Characteristics of a 13.56 MHz radiofrequency-driven multicusp ion source

Abstract

The characteristics of a radiofrequency (rf)-driven multicusp ion source are investigated. The ion source is an Nd-Fe-B magnetic multicusp type operated at 13.56 MHz with an internal quartz covered antenna. The source has been diagnosed by an rf-compensated Langmuir probe for uniformity, density and electron temperature. A retarding field energy analyser, and a multi-wire beam profile monitor and quadrupole magnet system have been used for beam energy spread and emittance measurements. Experiments were performed with argon gas and rf power up to 500 W. A plasma density of up to 1.5 × 10 18 m −3 was obtained. The rms beam emittance is found to be about 32 ± 4 mm mrad, and the energy spread of the argon beam is around 3.1 ± 0.5 eV at 3 kV extraction. The rf coupling to the extracting voltage could be suppressed by a 1.2 mH rf choke, which results in the reduction of the axial energy spread in the extracted beam.

Microcrystalline Silicon Thin Films and Triple-Junction Solar Cells

“…The µc-Si:H thin films and µc-Si:H solar cells were deposited in a large-area vertical in-line VHF-PECVD system [8]. The excitation frequency of this system is 40.68 MHz, with a shower-head electrode.…”

“…The excitation frequency increase from the standard excitation frequency of 13.56 MHz up to the VHF range leads to high deposition rates for amorphous and microcrystalline silicon [6] without reducing the quality of the material [7]. The homogeneous distribution of VHF power over the substrate area is difficult due to standing and evanescent waves on the electrode surface [8]. The uniformity of the thickness and structural properties for the µc-Si:H thin films are very important to obtain high efficiency tandem solar modules.…”

Characterization of a compact filament-driven multicusp ion source for low energy time-of-flight Rutherford backscattering spectrometry application

“…This quadrupole scan method is described elsewhere. 16 Varying strengths of the quadrupole magnet cause the beam profile at the monitor to change. The beam width measured at the beam profile monitor as a function of quadrupole strength has then been used to deduce the beam parameters, including the beam emittance.…”