JPS60113137A - Method and device for x-ray photoelectron spectrochemical analysis - Google Patents

Abstract

PURPOSE:To enable analysis of the local part on the extreme surface of a thin- walled nonconductive sample by impressing a voltage to the contact electrode on the rear, shifting the photoelectron spectrum by X-ray irradiation with respect to the spectrum in the other surface part, discriminating both and dividing the position. CONSTITUTION:A voltage is impressed on an electrode 14 in proximity to the local part of a sample 4 having about several tens mu thickness to change to potential in the local part and at the same time X-rays are irradiated from an X-ray gun 6 to release photoelectron which is conducted to an analyzer 8. The photoelectron is subjected to an energy sepn. by an energy scanning circuit 28 and is detected by a detector 10 according to the energy. An energy spectrum A1 is obtd. on an X-Y recorder 30 via an amplifier 26 and a selector switch 34 from the detection signal and the scanning signal. The spectrum A1 is proportional to the size of the local part and is similar to the spectrum A2 obtd. from the other surface. Only the energy corresponding to the impressed voltage appears with a shift.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an X-ray photoelectron spectroscopy method that uses soft X-rays as an excitation source and performs elemental analysis, state analysis, etc. of a sample using photoelectrons emitted from the sample; Regarding the device.

(B) Prior Art In general, Auger electron analyzers and X-ray photoelectron spectrometers are widely used as means for analyzing the extreme surface of a sample. The Auger electron analyzer is extremely difficult to analyze non-conductive samples such as electron ceramics, metal inclusions, and raw materials because the sample becomes charged. On the other hand, X-ray photoelectron spectrometers use X-rays as the excitation source, making it possible to analyze the very surface of non-conductive samples, but conversely, it is difficult to analyze localized areas because the radiation source cannot be detected. There is a problem.

For this reason, conventionally, as a local part of a non-conductive sample using an X-ray photoelectron spectrometer, the surface of the sample is covered with a mask, a small hole is formed in a part of this mask, and the X-ray is selected into the sample through the small hole. irradiate the target.

Alternatively, a method has been adopted in which photoelectrons emitted from the sample are enlarged and displayed using a lens system to partially select a specific position on the sample. However, in the former case, the signal from the mask material is superimposed on the signal from the analysis sample and is further affected by the gap between the mask and the sample, making measurement difficult. Furthermore, in the latter case, it has not yet been put into practical use due to the difficulty in designing the optical system and the low signal strength obtained from the sample.

(c) Purpose The present invention eliminates the above-mentioned spacing point, makes it possible to perform local partial irradiation on the extreme surface of a thin non-conductive sample by X-ray excitation, and further,
The purpose of this study is to make it possible to measure the two-dimensional distribution of elements on the sample surface as a collection of local areas.

(d) Structure In order to achieve such an object, the present invention brings an electrode into contact with the back surface of a thin non-conductive sample, applies a voltage to this electrode, and applies a voltage to the surface side of the sample corresponding to the electrode position. By changing the potential and measuring the energy of photoelectrons emitted from the sample surface It by irradiating the surface of the sample with X-rays, the energy spectrum obtained at the surface portion of the sample corresponding to the electrode position can be calculated by The energy spectrum obtained from other surface areas of the sample is analyzed to distinguish between the two and to perform positional resolution. The JT4 X-ray photoelectron spectrometer used for this purpose has a probe that is brought into contact with the back surface of a thin, non-conductive sample. While they are arranged in parallel, the electrode application power supply that applies a voltage to each of the electrodes and the electrode selection circuit that selectively switches and connects the electrode application power supply to the electrodes are arranged in a biased manner.

(e) Examples Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

Figure 1 shows a thin non-conductive sample 4 to be analyzed in the X-ray photoelectron spectrometer of this embodiment, an X-ray gun 6 that irradiates the surface of this sample 4 with X-rays, and An analyzer 8 that separates the energy of photoelectrons that are excited and emitted, and a detector 10 that detects the electrons energy-separated by the analyzer 8 are arranged, respectively.

Furthermore, one end of the probe 12 protrudes into the vacuum chamber 2 .

As shown in FIGS. 2 and 3, the probe 12 is composed of a large number of linear electrodes 14 arranged two-dimensionally in parallel via a solid material 16 such as ceramic. The flJ+ area of each electrode 14 is set in consideration of factors such as the necessary degree of positional resolution of the sample 4, detection sensitivity, sample thickness, and difficulty of the electrode type, but is usually about 0, 1 to 05-. It is. One end surface of this probe 12 is connected to the back surface 4 of the sample 4.
b. Reference numeral 20 designates an electrode application power source for applying a voltage to each electrode work 4 of the globe 12, and 22 represents an electrode selection circuit that selectively switches and connects the electrode application power source 2o to the electrode 14. Reference numeral 24 denotes an electrode scanning circuit that outputs an electrode scanning signal to the electrode selection circuit f&22 when the applied force 1 and voltage of the electrode 14 are two-dimensionally scanned. 26 is an amplifier that amplifies the photoelectronic detection signal outputted from the detector 10, 28 is an energy scanning circuit that performs energy setting for the analyzer 8, 30 is an XY recorder, and 32 is a CR
T, 34 is a changeover switch that selects and switches the output from the amplifier 26 between the XY recorder 30 and the CRT 32.

