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Sputter etching is a technique widely used by surface
scientists in the preparation of samples prior to analysis. In
certain circumstances it is preferable to have a low ion beam
energy in order to minimise surface damage hence maximise the
analysis of the “true” surface.
The AS500F was developed as a sputter cleaning source for
applications such as HREELS, LEED, SIMS, UPS, ESCA and AUGER. In
HREELS for example, where single crystal analysis is often
performed, it is important to protect the delicate lattice
structure from damage whilst sputtering. The AS500F is able to
perform such tasks with high beam current for rapid sample
cleaning yet incurring minimal sample damage due to its low beam
energy.
At 500eV the energy is low enough to prevent high penetration
of the source ions into the sample but not to the detriment of
cleaning efficiency. The focussed beam enables the high current
densities to be produced, hence the AS500F can often display
higher flux rates than seen in far more expensive sputter
cleaning sources.
Technical Specification:
Source type: Hot filament oscillating electron discharge
source. Twin filaments for extended service interval, user replaceable. Feed Gas: Inert gases
Gas Inlet: NW19 conflat port at ground potential. Precision leak
valve required ( better than 5 x 10-7E mbar across seal). Purge
line and purifier recommended.
Cooling: No source cooling required
Lifetime: Typically 3 months for filament replacement, 12 months
for source strip and clean.
Pumping: No special pumping required. Typical analysis chamber
pressure 1 x 10-5E mbar
Source lens: Extractor/ accelerator lens design. Fixed
accelerating voltage of 500V
Mechanical specification:
Working distance: 100mm +/- 50mm
Flange to sample: 250 mm +/- 50mm
Mounting flange: NW35 conflat
Electrical feed throughs: 10 way military spec plug
Minimum port i/d: 37mm
Construction: all UHV compatible stainless steel
Bakeout temperature: 200 deg C
Orientation: any
Control and power unit:
19 inch rack mount painted steel box, 2U height
115VAC or 230 VAC selectable
Filament: 0-4A
Discharge: 10W psu, 20mA - 100mA variable.
Beam potential: fixed at 500eV
Extractor: 0-500 V continuously variable.
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