Submicron-scale diamond selective-area growth by hot-filament chemical vapor deposition

•Diamond films were selectively grown with Ti/Au masks by hot-filament CVD.•Contamination from metal masks to diamond was effectively suppressed.•Submicron scale patterning with good surface morphology was realized.

Selective-area growth, which can be an alternative to ion implantation, is an important technology for processing diamond power devices. In conventional chemical vapor deposition (CVD), a portion of the metal mask (non-growing region) peels off and is unintentionally incorporated into the film; therefore, creating high-quality fine patterns is a great challenge. In this study, we developed a technique to fabricate fine structures on a submicron scale by employing hot-filament (HF) CVD. The mask pattern was kept intact during growth, and submicron-scale selective-area growth was realized. As a result, contamination-free metallic p+ diamond films possessing a smooth surface morphology were successfully selectively grown.