Metal and organic contamination effects on the characteristics of thin oxides thermally grown on silicon based wafers

Borionetti, G.; Geranzani, P.; Orizio, R.; Godio, P.; Bonoli, F.; Pagani, Francesco; Pello, C.

doi:10.1016/j.nimb.2006.10.060

Cited by 2 publications

(1 citation statement)

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“…Conversion rates of 1%-5% have been reported for a He + energy range of 3 keV to 25 keV [2][3][4][5][6]. However, metals are contaminants in semiconductor fabrication [7] influencing transistor threshold voltages [8]. Residual alkali metal vapour can also deposit on the interior of vacuum chambers, is hazardous to maintain, and if near electrostatic devices, can lead to increased rates of unwanted discharge.…”

Section: Introductionmentioning

confidence: 99%

Development of a negative helium ion source with non-metallic charge exchange

Jackle,

Bunevich,

Silva Lopez

et al. 2024

J. Inst.

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Negative helium ion (He−) beams are required for tandem accelerators used at research centers and implanter facilities. The common production method of such beams involves charge exchange between a positive helium ion (He+) source or beam, with a low pressure alkali metal vapour. However, the efficiency of this reaction is poor (only a small percentage) and the alkali metal vapour increases the potential flammability of the interior surfaces of the reaction chamber, as well as contributing to unwanted electrostatic discharge and target contamination downstream. In this paper we describe initial results from experiments using a focused He+ ion microscope (HIM) to measure charge uptake efficiencies after transmission through carbon membranes. The He+ beam (15 keV to 30 keV, 50 fA to 10 pA) collides with a non-metallic foil, and transmitted particles (He+, He0, and He−) are separated electrostatically into discrete beam spots and detected using a radiation camera (AdvaCam MiniPIX). A He− percentage uptake of 0.05 was observed using a 20 nm exfoliated graphite membrane consistent with previous reports. Future work will investigate the efficiency of charge exchange through other suitable membrane materials.

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