JPS62226554A - Charged particle energy analyzer - Google Patents

Abstract

PURPOSE:To take a solid angle larger as compared with the conventional electrostatic hemisphere type dispersive analyzer as well as to improve the extent of detection sensitivity, by leading charged particles converged by a decelerating lens system into a nondispersive analyzer having both low-pass and high-pass filters. CONSTITUTION:The photoelectron emitted out of a sample 1 is converged on an incident slit 3 by a decelerating lens system 2. Kinetic energy of the photoelectron passing through the incident slit 3 is more than a range of V1 (eV) whereby it reaches a low-pass filter after uniform rectilinear motion. At this low-pass filter, such a photoelectron whose kinetic energy is lower than that of V2 (eV) is reflected, moving toward an incident slit 7, and another photoelectron whose kinetic energy is higher than the V2 (eV) collides with a reflecting surface 5, losing it charge. The photoelectron passing through the incident slit 7 reaches a high-pass filter 8, and such a photelectron whose kinetic energy is lower than a range of V3 (eV) is reflected by a second grid 10, while another photoelectron whose kinetic energy is higher than this V3 (eV) passes through it, entering a detector 12, whereby such photoelectron that is within the range of V3-V2 (eV) is caught and detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charged particle energy analyzer suitable for ESCA, Auger electron spectroscopy, and the like.

(b) Prior art and its problems Conventionally, charged particle energy analyzers used in ESCA, Auger electron spectroscopy, etc. include electrostatic hemispherical dispersive analyzers and non-dispersive analyzers combined with energy filters.

The former dispersive analyzer is equipped with a deceleration lens system in front of the hemispherical analyzer, and the electron beam excited by the deceleration lens system is focused on the entrance slit of the hemispherical analyzer. If the solid angle of the electron beam is large, the electron beam cannot reach the hemispherical analyzer, which results in poor detection sensitivity.

On the other hand, the latter type of non-dispersive analyzer can obtain a large solid angle, but requires a converging lens or pre-stage filter to remove high-energy electrons emitted from the sample, and has a complex structure that does not reach the riser. Therefore, there was a limit to detection sensitivity.

The present invention has been made in view of the above points, and an object of the present invention is to provide a charged particle energy analyzer with improved detection sensitivity.

(c) Means for Solving the Problems According to the present invention, in order to achieve the above-mentioned object, a sample is irradiated with X-rays or an electron beam, and the energy of the charged particles emitted from the sample is analyzed. In a particle energy analyzer, a low-pass filter having a shape along a part of the circumferential surface of a spheroid, an entrance slit arranged at one focal position of the spheroid, and another focal position of the spheroid a spherical high-pass filter having a center of curvature at the other focal position, and a deceleration lens system having a focal point at the one focal position.

(D) Effect In the above configuration, the charged particles converged by the deceleration lens system are introduced into a so-called non-dispersive analyzer that is equipped with a low-pass filter and a high-pass filter. In addition to being able to make a large angle, there is no need to change the trajectory of the electron beam as much as in conventional non-dispersive analyzers, which improves the efficiency of introducing the excited electron beam into the analyzer.
Detection sensitivity is improved.

(e) Examples Examples of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of an embodiment of the present invention.

In the figure, l is a sample, and this sample l is irradiated with X-rays or electron beams from an excitation source 13. Reference numeral 2 denotes a deceleration lens system that converges photoelectrons as charged particles emitted from the sample 1 onto an entrance slit 3 of the main body of the apparatus. The deceleration lens system 2 of this embodiment includes three cylindrical electrode lenses 2a.
.

2b and 2c, and the potential of the cylindrical electrode lens 2c on the side of the entrance slit 3 is set to Vl.

11 is an outer wall of the analyzer main body, and the potential of this outer wall 11 is also set to Vl.

Reference numeral 4 denotes a low-pass filter that selectively reflects only photoelectrons with energy lower than the energy value of the photoelectrons from the incident slit 3. It consists of a reflective surface 5 having a shape and a grid 6 parallel to the reflective surface 5, and forms part of the circumferential surface of a spheroid, as shown in FIG. The reflective surface 5 of this low-pass filter 4 is V2
The potential is set to .

The entrance slit 3 is arranged at one focal point position 01 of the spheroid of the low-pass filter 4, and
The focus of the deceleration lens system 2 is also at the focus position 01.

