Progress Report on the Backscattering Standards Project

Abstract

An international group of laboratories have collaborated in a standards project aimed at examining the principal (and sometimes elusive) factors which can influence the absolute quantitative interpretation of backscattering analysis spectra. Identically prepared samples of Bi implanted* in Si, and others of 2000 Å Pt on oxidized silicon substrates were distributed to the participants together with a detailed prescription for comparative runs which all labs would then follow in nominally identical fashion.

Spectra were taken for the Bi implants, the Pt films and thin Si0₂/Si substrates scattering ¹He₊ ions at 1.9 and 1.0 MeV and using Si detectors at 165° to the incident beam.

The intercomparison of results obtained so far will be made, with special reference to energy straggling effects, absolute mass (atoms/cm²) and energy calibrations, and system linearity and resolution.

We will also discuss “reference” spectra from the same Pt films, obatained with the high resolution magnetic spectrometer at Bell Laboratories, with a system resolution of 650 eV.