JPS59170753A - Electron ray diffracting device - Google Patents

Abstract

PURPOSE:To prevent movement of a visual field and change in the visual field radius of a diffraction pattern when a convergent angle is changed by changing the excitation intensities of the 1st and 2nd convergent lenses and auxiliary lens cooperatively with the change in the excitation intensity of an objective lens. CONSTITUTION:An operator changes the front magnetic field lens 4a of an objective lens by adjusting an adjuster 12 so as to make the diffraction spot of the diffraction pattern on a fluorescent plate as large as possible within the range when the spots do not overlap each other while observing said spots. Control signals are supplied from converters 13, 14 to excitation power sources 9, 10 by which the excitation intensities of the 1st and 2nd convergent lenses 2, 3 are so excited that the image of an electron tun 1 is formed successively at the same magnification on a sample 5. The position and magnification of a rear magnetic field lens 4b change as well as a change in the output from the adjuster 12 but an auxiliary lens 15 crosses over the diffracted electron rays around a cylindrical part 6 in succession by a converter 17 and an excitation power source 16 and therefore the visual field radius of the diffraction pattern image is maintained max.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Use of 1+%''A-t] The present invention relates to an electron beam IIN apparatus for observing electron beam diffraction patterns.

[Prior Art] Figure 1 is for explaining a conventional electron diffraction apparatus for observing electron diffraction patterns.
is the electron gun, and 2.3 is the first. This is the second converging lens. 4a and 4b are front and rear magnetic field lenses of the objective lens 4, and a sample 5 is placed between these lenses 4a and 4b. This is a cylindrical part for cutting off electron beams that deviate greatly from the cylindrical part 6. When performing selected area observation in the center of this cylindrical part 6, a selected area diaphragm (not shown) is inserted.This cylindrical part A lens system 7 consisting of an intermediate lens and a projection lens is arranged at the rear stage of the lens system 6, and a fluorescent plate 8 is arranged at the rear stage of the lens system 7.

Using such a device, the electronic mirror 1 is
As a result, the electric F rays diffracted by J5 are imaged at the position CΔ by the rear magnetic field lens 41, and further If the object surface position of the intermediate lens is made to coincide with the position A, and the diffraction image that finally appears at the position A by one projection is projected onto the fluorescent plate 8'', the image shown in FIG. An electron diffraction pattern like this is obtained. When making this J, Una diffraction pattern, you may want to observe the pattern inside the diffraction spot by using J3 in the same figure.In order to easily observe the pattern in such cases, Spora 1 - Spora (It is desirable to project Spora 1 ~ as large as possible onto the fluorescent plate 8 within a range where the ends do not overlap. Change the size of Spora 1 ~ i= t, 2α in the figure
All you have to do is change the convergence angle shown by . At this time, the distance between Spora 1- and Spora 1 is i, t s'++, and
Since the diffraction image differs depending on which crystal plane the diffraction image is based on, it is necessary to be able to adjust the convergence angle 2α according to the picture. Therefore, C1 conventionally said convergence angle 2α
The adjustment is performed using the A1 device in the optical axis direction of the sample 5, that is, lFi'-
It was done by 4 votes and 4 shifts. 7j of A, the 7th coordinate of test 11 is shifted from the standard 7th position that falls on the centric goniometer. However, the eucentric goniometer changes the tilt angle of the sample only when the sample is in the standard 7 position! - (Also, the observation field of view can be kept the same.) If the sample deviates from the two standard positions as described above, the observation field of view will miss when the sample is tilted.

Furthermore, when the sample 5 is moved from one position to another, the lens action of the rear magnetic field lens 4b of the objective lens changes. Therefore, the visual field radius r of the diffraction image projected onto the fluorescent screen 8 becomes small, and the spora 1 to 1, which are attracting attention, may not be cut out.

1 Purpose of the Invention] 71\The invention solves such conventional drawbacks, and the field of view does not shift at all even when the convergence angle 2α is changed, and the sharpness of the field of view radius r of the diffraction pattern also changes. The purpose of this invention is to provide an electron beam diffraction device that does not leak.

[Structure of the Invention] The present invention provides an electronic mirror and a first lens for converging an electron beam. The second converging lens includes an objective lens, a cylindrical part that captures the electron beam that is largely off-axis, an intermediate lens and a projection lens, and a phosphor plate disposed after the projection lens. The device 1"7 (in this case, regardless of the change in the excitation intensity of the objective lens) 2 convergence 4! Lens excitation Ii! 'i 11 degrees due to change in excitation intensity of objective lens Regardless of the changes in +il + magnetic strength of the lens and objective lens, the electric r-ray that has passed through the auxiliary lens is
;j゛, means for changing the excitation intensity of the nonce in conjunction with the change in the excitation intensity of the objective lens in order to make the center of the cylindrical part It is characterized by covering -C.

[Example] The embodiments of the present invention will now be described in detail based on the drawings.

