Abstract

Single and polycrystal diamond thin films were etched in a 2.45 GHz microwave plasma system under electron cyclotron resonance (ECR) conditions, in pure oxygen plasma. A very intense (high mode) plasma was observed when the critical ECR field (875 Gauss) was at the microwave window and the magnetic field gradient was increasing away from the window. Because of the flexibility of moving magnetic coils along the length of the chamber, it was possible to establish high mode plasma conditions. Langmuir probe measurements of this high mode plasma showed that the ion current density was more than four times that of the normal mode. Under high mode plasma conditions, reproducible high diamond etching rates were achieved, up to 300 nm/min, for microwave power of 300 Watts and pressures of 3 mTorr of pure oxygen. SEM observations of etched samples revealed smooth surfaces with high uniformity.