Experimental investigation on collisionless heating in a finite size inductively coupled plasma

The electron energy probability functions (EEPFs) were measured in low pressure and planar-type inductively coupled plasma at various chamber heights. The plateau on the EEPFs was observed and the corresponding energy region was shifted to higher energy region with increasing chamber height. Since the electron mean free path is larger than the discharge gap length, the plateau shifting could be understood by an effect of collisionless electron heating. From calculated energy diffusion coefficient, a possible heating mechanism is the electron bounce resonance.