Full field chemical imaging of buried native sub-oxide layers on doped silicon patterns

TL;DR

This study employs energy-filtered X-ray photoelectron emission microscopy to map and analyze the spatial distribution and thickness of native sub-oxide layers at the SiO2/Si interface, revealing doping-dependent variations.

Contribution

It introduces a spectroscopic pixel-by-pixel analysis method for quantitative 3D mapping of sub-oxide layers with high spatial resolution.

Findings

Sub-oxide layer thickness varies with doping level and type.

Spatial resolution of 120 nm achieved in binding energy maps.

Quantitative analysis of sub-oxide distribution over p-n junctions.

Abstract

Fully energy-filtered X-ray photoelectron emission microscopy is used to analyze the spatial distribution of the silicon sub-oxide structure at the SiO2/Si interface as a function of underlying doping pattern. Using a spectroscopic pixel-by-pixel curve fitting analysis, we obtain the sub-oxide binding energy and intensity distributions over the full field of view. Binding energy maps for each oxidation state are obtained with a spatial resolution of 120 nm. Within the framework of a five-layer model, the experimental data are used to obtain quantitative maps of the sub-oxide layer thickness and also their spatial distribution over the p-n junctions. Variations in the sub-oxide thicknesses are found to be linked to the level and type of doping. The procedure, which takes into account instrumental artefacts, enables the quantitative analysis of the full 3D dataset.