JPH0888179A - Method and equipment for formation, working, and evaluation analysis of semiconductor material - Google Patents

Abstract

PURPOSE: To precisely attach single atoms or molecules on arbitrary position of the surface of solid material, by irradiating, with light, atoms or melecules to be moved, out of atoms or molecules which exist on a probe and the surface of specimen solid, and by selectively relieving or moving the atoms or molecules, with a lower voltage. CONSTITUTION: A carbon plate or a graphite plate is used as the source of carbon 2 to be attached, and moved under a probe 5. It is made to approach the plate, and a negative bias voltage is applied to the probe 5. The carbon 2 atoms are ionized, relieved, and attached on the tip of the probe 5. A tungsten substrate 1 is moved under the the probe 5 on which the carbon 2 atoms are attached. The probe 5 is made to approach the tungsten substrate 1, and the distance is kept to be about 2nm. The carbon 2 attached on the probe 2 is irradiated with ultraviolet rays capable of exciting the oscillation of Si-C bonds. A positive bias voltage is applied to the probe 5 and gradually increased, and the carbon 2 is moved on the tungsten substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming, processing, evaluating and analyzing a semiconductor material, and an apparatus used therefor. More specifically, the present invention deals directly with individual atoms or molecules and controls semiconductors with an accuracy of nanometer or less. Material formation, processing,
The present invention relates to an evaluation analysis method and an apparatus used for them.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices such as LSI, strict control of processing accuracy, material composition and structure, etc. is required as the degree of integration increases. Therefore,
In forming a semiconductor element, the atoms or molecules are controlled in units of atoms or molecules, and the atoms or molecules are arranged at desired positions to remove unnecessary impurities in the semiconductor material to improve the purity.
Technology for observing, evaluating and analyzing the state of the surface or cross section of semiconductor materials is indispensable.

As a typical means for processing a minute region for manufacturing these semiconductor elements, an electron beam epitaxial method for irradiating a sample with a focused electron beam to cause epitaxial growth from gas molecules, and accelerating and focusing ions. Then, there are FIB technology, photo-etching technology, etc. for etching or adhering to the substrate.

Further, as a typical means for discriminating the kind of atoms in a minute region on the surface of a semiconductor material, a sample is irradiated with a focused electron beam and the kind of atoms is judged by the X-ray peculiar to the generated element. X-ray microanalyzer, Auger electron spectroscope for detecting secondary electrons generated by irradiating sample with electron beam, Secondary ion mass spectrometry for accelerating and focusing ions and irradiating sample to detect secondary ions generated Equipment, a method of desorbing and ionizing adsorbed components with a laser, and analyzing with a mass spectrometer.In addition, for semiconductors and metals, a probe with a sharpened tip is brought close to the sample surface, and the probe is Scanning tunneling microscope (STM) that can identify each surface atom by observing the morphology of the sample surface by changing the tunnel current flowing between the sample and the probe by applying a voltage between the needles. By positioning the probe close to the sample surface and measuring the movement of the probe caused by the repulsive force acting between the atom of the probe and the atom of the sample surface with a laser interferometer, etc. Force microscope (AFM)
Scanning probe microscopes are known. On the other hand, in order to evaluate the morphology and structure of a semiconductor element, an electron microscope is used in which a sample is irradiated with an electron beam and an enlarged image of a substance is obtained by reflected or transmitted electrons.

[0005]

However, in the thin film forming method such as the electron beam epitaxial method and the FIB method, the accuracy of processing of the formation of the semiconductor element is limited to several nanometers, and the surface of the semiconductor material is uniformly processed. Although atoms or molecules can be attached, it has been difficult to attach them to a specific position of a semiconductor material with atomic order accuracy.

Further, in the semiconductor element produced by the thin film forming apparatus such as the electron beam epitaxial technique, it is inevitable that impurities such as carbon and oxygen are mixed, and it is difficult to form a semiconductor element thin film having a small amount of impurities. . Since the impurities in the semiconductor element are removed, heating the semiconductor element results in diffusion of atoms other than impurities, which is not generally applicable. Further, even in the method of locally heating the surface by irradiating the sample with a focused electron beam, the heated region has a depth of several hundred to several thousand nm and a width of several tens nm, which is on the order of nanometers. It was difficult to remove impurities in the area.

