JPH0722452U - Ion scattering spectrometer - Google Patents

Abstract

(57) [Summary] [Object] To provide an ion scattering spectroscopic analyzer with extremely high analysis accuracy by irradiating a sample with an ion beam having a kind, charge, energy, etc., according to the purpose of measurement. [Structure] Ion beam 30 generated from ion source 10
The charged particles other than the target are removed by the particle selecting means 1, and the ion beam containing only desired ions is pulsed by the chopping electrode 11 and the chopping aperture 12. Pulsed pulsed ion beam 3
The sample 13 is irradiated with 1 ′, and the scattered ions 32 ′ are detected by the detector 14. On the other hand, the pulse generator 20 sends a start signal to the time measuring means 22 at the same time as the fall of the pulse voltage, and the preamplifier 21 receives the detection signal of the scattered ions 32 of the detector 14 and tells the time measuring means 22. Send a stop signal. The time measuring means 22 measures the time between the start signal and the stop signal described above,
It is output to the computer 23 as a time signal.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a surface analyzer that analyzes a sample surface using an ion beam.

[0002]

[Prior art]

 A conventional ion scattering spectroscopy analyzer will be described with reference to FIG. An ion source 10 ionizes the gas supplied from a gas supply source (not shown) to generate ions, which are irradiated as an ion beam 30. A chopping electrode 11 is applied with a pulsed voltage at a predetermined cycle by the pulse generator 20. The ion beam 30 that has passed through the chopping electrode 11 is deflected by the applied voltage, its progress is blocked by the chopping aperture 12, and only passes through the hole of the chopping aperture 12 provided on the path when no voltage is applied. Then, the sample 13 is irradiated. Thereby, the ion beam 30 generated from the ion source 10 becomes a pulsed ion beam 31 according to the pulse voltage applied to the chopping electrode 11. Then, the ion beam 31 passing through the chopping aperture 12 collides with the sample 13 and the scattered ions 32 are detected by the detector 14.

On the other hand, the pulse generator 20 sends a start signal to the time measuring means 22 when the voltage of the chopping electrode 11 is set to zero, that is, the fall of the pulse voltage is used as a trigger. Further, the preamplifier 21 receives the detection signal of the scattered ions 32 detected by the detector 14 and sends a stop signal to the time measuring means 22. The time measuring means 22 measures the time from the above start signal to the stop signal and outputs it to the computer 23 as a time signal. Since the flight time of this scattered ion shows a value peculiar to the sample to be analyzed, the computer 23 analyzes the surface of the sample by comparing it with the flight times obtained in advance for a plurality of standard samples.

[0004]

However, several kinds of ions are generated from the ion source 10 and their energies are also different. Therefore, in the above-described conventional ion scattering spectroscopic analyzer, the ion source 10 The sample 13 is directly irradiated with the ion beam 30 containing several kinds of ions and energy generated from the above. In such a case, the flight time of the scattered ions 32 varies greatly depending on the type and energy of the irradiated ions, so scattered ions other than the desired ions become the background of the measurement, and accurate sample analysis cannot be performed. was there.

Therefore, the present invention was devised in order to solve these problems, and by irradiating the sample only with an ion beam having a kind, electric charge, energy, etc. according to the purpose of measurement. It is an object of the present invention to provide an ion scattering spectroscopic analyzer with extremely high analysis accuracy.

[0006]

[Means for Solving the Problems]

 The ion scattering spectrometer according to the present invention is characterized in that a particle selecting means is provided in front of the ion source so that only desired ions among the ions generated from the ion source are irradiated to the sample. .

[0007]

[Action]

 The operation of the ion scattering spectrometer according to the present invention will be described with reference to FIG. The charged particle other than the target is removed from the ion beam 30 generated from the ion source 10 by the particle selecting means 1, and the ion beam containing only desired ions is pulsed by the chopping electrode 11 and the chopping aperture 12. The sample 13 is irradiated with the pulsed pulsed ion beam 31 ′, and the scattered ions 32 ′ are detected by the detector 14. On the other hand, the pulse generator 20 sends a start signal to the time measuring means 22 simultaneously with the fall of the pulse voltage, and the preamplifier 21 receives the detection signal of the scattered ions 32 of the detector 14 and sends it to the time measuring means 22. Sends a stop signal to it. The time measuring means 22 measures the time between the above-mentioned start signal and stop signal and outputs it to the computer 23 as a time signal. At this time, since the ion beam applied to the sample is a monochromatic ion beam, it is possible to perform sample analysis with high accuracy without background.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of the ion beam generator according to the present invention. The same components as those of the ion beam generator shown in the conventional example are designated by the same reference numerals and the description thereof will be omitted. To do.

