N-type P-doped polycrystalline diamond

P-doped diamond grown on (110)-textured microcrystalline diamond: growth, characterization and devices

The formation and properties of (110)-textured P-doped microcrystalline CVD diamond were studied. Based on several microscopy techniques, with a special emphasis on electron backscattered diffraction, a detailed determination of the grain orientations with respect to the exact [110] axis is given. The different orientations present in the film, in combination with low phosphine concentrations in the gas phase, lead to a variation in P incorporation that can vary over three orders of magnitude, as determined with cathodoluminescence mapping. The role of the surface morphology in the observation of these large incorporation differences is explained. Hall measurements confirm that the films are n-type conductive with a thermal activation energy of 0.56 eV. Based on B-doped substrates, pn junctions were created, showing a rectification ratio of nearly 10(4) at ± 25 V.