First multicharged ion irradiation results from the CUEBIT facility at Clemson University

Abstract

A new electron beam ion trap (EBIT) based ion source and beamline were recently commissioned at Clemson University to produce decelerated beams of multi-to highly-charged ions for surface and materials physics research. This user facility is the first installation of a DREEBIT-designed superconducting trap and ion source (EBIS-SC) in the U.S. and includes custom-designed target preparation and irradiation setups. An overview of the source, beamline, and other facilities as well as results from first measurements on irradiated targets are discussed here. Results include extracted charge state distributions and first data on a series of irradiated metal-oxide-semiconductor (MOS) device targets. For the MOS devices, we show that voltage-dependent capacitance can serve as a record of the electronic component of ion stopping power for an irradiated, encapsulated oxide target.

A gas cell apparatus for measuring charge exchange cross sections with multicharged ions

“…The Clemson University Electron Beam Ion Trap (CUEBIT) facility has recently gone online. 21 To benchmark a new gas cell for multicharged ion experiments, we use a singly charged ion source and measure the charge exchange cross section for Ar + + Ar → Ar + Ar + for ion energies of 1-5 keV, which has a cross section (≈10 −15 cm 2 ) similar to what is found in MCI-neutral charge exchange. 11 The gas cell presented in this paper has been designed to attach to the CUEBIT and will be implemented into an experimental program to systematically explore and understand charge exchange with MCIs.…”

Tracking subsurface ion radiation damage with metal–oxide–semiconductor device encapsulation

“…To quantify these curve shifts, the flatband voltage (V FB ) was determined for each sample, where V FB was calculated based on the average doping concentration of the underlying Si substrate (5 Â 10 16 cm À3 ) as described in Ref. 26. The difference in flatband voltages (DV FB ) taken relative to a pristine (unirradiated) device/sample region was tracked for different samples across dose and charge states explored in these measurements.…”

“…25. For these irradiations, the SiO 2 targets were exposed to the focused beams of Ar Q1 with charge states of Q 5 1, 4, 8, and 11.…”

Effects of slow highly charged ion irradiation on metal oxide semiconductor capacitors

“…The highly charged ion irradiation was performed with the Clemson University Electron Beam Ion Trap (CUEBIT). The CUEBIT setup and basic operation have been reported in detail elsewhere, 23 and some previous results with electronic devices irradiated with the CUEBIT have also been reported. 24,25 The 12 mm × 12 mm Si/SiO 2 samples were mounted on a stainless steel platen and loaded into the CUEBIT target chamber.…”