JPH11176371A - Spin polarized scanning electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spin polarized scanning electron microscope by which a magnetic domain image can be easily focused. SOLUTION: Secondary electrons 4 emitted from a sample 3 with a probe electron beam 2 given from an electron gun 1 arrive at an electrostatic deflector 6 with a secondary electron collecting and transferring optical system 5. When the electrostatic deflector 6 is in a non-operated condition, the secondary electrons arrive at a secondary electron detector 7 to provide a secondary electron image. When the electrostatic deflector 6 is in an operated condition, the secondary electrons with their tracks curved 90 degrees arrive at a spin detector 8 to provide a magnetic domain image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a spin-polarized scanning electron microscope, and more particularly to a spin-polarized scanning electron microscope capable of easily focusing a magnetic domain image.

[0002]

2. Description of the Related Art Conventionally, focus adjustment in a spin-polarized scanning electron microscope is performed while observing a sample absorption current image or a secondary electron image. In the latter case, the secondary electrons are emitted by an electron detector placed near the sample. Or an electronic detector placed inside the spin detector.

[0003]

When the focus is adjusted by the above-mentioned prior art, the signal-to-noise ratio (S / N) cannot be made large in the sample absorption current image, so that it takes about one second to obtain a high-quality image. The above time was required, and focus adjustment was extremely difficult. On the other hand, in the secondary electron image, a high S / N ratio was obtained, so that high-quality images were continuously obtained at intervals of about 0.03 seconds, and the focus adjustment was easy. However, when a secondary electron detector is placed near the sample, an electric field is applied near the sample to guide the secondary electrons to the secondary electron detector. Even if focusing is performed in this state, a magnetic domain image is obtained thereafter. Occasionally, the secondary electron detector is deactivated to eliminate the electric field near the sample, and the secondary electrons are guided to the spin detector, so that there is a serious problem that the focus state changes. In addition, when the secondary electron detector is placed inside the spin detector, there is no shift between the focus states of the secondary electron image and the magnetic domain image, but there is a disadvantage that the spin detector has a complicated structure and is expensive. The problem to be solved by the present invention is to make it possible to easily focus a magnetic domain image by eliminating a shift of a focus state between a secondary electron image and a magnetic domain image, and to complicate a spin detector.
An object of the present invention is to provide an inexpensive spin-polarized scanning electron microscope.

[0004]

An object of the present invention is to provide a deflector which is located in a part of an electron optical system for guiding secondary electrons emitted from a sample to a spin detector and which is separated from the sample, When the focus is adjusted, the secondary electrons are guided to the secondary electron detector to obtain a high-quality secondary electron image at high speed, and when a magnetic domain image is obtained, the secondary electrons are spin detected. It can be solved by guiding to a container. When the deflector is placed away from the sample, the focus state is kept constant regardless of whether the deflector or the secondary electron detector is operating or not, so that the secondary electron image is focused. Thereby, the focus of the magnetic domain image can be adjusted.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A scanning probe microscope according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment in the vicinity of a secondary electron collection and transfer optical system of a spin-polarized scanning electron microscope according to the present invention. Secondary electrons 4 emitted from the sample 3 by the probe electron beam 2 from the electron gun 1 reach the electrostatic deflector 6 by the secondary electron collection and transfer optical system 5. Electrostatic deflector 6
Is in a non-operating state, the secondary electrons reach the secondary electron detector 7, and a secondary electron image can be obtained. Also, the electrostatic deflector 6
Is in the operating state, the trajectory of the secondary electrons is bent by 90 °, reaches the spin detector 8, and a magnetic domain image can be obtained. Since the electrostatic deflector 6 and the secondary electron detector are sufficiently far from the sample 3, the focus state is kept constant irrespective of whether they are operating or not operating. Therefore, it is possible to easily focus on the secondary electron image that can provide high-speed and high-quality images, and this is directly the focus state of the magnetic domain image. Here, the electrostatic deflector 6 may be a deflector in which a magnetic field or an electric field and a magnetic field are superimposed, and the deflection angle may be other than 90 ° as long as the secondary electron detector 7 and the spin detector 8 do not interfere with each other. Electrons incident on the electron detector and the spin detector may be deflected at different angles. Further, the positions of the secondary electron detector 7 and the spin detector 8 may be interchanged.

[0007]

Since the electrostatic deflector 6 and the secondary electron detector are sufficiently far from the sample 3, the focus state is kept constant irrespective of whether they are in operation or non-operation. Dripping. Therefore, it is possible to easily focus on a secondary electron image that can provide high speed and high image quality,
This directly becomes the focus state of the magnetic domain image.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment in the vicinity of a secondary electron collection and transfer optical system of a spin-polarized scanning electron microscope according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electron gun, 2 ... Probe electron beam, 3 ... Sample, 4 ... Secondary electron, 5 ... Secondary electron collection and transfer optical system, 6 ... Deflector, 7 ... Secondary electron detector, 8 ... Spin detector.

Claims (1)

[Claims] 1. A spin-polarized scanning electron microscope which scans the surface of a sample with a probe electron beam and detects the spin state of the emitted secondary electrons to obtain a magnetic domain image of the sample. A secondary electron is guided to a spin detector or a secondary electron detector by placing a deflector in a part of an electron optical system for guiding the secondary electron to an operating state or a non-operating state. Spin polarized scanning electron microscope.