Further, it is necessary to analyze in order to evaluate and confirm whether the formed semiconductor element has the composition and structure as designed, and where in the atomic arrangement on the semiconductor surface the impurities and adsorbed components are present. Become. However, regarding the semiconductor surface analysis, in the above-mentioned analysis methods such as the X-ray micro-analyzer, the minimum range that can be analyzed for irradiating an electron beam is 100 nanometers, and individual atoms or molecules are analyzed. No level analysis is possible.

On the other hand, in the recently developed scanning tunneling microscope, a probe with its sharpened tip is brought close to the sample, and a voltage is applied between the sample and the probe to change the tunnel current flowing through the probe. It is a device with the highest positional resolution that can identify the individual semiconductor surface atoms and see the surface irregularities, and is also a device that can evaluate the electronic state of the semiconductor surface. However, it has a drawback that it is not possible to discriminate the types of atoms and molecules existing on the surface.

In a scanning probe microscope having a probe such as a scanning tunneling microscope, electrons are emitted due to quantum mechanical tunneling effect when a voltage is applied between the sample and the probe. In addition, atoms or molecules on the sample surface or atoms or molecules attached to the probe are also ionized by electric field ionization and emitted from the sample surface or the probe. As a result, the released atom or molecule moves between the sample and the probe, and the atom or molecule can be attached to the sample surface from the probe or removed from the sample surface. Further, it is known that the emission of atoms or molecules due to this electric field ionization becomes easier to occur by heating the sample. However, this movement of atoms or molecules cannot always be controlled so as to selectively occur only in a specific target atom or molecule, and it cannot be used for manufacturing a semiconductor device.

Therefore, an object of the present invention is to provide a method for forming a material in which a single atom or molecule is accurately attached to an arbitrary position on the surface of a solid material, and an apparatus therefor. An object of the present invention is to provide a processing method and an apparatus for selectively removing impurities in a region.

Further, the present invention provides an analytical evaluation method and an apparatus therefor capable of precisely evaluating the arrangement or existence of atoms or molecules on the surface of a solid material or a fractured surface and discriminating the kind of atoms or molecules. The purpose is to

[0012]

The present inventor has conducted extensive studies on selective control of detachment of atoms or molecules from a sample or a probe caused by field ionization in the above-mentioned scanning probe microscope, and as a result, It was found that atoms or molecules can be selectively released by irradiating the probe with specific light, and the present invention has been completed based on this finding.

That is, the present invention is a method of forming a semiconductor material on a solid surface, which comprises an attaching step of attaching atoms or molecules for forming a semiconductor to a probe, and a probe attached with a specific atom or molecule. In order to adjust the position of the solid surface to form the semiconductor material, the position of the probe and the solid surface is moved to maintain the distance between the probe and the solid surface at a desired interval, and the light is transmitted to the probe. A light irradiation step of irradiating the attached atoms or molecules and exciting the atoms or molecules, and separating the atoms or molecules excited by the voltage applied between the probe and the solid surface from the probe, It comprises a method of forming a semiconductor material, including a desorption transfer step of moving the solid material surface to the solid surface and a deposition step of depositing the atoms or molecules transferred to the solid surface on the solid surface to form the semiconductor material on the solid surface.

Further, the present invention is a method of forming a semiconductor material on a solid surface, wherein the probe and the solid surface are adjusted so that the probe is aligned with the position of the atom or molecule to be removed on the solid surface. Positioning step of moving the position and maintaining the distance between the probe and the solid surface at a desired interval, and a light irradiation step of irradiating light to the atoms or molecules to be removed in the solid surface and exciting the atoms or molecules. A detachment transfer step of detaching an atom or a molecule excited by a voltage applied between the probe and the solid surface from the solid surface and moving it to the probe,
A method of forming a semiconductor material, which comprises a step of attaching atoms or molecules that have moved to the probe to the probe and removing the atoms or molecules from the solid surface.

Further, the present invention is a method for evaluating and analyzing a solid surface of a semiconductor material, which comprises aligning the probe with a position on the solid surface where an atom or molecule to be evaluated and analyzed is present. Positioning process that moves the position of the surface and keeps the distance between the probe and the solid surface at a desired distance, and light that irradiates the atoms or molecules to be analyzed in the solid surface with light to excite the atoms or molecules. During the irradiation process, atoms or molecules excited by the voltage applied between the probe and the solid surface are released from the solid surface and moved to the probe, and the fact that the atom or molecule has moved is detected between the probe and the solid surface. Of the atoms or molecules on the solid surface of the semiconductor material, characterized by distinguishing the type of atoms or molecules that have departed or moved, depending on the wavelength of the irradiated light, including the detection step of detecting the change in the current flowing through Way or Will also evaluate the atoms or molecules of the solid surface of the semiconductor material excited atoms or molecules of the light irradiation step is excitation by ionization, an analytical method.

