Determination of boron in uniformly-doped silicon thin films by isotope dilution inductively coupled plasma mass spectrometry

Abstract

Uniformly-doped silicon thin films were fabricated by ion beam sputter deposition. The thin films had four levels of boron dopant concentration ranging between 1 × 10¹⁸ and 1 × 10²⁰ atoms cm⁻³. Concentrations of the boron dopants were determined by isotope dilution inductively coupled plasma mass spectrometry to provide certified reference data for quantitative surface analysis by secondary ion mass spectrometry (SIMS). The boron-doped thin films were dissolved in 0.3 M LiOH solution spiked with appropriate amounts of ¹⁰B. The uncertainty of the determined boron concentrations, estimated by following the EURACHEM Guide, was less than 4%, and the detection limit of the method was 2.1 × 10¹⁷ atoms cm⁻³. The determined boron concentrations were compared with those obtained by SIMS analysis calibrated with a ¹⁰B ion implanted reference material (NIST SRM 2137). The two results showed a good agreement within the stated uncertainty of 5% for the SRM.