JPH10275585A - Scanning electron microscope for vacuum stm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning electron microscope for STM, which can observe SEM(scanning electron microscope) image and RHEED(reflected high speed electron beam diffraction) image with one electron gun. SOLUTION: A device, in which a scanning tunnel microscope and a scanning electron microscope are arranged in a vacuum container, is provided with a deflecting unit 30 for radiating electron beam at a low angle to a sample 2 and a detecting unit 21 for detecting the electron reflected from the sample 2. An electron beam from an electron gun 20 of the scanning electron microscope is made to enter the deflecting unit 30 so as to apply the beam to the sample 2, and the electron reflected from the sample 2 is detected by the detecting unit 21 so as to observe the reflected electron beam diffraction image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SEM for a vacuum STM in which a scanning tunneling microscope (STM) and a scanning electron microscope (SEM) are incorporated so that an STM image and an SEM image can be observed.

[0002]

2. Description of the Related Art In an STM used in an ultra-high vacuum, there is a demand to simultaneously observe the state of a sample and a probe by SEM or to observe the structure of the sample surface by reflection type high-energy electron diffraction (RHEED). there were. However, while the SEM irradiates the sample surface with primary electrons and detects secondary electrons emitted at that time, the RHEED irradiates the sample with an electron beam at a small angle, and the electron beam reflected at that time Since the diffraction image due to the interaction with the sample surface is viewed, the SEM
And RHEED differ greatly from each other in the angle of view of the sample, and when observing them simultaneously, two electron guns were required.

[0003]

As described above, the conventional apparatus requires an electron gun for obtaining the SEM image and the RHEED image when observing the STM image, the SEM image, and the RHEED image, and is extremely expensive. And needed space.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a device electron microscope for a vacuum STM which can observe a SEM image and a RHEED image with one electron gun.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a deflector for irradiating a sample with an electron beam at a low angle, and a reflected electron from the sample in an apparatus having a scanning tunnel microscope and a scanning electron microscope arranged in a vacuum vessel. And an electron beam from the electron gun of the scanning electron microscope is incident on the deflector to irradiate the sample, and reflected electrons from the sample are detected by the detector and reflected electron beam diffraction is performed. The image is made observable.

[0006]

Embodiments of the present invention will be described below. FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, a vacuum vessel 1 is maintained in an ultra-high vacuum,
In this, the STM scanner 10 facing the sample 2 and the STM
A probe 11 is arranged, and an electron gun 20 for SEM and a detector 21 for SEM are arranged on both sides of the STM scanner 10, respectively. The electron gun 20 includes a lens and a deflection system.
It is attached so that it can approach or retreat from. Further, a deflector 30 for irradiating the sample 2 with an electron beam at a shallow angle, an astigmatism corrector 31 for correcting distortion caused by bending the electron beam, and a detector for detecting reflected electrons from the sample. An RHEED detector 32 is provided.

In such a configuration, the STM probe 11 is driven by the STM scanner 10 to observe the STM image on the sample surface. When observing the SEM image, the electron gun 20 is used.
Is moved to the irradiation position 23, and the sample 2 is irradiated with an electron beam through the SEM electron beam path 25. Secondary electrons emitted from the sample at that time are detected by the SEM detector 21.

Next, the electron gun 20 is separated from the sample, and is retracted to the irradiation position 24 in the figure. The movable distance L at this time
Is secured by the bellows 22. At this position, the electron beam is deflected by a scanning coil (not shown) provided on the electron gun 20 and made incident on another deflector 30 provided outside the electron gun. When the sample is irradiated with an electron beam at an extremely shallow angle through the RHEED detector, a RHEED detector 3 composed of a fluorescent screen and the like arranged on the opposite surface
2, an RHEED image is obtained.

As described above, it is possible to observe both the SEM image and the RHEED image with only one electron gun without using two large electron guns. Note that the same can be easily performed by inclining the sample, but when the STM is arranged, it is necessary to reduce the vibration as much as possible, so that it is difficult to attach an inclining mechanism to the sample or the STM stage. Therefore, the sample or STM
It is more advantageous to observe the SEM image and the RHEED image by deflecting the electron beam using the scanning coil while keeping the electron gun 20 movable while keeping the electron gun 20 as it is.

FIG. 2 is a diagram showing an example of another embodiment of the present invention. This example also has the same basic structure as that of FIG. 1, except that the electron gun 20 is configured to be able to approach and retreat to the sample by the bellows 22 and to be tiltable. By providing the mechanism for moving and tilting the electron gun in this manner, the SEM can be changed by changing the angle of the electron gun itself irrespective of the deflection of the scanning coil of the electron gun.
Since the electron beam can be incident on the deflector 30 without using the deflection system described above, it is possible to observe the RHEED image in the same manner.

[0011]

As described above, according to the present invention, the electron gun of the SEM is provided with a moving or moving and tilting mechanism so that the electron gun approaches the sample when observing the SEM image and separates it when observing the RHEED image. The sample is irradiated with the electron beam at a shallow angle by irradiating the electron beam to a deflector separately arranged due to the inclination, and the reflected electrons can be detected with a fluorescent screen or the like. The RHEED image can be observed with one SEM electron gun It is also possible to do.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum container, 2 ... Sample, 10 ... STM scanner, 11
... STM probe, 20 ... electron gun, 21 ... detector, 22 ... bellows, 23 ... SEM irradiation position, 24 ... RHEED irradiation position, 25 ... SEM electron beam path, 30 ... deflector,
31: astigmatism corrector, 32: RHEED detector, 33: R
HEED electron beam path.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 37/28 H01J 37/28 B

Claims (3)

[Claims] 1. An apparatus in which a scanning tunnel microscope and a scanning electron microscope are arranged in a vacuum vessel, comprising a deflector for irradiating a sample with an electron beam at a low angle, and a detector for detecting reflected electrons from the sample. That the electron beam from the electron gun of the scanning electron microscope is incident on the deflector to irradiate the sample, the reflected electrons from the sample are detected by the detector, and the reflected electron beam diffraction image can be observed. Characteristic scanning electron microscope for vacuum STM. 2. The electron microscope according to claim 1, further comprising a moving mechanism for moving the electron gun of the scanning electron microscope toward and away from the sample, and moving the electron gun backward when observing a reflected electron beam diffraction image. A scanning electron microscope for vacuum STM, wherein an electron beam deflected in an electron gun is incident on the deflector. 3. The electron microscope according to claim 1, further comprising a mechanism for moving the electron gun toward and away from the sample, and tilting the electron gun when observing a reflected electron beam diffraction image. A scanning electron microscope for vacuum STM, wherein an electron beam from an electron gun is incident on the deflector.