High-precision and high-speed etching of diamond surfaces using Fe–Ni alloy catalyzed H–O plasma etching

Power devices with low losses are essential for achieving high-efficiency, low-cost, and miniaturized inverters and advance electronic technologies. Recently, diamond-based p-type groove semiconductor field-effect transistors have emerged as a hot research topic. Conventional method of fabricating surface grooves using inductively coupled plasma etching is costly and relatively slow. Here, we realized a novel diamond machining method using Fe–Ni alloy catalyzed H–O microwave plasma etching that can achieve high-rate and high-precision etching of diamond surfaces. Two major factors affecting the etching rate and pattern accuracy, wettability of diamond and carbon solubility with liquid metal, were identified. Oxygen added in H₂ plasma allows the wetting increase, resulting in an improvement in uniformity of the etch area, while keeping the etch rate as high as 3 μm/min. The developed approached is promising for low-cost diamond patterning in electronic devices fabrication processes.