APPLICATION OF THE INFINITE VELOCITY METHOD FOR QUANTIFYING NEGATIVE SECONDARY-ION EMISSIONS TO MULTILAYERED SAMPLES

This report illustrates, in a stepwise fashion, the application of a n ew method for quantifying SIMS results (termed the infinite velocity m ethod) to the depth profile analysis of multilayered samples. The two samples analysed comprised a silicon substrate implanted with cobalt a nd a silicon substrate bearing an oxide layer implanted with boron. Co ncentrations were extracted by: sampling the secondary ion emissions o ver several kinetic energies during the depth profile; correcting the resulting intensities for instrument transmission and sputter yield ef fects, so that these may be plotted against the inverse of the velocit y; and referencing the point at which the resulting curves intersect w ith the intensity axis (intensity at infinite velocity) to an element whose concentration is known, or to the sum of all major element inter cept data. Characteristic velocity data obtained from each cycle of th e depth profiles were also used to illustrate a new method for definin g the position of the interface. To illustrate the validity of these r esults, peak concentrations were compared with those calculated via th e integration method as well as Auger depth profile analysis.