LOW-ENERGY AR NEUTRAL BEAM ETCHING METHOD FOR X-RAY PHOTOELECTRON-SPECTROSCOPY

A simple Ar neutral beam gun capable of providing low-energy Ar atoms has been developed for surface cleaning and depth profile analysis in x-ray photoelectron spectroscopy, Auger electron spectroscopy, etc. Characterization of the Ar neutral beam gun is described. The effect of neutral beam bombardment was investigated for an Si(100) wafer and a polyethylene terephthalate (PET) film in order to reduce chemical damage by sputter etching in XPS. The neutral beam etching gun was composed of a Kaufman-type ion source, a gas collision chamber and an electrostatic deflector. This gun can work also as an ion gun by a simple operation mode change. Neutral and ion beam fluxes were measured using an absorption current plate made of stainless steel. Experimental results showed that the probability of neutralization in a charge exchange chamber was similar to 80% of the maximum between 1 x 10(-1) Pa and 2 x 10(-1) Pa, and the sputtering rate for SiO2 at 600 eV was 14 nm min(-1) which is similar to 30% lower than with a Kaufman-type ion gun. The bombardment process for an Si wafer was essentially the same for the Ar ion beam and the Ar neutral beam. However, it was observed that radiation damage to the PET film surface etched by the neutral beam was remarkably diminished as compared with that by the ion etching method This can be ascribed to the fact that the effect of electronic damage etching due to Ar-0 is less than that due to Ar+.