# US 8,541,738 B2 · Surface analyzer of object to be measured and analyzing method

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- Number: US 8,541,738 B2
- Document ID: US8541738B2
- Status: Granted
- Kind: B2
- Application number: 12/937,253
- Filed: 2009-04-07
- Published: 2012-03-15
- Granted: 2013-09-24
- Earliest claimed: 2008-04-09
- Assignees: Japan Science and Technology Agency; The University of Electro-Communications; National University Corporation Kobe University
- Applicants: Masahide Tona; Shunsuke Ohtani; Makoto Sakurai
- Inventors: Masahide Tona; Shunsuke Ohtani; Makoto Sakurai
- Web page: https://patentgrep.com/patent/US8541738B2

## CPC

- G01N 23/2255: using incident ion beams, e.g. proton beams
- G01N 23/2258: Measuring secondary ion emission, e.g. secondary ion mass spectrometry [SIMS] (mass-to-charge ratio analysis aspects of SIMS for material analysis G01N27/62)
- H01J 37/244: Detectors; Associated components or circuits therefor
- H01J 37/256: using scanning beams
- H01J 49/142: {using a solid target which is not previously vapourised}
- H01J 2237/08: Ion sources
- H01J 2237/2448: Secondary particle detectors
- H01J 2237/24585: Other variables, e.g. energy, mass, velocity, time, temperature
- H01J 2237/2527: Ions [SIMS]
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A surface analyzer 1 includes: a sample stage 6 for placing a sample 5; a source for generating multicharged ions 3 for irradiating a beam 4 of multicharged ions having a valence of 15 or higher to the sample 5 placed on the sample stage 6; a mass analyzer 8 for detecting secondary ions 7 generated as a result of irradiating the beam of multicharged ions 4 to the sample 5; a secondary electron detector 10 for detecting secondary electrons 9 generated as a result of irradiating the beam of multicharged ions 4 to the sample 5; and a controller of mass analyzer 12 for generating analysis start signals in response to the secondary electron signals received, and transmitting the start signals to the mass analyzer. The surface analyzer 1 enables high-quality analysis of the surface of the sample in short time by using the multicharged ions.

## Claims

### Claim 1

A method of analyzing a surface of a compound having an unknown composition ratio, comprising:
a first step of finding a relation between a valence of a multicharged ions beam and respective counts of secondary ions generated from specific elements on a surface of a standard compound in response to irradiation of the multicharged ion beam thereonto, by radiating the multicharged ions beam to the standard compound at multiple times while changing the valence of the multicharged ions beam each time, the standard compound being constituted of same constituent elements as the compound to be measured and having a known stoichiometric composition ratio;
a second step of finding a valence of the multicharged ions beam at which a count ratio of secondary ions from the specific elements is substantially equal to the stoichiometric composition ratio of the standard compound based on the relation between the valence of the multicharged ions beam and the respective counts of the secondary ions found in the first step; and
a third step of performing surface analysis of the compound with the unknown composition ratio by radiating a multicharged ions beam having the valence found in the second step to the compound with the unknown composition ratio.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the valence of the multicharged ions beam is changed within a range 15 or higher in the first step.

### Claim 3 (depends on 1)

The method according to claim 1, wherein, in the first step, a pulse of single multicharged ion having a valence of 15 or higher is irradiated onto the standard compound to repetitively perform a measurement per pulse, pieces of data obtained by this measurement are integrated, and when the average value converges on a certain value, irradiation of the pulse of single multicharged ion is stopped.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the valence of the multicharged ions beam is changed up to 50 in the first step.