Precursor gas composition optimisation for large area boron doped nano-crystalline diamond growth by MW-LA-PECVD

Abstract We report on the optimisation of precursor gas composition for the repeatable preparation of large area highly conductive boron doped nano-crystalline diamond layers with low sp 2 content using microwave plasma enhanced linear antenna chemical vapour deposition apparatus. The precursor gas composition parameter space was probed by varying the boron, oxygen and carbon atomic ratios whilst fixing all other parameters constant. By radically increasing the B content and careful consideration of the B and O content in the gas phase, thin B-NCD layers (∼300 nm) were prepared over large areas, repeatable, with high boron concentrations (∼2 × 10 21  at/cm 3 ) and electrical conductivity levels akin to B-NCD layers prepared in conventional MW PECVD systems (>35 S cm −1 ) with electrochemical properties suitable for industrial applications.