Next, a method of applying the X-ray photoelectron spectrometer 1 to perform local partial analysis of the sample 4, and then a method of measuring the two-dimensional distribution of elements on the surface of the sample 4 will be described. First, the sample 4 is placed on the top of the probe 12. This sample 4 is formed into a thin film with a thickness of approximately several microns. Then, the electrode selection circuit 22 selects an electrode 14 close to the local area S to be analyzed on the surface 4a of the sample 4, and applies a predetermined voltage to the selected electrode 14 from the electrode application power source 20 via the electrode selection circuit 22. Apply. Then, as shown in FIG. 3, an equipotential surface is formed on the sample 4, and this electrode 1
A local portion S on the surface 4a side of the sample 4 adjacent to the position 4 is also charged and the potential changes. In this state, try X41 gun 6 (
:''4 Irradiate the surface 4a with X-rays. The sample 4 is excited by the X-rays, and photoelectrons are emitted from its surface 4a.

These photoelectrons are detected by the analyzer 8. The photoelectrons guided to the analyzer 8 are energy-separated within the analyzer 8 by energy scanning by the energy scanning circuit 28, and are detected by the detector 1O according to the energy. This detector 1
After the photoelectronic detection signal output from 0 is amplified by the amplifier 26, it is sent to the XY recorder 3 by switching the changeover switch 34.
Sent to 0.

At the same time, the energy scanning signal output from the energy constant distortion circuit 28 is also sent to the XY recorder 30.

Therefore, the XY recorder 30 records an energy spectrum as shown in FIG. 4, for example. In other words, when the surface 4a of the sample 4 contains the same amount of ['L, the energy spectrum AI obtained from the local area S in particular shows that the energy of the photoelectrons emitted from the area changes due to the influence of charging. Therefore, it is proportional to the size of the local part S, and is similar to the energy spectrum A2 from other surface parts, and is shifted by the energy corresponding to the voltage applied to the electrode 14. appear. Therefore, the local portion S of the surface 4a of the sample 4 can be positionally resolved by distinguishing it from other surface portions Σ.

Next, in order to measure the two-dimensional distribution of a specific element on the surface 4a-H of the sample 4, first, the energy of the analyzer 8 is set to, for example, the energy spectrum A2 of one element in the local part S as described above. is fixed at one peak position E. Subsequently, an electrode scanning signal is generated from the electrode scanning circuit 24 and applied to the electrode selection quantity 22. The electrode selection circuit 22 sequentially selectively switches the connection between each electrode 14 and the electrode application power source 2C based on this electrode scanning signal, so that the electrode 14 is two-dimensionally scanned with respect to the sample 4. Further, the electrode scanning signal of the electrode scanning circuit 24 is outputted to the CRT 32 as a horizontal/vertical synchronizing signal. In parallel with the above, since X-rays are irradiated from the X-ray gun 6 onto the surface 4a of the sample 4, the photoelectron detection signal outputted from the detector 10 is sent to the CRT 32 as a brightness modulation signal via the amplifier 26 and the changeover switch 34. In other words, the CRT 32 displays a two-dimensional distribution image of the specific element to be analyzed.

In this embodiment, a linear electrode 14 is used as the electrode 14 of the probe 12, but as shown in FIG. Each electrode 54 may be connected to a terminal 56. Also, a large number of electrodes 14.54
The same purpose can also be achieved by scanning one electrode parallel to the sample 4 instead of using .

(F) Effect As described above, according to the present invention, the X
It is possible to analyze a localized portion of the extreme surface by linear excitation, and the excellent effect of being able to measure the two-dimensional distribution of elements on the sample surface as a collection of these localized portions can be obtained.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a configuration diagram of an X-ray photoelectron spectrometer, FIG. 2 is a plan view of a probe,
Figure 3 is a cross-sectional view showing part of the sample and probe, Figure 4 is a diagram of the energy spectrum obtained with the apparatus shown in Figure 1,
FIG. 5 is a perspective view showing another modification of the probe. 1...X-ray photoelectron spectrometer, 4...
Sample, 12, 50...Print, 14.54...
... Electrode, 16.52 ... Insulator, 20 ...
. . . Electrode application power supply, 22 . . . Electrode selection circuit. Applicant: Shimadzu Corporation Representative 4th Attorney Doma Patent Attorney 1) Hide Kazu Figure 2 V Figure 4 Strong

Claims (1)

[Claims] K) An electrode is brought into contact with the back surface of a thin non-conductive sample, and a voltage is applied to this electrode to change the potential on the surface side of the sample near the electrode position. X on the surface of
By measuring the energy of photoelectrons emitted from the surface of the sample by irradiating it with a beam, the energy spectrum obtained at the surface portion of the sample near the electrode position can be calculated from the energy spectrum obtained at other surface portions of the sample. An X-ray photoelectron spectroscopy method characterized by shifting the spectrum, distinguishing between the two, and performing position resolution. (2) It has a flowb that is brought into contact with the back surface of a thin non-conductive sample, and this flowb is composed of a large number of electrodes arranged two-dimensionally in parallel via an adhesive, and each of the electrodes 1. An X-ray photoelectron spectrometer comprising: an electrode application power source that applies a voltage to the electrode; and an electrode selection circuit that selectively switches and connects the electrode application power source to the electrode.