HIGH MASS RESOLUTION SECONDARY ION MASS-SPECTROMETRY VIA SIMULTANEOUS DETECTION WITH A CHARGE-COUPLED DEVICE

A method for high mass resolution secondary ion mass spectrometry (SIMS) is presented. A charge-coupled device is employed as a linear array detector, via binning, to simultaneously detect a small portion of the mass spectrum from a commercial SIMS instrument. The technique can be used for trace analysis and depth profilling. The method is compared to the conventional two-slit technique, and the limit of resolution of the simulataneous method is explored. Spectra from trace constituents in a glass matrix are presented with mass resolutions exceeding 10 500 M/DELTA-M. Detection limits well below 1 ppm are determined for a number of elements. Depth profiles of P-31- in Si, acquired at a mass resolution of 8000 M/DELTA-M, and As-75- in Ge, at a mass resolution exceeding 10 500 M/DELTA-M, are presented. The limits of the method, as well as potential applications and improvements, are discussed.