Further, according to the present invention, in order to adjust the probe to a specific position on the solid surface, the positions of the probe and the solid surface are moved to maintain the distance between the probe and the solid surface at a desired interval. Means for irradiating the probe or the solid surface with light to excite the atom or molecule, and the atom or molecule excited by the voltage applied between the probe and the solid surface from the solid surface Forming a semiconductor material, comprising: a detachment means, a moving means, a detecting means for detecting the movement by a change in an electric current flowing between the probe and the solid surface,
It consists of processing and analysis and evaluation equipment.

[0017]

According to the present invention, when an atom or molecule is detached and moved by electric field ionization by a voltage applied between the probe and the surface of the sample solid, the atoms or molecules present on the surface of the probe and the sample solid are moved. The atoms or molecules to be moved among the molecules are irradiated with light of a specific wavelength, and the atoms or molecules are excited by the energy of the light to cause resonance vibration or ionization, selectively targeting the atoms or molecules at a lower voltage. By detaching or moving, atoms or molecules are deposited on the solid surface or specific atoms or molecules are removed from the solid surface, so that it is possible to control on the atomic order in the formation and processing of semiconductor materials. Since the type of atom or molecule can be discriminated by the wavelength of the irradiated light, the solid surface can be analyzed and evaluated.

As described above, in a scanning probe microscope such as a scanning tunneling microscope, a voltage is applied between the probe whose tip is sharply sharpened and the solid surface of the sample to detect the tunnel current flowing through the probe. By doing so, it is possible to identify each atom or molecule and obtain an image of the individual constituent atoms or molecules on the solid surface. In addition, when the probe and the sample solid surface are brought close to the extent that a tunnel current flows and a potential difference of more than a certain level is given between the probe and the sample solid surface, not only tunnel electrons but also the probe surface or the sample solid surface exist. It is known that so-called electric field ionization is that the atoms or molecules existing therein are also ionized and depart from the probe surface or the sample solid surface and move toward the other surface to adhere.

However, the detachment of atoms or molecules from either the solid surface of the probe or the sample solid and the voltage at which the detachment occurs depend on the composition and structure of the solid surface, the type of detached atoms or molecules and the sample surface. It changes depending on the state of existence and the state of adsorption, and it is not possible to specify which atom or molecule will leave and move by simply applying a voltage, and it is also impossible to determine the type of atom or molecule that has left. .

Then, the atom or molecule to be moved is irradiated with light of a specific wavelength, that is, the atom or molecule to be moved is irradiated with light of a constant wavelength having energy capable of causing resonance vibration or ionization. By doing so, it was possible to selectively excite atoms or molecules and dissociate or move at a lower voltage. As a result, the target atom or molecule can be selectively manipulated.

FIG. 1 is a diagram schematically showing a detached state, and FIG. 2 is a schematic diagram showing a change in tunnel current with respect to an applied voltage at that time. That is, in FIG.
“O” indicates the same atoms that make up, and “O” drawn by hatching indicates different atoms. The different type of atoms 30 absorb and excite light of a specific wavelength to cause resonance vibration or ionization. The different atoms 30 are separated due to a bias voltage between the sample and the probe, move toward the probe, and attach to the probe. At this time, the tunnel current flowing through the probe changes as shown in FIG. That is, as the voltage between the probe and the solid surface of the sample increases, the tunnel current flowing through the probe also gradually increases, but it increases rapidly at a certain voltage, and then gradually again as in the beginning. Will increase. Atoms or molecules move when the tunnel current changes significantly.

As described above, the target atom or molecule can be selectively moved by irradiating with light of a specific wavelength, so that the following applications are possible.

(1) By depositing atoms or molecules attached to a probe on a substrate, a single atom or molecule can be attached accurately at any position on a solid surface in the production of semiconductor devices, etc. It is possible to obtain a semiconductor material controlled with the accuracy of

(2) By selectively releasing target atoms or molecules from the solid surface, impurities on the surface of the solid material can be removed in units of atoms or molecules, and the semiconductor is controlled in atomic order. The material can be obtained.

(3) The type of atom or molecule that has been separated by the conventional scanning tunneling microscope can be determined by determining the type of the detached atom or molecule of interest from the relationship between the wavelength used for excitation and the voltage. Therefore, it is possible to precisely evaluate the types and arrangements of atoms and molecules on the semiconductor surface or the fractured surface.

