Scanning Probe Microscope and Method of Observing Sample Using the Same

• US 20100325761A1
• Filed: 12/18/2008
• Published: 12/23/2010
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Inoue, Takashi, Watanabe, Masahiro, Nakata, Toshihiko, Okai, Makoto, Morita, Toshiaki, Hidaka, Kishio, Hirooka, Motoyuki
• Granted Patent: US 8,181,268 B2
• Time in Patent Office: Days
• US Class Current: 850/33
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01N 21/648 using evanescent coupling or surface plasmon coupling for the excitation of fluorescence
• CPC Class Codes: G01Q 60/06 SNOM [Scanning Near-field Optical Microscopy] combined with AFM [Atomic Force Microscopy]
• CPC Class Codes: G01Q 60/22 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: G01Q 70/12 Nanotube tips

Abstract

Optical information and topographic information of the surface of a sample are measured at a nanometer-order resolution and with high reproducibility without damaging a probe and the sample by combining a nanometer-order cylindrical structure with a nanometer-order microstructure to form a plasmon intensifying near-field probe having a nanometer-order optical resolution and by repeating approach/retreat of the probe to/from each measurement point on the sample at a low contact force.

Claims

1. A scanning probe microscope comprising a measurement probe having its interior embedded with a metal structure, a cantilever for supporting said measurement probe, cantilever drive means for driving said cantilever to scan said measurement probe three-dimensionally in relation to an inspection objective sample, displacement detection means for detecting a deformation of said cantilever, and near-field optical image acquisition means for generating near-field light rays between said measurement probe embedded with the metal structure and the surface of said inspection objective sample and acquiring a near-field optical image of the surface of said inspection objective sample.

2. A scanning probe microscope according to claim 1 further comprising an AFM image generation means for generating an atomic force microscopic image (AFM image) of said inspection objective sample surface by processing a signal obtained by detecting a deformation of said cantilever with the help of said displacement detection means.

3. A scanning probe microscope according to claim 1, wherein said near-field optical image acquisition means includes a laser irradiation optical system for irradiating a laser beam on one end of said measurement probe embedded with the metal structure, near-field light ray detection optical system for detecting near-field light rays generated between the other end of said measurement probe and the surface of said inspection objective sample by causing the other end of said measurement probe to approach the surface of said inspection objective sample under the irradiation of the laser beam by said laser irradiation optical system, and a near-field optical image processing system for processing a signal obtained by detecting said near-field light rays with the help of said near-field light ray detection optical system to obtain a near-field optical image of said sample surface.

4. A scanning probe microscope according to claim 1, wherein said measurement probe is formed of a carbon nanotube or a metal nanotube and a gold particle or silver particle, or a gold rod or silver rod is embedded in the interior of the carbon nanotube or metal nanotube.

5. A scanning probe microscope according to claim 1, wherein said measurement probe is formed of a carbon nanotube or a metal nanotube, the tip end of the carbon nanotube or metal nanotube caused to approach the surface of said inspection objective sample is sharpened and a gold particle or silver particle is embedded in the tip end.

6. A scanning probe microscope according to claim 3, wherein the length of said measurement probe is adjusted such that near-field light rays of maximum intensity can be obtained in accordance with a wavelength of the laser beam irradiated from said laser irradiation optical system.

7. A scanning probe microscope according to claim 3, wherein said laser irradiation optical system further includes a polarization light ray control unit for controlling the state of polarization of a laser beam irradiating on one end of said measurement probe embedded with the metal structure.

8. A scanning probe microscope according to claim 3 wherein said laser irradiation optical system irradiates a white light laser beam on one end of said measurement probe embedded with the metal structure, said near-field light ray detection optical system detects near-field light rays generated between the other end of said measurement probe and the surface of said inspection objective sample by separating wavelengths of the near-field light rays, and said near-field optical image processing system processes individual signals detected through the wavelength separation to synthesize them, thus obtaining a color near-field ray optical image of the surface of said sample.

9. A scanning probe microscope according to claim 3, wherein said cantilever includes a light guide quarter of pyramid shape for guiding the beam from said laser irradiation optical system to said measurement probe.

10. A scanning probe microscope according to claim 9, wherein said near-field light ray detection optical system has a light shield plate for selectively passing the near-field light rays generated between the other end of said measurement probe and the surface of said inspection objective sample.

11. A scanning probe microscope according to claim 1, wherein said measurement probe is formed of a carbon nanotube or a metal nanotube, the carbon nanotube or metal nanotube has its upper end embedded with metal carbide or a fluorescent particle and has its lower end embedded with a gold particle or silver particle, or a gold rod or silver rod.

12. A method of observing a sample by using a scanning probe microscope in which a cantilever for supporting a measurement probe having its interior embedded with a metal structure is driven to scan said measurement probe three-dimensionally in relation to an inspection objective sample, a deformation of said cantilever due to the three-dimensional scan is detected, and a near-field optical image of the surface of said inspection objective sample is acquired by using said measurement probe embedded with the metal structure.

13. A sample observing method using a scanning probe microscope according to claim 12, wherein an atomic force microscopic image (AFM image) of said inspection objective sample surface by processing a signal obtained by detecting a deformation of said cantilever.

14. A sample observing method using a scanning probe microscope according to claim 12, wherein a near-field optical image of said sample surface is obtained by irradiating a laser beam on one end of said measurement probe embedded with the metal structure, detecting near-field light rays generated between the other end of said measurement probe and the surface of said inspection objective sample by causing the other end of said measurement probe to approach the surface of said inspection objective sample under irradiation of the laser beam, and processing a signal obtained by detecting the near-field light rays.

15. A sample observing method using a scanning probe microscope according to claim 12, wherein the near-field light rays are detected by using as said measurement probe a carbon nanotube or metal nanotube having its interior embedded with a gold particle or silver particle or a gold rod or silver rod.

16. A sample observing method using a scanning probe microscope according to claim 12, wherein the near-field light rays are detected by using as said measurement probe a carbon nanotube or metal nanotube having its upper end embedded with metal carbide or a fluorescent particle and having its lower end embedded with a gold particle or silver particle or a gold rod or silver rod.

17. A sample observing method using a scanning probe microscope according to claim 12, wherein said measurement probe is formed of a carbon nanotube or metal nanotube, the tip end of the carbon nanotube or metal nanotube caused to approach the surface of said inspection objective sample is sharpened and said tip end is embedded with a gold particle or silver particle.

18. A sample observing method using a scanning probe microscope according to claim 14, wherein the length of said measurement probe is adjusted such that near-field light rays of maximum intensity can be obtained in accordance with a wavelength of the laser beam irradiated from said laser irradiation optical system.

19. A sample observing method using a scanning probe microscope according to claim 14, wherein the laser beam irradiated on one end of said measurement probe embedded with the metal structure is a laser beam the polarization state of which is controlled.

20. A sample observing method using a scanning probe microscope according to claim 14, wherein the laser beam irradiated on one end of said measurement probe embedded with the metal structure is a white light laser beam, near-field light rays generated between the other end of said measurement probe and the surface of said inspection objective sample are detected by separating wavelengths of the near-field light rays and a signal obtained through the wavelength separation detection is processed to obtain a colored near-field optical image of said inspection objective sample surface.