Growth and Comparison of High-Quality MW PECVD Grown B Doped Diamond Layers on {118}, {115} and {113} Single Crystal Diamond Substrates

The use of {113} oriented single crystal diamond substrates has been reported for CVD growth of high-quality p-type layers with increased doping efficiency, compared to the {100} orientation, and excellent electrical properties. In this work we expand the range of crystal orientations to include the {118} and {115} planes and study the effect of B doping level in the gas phase with B/C ratios from 250 up to 2000 ppm. We demonstrate the growth of high-quality B doped SCD layers, with low RMS roughness (<2 nm) and high surface chemical purity (99% C with >1% B) for all orientations. Boron incorporation is shown to be dependent not only on the B/C in the gas phase, but also on the crystallographic orientation, with orientations with a higher density of {100}/{111} steps and risers exhibiting higher B incorporation into the solid from the gas phase (4 x 10(19) cm(-3) up to 1 x 10(21) cm(-3)). Finally, using electro-chemical techniques, we confirm, for the first-time, high-quality electrodes on such orientations. Novelty statement: In this work we report, for the first time, MW PECVD of high-quality boron doped diamond layers on vicinal {118} and {115} single crystal substrates, which are confirmed, via electro-chemical characterisation, to be excellent electrodes.