Effect of dopant on the accuracy of oxygen measurement in silicon by Gas Fusion Analysis

The effect of dopant species on the accuracy of measuring oxygen content in heavily doped silicon slugs by Gas Fusion Analysis (GFA) was investigated. The correlation between the measurements of GFA, Fourier Transform Infrared Spectroscopy (FTIR) and Secondary Ion Mass Spectroscopy (SIMS) was obtained from lightly doped slugs. The GFA results of heavily doped slugs were measured against SIMS. The effect was different from different dopant species. Heavily boron-doped slugs showed the least effect with respective to lightly doped slugs. There was a slight reduction in GFA measured oxygen content, using SIMS as a reference, when boron and oxygen concentrations were high. All the n(+) slugs showed a greater effect which had lower GFA readings than the lightly doped samples when the SIMS value was higher than 17 ppma. The lower GFA oxygen for the heavily doped slugs in regards to SIMS data were explained by the easiness of oxygen to form oxides relative to the formation of carbon monoxide.