Investigation on microwave plasma diamond etching

This paper reports a Lambda Technologies, 2.45 GHz, 1.5 kW, microwave plasma-assisted etching reactor utilized to develop anisotropic and high rate etching processes on a variety of diamond substrates including polycrystalline, nanocrystalline and single substrates. This etching system consists of a 25 cm diameter discharge located inside a 30 cm microwave resonant cavity applicator. The plasma etcher also incorporates a rf bias for the substrate that operates at 13.56 MHz with induced dc bias up to 250 V.m The electron temperature T_e, charge density n_e and electron energy distribution function (EEDF) are measured using a single Langmuir probe (SLP). Direct comparisons are made at selected pressures for the reactor operating with and without electron cyclotron resonance (ECR) magnets.