Plasma etching of CVD diamond films using an ECR-type oxygen source

摘要

The etching characteristics of CVD (chemicalvapour deposition) diamond films processed with an ECR(electron cyclotron resonance) oxygen plasma are investigated.The etching rate increases linearly with increasing microwavepower in the range from 100 to 300 W. For any value ofmicrowave power, the etching rate first increases with increasinghas flow rate, reaches a maximum rate at a gas flow rate of 3sccm (standard cc min -1),and then decreases gradually withfurther increase in the gas flow rate. The etching rate increaseslinearly with increasing negative bias voltage in the range from 0to –600V. The etching rate for 100 and 300W of microwavepower and a negative bias of –600V is 17 and three times greater,respectively, than that for 0 V bias. The surface roughnessincreases with increasing microwave power in the range from 0to 300W. The surface roughness before etching is eight timesgreater than that obtained after plasma etching with 300W ofmicrowave power. The Raman spectrum of a CVD diamond filmafter oxygen plasma etching for 1 h shows not only a diamond(sp3 bonding)peak at 1333 cm-1, but also a broad non-diamond(sp2 bonding)peak around 1500 cm-1. However, as the etchingtime increases, the broad non-diamond peak around 1500 cm-1 disappears.