Dependence of mode transition points and hysteresis upon plasma pressure in a re-entrant configuration of inductively coupled plasma

Abstract

This paper reports the investigation of E ↔ H mode transition points and the width of the hysteresis in a re-entrant configuration of inductively coupled plasma. The E → H and H → E transition density and transition power were measured at various plasma pressures, and the E → H transition density is found to have little change at low pressures (ν/ω ≪ 1), but to clearly increase when the argon pressure exceeds a certain value. The E → H transition power versus the pressure shows a minimum transition power at 4 Pa (ν/ω = 1) for argon, and in addition, the reverse H → E transition density exhibits the same trend seen for the E → H transition density, though the H → E transition power shows a decrease with the pressure. In this paper, the width of the hysteresis loop is defined as the difference between the H → E transition power and the E → H transition power, so the hysteresis loop tends to be wider as the pressure increases. This work is useful to understand the E ↔ H mode transition and to control the transition points in real plasma processing.