JP2000028556A - Spectral analysis method for energy of charged particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the charge of a sample under a controlled condition to provide an energy spectrum in an accurate position with a stable peak shape all the time, when the energy of a charged particle is dispersed into its spectral components to be measured. SOLUTION: A sample is pulverized, and resulting pulverized powder 1 is used for analysis in a state that the powder 1 is embedded into a conductive material 2, in a energy spectral analysis method of a charged particle where energy of the charged particle is dispersed into its spectral components in an Auger electron spectroscopy or an X-ray electron spectroscopy to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle energy spectroscopy method for performing energy spectroscopy and measurement of charged particles, for example, charged particles emitted from a sample such as Auger electron spectroscopy and X-ray electron spectroscopy. For energy spectroscopy and measurement.

[0002]

2. Description of the Related Art As represented by Auger electron spectroscopy and X-ray electron spectroscopy, charged particles are subjected to energy spectroscopy.
In the analysis method for measurement, charged particles are emitted by excitation, so that the charge state of the sample changes during measurement for a fundamental reason. Similar changes occur when charged particles are used as an excitation source as in Auger electron spectroscopy or when ion beam irradiation is performed during depth analysis.

At this time, if the sample is an insulator or a substance having a high dielectric constant, the potential of the sample changes significantly. For this reason, the energy spectrum obtained as a measurement result shifts in the energy direction by the sample potential, and the exact energy position of the peak becomes unknown, or the potential changes over time, or the charged state locally changes. If they are different, significant adverse effects occur, such as a change in the peak shape itself.

As a method of solving the problem, (1) irradiating a neutralizing electron beam (such as X-ray electron spectroscopy). (2) The sample is tilted with respect to the incident electrons (such as Auger electron spectroscopy). (3) Put a metal net on the upper part of the holder (X-ray electron spectroscopy, etc.). (4) Apply a conductive substance to the sample surface. (5) Introduce ionized gas into the analysis room (X-ray electron spectroscopy, etc.). Are often used.

[0005]

However, in the case of an insulator having an extremely high dielectric constant, the effects of the above methods (1), (2) and (3) are not always great, and In many cases, the method of obtaining conduction near the measurement location as in (4) and (5) has a larger effect of suppressing charge-up. However, in an analysis chamber requiring an ultra-high vacuum atmosphere, the amount of gas introduced is limited, that is, the method (5) has an upper limit on the amount of charge suppression. In the method (4), specifically, a metal piece is brought into close contact with the surface, or a metal film is patterned and applied so as not to cover the measurement site. However, metal pieces cannot always be adhered well, and it is not easy as a method to apply a metal film in a pattern.

SUMMARY OF THE INVENTION It is an object of the present invention to measure the energy of a charged particle, such as an electron, in a state where the charge of the sample is suppressed, so that the energy spectrum can always be obtained at an accurate position with a stable peak shape. It is to provide a method that enables

[0007]

That is, the present invention provides a charged particle energy spectroscopy method for measuring the energy of a charged particle, such as Auger electron spectroscopy or X-ray electron spectroscopy, and pulverizing a sample. Characterized in that the sample pulverized material is subjected to analysis in a state of being embedded in a conductive material,
The present invention relates to a charged particle energy spectroscopic analysis method (hereinafter, referred to as a method of the present invention).

According to the method of the present invention, the sample is crushed, and the crushed sample is embedded in a conductive substance and is used for analysis. The distance between the conductive material and the conductive material is small, so that electrons can easily enter and exit at the measurement site, and charging can be easily and reliably prevented. As a result, the measurement is performed in a state where the charging of the sample is suppressed, and the energy spectrum is always obtained at an accurate position with a stable peak shape.

The method of the present invention is, in principle, the same as the method described in (3) and (4) above, which enables charge transfer in the vicinity of the measurement position. There is an advantage that charging can be easily and surely suppressed because it is only necessary to bury the material in the conductive material.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of the present invention, the distance between a measurement site irradiated with an excitation probe for measurement and a conductive material in contact with the measurement object (sample) is reduced by crushing the measurement target (sample) into smaller pieces. Can be further reduced and therefore
The finer the powder, the easier it is for electrons to enter and exit from the measurement site, and the more the charge can be sufficiently prevented. For this reason, it is preferable to crush the sample made of an insulator to an average particle size of 20 μm or less to reduce the particle size, and embed the sample crushed product in a metal.
This makes it possible to measure the insulator while suppressing measurement disturbance due to sample charging. However, the optimum value of the particle size after the reduction of the particle size is unconditionally determined because it depends on the dielectric constant of the measured object and the current amount of the excitation probe.

