Olympus Optical Company, Ltd.

Tsugiko Takase

Takao Okada

Hirofumi Miyamoto

Shuzo Mishima

Hiroshi Kajimura

Hiroko Ohta

Hiroko Ota

Akitoshi Toda

Akira Yagi

Hisanari Shimazu

Yoshinori Ohta

Hideo Adachi

Hideo Tomabechi

Kiyozo Koshiishi

Seizo Morita

Yuzo Nakamura

Sadao Shigetomi

Chiaki Sato

Yasushi Satoh

Toshiaki Matsuzawa

Yoshimitsu Enomoto

Yasuhiro Sugawara

Takaaki Takenobu

Scanning tunnel microscope

A scanning tunneling microscope has an STM unit including a probe for scanning the surface of an object. The STM unit has at its outer peripheral surface a cylindrical enclosing member extending towards an object table. When the object is observed, the object table is elevated or the STM unit is lowered, so that the enclosing member is urged upon the table. The table and the STM unit constitute one body. As a result, relative movement between the object and the probe can be prevented, and also influence due to vibration can be prevented. In addition, the enclosing member isolates the object and the probe from the outside space, whereby electric noise, magnetic noise, sound noise and air flow are shielded. Thus, the influence due to external vibration can be reduced, and the stability is enhanced.

Scanning tunneling microscope

A hole is formed in a silicon substrate, passing through the substrate. An insulating film is formed on one face of the silicon substrate and one open end of the hole is thus closed by the insulating film. An antireflection film is attached to that area of the insulating film by which the one open end of the hole is closed. An optical fiber is fitted and fixed in the hole. An optically-transparent conical probe is formed on the area of the insulating film which corresponds to the hole in the silicon substrate and the probe is coated by a metal film while leaving a tip of the probe not coated. A fine aperture is thus formed at the tip of the probe to allow light to enter into the probe through the fine aperture. The metal film prevents light reflected from entering into the probe and light from being leaked from the probe, and it is connected to an electrode to use tunnel current to position the fine aperture near a sample.

Probe unit for near-field optical scanning microscope

A scanning probe microscope comprises a cantilever having a conductive probe positioned near a sample, an actuator for moving the sample to and away from the probe, a circuit for applying a bias voltage between the probe and sample to produce a tunnel current therebetween, a circuit for detecting the produced tunnel current, a circuit for detecting the amount of displacement of the probe resultant from interatomic forces acting between atomics of the probe and sample, thereby producing signals, a circuit for providing the actuator for feedback in response to the output signals from the circuit to retain constant the distance between the probe and sample, thereby causing the actuator to move the sample, a circuit for forming an STS image data from the detected tunnel current, a circuit for forming an STM image data from the detected tunnel current, and a circuit for forming an AFM image data. Thus, the STS, STP and AFM images are separately obtained simultaneously.

Scanning probe microscope having cantilever and detecting sample

An atomic force microscope comprises a probe having a sharply-pointed tip end. The probe is supported on the free end portion of a cantilever and is close to the surface of a specimen. When an interatomic force is produced, the cantilever is deformed, and the probe is displaced. The displacement of the probe is detected by an optical system. A light beam emitted from a light source is collimated by a lens, and reflected by a polarized beam-splitter, and also by a half-mirror. Then, the light beam passes through a quarter wavelength plate and an objective lens, such that the light is converged on the cantilever. The reflected light beam from the cantilever returns along the same optical path and passes through the splitter. The light beam is divided into two light beams at the splitter. These two light beams are reflected by respective prisms and are then incident on respective photodetectors. These photodetectors detect the displacement of the probe.

