost a factor of 2. The boron concentration has been determined in approximately the same surface layer as the capacitance measurements by detecting the alpha -particles emitted during irradiation with 700 keV protons using the reaction ¹¹B(p, alpha ₁)⁸Be* to 2 alpha ₂. A quantitative correlation has been obtained between the boron and acceptor concentrations.