Diamond Etching

The properties of diamond are unique; it is the hardest material known, and it has a very wide optical transparency window (from 220 nm to 3120nm) allied with a high thermal conductivity (2000 Wm-1K-1), all attractive features for optical and optoelectronic structures.

Additionally, it is anticipated that diamond-based electronic devices will deliver outstanding performance due to the material’s high carrier mobility and high breakdown field. There have been recent studies of replacing certain silicon MEMS with thin diamond MEMS structures.

The hardness and chemical inertness of diamond mean that wet etching is not feasible.  The problem of diamond etching is solved in Oxford Instruments RIE or ICP systems. Here oxygen-containing plasmas provide O-radicals in conjunction with ion bombardment to break the strong carbon-carbon bonds and successfully dry etch diamond.

SEM image shows 10µm deep, anisotropic diamond etch at 500 nm/ min The Ti mask was too thin and is eroded.