A particle selecting unit 1 has a function of selectively removing, from the ions generated from the ion source 10, ions having an undesired charge number and energy, and undesired types of ions. This may be anything as long as it has a function of selectively extracting only ions having a desired charge number and energy and the directions of the incident beam and the outgoing beam do not change.

Specific examples of the particle selecting means 1 include a Wien filter and an Ω type energy analyzer. FIG. 2a is a schematic view of a Wien filter, in which a frame body 1a is provided with through holes 1b and 1c through which the ion beam 30 passes, and the frame body 1 is perpendicular to the traveling direction of the ion beam 30. The electric field E and the magnetic field B (direction perpendicular to the paper surface) are applied in various directions. Then, only the ions in which the deflection force FE due to the electric field E and the deflection force FB due to the magnetic field B are balanced go straight out and emerge from the through hole 1c, and the other ions are deflected as shown in the figure, and then on the wall surface of the frame 1a. The course is cut off. Therefore, by controlling the strengths of the electric field E and the magnetic field B in the frame body 1, it becomes possible to select only desired ions. Further, FIG. 2b shows a schematic view of the Ω type energy analyzer. Like the Wien filter, the frame body 1a ′ is provided with through holes 1b ′ and 1c ′ for allowing the ion beam 30 to pass therethrough. By forming four sets of magnetic fields in a'and controlling the strength of these magnetic fields, desired ions are selected and emitted from the through hole 1c '. Further, the above-mentioned desired particle selecting means has a feature that only desired ions can be selected without changing the directions of the incident and outgoing beams.

Next, the operation of the present invention will be described. Referring to FIG. 1, the ion beam 30 generated from the ion source 10 has charged particles other than the target particles removed by the particle selecting means 1, and the ion beam 30 contains only desired ions. Are pulsed by the chopping electrode 11 and the chopping aperture 12. The sample 13 is irradiated with the pulsed pulsed ion beam 31 ′, and the scattered ions 32 ′ are detected by the detector 14. On the other hand, the pulse generator 20 sends a start signal to the time measuring means 22 simultaneously with the fall of the pulse voltage, and the preamplifier 21 receives the detection signal of the scattered ions 32 of the detector 14 and the time measuring means 22. Send a stop signal to. The time measuring means 22 measures the time between the start signal and the stop signal, and outputs it as a time signal to the computer 23.

At this time, since unnecessary ions are removed from the ions generated from the ion source 10 and only the desired monochromatic ion beam is irradiated onto the sample, the background generated by the unnecessary ion beam is measured from the measurement data. It is possible to reduce the noise, which makes it possible to analyze the sample with higher accuracy. If the ion source 10 is disposed so as to be inclined with respect to the chopping electrode 11, neutral particles can be removed together.

[0014]

[Effect of device]

 According to the present invention, of the ions generated from the ion source, ions having a charge number and energy other than the intended one can be removed, and only the desired ions can be irradiated onto the sample as an ion beam, so that the back-up caused by unnecessary ions can be eliminated. It is possible to remove the ground and provide an ion scattering spectroscopic analyzer with extremely high analysis accuracy.

[Brief description of drawings]

FIG. 1 is an overall view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of a particle selection unit according to the present invention.

FIG. 3 is a diagram showing a conventional ion scattering analyzer.

[Explanation of symbols]

 1 ... Particle selection means 10 ... Ion source 11 ... Chopping electrode 12 ... Chopping aperture 13 ... Sample 14 ... Detector

Claims (1)

[Scope of utility model registration request] 1. An apparatus for analyzing a sample surface by irradiating a sample with an ion beam and measuring the time of flight of ions scattered from the sample surface, by providing a particle selection means in front of the ion source, An ion scattering spectroscopic analyzer characterized in that the sample is irradiated with only desired ions among the ions generated from the source.