Atomic force microscope

Probe for a scanning tunneling microscope

White light emitted from a light source is made incident on a spectroscope via a lens. The light from the spectroscope is converged by a lens and fed to one end of an optical fiber. The other end of the fiber is provided with a probe. The probe has a pointed end portion coated with a total reflection film and a transparent electrically conductive film. The probe is attached to a cylindrical piezoelectric actuator via a metal frame. Thus, the probe is scanned along the surface of a sample, and the distance between the probe and the surface of the sample is controlled. The light emitted from the tip of the probe and transmitted through the sample is converged by a lens system and radiated on a photoelectrical conversion element. The output from the photoelectrical conversion element is processed by a signal processor, and the processed result is displayed on a display. A driver circuit scans the probe along the surface of the sample, and controls the distance between the probe and the sample upon receiving a tunnel current. The output from the driver circuit is processed by the signal processor and an STM image is displayed on the display.

A probe for scanning a sample is attached to a probe electrode supported by a cylindrical piezoelectric actuator. The actuator has four drive electrodes on its periphery, and deforms in the three axial directions in accordance with the voltage applied to the drive electrodes. A girdling electrode is provided between the actuator and the probe electrode. The girdling electrode is insulated from the probe electrode and the drive electrodes by insulator members provided on its upper and lower surfaces. A bias voltage signal S1 is input to an operational amplifier of which the output is connected to the girdling electrode. The amplifier is a voltage follower for equalizing the potential of the girdling electrode to that of the bias voltage signal S1. An operational amplifier has a non-inversion input to which the bias voltage signal S1 is input, and an inversion input connected to the probe electrode. While equalizing the potential of the probe electrode to that of the bias input voltage S1, the amplifier converts a tunnel current flowing between the probe and the sample to a voltage signal S2. An operational amplifier subtracts a bias voltage component from the voltage signal S2, and outputs a tunnel current signal S3.

Measuring device in a scanning probe microscope

A scanning tunneling microscope includes an observation optical system for optically observing the surface of an object. The optical system is fixed on an optical system fixing member. The optical system is moved in a direction (Z-direction) vertical to the surface of the object by means of a motor, whereby the focal point of the optical system is adjusted. An STM measurement probe supported by an optically transparent member is disposed between the optical system and the object. When the object is optically observed, the probe is displaced from the focal point by means of a micrometer. Thus, an optical observation image of the surface of the object, which is not affected by the shadow of the probe, can be obtained. When the STM measurement is carried out, a probe unit enables the probe to scan the surface of the object, and an STM image is obtained by a conventional method.

A scanning tunneling microscope includes a piezoelectric driver expanding and contracting according to a voltage applied thereto to adjust the distance between a sample and a probe. A servo circuit outputs a servo voltage to control the expansion and contraction of the piezoelectric driver to keep a tunnel current flowing between the sample and the probe at a constant value. A correction voltage generating circuit generates a given correction voltage to correct a voltage to be applied to the piezoelectric driver. An adding circuit adds the servo voltage and the correction voltage together and supplies an added output to the piezoelectric driver. A control circuit controls the correction voltage according to the servo voltage to set the added output to a given reference voltage.

Scanning tunneling microscope having proper servo control function

A probe unit includes a disk-like substrate made of transparent material, a transparent electrode coated on all over the substrate, and a metal wire whose sharp tip is projected vertically and upwardly from the center of the substrate through the transparent electrode. The metal wire is made of Pt-Ir, which incudes a sharp tip projected from the upper surface of the substrate and a stem embedded in a hole of the electrode and fixed to the electrode and substrate by conductive adhesive.

Probe unit for an atomic probe microscope

A scanning tunnel microscope includes a piezo-actuator movable in a direction Z perpendicular to the surface of a sample and provided with a scanning probe projected downward from the bottom thereof. The scanning probe is moved in the direction Z by the piezo-actuator. The piezo-actuator includes a position measuring probe projected therefrom, parallel to the surface of the sample, from the lower end of one side thereof. A reference sample having concaves formed on a surface thereof at predetermined intervals is fixed to the piezo-actuator. When the scanning probe is moved in the direction Z, the position measuring probe is moved along the reference sample, so that tunnel current having a waveform which reproduces the shape of the concaved surface of the reference sample is detected. Thus, the moving distance of the scanning probe can be obtained from the waveform of tunnel current detected.

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Hachioji, Japan

Tsugiko Takase