Plasma etching and patterning of CVD diamond at <100°C for microelectronics applications

Abstract Oxidation resistance of diamond is an important characteristic to be considered in high-temperature microelectronics and other applications. We have tested the stability of CVD diamond by exposing it to Ground State Atomic Oxygen (GSAO, O) at a temperature of 74°C. Polycrystalline diamond is quite stable at this temperature using O. We have also tested the stability of diamond using Excited State Atomic Oxygen (ESAO, O*). Initially, CVD diamond was exposed to O* for 15 min at 63°C, and diamond etching was observed. We have also carried out the experiments at different time intervals such as 30 and 45 min. The etching rate of the polycrystalline diamond using O* is ≈ 0.2–0.25 m/min at 63°C. We have successfully patterned the diamond (polycrystalline and single crystal) using a Ni mask by exposing the sample to O* for a longer time. O* etched the diamond uniformly in all the directions of the diamond crystal as opposed to the molecular oxygen. Stability of the single crystal diamond has been tested using O* by using Ni mask material. We were able to etch the single crystal diamond (type IIa, 100 orientation) quite uniformly. The etching rate of single crystal diamond using O* was observed to be 0.3 m/min.