The present invention will be described below with reference to examples.

[0027]

EXAMPLES (1) A method for forming a semiconductor material with an atomic accuracy will be described.

After mounting the sample piece on the sample mounting table and evacuating it to a vacuum, the sample mounting table is moved while observing the sample piece and the probe of the scanning probe microscope with an optical microscope, and the sample is scanned with the scanning probe microscope. Observe the atomic arrangement image on one surface to confirm the position where the atom or molecule is attached.

Next, a specific atom or molecule to be incorporated as a semiconductor material is attached to the probe by the attaching step. As the attaching step, for example, the probe is moved to a material surface made of a pure substance of the target atom or molecule, the probe is brought close to a height of about 1 to 5 nm from the sample surface, and a voltage is applied to the target atom. Alternatively, the molecule is attached to the probe. In addition, as another attachment method, a method of attaching a target atom or molecule to the probe surface by a method such as providing a special pretreatment chamber and performing atom or molecule epitaxy, metal or molecule vapor deposition in the treatment chamber, and the like can be given. To be

In this way, the probe with the atom or molecule attached to the tip is aligned with the position where the semiconductor material is to be incorporated in the next alignment step, and the distance between the probe and the sample is kept constant. Is adjusted and held. For positioning movement, the sample mounting table on which the sample is placed is moved by a step motor, etc., and roughly aligned in the micron order, and then the probe is controlled with a piezo element, etc. Align to. Further, the distance between the probe and the sample surface is also adjusted and held with accuracy of nanometer or less by the piezo element.

After that, in the light irradiation step, light having a specific wavelength is irradiated to the atoms or molecules attached to the probe, and the atoms or molecules are excited by the light. A voltage applied between the probe and the sample surface causes excited atoms or molecules to leave the probe and move to the sample surface. A semiconductor material is formed through a deposition step in which atoms or molecules that have migrated to the sample surface are deposited on the sample surface. That is, the probe is irradiated with light to excite the atoms or molecules attached to the probe, a voltage is applied between the probe and the solid surface, and when the voltage is gradually increased, the probe adheres to the probe. The generated atoms or molecules are detached and moved by electric field ionization and deposited on the surface of the sample solid.

The wavelength of the irradiation light in the irradiation step is a wavelength having energy capable of exciting the resonance vibration of the target atom or molecule, and it varies depending on the type of the target atom or molecule, but in general, Wavelengths from visible light to far infrared light can be used. In the case of an atom, the target of the resonant vibration to be excited is the natural vibration between the bond with an atom around the atom, and in the case of a molecule, the bond between the adsorption site or the reaction site and the molecule. For example, the natural vibration between the molecules or the natural vibration of the internal bond of the molecule itself can be used. The wavelength of light that can excite such resonance oscillation is, for example, 16.5 μm that excites Si—C bonds when it is desired to move carbon on the surface of silicon, and oxygen that moves on silicon. If you want to
A wavelength of 8.5 μm or 9.1 μm that excites the Si—O bond can be used. Further, in the case of a molecule, for example, when it is desired to move the N-alkyldiazopiperidinedione, a wavelength of van der Waals force can be used.

Further, in the case where the target molecule is polarized, the same purpose can be achieved by using microwaves to cause polarization.

On the other hand, as the kind of light, laser light having a high brightness and a strong monochromatic light beam is preferable, but light of a specific wavelength obtained by dispersing a continuous light source with an optical filter, a prism or a diffraction grating should also be used. You can

By repeating the above operation in this manner, atoms or molecules can be successively implanted on the surface of the sample solid. Further, different atoms or molecules can be deposited on the surface of the sample solid by changing the kind of atoms or molecules attached to the probe, and semiconductor materials having various compositions can be formed.

(2) A method for removing impurities on the surface of a solid material in units of atoms or molecules to form a semiconductor material with an accuracy of atomic order will be described.

In this case also, as described above, after the probe is adjusted and held at a distance such that a tunnel current flows, facing the atom or molecule to be removed on the solid surface,
A bias voltage is applied between the probe and the solid surface. Then, the solid surface is irradiated with light having a specific wavelength that excites vibrations peculiar to the atoms or molecules to be removed from the solid surface. As a result, the atom or molecule to be removed on the solid surface is excited, and the atom or molecule to be removed on the solid surface is released due to the voltage applied between the probe and the solid surface, and the atom or molecule is removed to the probe. Moving. Atoms or molecules attached to the probe are removed from the probe by the method described above. This enables processing of semiconductor materials such as removal of impurities on the atomic order with an accuracy of nanometer or less.