I (J5 in Figure 3, which shows another example), is the first one!
The same number (=J and C1) is given to the l'+1 component (same as lens 1). In the same figure, 9 and 10 are the power supplies of the 1st and 2nd converging lenses, respectively. .11 is the excitation) and competition) U source of the objective lens 4. This excitation'f, 1 to power supply 11. The excitation 14 current of J and RI is adjusted by the regulator 12 so that
The excitation current of 9.10 is controlled based on the signal which converts the control signal of each 'Z regulator 12 into the converter 13.1/l' (1fI4). When changing the output signal, especially when avoiding changing the excitation power of the objective lens, the electronic mirror (or its crossover)
This is for changing the excitation intensities of the first and second converging lenses 2 and 3 in conjunction so that an image of the same spora 1 to diameter is formed on the sample 5. converter 13
3°1/I, the control signal from the regulator 12 is the first. This is converted into a control signal for exciting the second converging lenses 2 and 3 as necessary. These converters 13 and 14 each consist of a memory and a readout mechanism. ! I At this point, the front magnetic field lens 4a
How does that position become a drum? (zono☆ka E-δ
), Ma, check in advance how the magnification changes at that time (the amount of change ΔN・1), and adjust the -C first according to this change.
The degree to which it is necessary to excite the second converging lens 2.3 is determined theoretically or experimentally, and the control signal value that provides this necessary excitation strength 19 is set for each of the adjusters 12 (1 [corresponding to 1). Furthermore, an auxiliary lens 15 is provided between the objective lens 4 and the N-shaped portion 6. The signal from the regulator 12 is converted to a converter] 7C' change 1φ
It is controlled based on the husband and father in law. The converter 17 also has a number of memory blocks, and when the excitation intensity of the objective lens 4 is changed without changing the output signal of the adjuster 12 (this Changes (do not rely on the diffracted electron beam at the center of the cylindrical part 6 [ ] 1 space A-bar (it is necessary to control the power supply 16 at g2) are stored in No. 13. First, it converges and narrows down the lens.

In such a configuration, when the output signal of the adjuster 12 is changed, the C objective lens front magnetic field lens 4-a changes due to this change, but the converter 13 that converts the output signal of the adjuster 12 changes. nil iJl (i
<The bow is linked to this change and -C changes, respectively excitation power source 9,
Since it is supplied to 10, N! 1 + The excitation intensity of the second converging lenses 2, 3 is such that the image of the electron gun (or its crossover) is subsequently imaged on the sample i"l 5 at the same magnification. Therefore, this As the object point position of the lens 4a moves as shown in FIG. 3 due to the change, the convergence angle 2α can be avoided. l~
While observing the above, adjust the output of the adjuster 12 so that the spoiler]~ becomes as large as possible without overlapping.

In addition, as the output signal of the regulator 12 changes, the position and ratio of the gastric lens 4b also change. Since the signal is supplied to the excitation power supply 1G, the auxiliary current 15] is pulled out and the diffraction electricity is reduced to -1) a. Ru. 11
With the adjustment of the convergence angle 2α, the number of cuts 1 to 41 of the 1h power line does not increase.

[Effect J To description 1. It is possible to continuously change the convergence Φμ without changing the 7 position of l. It is important to keep the magnification constant when applying the electron beam to the sample (to avoid the cross-over of the electron beam to the sample). - Kawakobo t-, f
Continuously change the diameter from Q to diffraction spora 1 (adjust 4'l")
Furthermore, the convergence angle is adjusted to keep the field of view diameter of the diffraction pattern image at its maximum.

[Brief explanation of the drawing]

Figure 1 shows l', xl C for explaining a conventional device.
Figure 2 shows the diffraction spora 1~ projected on the fluorescent screen 1 and the diameter of the field of view.
Figures 1 and 3 show an embodiment of the present invention.
ri■1 non-switch, 41): j thread 7'5 magnetic field lens, 5:
Trial 1, G: Cylindrical part, 7: Lens system, 8: Fluorescent screen, 5]
, 10, 11, 16: I+Jl field power supply, 12:
Adjuster, Go ζ3゜1/1.17: Converter, 15: Auxiliary L
Lens C: optical axis, )〈collar. Patent Applicant: 11 Electronics Co., Ltd. Representative: Ito - Person

Claims (1)

[Claims] An electron gun and a first device for converging the electron beam from the electron gun. The second converging lens is very far off-axis from the objective lens.1. : A device equipped with a cylindrical part for transmitting an electron beam, an intermediate and projection lens, and a light plate placed after the projection lens. The excitation intensity of the first and second converging lenses is linked to the change in the excitation intensity of the objective lens so that the electron beam is irradiated with an imaging spot of the same diameter on the sample surface regardless of the change in the excitation intensity. an auxiliary lens disposed between the objective lens and the intermediate lens; and a means for causing the electron beam to pass through the auxiliary lens to always be directed to the cylindrical portion regardless of changes in the excitation strength of the objective lens. means for changing the excitation strength of the auxiliary lens in conjunction with the change in the magnetic strength of the objective lens in order to cross over to the center of the auxiliary lens.
An electron beam diffraction apparatus characterized by: