Characterization of pulse-modulated inductively coupled discharges in argon and chlorine

Summary form only given. The characteristics of pulse modulated inductively coupled plasmas in argon and chlorine have been experimentally investigated. Measurements were performed for peak rf powers between 150 and 400 W, duty cycles between 10 and 90%, pulse repetition frequencies between 3 and 20 kHz, and argon or chlorine gas. Over this parameter space, measurements were performed of the forward and reflected rf power into the matching network, coil voltage, rf variation of the plasma potential using a capacitive probe, electron density using a microwave interferometer, and Cl density using laser photodetachment spectroscopy. These measurements indicate that for the firs 50-100 rf cycles of each rf pulse, the discharge may be operating in a capacitive discharge mode with rf variations in the plasma potential of several hundreds of volts and relatively low electron density. Measurements of the electron density in pulse modulated chlorine discharges indicate that the steady state electron density is a function of the duty cycle; the steady state electron density is lower for higher duty cycles.