(3) A method for discriminating the kinds of atoms and molecules on the semiconductor surface or the fractured surface and precisely evaluating the arrangement of atoms and molecules will be described.

After mounting the sample piece on the sample mounting table and evacuating the system to a vacuum, the sample is cooled to a low temperature with liquid nitrogen or the like by a cooler provided on the sample mounting table, and the sample piece and the scanning probe are scanned by an optical microscope. While observing the probe of the microscope, the sample position is adjusted by the step motor added to the sample mounting table, and the measurement site of the sample piece is aligned with the probe position of the scanning probe microscope. The adsorbed material or oxide film on the surface is removed by etching with an ion beam using an ion beam irradiation device or the like to expose a clean surface, and an atomic array image on the surface of the sample piece is observed with a scanning probe microscope. The observation is performed in a constant current mode in which the height of the probe is adjusted so that the tunnel current flowing through the probe is constant.

An atom or molecule to be analyzed is selected from the obtained atomic array image, and the probe is adjusted and held right above it. In this alignment step, the height of the probe is kept at a constant distance within a range of about 1 to 5 nm from the sample surface.

Then, in the light irradiation step, as described above, light of a wavelength having energy capable of exciting the resonance vibration of the target atom or molecule is irradiated toward the target atom or molecule on the sample surface for analysis. And excite.

Excitation of atoms or molecules by light can also be achieved by ionization by light. In order to ionize an atom or molecule, it is necessary to irradiate with light having an energy larger than the ionization energy of the electron possessed by the atom or molecule for analysis. Generally, since the ionization energies of these atoms or molecules are large, the irradiation light is
Light rays having a short wavelength and high energy such as vacuum ultraviolet rays, X-rays, and γ rays are used.

Further, such ionization is not performed by irradiating short wavelength light having sufficiently high energy, such as vacuum ultraviolet rays, to ionize in a single step, but using light having longer wavelength and lower energy. It can also be excited and ionized stepwise. That is, by simultaneously irradiating light having a wavelength capable of exciting an atomic orbital or molecular orbital peculiar to an atom or molecule and light having a wavelength corresponding to the difference between the ionization energy and the energy of this excited state, Alternatively, the molecule can be ionized in a stepwise excited state. In this case, long-wavelength ultraviolet light with lower energy than in the case of one-step ionization ~
Light can be used in the visible light to infrared light region.

That is, when light having a large energy is irradiated to ionize the atoms or molecules to be analyzed, the atoms or molecules having a smaller ionization energy than the atoms or molecules to be analyzed are also ionized. In the case of multi-stage ionization by irradiation with light having a long wavelength and a small energy, the probability that atoms or molecules other than the purpose of analysis are ionized is reduced, and the analysis accuracy is improved.

For ionizing atoms or molecules by light irradiation, wavelengths of visible light to infrared light can be used. For example, infrared light can be used for analysis of N-alkyldiazopiperidinedione. .

Next, the tunnel current flowing through the probe was measured while gradually applying a bias voltage from 0 V to the probe,
Detect changes in current. If the tunnel current changes abruptly at the detachment voltage of the target atom or molecule, it indicates that the atom or molecule has detached. If the target atom or molecule does not exist, the current does not change at the detachment voltage. That is, the type of atom or molecule can be discriminated from the relationship between the wavelength of light that excites resonance vibration or ionization that is applied to the atom or molecule of interest for analysis and the desorption voltage. On the other hand, as a result of the analysis, the atom or molecule that has detached from the solid surface, moved to the probe, and attached to the probe is removed from the probe by the same method as described in (1). By repeating this series of operations, the distribution state of atoms or molecules on the solid surface can be measured.

In the above description, the case where the kind of atom or molecule is discriminated from the change in tunnel current when the distance between the probe and the solid surface is kept constant and the voltage between the probe and the solid surface is changed is explained. However, the same result can be obtained by changing the wavelength of the irradiation light while applying a constant voltage.

Further, by applying a constant voltage between the probe and the surface of the solid and changing the distance between the probe and the surface of the solid, it is possible to discriminate the kind of atom or molecule from the change of the tunnel current. it can. Specifically, while applying a constant voltage between the probe and the solid surface, the solid surface is irradiated with light having a specific wavelength, and the probe is brought closer to the solid surface to narrow the gap between them. In this case, it is possible to detect a change in tunnel current due to detachment of atoms or molecules.

