Theoretical models for doping diamond for semiconductor applications

Diamond is a material with superlative properties in terms of carrier mobilities and device characteristics for high power electronics applications. Although p-type diamond is routinely available using boron, n-type material via impurity doping during the growth of diamond has historically been limited in success, partly because nitrogen is a hyper-deep donor, but compounded by the compact lattice leading to low solubilities for alternative species. Implantation doping is often hampered by persistent residual damage leading to significant levels of compensation and the formation of dopant complexes with lattice vacancies. Experiment has been augmented by the application of quantum-chemical methods to assess the likely properties should specific impurities or impurity complexes be realisable in real materials. The review outlines many of the doping strategies explored for diamond, including simple impurity doping and co-doping.