High dynamic range quantitative image depth profiling of boron in patterned silicon dioxide on silicon

Abstract

A high sensitivity, high dynamic range imaging system has been developed for secondary ion mass spectrometry(SIMS). The combination of stigmatic imaging and dynamic primary ion beamsputtering provided by the ion microscope (Cameca IMS‐3f) permits acquisition of SIMSimage depth profiles, i.e., three‐dimensional maps of elemental composition. In this study a methodology was developed which allows transformation of raw image ion intensities to elemental concentration. First, the response of the dual microchannel plate/phosphor screen charge coupled device detector was determined and correction procedures developed from this information were applied to an SiO2 on Si sample. Sensitivity factors were then generated for an impurity, boron, in the SiO2 and Si, respectively. The detector correction and elemental sensitivity factors were applied to the entire image depth profile set in an effort to produce a quantitative image depth profile. Local area depth profile of selected areas of the sample were then generated and compared to depth profiles produced using the standard SIMSdetector, the electron multiplier.