Secondary electron imaging of doped patterns inverts its contrast along the energy scale.
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Secondary electron contrast is proportional to the dopant density.
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At units of eV the p-type doped patterns can be visible by means of mirror imaging.
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Photoemission electron images have the contrast proportional to the dopant density.
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Energy filtered PEEM images visualize even low dopant densities.
Abstract
Methods available for the mapping of dopants in silicon-based semiconductor structures with p-type as well as n-type doped patterns using low and very-low-energy electrons are reviewed together with the results of demonstration experiments.