JPH0766774B2 - Sample surface analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an analyzer in which an X-ray high electron analyzer and a scanning tunneling microscope are combined.

(Prior Art) Although the X-ray photoelectron analysis method can analyze the element surface of the sample and the bonding state of the elements, it cannot know the fine shape structure of the sample surface. On the other hand, the scanning tunneling microscope can observe the shape structure of the sample surface on an atomic scale, but cannot directly know the relationship between the observed shape structure and the chemical bonding state of the constituent elements of the sample surface. Conventionally, there are devices that combine a scanning electron microscope and a scanning tunnel microscope, but the scanning electron microscope can only observe the shape of the sample surface. Although it can be said that the analysis position can be confirmed by observing with a scanning electron microscope, it is not possible to obtain information about the elements forming such a structure.

For this reason, in the case of observing the fine structure of the sample surface in association with the constituent elements, there is no choice but to perform the X-ray photoelectron analysis of the sample surface and then transfer the sample to a scanning tunneling microscope for observation. Since both the X-ray photoelectron analyzer and the scanning tunnel microscope are high-vacuum devices, the sample must first be exposed to the atmosphere when it is transferred from the X-ray photoelectron analyzer to the scanning tunnel microscope. The components are adsorbed or oxidized, and the observation result with the tunnel microscope does not correspond to the original elemental composition of the sample surface.

(Problems to be Solved by the Invention) In the present invention, the analysis of the correlation between the elemental composition of the sample surface and the fine structure, the analysis of the growth process when a thin layer is grown on the sample surface, etc., are performed without disturbing the atmosphere. The purpose is to obtain a device to obtain.

(Means for Solving the Problem) An X-ray photoelectron analysis apparatus and an ion irradiation means in one vacuum outer casing, a means for moving a sample between the ion irradiation means and the X-ray photoelectron analysis apparatus, and A scanning tunneling microscope in which the probe can advance and retreat to the sample position of the X-ray photoelectron analyzer, and the probe is arranged to face the probe at a position retracted from the sample position in the X-ray photoelectron analyzer. An electric field microscope composed of a channel plate and a means for applying a high voltage between the probe and the upper and lower channel plates at this position was arranged.

(Operation) If the scanning tunnel microscope is installed in the outer casing of the X-ray photoelectron analyzer, the sample of the scanning tunnel microscope is moved between the two without moving the sample or moving the sample. It is easy to expose it to the analysis position, and the sample can be observed by both devices while it is installed in the vacuum enclosure.
Not disturbed by the atmosphere. Further, in the present invention, since the ion irradiation means is provided in the same vacuum outer casing, the sample surface can be cleaned by ion bombardment, ion etching, etc., and the growth process of the sample surface layer can be observed by a scanning tunneling microscope. It is necessary to keep the tip of the probe in the same shape to obtain a tunnel microscope image, but since the electric field microscope using the probe of the tunnel microscope as a sample is provided in the same vacuum container, the shape of the probe tip can be confirmed. The reliability of the observation result also becomes high.

(Example) An example of the present invention is shown in the drawing. FIG. 1 is a diagram in which the arrangement of each part of the device is developed in a horizontal row.
As shown in the figure. 1 is an outer casing and is connected to the exhaust system 2 and is 10 ^-10 T
Exhausted to about orr. Inside the outer casing, 3 is an X-ray gun, and 4 is a sample stage, which is arranged below the X-ray gun and has a fine movement mechanism in the X, Y, and Z axis directions. S is a sample set on the sample stage. An ion gun 5 is arranged next to the X-ray gun in the outer casing. Reference numeral 6 is a sample table arranged below the ion gun 5, and is provided with a heater 7 for heating the sample. Reference numeral 8 is a preliminary vacuum chamber for introducing a sample, and 9 is a gate valve. An electron energy analyzer 10 is a double spherical electrode type, and the electron incident side desires the X-ray irradiation region of the sample surface. Reference numeral 11 denotes an electron detector, on which electrons of a specific energy having passed through the electron energy analyzer 10 are incident and detected. A probe 12 of the scanning tunneling microscope is fixed to the lower surface of the X, Y, Z three-axis direction fine movement device 13. This fine movement device is composed of three piezoelectric elements arranged in three axial directions, can move left and right along the horizontal guide 14 in FIG. 1, and when it is positioned at the left end of the guide 14, the probe 12 Is located at the observation point on the sample surface. This observation point is located at the center of the X-ray irradiation area on the sample surface by the X-ray gun, which is also the electron energy analyzer.
It is also the intersection of the 10 optical axes and the sample surface. When the fine movement device 13 of the probe is located at the right end of the guide 14 in FIG.
A multi-channel plate 15 is arranged at a position below 12. At the right end of the guide of the fine movement device 13,
A high voltage can be applied to 12, and the output of the multi-channel plate is displayed as an image on a CRT (not shown). This image when a high voltage is applied to the probe 12 is a field electron microscope image of the probe tip, and by observing this image at any time, it is possible to detect the presence or absence of a change in the probe tip. The guide 14 is located below the electron energy analyzer in FIG. 1, but the actual arrangement is as shown in FIG.
The line gun 3, the ion gun 5, and the electron energy analyzer 10 are arranged in a direction orthogonal to the three-way arrangement.

