STUDIES ON CHEMICAL SPUTTERING OF SILICON AND CARBON IN AR-H-2 GLOW-DISCHARGE PLASMA BY OPTICAL-EMISSION SPECTROSCOPY

The chemical sputtering of silicon and carbon by a glow discharge plasma with Ar-H-2 gas mixtures was investigated by optical emission spectroscopy. The sputtering rates increased with both increasing hydrogen concentration and increasing operating power. The emission intensity of silicon atoms increased drastically with increasing hydrogen concentration up to 13% in the case of a silicon cathode while in the case of a carbon cathode the emission intensities of CH, C2 and carbon decreased in the H-2 concentration range above about 2% with an operating current of 35 mA. This is probably caused by the quenching of metastable argon atoms due to CH4 molecules produced in the process of the chemical sputtering of carbon. A series of plots of the emission intensity ratios Si I(288.2 nm):Ar I(750.4 nm) and CH(431.4 nm):Ar I(750.4 nm) against the sputtering rate can be represented by one curved line; as a result, the estimation of the chemical sputtering rates of silicon and carbon is possible by monitoring emission intensities.