Control of Fluorocarbon Radicals by On-Off Modulated Electron Cyclotron Resonance Plasma

Abstract
The CF, CF2 and CF3 radical densities were investigated using infrared diode laser absorption spectroscopy (IRLAS) in a CHF3 electron cyclotron resonance (ECR) plasma with varying on-off period of the microwave source, as well as continuous wave (CW). The ratio of CF and CF2 radical densities to CF3 radical density was successfully controlled through variation of the duty cycle in a constant pulse width, together with the deposition rate of fluorocarbon films. Furthermore, the radical densities were discussed in comparison with intensities of emission lines F*, Ar* and Hα.