RU2407102C2 - Method for generation of nanostructures - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: in method for generation of nanostructures on substrate, by means of controlled laser action at sample via substrate with gap between sample and substrate, varying parametres of laser radiation and distance between substrate and sample, selection of nanoparticles is carried out, which in process of deposition form a nanostructure on substrate with gap from several microns to 2 mm in air atmosphere.

EFFECT: production of lengthy arrays of nanostructures with the possibility to provide efficient control of shape and alignment of synthesized particles, selection of light and heavy particles to obtain higher homogeneity of nanostructures.

3 cl, 1 dwg

Description

The invention relates to nanotechnology and the production of nanostructures, to a method for producing extended arrays of nanostructures and nanopowders from various materials (carbon, carbon-containing, metals, multicomponent alloys), as well as to the production of nanostructured composite materials as an intermediate product in the production of nanostructures. It can be used in microelectronics, electrical engineering, in optical and nonlinear optical systems and devices, magneto-optical systems, as well as for creating new magnetic information carriers.

A known method of forming thin films on a semiconductor substrate and a device for its implementation (RF Patent No. 2046450, IPC H01L 21/30). The method includes preparing the applied liquid on a semiconductor substrate, which is mounted on a rotating table equipped with a vacuum grip. At the first stage, the substrate is rotated around a horizontal axis in the reservoir with the applied liquid. In a second step, the substrate is removed from the reservoir and rotated at an increased speed. After that, the substrate is lowered into the tank with the formation of a gap between the substrate and the surface in the liquid tank, a filtered applied liquid is supplied from below to the surface of the rotating substrate under pressure, then the stage with the substrate is rotated at an increased speed before returning to its original position, and the waste liquid is discharged from reservoir into the recirculation system and through the filter is sent to a repeated film deposition cycle.

A known method of photochemical deposition of thin films and a device for its implementation (RF Patent No. 2059322, IPC H01L 21/31). The method includes heating the substrate in an atmospheric pressure reactor, supplying a mixture of reacting gases, irradiating the deposition zone with vacuum ultraviolet radiation of excimer inert gas molecules of a gas-discharge barrier-type plasma at a voltage of 1-20 kV and a frequency of 1-20 kHz, the radiation spectrum being selected from the absorption spectrum of reacting gases. The disadvantages of this method are: 1) an atmospheric pressure reactor is required to obtain thin films; 2) it is necessary to irradiate the deposition zone with ultraviolet radiation of excimer inert gas molecules of a gas-discharge barrier-type plasma.

As a prototype, a method for producing a film coating with the properties of carbon glass and an installation for implementing the method were selected (RF Patent No. 2340550, IPC СВВ 31/00). In an inert gas atmosphere with a fixed pressure exceeding the pressure at the triple point of carbon, a highly oriented graphite sample is vaporized with a laser pulse within the local zone in such a way as to overheat the carbon relative to the equilibrium melting point of graphite corresponding to this fixed pressure. Evaporation is carried out through a quartz glass plate installed with a gap of 10-100 μm relative to the sample. Precipitation of the resulting vapor is carried out on the part of the sample adjacent to the local zone. To implement the method, the device comprises a sample of highly oriented graphite placed in an inert gas atmosphere, a quartz plate located above it, a pulsed laser in optical communication with them, a pyrometer for detecting the temperature of liquid carbon and a photodetector for detecting the power of the laser pulse, as well as a device for changing the relative position sample and quartz plate, made in the form of a split spring gasket, which is pressed by a nut. The proposed invention provides an increase in the continuity and uniformity of the resulting coatings with the structure of glassy carbon.

The disadvantages of the above method include the fact that in order to obtain films, an inert gas atmosphere with a fixed pressure exceeding the pressure at the triple point of carbon is required. As a result, the required pressure at a given point in the classical diagram is 20–40 kPa. This leads to significant technological difficulties. Also, with the technological cycle of the prototype it is not possible to obtain extended arrays of nanostructures, nanopowders.

