Surface morphology and electrical properties of boron-doped diamond films synthesized by microwave-assisted chemical vapor deposition using trimethylboron on diamond (100) substrate

Abstract

Prime novelty: The smoothness of the synthesized boron-doped diamond was improved by the pre-treatment of a hydrogen plasma. Moreover, the Hall mobility also increased with this pre-treatment. Surface morphology and electrical properties, such as electrical conductivity, hole concentration and Hall mobility, were investigated for boron-doped diamond films, which were synthesized by microwave-assisted chemical vapor deposition (MPCVD) on a (100) diamond substrate. Trimethylboron (TMB) was used as a dopant source and methane (CH4) was used as a carbon source. The morphology of the synthesized diamond surface depended on the MPCVD conditions such as TMB and CH4 concentrations in the gas phase, and lower concentrations of TMB and CH4 lead to a smoother surface. When the substrate was treated in a hydrogen plasma, the electrical properties of the boron-doped diamond films, as well as the smoothness of the surface, were improved. After optimizing the synthesis conditions, Hall mobility reached to 2020 cm2 V−1 s−1 at 243 K for a diamond film with a hole concentration of 5×1012 cm−3.