Properties of diffused diamond films with n-type conductivity

Abstract High quality, freestanding “white” CVD diamond films, 230 μm thick, polished on both sides and with resistivity 10 14 Ω cm were used for diffusion of impurities to obtain n-type conductivity. Diffusion of lithium, oxygen and chlorine was performed under a bias. Auger analysis was used to determine the impurity concentrations. After diffusion, the concentrations of Li, O and Cl in the diamond films were found to be about (3–4) × 10 19 cm −3 . Raman scattering, cathodoluminescence, microwave photoconductivity, electron spin resonance, optical absorption, Hall effect and electrical conductivity measurements were employed for the film characterization. The measurements showed that the initial high structural quality of the film was not deteriorated after diffusion. The hall effect measurements showed n-type conductivity. The sheet resistance of the diffused layer was 10 5 Ω/□. The carrier mobility was estimated to be about 50 cm 2 V −1 s −1 .