DETECTION OF METALLIC IMPURITIES BY RESONANCE IONIZATION MASS-SPECTROMETRY (CORRECTED VERSION OF LA014)

A resonant ionization mass spectrometer based on a quadrupole SIMS cou pled to a tunable dye laser has been developed for the detection of tr ace amounts of metallic impurities in semi conductor materials. The ap propriate wavelength to ionize various metals with one color, one reso nance (1 + 1) process has been determined. The detection limit of the apparatus has been measured for chromium using different standards wit h known concentrations of impurities and a value of 0.2 ppm has been f ound. A study of different metals has shown that his result is nearly independent of the matrix. A depth profile with this instrument is pre sented for titanium in silicon.