JPH02145950A - X-ray photoelectron analyzer - Google Patents

Abstract

PURPOSE:To enable efficient analysis without limit to an adaptive sample by performing an analysis with a background corrected by a single scanning of a sample surface. CONSTITUTION:A sampled stage 1 is driven two-dimensionally in two directions of x and Y with x-way and y-way drivers 2x and 2y. X-ray photoelectrons of a sample surface are accelerated or decelerated properly with an electron accelerating lens system 4 laced between a sample S and a slit 3s on the electron incident side of an energy analyzer 3 and an image thereof is formed on a surface of the slit 3. A plurality of electron detectors 51, 52 and 53 are arranged in such a direction that an energy spectrum is dispersed with the analyzer 3 and one thereof is placed at a point A corresponding to a peak P and hence, adjacent electron detectors measure a background intensity. Thus, by subtracting an output 1b or Ic of the electron detector at an adjacent point B or C from an output 1a of the electron detector placed at the point A, a true peak height H is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is suitable for measuring the distribution of elements on a sample surface or the distribution of bonding states of elements. Regarding a photoelectron analyzer.

(Prior Art) X-ray photoelectron analysis is an effective method for measuring the elemental composition or the bonding state of elements on the surface of a sample. Normally, when performing this type of measurement, a sample is irradiated with X-rays, the X-ray photoelectrons emitted from the sample are analyzed with an energy analyzer, the energy spectrum of the X-ray photoelectrons is measured, and the position of the peak that appears in the energy spectrum is measured. Elements are determined based on this, or the bonding state of that element with other elements within the sample is determined based on the shift in the peak position of one element.

By the way, when applying the above-mentioned X-ray photoelectron analysis method to the measurement of element distribution on the sample surface, it is necessary to scan the sample surface, so an energy analyzer is used to perform energy scanning for each pixel area on the sample surface. If the operation of measuring the energy spectrum is carried out, it would take a very long time to measure the entire sample surface, which is practically impossible.

Therefore, when performing area analysis or line analysis of a sample surface using X-ray photoelectron analysis, the energy of the energy analyzer is fixed to the peak position of the element to be measured, and the sample surface is scanned. is used. However, in the energy spectrum of X-ray photoelectrons, the peaks of each component element are superimposed on a strong background that includes information on matrix components and other elements, so if the background is constant over the entire sample, the above method can be used. The measurement results obtained can also show the relative change in the distribution concentration of the target element, but if the background intensity differs depending on the location, the combination of the background change and the concentration change of the target element is the target element. The measurement itself becomes meaningless as it is expressed as a change in concentration. For this reason, set the energy of the energy analyzer to a value slightly outside the peak of the target element, scan the sample surface, first obtain the background distribution of the sample surface, and then set the energy of the energy analyzer to a value slightly outside the peak of the target element. There was no choice but to perform surface analysis by scanning the sample surface again at least twice in accordance with the peak, and subtracting and displaying the previous measurement results.

(Problems to be Solved by the Invention) The present invention is an X-ray photoelectron analysis method that can be used to perform surface analysis or line analysis of a sample surface without measuring the entire energy spectrum. An object of the present invention is to provide an X-ray photoelectron analyzer that can perform background correction without performing multiple scans.

(Means for solving the problem) In the electron energy analyzer, a plurality of electron detectors are arranged in the energy spectrum dispersion direction, and the electron energy analyzer is arranged so that the X-ray photoelectron of the target element is incident on one of them. The applied voltage was set, and the output of the adjacent electron detector was subtracted from the output of the same electron detector to obtain the peak detection output of the target element without background information.

(Function) The energy distribution of X-ray photoelectrons generally takes the form shown in Figure 3. Here, P is the peak of the target element and B is the background. In the present invention, the electron energy analyzer has a plurality of electron detectors arranged in the dispersion direction of the energy spectrum, and one of them is placed at point A corresponding to peak P in FIG. The electronic detector will measure the background intensity. Therefore, by subtracting the output Ib or Ic of the electron detector at the adjacent point B or 0 from the output ra of the electron detector placed at point A, the true peak height H can be found.

It goes without saying that it is better to subtract the average (Ib+Ic)/2 of the outputs of the electron detectors B and C on both sides from Ia instead of subtracting the output of the electron detector on one side.