By cooling the sample with liquid nitrogen, liquid helium, or the like, it is possible to suppress vibrations of atoms or molecules other than the analysis target atom or molecule that has undergone resonance vibration or ionization by light, and thus noise Less measurement is possible and analysis accuracy is improved.

In order to evaluate the semiconductor surface or the semiconductor internal structure by the above method, it is possible to discriminate the kinds of atoms and molecules in a cleavage plane where a semiconductor material is cleaved, and to precisely evaluate the arrangement of atoms and molecules. .

Next, an apparatus used for performing the above method will be described.

FIG. 3 is a diagram showing an example of a scanning probe portion of the apparatus of the present invention, and FIG. 4 is a diagram showing an example of a schematic configuration of the entire apparatus. In FIG. 3, reference numeral 1 indicates a semiconductor material sample to be analyzed or formed, and reference numeral 2 is a pure substance source for supplying atoms or molecules to the probe 5 when implanting atoms or molecules in the semiconductor material. It is a sample substance or a sample substance to be attached in order to remove and remove atoms or molecules attached to the probe 5 when removing impurities from the semiconductor material for purification or evaluation of the semiconductor material.

The semiconductor material sample 1 and the sample substance 2 are placed on the sample mounting table 3, and the sample mounting table 3 is step motor 4
Is controlled so that the probe 5 can be independently moved in a direction parallel and perpendicular to the mounting table and the probe 5 can be positioned at a specific portion of the semiconductor material sample 1 in micron order. The probe 5 is a fine chip whose tip is sharply sharpened, and is made of metal such as silicon, tungsten, or platinum. The probe 5 is independently movable in a direction parallel to and perpendicular to the mounting table by the piezo element 6, and is controlled to a specific position on the sample surface with an accuracy of 0.1 nm or less. Therefore, by the step motor 4 and the piezo element 6, the probe 5 can move between the semiconductor material sample 1 and the sample substance 2,
The semiconductor material sample 1 can be scanned and the position of a specific atom or molecule on the surface of each sample can be positioned with extremely high accuracy.

A heating / cooling device 7 is externally connected to the sample mounting table 3 so that the sample can be cooled or heated. Cooling is mainly used to suppress vibration of atoms or molecules other than those excited by light, and heating is used to facilitate the detachment of atoms or molecules. To be done. Generally, liquid nitrogen or liquid helium is circulated as a cooling means, and an electric heater or the like is used as a heating means.

In FIG. 3, the sample substance 2 is illustrated as being placed side by side on the sample stage 3 together with the semiconductor element sample 1 in order to make the structure easy to understand. It is preferable from the standpoint of operation that a separate mounting table is provided so that the sample substances 2 can be controlled separately, and that the mounting is performed, or that a pretreatment chamber that stores the sample substance 2 is separately provided. In this pretreatment chamber, for example, a vapor deposition device or an atom or molecule epitaxy device can be incorporated in order to attach atoms or molecules to the probe.

Then, these are housed in a chamber 8 having a transparent window 9 so that they can be operated even under vacuum.

Reference numeral 10 indicates a light beam irradiation device, which is a device for irradiating the probe or the sample with light of a specific wavelength in order to separate a specific atom or molecule from the solid surface of the sample or the probe. As the light beam irradiation device, it is preferable to use a laser light irradiation device that can obtain a monochromatic light beam with high brightness, but a device that irradiates monochromatic light obtained by dispersing a continuous light source with a filter, a prism or a diffraction grating is also used. can do. The light is applied to the sample or the probe through the transparent window 9 provided in the chamber 8.

Reference numeral 11 indicates an ion beam irradiation apparatus, which is used for peeling off deposits and oxides on the sample surface to expose a clean surface, and generally an inert gas such as argon is used. Ion beam irradiation is performed toward the sample surface in the chamber 8.

Reference numeral 12 indicates an optical microscope, which is provided for observing the sample and the probe, and can be observed through a transparent window 9 provided in the chamber 8.

FIG. 4 is a diagram showing the configuration of the entire apparatus including the scanning probe section. A configuration 20 capable of applying an arbitrary bias voltage between the probe 5 and the semiconductor material sample 1 or sample material 2 is shown. Is taking. The tunnel current from the probe 5 is detected by the current detection circuit 21 and is also fed back to the servo circuit 22 that controls the piezo element 6 that determines the position of the probe 5, so that a constant current flows through the probe. The distance between the sample 1 and the probe 5 is adjusted.

