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Boron-doped diamond exhibits a characteristic S-shaped I-V curve at room temperature [1] with two electrical conductivity states, i.e., low and high conductivity, at high electric fields (50 – 250 kVcm-1) due to the carrier freeze-out and impurity impact ionization avalanche effect. To our knowledge, the carrier multiplication during the change of the conductivity state has not been studied. In this article, we investigate theoretically the effect of acceptor concentration and compensation level on the carrier multiplication coefficient at room temperature to determine the optimal dopants concentration of maximum carrier multiplication. The room temperature hole concentration of boron-doped diamond has been calculated for various acceptor concentration and compensation ratio by solving numerically the charge neutrality equation within the Boltzmann approximation of the Fermi-Dirac statistic. These values were used to determine theoretical carrier concentration multiplication coefficients as a function of the acceptor concentration and compensation ratio. The calculated multiplication coefficient is maximum for an acceptor concentration of ca. 2 1018 cm-3 and it increases with the compensation above 0.2 %. These theoretical values are consistent with the ratio of the carrier concentration at room temperature and the acceptor concentration available in the literature as well as the current multiplication observed in boron-doped diamond due to impurity impact ionization avalanche [1].
Keywords: Boron-doped diamond, semiconductor, carrier multiplication coefficient, impurity impact ionization.© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.