(Embodiment) FIG. 1 shows an apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a sample stage, which is driven two-dimensionally in two xy directions by X-direction and X-direction driving devices 2x and 2y. S is a sample placed on the sample stage. 3 is a hemispherical energy analyzer, and 4 is an electron accelerating lens system placed between the sample S and the electron incident side slit 3S of the energy analyzer 3, which accelerates the X-ray photoelectrons on the sample surface and decelerates the acid appropriately. and forms its image on the surface of the slit 3. X is an xl X-ray source that irradiates the sample surface. With the above configuration, X-ray photoelectrons emitted from a minute region at a specific position on the sample surface are focused onto the slit 3S of the energy analyzer 3 and made incident on the energy analyzer 3.

A plurality of electron detectors 51, 52, and 53 are arranged on the energy spectrum image plane on the energy emission side of the energy analyzer 3. These electron detectors are aligned in the dispersion direction of the energy spectrum. Reference numeral 6 denotes a computer (CPU) and a memory, and the CPU drives the sample stage two-dimensionally in the xyx directions to scan the sample surface with an X-ray beam, and also uses data on the position of the sample stage as address data for each electron detector 51. 52. Take the output of 53 into memory. Reference numeral 7 denotes a power source for generating voltage to be applied to the energy analyzer 3 and the electron lens system 4, which is controlled by the CPU and applies a voltage to the energy analyzer 3 such that X-ray photoelectrons of the target element are incident on the central electron detector 52. and is applied to the lens system 4. The electron detectors 51 to 53 are all channeltron type electron detectors, and as shown in FIG. be. Therefore, the output of each electron detector 51 to 53 is the area At, A2 . Corresponding to A3, the detection output I of X-ray photoelectrons of the desired target element is given by 1=A2-(A1+A3)/2 since it is a double hatched area in area A2. The CPU calculates the above I, stores it in the memory, reads the data from the memory in TV mode y, and
Display on RT as a concentration distribution map of the target element.

In the energy analyzer 3, two detectors 51 and 52
Or the energy difference ΔE of detected electrons between 52 and 537
If E is the path energy set in the energy analyzer, that is, the energy of the electrons incident on the detector 52, then Δ
There is a relationship called EOeE. In the present invention, it is necessary to place the detector 51, 53 at a location slightly away from the rising point of one peak of the X-ray photoelectron spectrum, but the half-value width of the peak of the X-ray photoelectron spectrum depends on the elements and their bonding states. V is fixed and differs for each peak. Therefore, for the peak to be measured, the detector 51.53
Instead of changing the position of the target X-ray photoelectrons, the lens system 4 decelerates them appropriately, sets the energy E when it enters the energy analyzer, and adjusts the bus energy of the energy analyzer to that value. Since ΔE changes in proportion to and E, E±ΔE can be adjusted to a value slightly distant from the rising point of the peak of the target X-ray photoelectron.

In the above embodiment, scanning of the sample surface is performed by driving the sample stage in the x and y force directions, but the electron lens system 2
It goes without saying that a deflection electrode may be disposed at the surface of the sample and the sample surface may be scanned electro-optically.

(Effect of the invention) Conventionally, background correction is not normally performed in area analysis, line analysis, etc. using X-ray photoelectron analysis, so the samples that can be analyzed are limited, and even if background correction is performed, it requires multiple times. This required scanning the sample surface, which was extremely inefficient, but with the present invention, it is possible to perform analysis with background correction by scanning the sample surface once, so there is no limit to the applicable samples, making analysis more efficient. Now I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram illustrating the operation of the embodiment, and FIG. 3 is a diagram illustrating the principle of the present invention. 1...Sample stage, S...Sample, 2X, 2y...
・X. y-direction drive device, 3... Energy analyzer, 4... Electron lens system, 51.52.53... Electron detector, 6.
... CPU, 7... Voltage power supply. sI diagram agent patent attorney Kosuke Agata 1135! ff

Claims (1)

[Claims] A plurality of electron detectors are arranged in the dispersion direction of the energy spectrum of the electron energy analyzer, and a calculation means is provided for subtracting the output of an adjacent electron detector from the output of one of the electron detectors. X-ray electron analyzer.