Reactive ion etching of CVD diamond thin films in O2/CF4 plasma

Reactive ion etching of chemical vapor deposition (CVD) diamond thin films was investigated in O2 gas plasma mixed with CF4 and electrodes distance. The optical emission spectrum of plasma species in excited electronic states was measured in order to know the information of relationship between etching rate of diamond and the concentrations of key reactive species. The RF power (13.56 MHz) was fixed at a constant 100 W. The large etching rate was obtained by using O2/20% CF4 at electrodes distance of 1.5 cm, O2 flow rate of 20 sccm and total pressure of 20 Pa. Etched diamond surface was observed SEM micrographs. The diamond surface in O2/20% CF4 plasma was smoother as compared with one in pure O2 plasma. The emission intensity of O had a peak around O2/20% CF4. The results of etching rate and emission intensity agree well with each other.