Arsenic decay study in SIMS depth profile under O2+ beam bombardment.

Abstract

SIMS is widely used for the process control in the field of LSI manufacture. The reason is that SIMS is the only surface sensitive technique to quantify the low concentration of impurities like Arsenic (As), Boron (B), and Phosphorus (P). The concentration of the impurities would typically be lower than ppb (parts par billion).In this paper, Arsenic distribution was measured by O2+ beam bombardment for different primary beam energies, incident angles and raster sizes. The sample where the Arsenic ion was implanted into SiO2 layer was prepared to study the pile-up of Arsenic into the interface of SiOx/Si. The following two items are the results of this study.(1) The arsenic distortion heavily increased with both higher beam energy and lower incident angle.(2) To avoid the As distortion effect, experiments must be done with O2+ primary beam which has the energy lower than 8 keV and incident angle higher than 45°.