Each of these units is controlled by the computer 23, and the image arrangement 24 can display an atomic arrangement image and the like.

The first to fourth examples will be further described below.

Example 1 Carbon was deposited on a tungsten plate using the apparatus shown in FIG. The probe used was a conical tip of n-type silicon crystal with a diameter of 20 μmφ, a height of 30 μmφ, and a conical tip with a radius of curvature of 10 nmφ. The tip was flushed in a vacuum device to remove the oxide film. . A carbon or graphite plate is used as the source of carbon to be attached, and after removing the adsorbed components on the surface by sputter etching the surface with an ion beam, move it to the bottom of the probe and bring it closer to the probe. Was applied to apply ionization and desorption of carbon atoms to attach the carbon atoms to the tip of the probe.

Next, the tungsten substrate is moved under the probe having carbon atoms attached thereto, and the probe is brought close to the tungsten plate and kept at a distance of about 2 nm to excite the vibration of the Si--C bond at a wavelength of 16.5 μm. The infrared light of No. 2 was irradiated on the carbon attached to the probe, and a positive bias voltage was applied to the probe to gradually increase the voltage from 0V. As the voltage increased, the tunnel current flowing through the probe gradually increased, and sharply increased at about 10V. This change indicates that carbon has migrated onto the tungsten plate. Then, by scanning on the tungsten substrate, it was confirmed that carbon atoms were deposited on the tungsten substrate.

Example 2 Oxygen atoms in the silicon epitaxial film were removed by using the apparatus shown in FIG. The probe of the device used is a tungsten tip having a diameter of 20 μmφ, a height of 30 μmφ, and a radius of curvature of the tip of the cone of 10 nmφ. Keep the probe at a height of about 2 nm from the sample surface, irradiate the sample surface with a PbSe semiconductor laser with a wavelength of 8.5 μm that can excite Si-O bond vibration, and apply a +10 V pulse voltage to the probe By scanning the surface, oxygen existing between lattices of the Si crystal was desorbed. The desorption of oxygen was confirmed by comparing the atomic arrangement images before and after laser irradiation.

Example 3 Using the apparatus shown in FIG. 4, the oxygen present on the silicon surface was analyzed. The probe of the device used was a conical tip of n-type silicon crystal, and had a diameter of 20 μmφ, a height of 20 μmφ,
The radius of curvature of the tip of the cone is 10 nmφ. Atomization was performed by irradiating infrared light having a wave number of 1100 cm ⁻¹ capable of exciting Si—O vibration with a carbon dioxide gas laser, and the sample was cooled to liquid nitrogen temperature. Keep the distance between the sample and the probe at 2 nm,
The voltage was gradually increased from 0 V with the probe being negative. The tunnel current increased with the increase in voltage, but about +
Intermittent changes were observed at 1.3V. This confirmed that the oxygen atoms on the surface of the sample solid were desorbed.

Example 4 Using the apparatus shown in FIG. 4, N- adsorbed on the silicon surface was used.
Analysis of the alkyl piperidine dione molecule was performed. The probe of the device used is a metallic tip made of platinum-iridium, and has a conical shape with a diameter of 20 μmφ and a height of 30 μmφ.
The radius of curvature of the tip of the cone is 10 nmφ or less. The wavelength of light for ionizing molecules is 532 nm.
The analysis sample was cooled to the liquid nitrogen temperature using Nd.YAG laser beam. The distance between the sample and the probe was kept at about 5 nm, and the voltage was gradually increased from 0 V with the probe being negative. It was confirmed that the tunnel current also increased as the voltage increased, and the N-alkylpiperidinedione molecule was desorbed from the intermittent change of the tunnel current at +2.5 V and attached to the probe.

As described above, according to the present invention, it is possible to directly manipulate an atom or molecule, which has been difficult in the past, to form a material having a desired composition and structure in a very small area, and to make a material in the extremely small area. Since it is possible to selectively remove impurity atoms or molecules present on the material surface of
(1) Large-scale integrated circuit elements and compound semiconductor materials can be formed on the order of atoms and molecules. (2) A recording material such as a magnetic tape or a magnetic disk or an optical semiconductor material having a superlattice structure can be obtained.

Furthermore, since it is possible to directly discriminate the kind of atom or molecule, which has been difficult in the past, for example,
(1) By observing the atomic array image on the sample surface, the type of the observed atom or molecule can be determined, and the two-dimensional distribution of the specific atom or molecule can be known. (2) When performing the analysis, the sample can be directly analyzed directly without pretreatment such as polishing or milling, which facilitates the analysis and is an extremely effective means for evaluating the semiconductor substrate or the LSI process.

