JPS61184445A - X-ray photoelectric spectroscopic apparatus - Google Patents

Abstract

PURPOSE:To make an analytical region localizable and to also facilitate the surface scanning of a specimen, by together using the irradiation of electron beam. CONSTITUTION:Modulated electron beam B is converged to one point on a specimen 1 irradiated with X-rays E and, at this time, X-ray photoelectron (e) is detected by a detector 6 through an energy analyser 5. The photoelectron energy emitter from the point receiving the irradiation of electron beam B of the specimen 1 is varying in synchronous relation to AC modulating electron beam B and, therefore, converted to a high and low intensity modulation signal by the passage through the energy analyser 5. As a result, by taking out a signal component with modulated frequency from a lock-in amplifier 7, the detection signal only of the X-ray electron at the electron beam irradiation point on the surface of the specimen 1 can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an X-ray photoelectron spectroscopy device that enables analysis of minute areas.

- Conventional technology X-ray photoelectron spectroscopy is a method of irradiating a sample with X-rays and analyzing the energy of photoelectrons emitted from the sample.
Since there is no suitable convergence means for the line, it is difficult to analyze minute areas of the sample using this method, and currently analysis information is obtained from areas on the order of mm. These proposals use diffraction to focus X-rays, and a photoelectron energy analyzer forms an image of the sample surface using photoelectrons, and extracts information from only a specific area in this image. However, the former makes it difficult to scan the sample surface, and the latter makes it difficult to obtain sufficient positional resolution.

C.1 Problems to be Solved by the Invention The present invention aims to provide an X-ray photoelectron analyzer that can easily scan the surface of an electrically insulating sample and has high positional resolution.

2.Means for resolving the problem At the same time, the sample surface is irradiated with X-rays, and the analysis point on the sample surface is
A low-acceleration electron beam is converged in a range where secondary electrons are not emitted, the intensity of this electron beam is modulated at an arbitrary frequency, and the photoelectrons emitted from the sample are energy-analyzed to detect only photoelectrons with a specific energy. Only the signal components synchronized with the modulation frequency of the electron beam are extracted from the above.

(e) Function When an insulating sample is exposed to X-rays and emits photoelectrons, it becomes positively charged and maintains the potential created by the leakage current. When the sample is irradiated with an electron beam, this positive charge is neutralized and the potential of the sample decreases. The detected energy of the photoelectron is the sum of the energy that the photoelectron originally has and the energy given by the potential difference between the sample and the photoelectron 1 extraction electrode.

Therefore, if the intensity of the electron beam irradiating the sample is modulated at a certain frequency, the potential on the sample surface changes accordingly, and if the value of the energy to be detected is set to a specific value, the energy The photoelectron detection signal fluctuates in synchronization with the modulation frequency of the irradiated electron beam. The above is X
This is true only in the part of the sample surface that is irradiated with the electron beam, so by extracting only the component that is synchronized with the modulation frequency of the irradiated electron beam from the detection signal of a specific energy, it is possible to Only the information on the X-ray photoelectrons at the point being irradiated can be extracted. The specific energy in the above explanation is not fixed,
It goes without saying that it can be selected from a variety of options, and energy scanning is possible.

Embodiment The drawings show an embodiment of the present invention. A sample 1 is placed on a test tilt table 2. 3 is an X-ray source, and 2 is an X-ray that irradiates the sample. 4 is an electron gun, which focuses the electron beam B on one point on the sample 1). S is an electron acceleration power source. In the electron gun 4, an AC signal is applied between the filament F and the Wehnelt electrode W via a transformer T, and modulates the electron beam current forming the electron beam B.

X-ray photoelectrons e are emitted from the X-ray irradiation area of sample 1. 5 is an electron energy analyzer, and 6 is an electron detector that detects the electrons that have passed through the energy analyzer 5. The output signal of the detector 6 is input to a lock-in amplifier 7.

Since the primary side of the transformer T is excited by the alternating current that drives the lock-in amplifier 7, the lock-in amplifier 7 extracts only the signal component synchronized with the modulation frequency of the electron beam B from the output signal of the detector 6. This is input to the XY recorder 8 as a Y-axis drive signal for the XY recorder. An energy scanning power source 9 changes the voltage applied between the electrodes of the energy analyzer 5 to change the energy of electrons passing through the energy analyzer 5, and also applies an X-axis drive signal to the XY recorder 8.

As mentioned in the previous section, the energy of photoelectrons emitted from the point of sample 1 that is irradiated with electron beam B fluctuates in synchronization with the alternating current that modulates electron beam B, so the energy analyzer When the energy of an electron that can pass through 5 is a value, the photoelectron that is emitted from the electron beam irradiation point of the sample and has the above energy fluctuates around that energy, assuming that there is no modulation of the electron beam. By extracting the signal component of the modulation frequency with an amplifier, a detection signal of only the X-ray photoelectrons at the electron beam irradiation point on the sample surface can be obtained.

Effects: The X-ray photoelectron analyzer of the present invention has the above-described configuration, and since the analysis area is limited to the irradiation point of the electron beam, it is possible to analyze a minute area, and the resolution of the position of the analysis point is high.
Scanning of the sample surface is also possible very easily.

[Brief explanation of drawings]

The drawing is a block diagram showing the configuration of an embodiment of the present invention.

Claims (1)

[Claims] An X-ray source that irradiates the sample surface with X-rays, an electron gun that focuses the electron beam on a single point on the sample surface, and an energy analyzer that analyzes the energy of electrons emitted from the sample. an electron detector for detecting electrons that have passed through the electron gun, an electron flow modulating means for the electron beam is provided in the electron gun, and means for extracting a signal synchronized with the modulated alternating current of the modulating means from the output signal of the electron detector. An X-ray photoelectron spectrometer was installed.