7 is an exit slit, and this exit slit 7 is arranged at the other focal point 02 of the spheroid. 8
is a high-pass filter that selectively transmits only photoelectrons having an energy higher than the energy value of the photoelectrons from the output slit 7, and this high-pass filter 8 has a concentric spherical surface whose center of curvature is the other focal point o2. 9. 1st and 2nd grids of shape. Consists of IO. The first grid 9 of this high-pass filter 8 is connected to Vl, and the second grid 1
0 is set to the potential of V3.

12 is a detector such as an electron multiplier that captures photoelectrons that have passed through the high-pass filter 8.

FIG. 2 is a diagram showing the filter characteristics of the embodiment shown in FIG. 1. Based on FIG. 2 and FIG. 1, the operation of the charged particle energy analyzer having the above configuration will be explained.

Photoelectrons emitted from the sample 1 are focused on the entrance slit 3 by the deceleration lens system 2, as shown by the imaginary line in FIG. The kinetic energy of photoelectrons passing through this entrance slit 3 is equal to or higher than Vl (eV). The photoelectrons that have passed through the entrance slit 3 undergo uniform linear motion and reach the low-pass filter 4 . In the low-pass filter 4, photoelectrons with kinetic energy lower than V 2 (eV) are reflected and move toward the output slit 7,
Photoelectrons with kinetic energy higher than V2 (eV) collide with the reflective surface 5 and lose charge. Therefore, the kinetic energy of photoelectrons passing through the low-pass filter 4 is:
It is in the range of 2.

The photoelectrons that have passed through the output slit 7 reach a single pass filter 8 . In the high-pass filter 8, photoelectrons with a kinetic energy lower than V 3 (eV) are reflected at the second grid 10, and photoelectrons with a kinetic energy higher than V 3 (eV) pass through and enter the detector 12.

Therefore, the detector 12 captures and detects photoelectrons in the energy range of V3 to V2 (eV) indicated by diagonal lines in FIG.

In this way, in the charged particle energy analyzer of the present invention, the so-called non-dispersive type analyzer equipped with the a-pass filter 4 and the high-pass filter 8 is provided with the deceleration lens system 2, so that the solid angle of the electron beam is Furthermore, unlike conventional non-dispersive energy analyzers, there is no need to change the trajectory of the electron beam, so there is no need for converging lenses or curved filters, which improves detection sensitivity. At the same time, purchasing becomes relatively easy.

Furthermore, in the charged particle energy analyzer of the present invention,
a deceleration lens system 2 having a focal point at one focal position of the spheroid of a low-pass filter 4 having a shape along the circumferential surface of the spheroid; and a spherical surface having a center of curvature at the other focal position of the spheroid. Since a high-pass filter 8 having the shape of a shape is provided, by installing a microchannel plate after the high-pass filter 8, it becomes possible to observe an image of the sample 1, that is, perform imaging.

(f) Effects As described above, according to the present invention, in a charged particle energy analyzer that irradiates a sample with X-rays or electron beams and analyzes the energy of charged particles emitted from the sample,
A charged particle energy analyzer that irradiates a sample with X-rays or electron beams and analyzes the energy of charged particles emitted from the sample includes a low-pass filter having a shape along a part of the circumferential surface of a spheroid; an entrance slit disposed at one focal position of the spheroid; an exit slit disposed at the other focal position of the costal spheroid;
Since it includes a spherical high-pass filter having its center of curvature at the other focal position and a deceleration lens system having a focal point at the one focal position, detection sensitivity is improved and imaging becomes possible.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
It is a filter characteristic diagram of the example of a figure. l...Sample, 2...Deceleration lens system, 3...Entrance slit, 4...Low pass filter, 7...Output slit, 8...High pass filter.

Claims (1)

[Claims] (1) In a charged particle energy analyzer that irradiates a sample with X-rays or electron beams and analyzes the energy of charged particles emitted from the sample, a low-pass filter having a shape along a part of the circumferential surface of a spheroid is used. an entrance slit placed at one focal position of the spheroid; an exit slit placed at the other focal position of the spheroid; and a spherical high-pass with the other focal position as the center of curvature. A charged particle energy analyzer comprising: a filter; and a deceleration lens system having a focal point at the one focal position.