In the present specification, the formation and evaluation of semiconductor materials and semiconductor elements have been mainly described as an example, but the present invention is not limited to semiconductors, and individual atoms or molecules themselves are arranged and controlled with an accuracy of nanometer or less. When it is necessary to observe, it can be widely applied to cases such as preparation and development of catalysts and formation of monomolecular films.

[0071]

According to the present invention, atoms or molecules can be directly manipulated to form and process a semiconductor material having a desired composition and structure with an accuracy of nanometer or less. Further, since it becomes possible to directly discriminate the type of atom or molecule, it becomes possible to evaluate and analyze the surface of the semiconductor material.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a state in which atoms or molecules are released.

FIG. 2 is a schematic diagram showing a change in tunnel current with respect to a bias voltage.

FIG. 3 is a diagram showing an example of a configuration of a probe portion of the device of the present invention.

FIG. 4 is a diagram showing an example of the configuration of the entire apparatus of the present invention.

[Explanation of symbols]

 1 semiconductor material sample 2 sample substance 3 sample mounting table 4 step motor 5 probe 6 piezo element 7 heating / cooling device 8 chamber 9 transparent window 10 light beam irradiation device 11 ion beam irradiation device 12 optical microscope 30 heteroatom

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Miyuki Takenaka 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Miki Honma Komukai-Toshiba, Kawasaki-shi, Kanagawa Machi 1 Stock Company Toshiba Research and Development Center

Claims (5)

[Claims] 1. A method for forming a semiconductor material on a solid surface, comprising: an attaching step of attaching atoms or molecules for forming a semiconductor to a probe; and a step of attaching a specific atom or molecule to the probe. In order to match the position of forming the semiconductor material, the position of the probe and the solid surface is moved to maintain the distance between the probe and the solid surface at a desired interval, and the light is attached to the probe. Irradiating the atom or molecule
A light irradiation step to excite atoms or molecules, an atom or molecule excited by a voltage applied between the probe and the solid surface is detached from the probe, and a desorption transfer step of moving to the solid surface, A method of forming a semiconductor material, comprising: a step of depositing atoms or molecules transferred to a solid surface on the solid surface to form a semiconductor material on the solid surface. 2. A method of forming a semiconductor material on a solid surface, wherein the position of the probe and the solid surface is moved in order to align the probe with the position of the atom or molecule to be removed on the solid surface. A positioning step of keeping a distance between the probe and the solid surface at a desired interval, a light irradiation step of irradiating light to an atom or molecule to be removed in the solid surface to excite the atom or molecule, and a probe. An atom or molecule that is excited by the voltage applied to the solid surface is released from the solid surface and is moved to the probe, and the atom or molecule that has moved to the probe is attached to the probe. And a removal step of removing atoms or molecules from the solid surface, the method for forming a semiconductor material. 3. A method for evaluating and analyzing the solid surface of a semiconductor material, wherein the position of the probe and the solid surface is adjusted so that the probe is aligned with the position of the atom or molecule to be evaluated and analyzed in the solid surface. A step of moving and maintaining the distance between the probe and the solid surface at a desired interval, and a light irradiation step of irradiating light to the atoms or molecules to be evaluated and analyzed in the solid surface, and exciting the atoms or molecules, Atoms or molecules excited by the voltage applied between the probe and the solid surface are released from the solid surface, moved to the probe, and the movement is detected by the current flowing between the probe and the solid surface. A method of evaluating and analyzing an atom or molecule on a solid surface of a semiconductor material, characterized by determining the type of atom or molecule that has desorbed or moved, depending on the wavelength of the irradiated light, including a detection step of detecting the change. 4. The excitation of atoms or molecules in the light irradiation step is excitation by ionization.
5. A method for evaluating or analyzing atoms or molecules on the solid surface of the semiconductor material according to. 5. A positioning means for moving the positions of the probe and the solid surface to keep the distance between the probe and the solid surface at a desired interval in order to align the probe with a specific position on the solid surface, and an optical device. The probe or solid surface is irradiated with light to excite atoms or molecules, and the atoms or molecules excited by the voltage applied between the probe and the solid surface are decoupled from the solid surface and probed. A device for forming, processing, and analyzing and evaluating a semiconductor material, comprising: a detection unit that is moved to a needle and detects the movement based on a change in a current flowing between a probe and a solid surface.