Ion energy distributions in a dc biased rf discharge

Abstract

We measured quasisimultaneously the energy distributions of positive ions at the powered rf and grounded electrode of a parallel plate 13.56 MHz discharge using an energy selective mass spectrometer. The resulting ion energy distributions reflect the discharge potential conditions expected from a capacitive plasma sheath model. By means of an externally supplied dc bias of the powered electrode we are able to influence the potential structure and to control ion energy and ion flux independently. The ratio between mean ion energy and mean sheath thickness reflects the effect of collisions on the ion energy distributions and enables estimates of sheath thickness and bulk plasma parameters to be made which are compared with values obtained by Langmuir probe measurements. We are able to demonstrate that changes in sheath potential also affect, via secondary electrons, the ionization regime in the discharge and this can be utilized to control the species composition in the discharge.

Ion beam sputtering of germanium – Energy and angular distribution of sputtered and scattered particles

“…For a reasonable interpretation of the ESMS signal, the transmission probability of the ESMS and the ionization probability of the sputtered particles must be taken into account. The transmission probability was simulated by Zeuner et al [24] for another ESMS that uses quite the similar ion optics. There is unfortunately no work reporting on the ionisation probability of sputtered Ge, but there are generalized considerations like in [25].…”

Reactive ionized physical vapor deposition of thin films

“…RF sheaths are typically wider than DC sheath [33] and if both the plasma ion population (X + plasma = Ar + , N 2 + , or N + ) and the populations of the 5 corresponding neutral atoms/molecules (X) are large, symmetric charge exchange reaction are likely to occur. N 2 and Ar are the background gases.…”

Spatially resolved measurements in r.f. capacitive discharges in argon and nitrogen

“…amplitude across the plasma sheath the saddle structure changes to a single peak. This is usually the case at the grounded electrode where the sheath modulation is given only by the plasma potential oscillations [2,7]. If the collisions cannot be neglected they result in widening of the IED.…”

“…The ion energy spectrometer in the center of grounded or driven electrodes is used in common set-ups [1,2]. The measurements aside from electrodes were proven for different distance from electrode edges by [3,4].…”