Breakdown characteristics of different grades of CVD diamond samples

500/spl mu/m thickness CVD diamond samples of different grades related to the sp2/sp3 phase ratio and able to be used as substrates in power electronic applications have been characterized. The following conclusions may be drawn: breakdown and resistivity values of thick CVD diamond are far from the ones claimed for thin film (/spl sim/MV/cm). and for the natural materials (/spl sim/10 MV/cm) Samples presenting the largest amount of nitrogen behave from an electrical point of view better than pure "undoped" diamond samples.