JPS5826773B2 - Sample irradiation current detection device for electron microscopes, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sample irradiation current detection device for an electron microscope or the like.

Conventionally, in electron microscopes and the like, a Faraday cage is used as a means for measuring sample current, and this Faraday cage is built into an observation chamber or a sample holder.

In order to make the electron beam enter the Faraday cage, it is necessary to move the sample or insert the Faraday cage onto the optical axis, so it is difficult to continue observing and analyzing the sample while constantly monitoring the sample current. Met.

In addition, when a Faraday cage is incorporated into a sample holder, there is a drawback that the structure of the holder becomes complicated.

The present invention eliminates the above-mentioned drawbacks by:1. The present invention provides a sample current monitor that can measure the sample current at any time and allows easy observation and restart of analysis after measurement.

A detailed explanation will be given below based on the embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and 1 is a sample.

This sample is irradiated with an electron beam 2 generated from an electron gun (not shown), which is narrowly focused by a focusing lens system, as shown by a solid line.

X-rays X are generated from the sample by the electron beam irradiation, and these X-rays
The line X is analyzed by a non-dispersive analyzer 3.

Reference numeral 4 denotes an adsorbent made of a conductive material that surrounds the sample 1. The adsorbent is cooled in a cooling tank (not shown) to adsorb gas molecules near the sample and prevent contamination of the sample. This is to prevent this.

The adsorbent is fixed to a mirror body such as an objective lens (not shown) in an electrically and thermally insulated state, and furthermore, the adsorbent is grounded via an ammeter 5.

6 is a deflection coil installed above the trap.

However, if the electron beam 2 is deflected by supplying a predetermined current to the deflection coil 6 and the electron beam is irradiated onto the adsorbent 4 as shown by the dotted line in the figure, the electron beam will be applied to the adsorbent. 4 and flows through the ammeter 5, the current value of the sample irradiation electron beam 2 is displayed on the ammeter.

As explained in detail above, in the present invention, the current of the electron beam for sample irradiation can be measured without moving the sample or inserting a Faraday cage onto the optical axis, and moreover, by stopping the deflection of the electron beam by the deflection coil. , the electron beam immediately returns to its original irradiation position, making it possible to restart the analysis.

It should be noted that the above-mentioned embodiment is only an illustration of the present invention, and various modifications may be made in implementation.

In other words, as shown in the cross-sectional view of FIG. 2, by integrally installing a shielding plate 8 having an open lower part on the electron beam irradiated part of the adsorbent 4, the absorbed electrons are absorbed from the electron beam irradiated part of the adsorbent 4. It is possible to absorb generated secondary electrons and reflected electrons.

This makes it possible to more accurately measure the current value of the electron beam for irradiating the sample.

[Brief explanation of drawings]

FIG. 1 is a schematic structural diagram showing one embodiment of the present invention, and FIG. 2 is a sectional view of essential parts showing another embodiment of the present invention. In the figure, 1 is a sample, 2 is an electron beam, 3 is a non-dispersive X-ray analyzer, 4 is an adsorbent, 5 is an ammeter, and 6 is a deflection coil.

Claims (1)

[Claims] 1. A means for focusing the electron beam from the electron gun and irradiating the sample; an adsorbent that surrounds the sample and is attached to the mirror in a state where it is electrically and thermally isolated;
A means for cooling the adsorbent, a deflecting means for deflecting the electron beam irradiating the sample to irradiate the adsorbent, and a means for detecting the current of the electron beam absorbed by the adsorbent by the deflecting means. A sample irradiation current detection device for an electron microscope, etc., characterized by the following.