electron-probe microanalyzer, EPMA

An instrument that performs element identification, quantitative element analysis and element distribution analysis in a specimen by illuminating a specimen surface with a fine electron probe and measuring characteristic X-rays generated. Since the "electron-probe microanalyzer (EPMA)" usually has an electron optical system similar to a SEM, backscattered electron images and secondary electron images are used for searching a specimen position to be analyzed. An optical microscope is also installed in an EPMA for searching a specimen position. Multiple wave-dispersive spectrometers (WDS) are incorporated in the EPMA for spectroscopic analysis of characteristic X-rays to achieve a high detection efficiency. The energy resolution of WDS is about 10 eV, whereas that of an energy dispersive spectrometer (EDS) is about 130 eV. The EPMA with the WDS is possible to conduct electronic structure analysis for favorable cases. The EPMA has a high performance of a detection limit of several tens of ppm and an error of 1% for quantitative composition analysis. The minimum specimen area to be analyzed is about 1 μm in diameter. A recent instrument equipped with an FE gun enables composition analysis of a specimen area of 0.1 μm in diameter.

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