An example of the sample measurement procedure by the above-mentioned apparatus will be described. The sample is transferred from the preliminary exhaust chamber 8 onto the sample stage 6, the sample is heated by the heater 7 to remove the adsorbed substance, or the ion gun 5 is operated to etch the sample surface with an ion beam,
After the sample surface is further cleaned, the sample is transferred onto the sample stage 4. The X-ray gun 3 is operated to irradiate the sample surface with X-rays, and the X-ray photoelectrons emitted from the sample are subjected to energy analysis by the electron energy analyzer 10. During this time, the probe 12 has been moved to the right end position of the guide in FIG. After the X-ray photoelectron analysis is completed, a high voltage is applied to the probe 12, and an electric field microscope image at the tip of the probe is observed, and if necessary, that image is recorded. Next, move the probe 12 to the left end of the guide in FIG.
The position of the sample S in the Z direction is adjusted, the probe 12 is finely moved in the X and Y directions to scan the sample surface, and a scanning tunneling microscope image is recorded.

The image signal of the tunnel microscope is a Z direction drive signal of the fine movement device 13 when the probe is finely moved in the Z direction so that the current flowing through the probe is constant while scanning the sample surface in the X and Y directions. Is. After the above measurement is completed, the sample is moved onto the sample table 6, the ion gun 5 is operated, the sample surface is etched by the ion beam, the sample surface is finely ground, and again the X-ray photoelectron analysis and the scanning tunneling microscope image Captures video signals. At this time, prior to the signal acquisition of the tunnel microscope image,
The field electron microscope image of the tip of the probe 12 is observed to confirm whether it is the same as the previous measurement. The above-described operation can be repeated below to proceed with the analysis in the depth direction of the sample surface.

Although only X-ray photoelectron analysis and observation by a scanning tunneling microscope are performed in the apparatus of the above-described embodiment, a mass analyzer for scattered ions is additionally provided so that scattered ion mass analysis can be performed by using the ion gun 5. Of course, it is also possible.

(Effect of the Invention) According to the present invention, the atomic level structure of the sample surface and the attached state of the attached atoms can be observed by the scanning tunneling microscope, and the chemical structure corresponding to the atomic structure can be observed by the combined use with the X-ray photoelectron analysis method. It is possible to obtain reliable information on the relationship between the chemical structure of the sample surface and the atomic level structure, since the physical structure can be determined and there is no risk of being polluted by the atmosphere during the process. Then, an electric field microscope that uses the scanning tunneling microscope's probe itself as a sample was installed so that it could be checked for changes in the probe tip shape, so tunnel microscope images to be compared with each other can be obtained with the same tip probe. This guarantees the reliability of the analysis results.

[Brief description of drawings]

FIG. 1 is a developed side view of the arrangement of each part of the apparatus of one embodiment of the present invention, and FIG. 2 is a plan view of the apparatus of the same embodiment. 1 ... Outer casing, 2 ... Exhaust system, 3 ... X-ray gun, 4 ... Sample stage, 5 ... Ion gun, 6 ... Sample stand, 7 ... Heater, 8 ... Preliminary vacuum chamber, 9 ...... Gate valve, 10 …… Electron energy analyzer, 11 …… Electron detector, 12 …… Tip,
13 ... Tip fine movement device, 14 ... Guide, 15 ... Multi-channel plate, S ... Sample.

Claims (1)

[Claims] 1. An X-ray photoelectron analysis apparatus and an ion irradiation means in one vacuum casing, a means for moving a sample between the ion irradiation means and the X-ray photoelectron analysis apparatus, and the X-ray photoelectron analysis. A scanning tunneling microscope in which the probe can advance and retreat to the sample position of the device, and a channel plate and a position of the channel plate which are arranged to face the probe at a position where the probe is retracted from the sample position in the X-ray photoelectron analyzer. And a field surface microscope comprising a probe and means for applying a high voltage between the upper and lower channel plates.