Quantification of dopant implants in oxidized silicon on sapphire using secondary-ion mass spectrometry

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Abstract
By measurement of ion and sputter yields from thermally grown SiO2 and single crystal Si it has been possible to quantify 11B range profiles measured by secondary-ion mass spectrometry from device-type silicon on sapphire wafers implanted through a gate oxide. Contrary to theoretical predictions, no step in 11B concentration is observed at the SiO2/Si interface after calibration. Measured ion ranges in SiO2 and Si agree well with those of other works and with theoretical predictions by Johnson and Gibbons and Biersack. Ranges in SiO2 are found to be around 20% greater than those calculated by Smith. Under 4-keV 16O2+ primary-ion bombardment, the relative yields (SiO2/Si) are found to be the following: sputtering, 2.05; 11B+ ion yield, 2.25; degree of 11B+ ionization, 1.10. The oxygen primary beam is apparently inert in the SiO2, but reacts with the Si to form a mix SiOm where m=1.95 under steady-state conditions.