JPS6057533B2 - Reed Augier analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in Reed-Augier analyzers.

As shown in FIG. 1, a conventional Reed-Ausier analyzer has a hemispherical collector electrode 7 whose inner surface is coated with a fluorescent substance 6.
and four hemispherical wire mesh electrodes 1, 2, 3, and 4 are provided concentrically at intervals so that the collector electrode is on the outside, and are grounded through power sources 10, 11, and 13, respectively,
The sample is placed at the center of the hemisphere.

The primary electrons that have passed through the shield cylinder 8 collide with the surface of the sample 1, and the secondary electrons, including Augier electrons, generated on that surface pass through the concentric spherical wire mesh electrodes 1, 2, 3, and 4, and pass through the collector electrode. Reach 7. Of these secondary electrons, the Auger signal portion is detected by adding an AC perturbation voltage 9 to the DC blocking voltage 8 . On the other hand, the lead image is observed as diffracted electrons colliding with the fluorescent material 6 coated on the inner surface of the concentric hemispherical collector electrode.

However, this analyzer has the following problems.

(1) An alternating current perturbation voltage of several volts is applied to the wire mesh electrodes 2 and 3, while the Auger signal voltage becomes a minute voltage of about several mV to several μV.

Therefore, it is extremely difficult to prevent the alternating current perturbation voltage from entering the collector electrode 7 using only the wire mesh electrode 4, and requires advanced technology in manufacturing the device. (2) Secondary electrons emitted from the surface of the sample 1 pass through the wire mesh electrode 3, and a portion of them collide with the wire mesh electrode 4 to generate secondary electrons, which are added to the Auger signal as shot noise. .

(3) When observing a lead image, it is difficult to observe a clear lead image because the lead image is observed through four wire mesh electrodes due to the structure.

The present invention has been made to solve these problems.

The Reed-Augier analyzer of the present invention will be explained with reference to FIG. 2. 1 is a wire mesh electrode, 5 is a transparent conductive film, 6 is a fluorescent substance, 7 is a collector, 8 is a shield cylinder, and 9 is a collector acceleration voltage. , 18 is the blocking voltage, 11 is the AC perturbation voltage, 12
is the sample, 13 is the bias voltage, 14 is the LC resonance circuit, 1
5 indicates a reed/ausier changeover switch. First, the primary voltage that passed through the shield cylinder 8 collides with the surface of the sample 12,
Secondary electrons including Augier electrons are generated on that surface. These secondary electrons undergo an energy change due to an AC perturbation voltage 11 applied between the sample 12 and the ground, pass through the wire mesh electrode 1, and reach the transparent conductive film 5. On the other hand, since the blocking voltage 10 is directly applied to the surface of the transparent conductive film 5 through the L of the LC resonant circuit 14, only electrons with an energy higher than this blocking voltage 10 reach the collector, and electrons with an energy lower than 10 reach the collector. All of the electrons are reflected on the surface of the transparent conductive film 5, and therefore the energy analysis of the electrons is performed on this surface. The secondary electrons that have reached the collector 7 have an AC perturbation voltage of 1
Since the frequency f is modulated by 1, the LC resonator 14
By tuning to f1 or g, only the Auger signal contained in the secondary electrons or its differential signal is detected by the collector 7. When used as a lead device,
This is done by setting the AC perturbation voltage 11 to zero and simultaneously switching the Reed-Augier changeover switch to the collector acceleration voltage 9.

First, the primary electrons passing through the shield cylinder 8 are diffracted on the surface of the sample 12, and after passing through the wire mesh electrode 1, they are accelerated by the transparent conductive film 5, and collide with the fluorescent material 6, producing a diffracted electron image on the surface. This diffraction image is observed only through the wire mesh electrode 1.
In this case, the wire mesh electrode 1 serves to pass only internally diffracted secondary electrons by adjusting the bias voltage 13;
Depending on the shape of the sample 12, the electric field may not be radial around the sample, causing some distortion in the diffraction image.

In such a case, it goes without saying that this distortion can be removed by adding one more wire mesh electrode to the front of the wire mesh electrode 1 and grounding it. Further, the transparent conductive film 6 can also be replaced with a wire mesh. As is clear from the above description, the apparatus of the present invention has been improved to use one, or in some cases two wire mesh electrodes, and to apply an alternating current perturbation voltage between the sample surface and ground. As a result, it has the following features. (1)
A blocking voltage is applied to the transparent conductive film 5, and the minimum value of the passing energy is determined on the surface of this film, so that the conventional problem of field penetration between the meshes does not occur at all.

Therefore, resolution is improved. (2) Leakage of the AC perturbation voltage 11 to the collector electrode 7 is carried out through the AC grounded wire mesh electrode 1, but since the distance between the sample and the wire mesh electrode 1 is sufficiently large, compared to the conventional one, The effect can be minimized.

(3) In the conventional device, the secondary electron current generated from the electrons colliding with the fourth wire mesh electrode 4 is added to the Auger signal as shot noise, but in the device of the present invention, there is no fourth wire mesh electrode. Therefore, noise generated from the electrode is completely eliminated. (4) Since the number of wire mesh electrodes is three less than that of the conventional device, the structure is simpler and the manufacturing cost is accordingly lower.
(5) When used as a lead, the number of wire mesh electrodes is three fewer than in the conventional device, so the image observed only in that area becomes clearer.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional Reed-Augier analyzer, and FIG. 2 is a schematic diagram of a Reed-Augier analyzer of the present invention. 1 is a wire mesh electrode, 5 is a transparent conductive film, 6 is a fluorescent material, 7 is a collector, 8 is a shield cylinder, 9 is a collector acceleration voltage, 1
0 is the blocking voltage, 11 is the AC perturbation voltage, 12 is the sample, 13
14 indicates a bias voltage, 14 indicates a (1) resonant circuit, and 15 indicates a Reed-Augier changeover switch.

Claims (1)

[Claims] 1 A fluorescent substance is coated on the inner surface of the electrode, and a negative DC blocking voltage and a positive DC accelerating voltage are switched through a tuning circuit to a hemispherical collector electrode on which a conductive film is formed or a wire mesh is provided on the surface. In addition, one or two hemispherical wire mesh electrodes are provided at certain intervals on the inner surface of the collector, which are grounded through a DC power source, and further between the sample surface and the ground. A Reed-Auger analyzer characterized in that it is configured to apply an alternating current perturbation voltage.