Accurate secondary ion mass spectrometry analysis of shallow doping profiles in Si based on the internal standard method

Abstract

An accurate quantitative analysis of shallow dopant profiling has been investigated by secondary ion mass spectrometry (SIMS) with an internal standard method. In this method, the internal standard layer is formed by polycrystalline silicon (poly-Si) deposition and followed by standard ion implantation on the Si substrate to be measured. The reproducibility of the measurements for the dopant profiles in the substrate is found to be less than ±5%. A chemical absolute quantitative analysis of implanted dosage is also proposed. The dopant profiles in Si substrates obtained by the internal standard SIMS method, calibrated by the chemical analysis, agree well with the results of capacitance–voltage measurements for metal–oxide–semiconductor diodes. The practical usefulness of the internal standard SIMS method for quantitative dopant profiling is demonstrated by analyzing typical doping profiles in device fabrication processes.