AN EMISSION STUDY WITH A MODERATE POWER RADIO-FREQUENCY GRIMM-TYPE GLOW-DISCHARGE SOURCE

Characteristics of a conventional Grimm-type glow discharge source wit h a moderate power radio frequency (rf) source are investigated. The s ource is operated at argon pressures of 0.6-8 torr and powers of 10-15 0 W with a 13.56 MHz generator and an L-type matching network. The des ign and operation of the source are described and various analytical p arameters are discussed for both metallic and non-conducting samples. The dc self-bias voltage at the sample electrode shows a maximum at ab out 0.6 torr, but sputtering rate is maximized at 2 torr. Several meta l and non-conducting samples are used to determine sputtering rate, sp ectrum and shape of crater. Sputtering rates of metals are obtained in the range of 160-2300 mu g/min, while those of non-conducting materia ls are in the range of 30-100 mu g/min at an rf power of 150 W. Spectr al intensity of various samples are measured and influence of pressure and rf power is described. Analytical curves with low alloy steel sam ples are shown for several elements as an example of quantitative appl ication with the source. Except for Pyrex samples, all of the craters formed by the rf glow discharge have the same type as those obtained w ith direct current (dc) glow discharge.