Spatiotemporal evolution of electron energy distribution and plasma parameters in short-pulse magnetron discharges

Abstract

Summary form only given. Spatiotemporal evolution of electron energy distribution function (EEDF) and plasma parameters such as electron density, electron temperature, and plasma and floating potentials has been investigated using spatially and temporally resolved single Langmuir probe measurements in DC and mid-frequency, short-pulse magnetron discharges with a repetition frequency of 10 kHz and duty cycle of 10%. With the pulsed discharge of short duty cycle, we could obtain a peak electron temperature more than 10 eV during the early phase of the pulse-on near the cathode fall region, which is about 3 times higher than the steady state value of electron temperature in DC discharge. The temporal evolution of the measured EEDFs shows the initial efficient electron heating during the early phase of the pulse-on and the subsequent relaxation of electron energy by inelastic collisions and diffusive loss. High-energy electrons generated during the pulse-on phase diffuse the downstream region toward the grounded substrate, resulting in a bi-Maxwellian EEDF composed of background low-energy electrons and high-energy electrons. The results of spatially and temporally resolved probe measurements are presented and the enhanced efficiency of electron heating in the short-pulse discharge is explained on the basis of the global model of pulsed discharge