In this case, it is preferable to use a soft metal having high conductivity, such as gold or indium, as the metal, and mount the crushed sample on the sample support while embedding and fixing the sample by a method such as press fitting. For example, a crushed sample is pressed against a metal with a pestle, and particles touched by the pestle on the upper surface and particles not embedded in the metal are sieved off to clean the surface and expose the particles directly in contact with the metal to the surface.

For example, a measured substance is pulverized with an agate mortar or the like to an average particle diameter of 20 μm or less to reduce the particle diameter, and as shown in FIG. (For example, gold or indium) by embedding and fixing by the above-described method such as press-fitting, and fixing this on the sample support 3, the charge at the time of measuring the insulator by the scattered electrons 4 and the like is transferred from the metal 2 to the support 3. Can be discharged, so that charging can be suppressed.

[0013]

Next, the present invention will be described in detail with reference to examples.

In this embodiment, the object to be measured is lithium oxide (Li ₂ O), but the Li ₂ O crystal has a high resistance value,
Susceptible to measurement disturbance due to charge-up. Under the following conditions, Li ₂ O powder crystals (unground material) were embedded and fixed in metal indium by a press-fitting method, and Auger electron spectroscopy was performed under the following conditions.

[0015]

The Auger electron spectroscopy spectrum thus obtained is shown in FIG. 2 (however, in Reference Examples 1 and 2, unmilled particles (Li ₂ O: However, in these Reference Examples, the individual to be measured is different). ) And argon ion sputter cleaning was performed until no carbon from the contamination source was detected from the surface). The horizontal axis is the kinetic energy of the electrons, and the vertical axis is the derivative of the intensity. The Auger peak appears as a peak protruding in the vertical direction of the vertical axis at the energy position unique to the element.

From FIG. 2, it can be seen that Auger electron spectroscopy shows that the kinetic energy of the unmilled sample (Reference Example 1 and Reference Example 2) having a particle size of approximately 100 μm φ is shifted to a higher energy side due to charging. Or broadening of the peak width occurs. Moreover, due to the difference between Reference Example 1 and Reference Example 2, the behavior of the change in the spectrum differs depending on the measurement particles and the measurement positions, and the reproducibility is poor.

On the other hand, the average particle size is 10 μmφ by using an agate mortar.
FIG. 2 shows an Auger electron spectroscopy spectrum of a sample (the present invention) in which the Li ₂ O crystal crushed to the maximum size is embedded in metal indium by the press-in method and fixed. As compared with Reference Examples 1 and 2 in FIG. 2, the peak is sharpened, and no shift in the energy direction occurs. In this case, the pulverization was performed in an argon atmosphere (oxygen concentration <10 ppm vol%, dew point −60 ° C.) in order to avoid deterioration of the sample due to exposure to the atmosphere.

Although the present invention has been described with reference to the embodiment and the examples, these can be further modified based on the technical idea of the present invention.

For example, the state of embedding of the crushed sample in the conductive substance, the method of embedding, the type of each substance, and the like may be variously changed. A method other than the press-fitting method may be employed, but the physical press-fitting method does not cause heat damage to the sample. The measurement can be performed by X-ray electron spectroscopy or the like in addition to Auger electron spectroscopy.

[0021]

According to the present invention, as described above, the sample is pulverized, and the sample pulverized material is used for analysis in a state of being embedded in a conductive substance. The distance between the site and the conductive substance in contact with the site is small, so that electrons can easily enter and exit at the measurement site,
Charging can be easily and reliably prevented. As a result, the measurement is performed in a state where the charging of the sample is suppressed, and the energy spectrum is always obtained at an accurate position with a stable peak shape.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view (A) showing a situation where charged particle energy spectroscopy is performed based on the present invention, and an enlarged plan view (B) of a part thereof.

FIG. 2 is an Auger electron spectroscopy spectrum of various samples.

[Explanation of symbols]

1: Sample (crushed), 2: Metal, 3: Support, 4: Scattered electrons

Claims (4)

[Claims] 1. A charged particle energy spectroscopy method for performing energy spectroscopy and measurement of charged particles, characterized in that a sample is pulverized and the sample pulverized material is subjected to analysis in a state of being embedded in a conductive substance. Particle energy spectroscopy method. 2. The method according to claim 1, wherein the sample made of an insulating material has an average particle size of 20.
The charged particle energy spectroscopy according to claim 1, wherein the particles are crushed to a particle size of not more than μm to reduce the particle size, and the crushed sample is embedded in a metal to suppress measurement interference due to charging of the sample and measure the insulator. Method. 3. The charged particle energy spectroscopic analysis method according to claim 2, wherein a soft and highly conductive metal is used as the metal, and the sample is mounted on a sample support in a state where the ground sample is embedded and fixed. 4. The charged particle energy spectroscopy method according to claim 1, which is applied to Auger electron spectroscopy or X-ray electron spectroscopy.