Development of the electron impact cross section set for CHF3. Monte Carlo simulation of the swarm experiments in pure CHF3 and CHF3/Ar mixtures

Abstract

Trifluoromethane (CHF3) is widely used in semiconductor processing. However, electron collision cross section set in CHF3 is not finally completed and verified yet. Cross section sets developed before were tested only in pure CHF3 and calculations with these sets do not describe swarm parameters in CHF3 diluted by Ar. In this work a numerical code based on the Monte Carlo method has been developed and used to calculate swarm parameters in pure CHF3 and Ar/CHF3 mixtures. Calculations in CHF3 diluted in Ar allowed us to validate the absolute value of vibration cross sections. The values and the shapes of momentum transfer, attachment and dissociation cross sections in CHF3 were renormalized on the base of the thorough analysis of all available experimental data and quantum-mechanical calculations. As a result physically well-grounded cross section set for CHF3 was developed and verified on various swarm experiments in CHF3 and CHF3/Ar mixtures.