The technical result of this invention is the production of nanostructures, for example, extended arrays of nanostructures, homogeneous thin films, nanopowders with the ability to effectively control the shape and orientation of the synthesized particles, selection of light and heavy particles to obtain greater uniformity of the arrays of nanostructures on the substrate.

This technical result is achieved by the fact that in the method of forming nanostructures on the substrate, by controlled laser irradiation of the sample through the substrate with a gap between the substrate and the sample, by varying the laser radiation parameters and the distance between the sample and the substrate, the selection of nanoparticles that form the nanostructure during deposition on a substrate with a gap of a few microns to 2 mm in an air atmosphere. Also, a sample with a nanostructured surface or a nanoporous material can be used as a sample.

The gap can be created using technological equipment that allows you to adjust the height between the substrate and the sample and determine the preferred direction of plasma propagation, for example, the substrate on which the deposition occurs can be fixed on a platform with a stepper motor, thereby changing the distance between the substrate and the sample.

The substrate for spraying is made of transparent material for laser radiation with a given long wavelength. It is also possible to use opaque substrates in which a hole is made for the passage of laser radiation.

Laser radiation 1 is applied to sample 3. As a result, an erosion plasma torch is formed, the particles of which are deposited on a cold substrate 2. There is a distance between the sample and the substrate, which is created by the interlayer 4. If the initial target is two-component, then the plasma torch will contain heavy and light particles, and the effect of exacerbation will be observed during the expansion of heavy particles, provided that heavier particles propagate in a cloud of light particles. Such an observation and an aggravation effect are shown in the work “Selected Problems of the Theory of Laser Ablation” by S. I. Anisimov and B. S. Lukyanchuk, journal Uspekhi Fizicheskikh Nauk.

The inventive method for controlling and producing nanostructures is based on studies of the physicochemical processes of the formation of nanoparticles and nanostructures under the action of laser radiation. In the present method, the formation of nanostructures is carried out under the influence of laser radiation.

A feature of the method lies in laser-plasma technologies. The use of laser plasma allows one to improve the selection of atoms to the size of obtaining individual nanoparticles of the order of 2-50 nm, and the exacerbation effect makes it possible to achieve selection of heavy and light particles. This process can occur in an atmosphere of air due to oversaturation of vapors that do not interact with the environment. By changing the distance between the sample and the substrate, controlling the geometry of the channel for plasma motion, it is possible to achieve the selection of the deposited particles. By varying the parameters of laser radiation, it is possible to ensure that heavy particles cannot reach the cold substrate or that light particles leave the deposition region. The proposed method for the formation of nanostructures, for example, extended arrays of nanostructures, thin films and nanopowders allows you to reduce the cost of the technological cycle of obtaining finished products with the possibility of further application.

The resulting thin films can be used as protective or decorative coatings (for example, titanium oxide and nitride, aluminum oxide, zinc oxide, etc.), extended arrays of nanostructures, if alternated, allow them to be used as micro- and nano- electronic devices, due to different conductivity in the layers of the material, the resulting nanopowders can be used in various industries as fillers, catalysts, etc.

An example implementation of the method. The drawing shows a diagram of the formation of nanostructures. By applying laser radiation 1 to sample 3, a plasma torch is formed, from which particles fly out, which are deposited on a cold substrate 2. There is an adjustable gap between the sample and the substrate, which is created using the interlayer 4.

Claims (3)

1. A method of forming nanostructures on a substrate by controlled laser exposure of the sample through the substrate with a gap between the sample and the substrate, characterized in that, by varying the parameters of the laser radiation and the distance between the substrate and the sample, the selection of nanoparticles, which during the deposition process form a nanostructure on the substrate with a gap of a few microns to 2 mm in an air atmosphere. 2. The method according to claim 1, characterized in that the material with a nanostructured surface is used as a sample. 3. The method according to claim 1, characterized in that the sample uses nanoporous material: mesoporous materials, nanoporous carbon.