ACCURATE SECONDARY-ION MASS-SPECTROMETRY ANALYSIS OF SHALLOW DOPING PROFILES IN SI BASED ON THE INTERNAL STANDARD METHOD

An accurate quantitative analysis of shallow dopant profiling has been investigated by secondary ion mass spectrometry (SIMS) with an intern al standard method. In this method, the internal standard layer is for med by polycrystalline silicon (poly-Si) deposition and followed by st andard ion implantation on the Si substrate to be measured. The reprod ucibility of the measurements for the dopant profiles in the substrate is found to be less than +/-5%. A chemical absolute quantitative anal ysis of implanted dosage is also proposed. The dopant profiles in Si s ubstrates obtained by the internal standard SIMS method, calibrated by the chemical analysis, agree well with the results of capacitance-vol tage measurements for metal-oxide-semiconductor diodes. The practical usefulness of the internal standard SIMS method for quantitative dopan t profiling is demonstrated by analyzing typical doping profiles in de vice fabrication processes. (C) 1996 American Vacuum Society.