JPS6158941B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion microanalyzer that analyzes a sample surface by slightly moving a sample, and particularly to an ion microanalyzer that does not change secondary ion extraction efficiency when the sample is slightly moved.

FIG. 1 is a schematic diagram of the main parts of a conventional ion microanalyzer. In the figure, one or more samples 3 are mounted on the sample holder 4,
A primary ion beam 1 is irradiated. Positive secondary ions 6 released from the sample 3 by primary ion irradiation are directed by an extraction electrode 5 having a potential lower than the sample potential and guided to a mass spectrometer (not shown). The sample holder 4 has openings 2A and 2B for primary ion injection and secondary ion extraction, and is surrounded by an auxiliary electrode 2 maintained at the sample potential. The auxiliary electrode 2 is preferably a hemispherical mesh electrode, which not only increases the efficiency of extracting secondary ions, but also serves to prevent charge build-up on the sample when negative primary ions are irradiated onto the sample. It is something.

In these conventional devices, when micro-movement of the sample is performed, the sample holder 4 and This has the drawback that the distance between the extraction electrodes 5 varies greatly, and therefore the electric field between them changes, resulting in a great change in the efficiency of extracting secondary ions.

The present invention improves the above-mentioned drawbacks by arranging a correction electrode having substantially the same potential as the sample so as to be substantially flush with the sample mounting surface of the sample holder between the sample holder and the auxiliary electrode.

FIG. 3 is a schematic diagram of one embodiment of the present invention, in which reference numeral 7 denotes a correction electrode mounted on the same surface as the sample 3 mounting surface of the sample holder and maintained at the sample potential. The correction electrode 7 may be a metal plate or a mesh plate, and is attached to the sample holder 4, the auxiliary (mesh) electrode 2, or any other suitable holder.

Since the ion microanalyzer of the present invention is equipped with the correction electrode 7 as described above, even when the sample holder 4 is placed farthest from the extraction electrode as shown in FIG. held at a potential. Therefore, the electric field between the two poles does not change depending on the sample position, and changes in the secondary ion extraction efficiency can be suppressed.

Figure 4A shows the relationship between the sample position and secondary ion intensity in the conventional device, and Figure 4B shows the same relationship in the device of the present invention. , B, respectively. These results show that according to the present invention, changes in secondary ion extraction efficiency due to sample position can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of a conventional ion microanalyzer, FIGS. 2A and B are diagrams showing the state of the sample in FIG. Figures 4A and 4B are charts showing the relationship between sample position and secondary ion intensity. 2... Auxiliary electrode, 4... Sample holder, 5... Extraction electrode, 7... Auxiliary electrode.

Claims (1)

[Claims] 1 In an ion microanalyzer that irradiates a sample with a primary ion beam and guides secondary ions generated from the sample to a mass spectrometer for analysis, a sample holder and a Next, an auxiliary electrode having an aperture through which the ion beam passes, and a correction electrode having approximately the same potential as the sample, which is placed between the sample holder and the auxiliary electrode so as to be on the same plane as the sample mounting surface of the sample holder. An ion microanalyzer that is characterized by the following: