JPH05234557A - Electron beam quantity measuring device - Google Patents

Abstract

PURPOSE:To secure the measurement of crystallinity, and set the optimal exposure quantity for the diffracted electron beams at the time of photographing a diffraction image of the electron beam by providing a transmitted electron beam measuring element, a diffracted electron beam quantity measuring element and a current meter. CONSTITUTION:In a body 1 of an electron microscope, electron beams 3 generated from an electron gun 2 are incident on the sample 5 placed under a convergent lens 4. The electron beams 6 transmitted through the sample 5 without receiving the influence of the sample 5 and the electron beams 7 diffracted and scattered by the sample 5 among the electron beams 3 from an electron beam diffraction image 9 on the rear focal surface of an objective lens 8, and the electron beams 6 are incident on a transmitted electron beam quantity measuring element 11 through an image-formation lens 10, and the electron beams 7 are incident on a diffracted electron beam quantity measuring element 12 through the image-formation lens 10. Current meters 13, 14 are connected to each measuring element 11, 12 to read the flowing current, and the output thereof is transmitted to a computing circuit 15 or an exposure meter 17 to perform the predetermined computing, and a computed value is displayed on a display unit 16. Crystallinity of the sample 5 is thereby grasped as a numeric value, and the appropriate exposure quantity at the time of photographing a diffraction image of electron beam can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron dose measuring device for a transmission electron microscope, and more particularly to measuring the crystallinity of a sample and improving the performance of an exposure meter.

[0002]

2. Description of the Related Art In a conventional apparatus, it has not been considered to separately measure an electron dose transmitted without being influenced by a sample and an electron dose diffracted or scattered by the sample. Therefore, when investigating the crystallinity of a sample, the electron beam diffraction image obtained from the sample was observed, and the observer visually judged the pattern of the diffraction image. Therefore, the judgment of the crystallinity varies depending on the observer or the time of observation, and the result is only abstract. Furthermore, when the difference in crystallinity was very small, it was difficult to determine the difference, and only ambiguous results were obtained. Moreover, since the total transmitted electron dose was measured when the electron beam diffraction image was taken, it was impossible to set the optimum film exposure amount only for the diffracted electron beam, for example.

[0003]

The above-mentioned prior art does not consider the point of measuring the crystallinity of the sample, and there are differences between the observer and the observer in judging the crystallinity of the sample. There was a problem that the crystallinity occurred and the crystallinity could not be determined.

Further, no consideration is given to the setting of the optimum exposure amount of the diffracted electron beam at the time of photographing the electron beam diffraction image, so that the photographer can set the exposure amount by changing the conditions. I had to take a lot of pictures, which was a lot of waste.

An object of the present invention is to make the crystallinity measurement more reliable by grasping the crystallinity of the sample numerically and grasping it concretely. Further, when the electron beam diffraction image is taken, the optimum exposure amount is set appropriately for the diffracted electron beam.

[0006]

[Means for Solving the Problems] The above objects are a transmission electron dose measuring element and an ammeter for measuring an electron dose transmitted without being influenced by a sample, and a diffraction for measuring an electron dose diffracted and scattered by the sample. By providing the electron dosimeter and its ammeter, the respective electron doses are simultaneously measured separately, and they are arithmetically processed according to the purpose, or they are directly used as the input of the exposure meter.

[0007]

In order to measure the electron dose transmitted through the sample, the transmission electron dose measuring element and the diffracted electron dose measuring element are installed behind the image formation position of the electron beam diffraction image when viewed from the sample side. In order to make the target electron beam enter the position of each probe, it is performed by the operation of adjusting the magnification of the electron beam diffraction image with the imaging lens. There is no problem in implementation. The electron dose incident on each probe is measured by a separate ammeter.
Each measured value is input to an arithmetic circuit or an exposure meter depending on the purpose. For example, when measuring the crystallinity of a sample, each measured value enters an arithmetic circuit, calculates the ratio, and displays it on the display unit. Generally, an electron beam diffraction image of a substance having high crystallinity has high brightness at a diffraction point, but an electron beam diffraction image of a substance having low crystallinity has low brightness. Here, when the electron dose transmitted through the sample is A and the electron dose diffracted and scattered by the sample is B,
The larger the value of B / A, the higher the crystallinity, and the smaller the value, the lower the crystallinity. Therefore, the crystallinity of the sample can be clearly understood by displaying the ratio as a numerical value.

Further, when the electron beam diffraction image is taken, each measured value is input to the exposure meter. The measurer can select one of the measurement values A and B and input it to the exposure meter by taking an image with the transmitted electron beam as the reference or with the diffracted electron beam as the reference or depending on the purpose. This makes it possible to easily set the optimum exposure amount when the electron beam diffraction image is taken.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 is a mirror body of an electron microscope. The electron beam 3 emitted from the electron gun 2 in the mirror body 1 is incident on the sample 5 placed below the converging lens 4. Sample 5 of electron beam 3
The electron beam 6 that has been transmitted without being affected by and the electron beam 7 that is diffracted and scattered by the sample 5 forms an electron beam diffraction image 9 on the back focal plane of the objective lens 8. The electron beam diffraction image 9 is enlarged by the imaging lens 10, the transmitted electron beam 6 is incident on the transmitted electron dose probe 11, and the diffracted electron beam 7 is incident on the diffracted electron dose probe 12. The transmitted electron dosimeter 1
An ammeter 13 is connected to 1 and an ammeter 14 is connected to the diffracted electron dose measuring element 12 to read the current flowing through each element. The outputs of the ammeters 13 and 14 are the calculation circuit 15 or the exposure meter 17
Be transmitted to. When the value read by the ammeter 13 is A and the value read by the ammeter 14 is B, the operation circuit 15 performs an operation of B / A, and the value is displayed by the display unit 1.
6 is displayed. FIG. 2 is an example of an electron diffraction image of an amorphous sample, and FIG. 3 is an example of an electron diffraction image of a crystalline sample. In the case of FIG. 2, the ratio of the diffracted electron dose B to the transmitted electron dose A is very small. On the other hand, in the case of FIG. 3, the ratio of B to A becomes large. Thus, the crystallinity can be measured by the value of B / A.

Alternatively, when an electron diffraction image is taken, either the current value A or B is determined by the exposure meter 17 depending on whether the transmission electron beam 6 or the diffraction electron beam 7 is used as a reference. And input. The exposure meter 17 determines an appropriate exposure amount corresponding to either A or B. This allows the measurer to reliably capture the required electron beam diffraction image.

[0011]

According to the present invention, the crystallinity of a sample can be understood numerically from the ratio of the diffracted electron dose to the transmitted electron dose. Further, by separately measuring the transmitted electron dose and the diffracted electron dose, it is possible to know the proper exposure amount when the electron beam diffraction image is photographed.

[Brief description of drawings]

FIG. 1 is a diagram showing an electron microscope and an electron dose measuring apparatus according to an embodiment.

FIG. 2 is a diagram showing an example of an electron diffraction image of an amorphous sample.

FIG. 3 is a diagram showing an example of an electron diffraction image of a crystalline sample.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron microscope body, 2 ... Electron gun, 3 ... Electron beam, 4 ... Converging lens, 5 ... Sample, 6 ... Transmission electron beam, 7 ... Diffraction electron beam, 8 ... Objective lens, 9 ... Electron diffraction image, 10 ... Imaging lens, 11 ... Transmission electron dose measuring element, 12 ... Diffraction electron dose measuring element, 13 ... Ammeter, 14 ... Ammeter, 15 ... Arithmetic circuit, 16 ... Display part, 17 ... Exposure meter.

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[Procedure amendment]

[Submission date] December 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a diagram showing an electron microscope and an electron dose measuring apparatus according to an embodiment.

FIG. 2 is a photograph of an electron diffraction image of an amorphous sample.

FIG. 3 is a photograph of an electron diffraction image of a crystalline sample.

[Explanation of Codes] 1 ... Electron microscope mirror body, 2 ... Electron gun, 3 ... Electron beam, 4 ... Converging lens, 5 ... Sample, 6 ... Transmission electron beam, 7 ... Diffraction electron beam, 8 ... Objective lens, 9 ... Electron beam diffraction image, 10 ... Imaging lens, 11 ... Transmission electron dose gauge, 12 ... Diffraction electron dose gauge, 13 ... Ammeter, 14 ... Ammeter, 15 ... Arithmetic circuit, 16 ... Display section, 17 ... Exposure Total.

Claims (1)

[Claims] 1. A transmission electron microscope equipped with a converging lens system for irradiating a sample with an electron beam and an imaging lens for enlarging an electron beam emitted from the sample, wherein the sample is transmitted without being affected by the sample. An electron dose measuring device having a function of simultaneously and separately measuring both the electron dose that was performed and the electron dose that was diffracted or scattered by the sample.