阅读说明：本技术 纳米多孔碳氧硅薄膜的制备方法及薄膜 (Preparation method of nano porous carbon silicon oxide film and film ) 是由 刘纯宝 蔡鲁刚 陈兰芳 于 2019-10-16 设计创作，主要内容包括：本发明提供了一种纳米多孔碳氧硅薄膜的制备方法及薄膜,该方法包括：利用氧化法对硅衬底的表面进行处理,在所述硅衬底上形成非晶态氧化硅层；对形成有所述非晶态氧化硅层的所述硅衬底的表面进行碳离子注入,在所述硅衬底上形成碳氧硅混合层；对形成有所述碳氧硅混合层的所述硅衬底的表面进行离子透射辐照,在所述硅衬底上形成包含纳米径迹孔隙的碳氧硅混合层。通过上述方案能够实现纳米多孔碳氧硅薄膜的可控制备。(The invention provides a preparation method of a nano porous carbon oxygen silicon film and the film, and the method comprises the following steps: processing the surface of a silicon substrate by using an oxidation method, and forming an amorphous silicon oxide layer on the silicon substrate; injecting carbon ions into the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate; and carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate. The controllable preparation of the nano porous carbon oxygen silicon film can be realized by the scheme.)

1. A preparation method of a nano porous carbon oxygen silicon film is characterized by comprising the following steps:

processing the surface of a silicon substrate by using an oxidation method, and forming an amorphous silicon oxide layer on the silicon substrate;

injecting carbon ions into the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate;

carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano-track pores on the silicon substrate as a nano porous carbon-oxygen-silicon film; wherein the energy of the ion transmission irradiation is higher than that of the carbon ion implantation.

2. The method of preparing a nanoporous carbon monox film as defined in claim 1 wherein the oxidation process is a dry-wet combination oxidation process.

3. The method of preparing a nanoporous carbon-oxygen-silicon thin film as defined in claim 1,

performing carbon ion implantation on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate, wherein the carbon-oxygen-silicon mixed layer comprises:

performing carbon ion implantation on the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer buried under the silicon oxide layer on the silicon substrate;

performing ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano-track pores on the silicon substrate, wherein the method comprises the following steps:

and carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores between the silicon substrate and the silicon oxide layer.

4. The method for preparing a nanoporous carbon-oxygen-silicon thin film as claimed in claim 1, wherein the step of forming a mixed layer of carbon-oxygen-silicon containing nano-track pores on the silicon substrate by subjecting the surface of the silicon substrate on which the mixed layer of carbon-oxygen-silicon is formed to ion transmission irradiation comprises:

and carrying out lead ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate.

5. The method for preparing a nanoporous silicon oxy-silicon film according to any one of claims 1 to 4,

performing carbon ion implantation on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate, wherein the carbon-oxygen-silicon mixed layer comprises:

under the condition of normal temperature, injecting carbon ions into the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate;

performing ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano-track pores on the silicon substrate, wherein the method comprises the following steps:

and under the normal temperature condition, carrying out ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate.

6. The method for preparing a nanoporous carbon-oxygen-silicon thin film as claimed in claim 4, wherein the energy range of the carbon ion implantation is 60 KeV-120 KeV; the dosage range of carbon ion implantation is 2 x 10¹⁷～1.2×10¹⁸(ii) a The energy range of lead ion transmission irradiation is 700 MeV-900 MeV; the irradiation dose range of lead ion transmission irradiation is 5 multiplied by 10¹¹～5×10¹²。

7. The method of preparing a nanoporous carbon-oxygen-silicon thin film as claimed in claim 2, wherein the forming of the amorphous silicon oxide layer on the silicon substrate by treating the surface of the silicon substrate using an oxidation process comprises:

putting a silicon substrate into a quartz tube with sealing plugs at two ends;

introducing oxygen from the first conduit to a position below the water level in the first container, and then introducing the oxygen above the water level in the first container into the quartz tube through the second conduit passing through the sealing plug at one end of the quartz tube; oxygen enters the second container through a third conduit passing through a sealing plug at the other end of the quartz tube, and then the oxygen in the second container enters the liquid in the third container through a fourth conduit;

heating the quartz tube to a first temperature and the first container to a second temperature under the condition that oxygen passes through the quartz tube, and forming an amorphous silicon oxide layer on the silicon substrate after keeping for a set time; wherein the first temperature range is 1000-1200 deg.C, and the second temperature range is 60-100 deg.C.

8. The method of claim 7, wherein the silicon substrate is a silicon wafer.

9. The method of preparing a nanoporous carbon-oxygen-silicon thin film as defined in claim 1,

performing carbon ion implantation on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, wherein before forming a carbon-oxygen-silicon mixed layer on the silicon substrate, the method further comprises the following steps:

determining the energy value of a carbon ion beam used for carbon ion implantation according to the depth requirement of the nano porous carbon oxygen silicon film to be prepared in the silicon substrate; and/or

Determining the dosage value of a carbon ion beam used for carbon ion implantation according to the thickness requirement of the nano porous carbon-oxygen-silicon film to be prepared or the track length requirement of nano track pores in the nano porous carbon-oxygen-silicon film; and/or

Determining the beam spot shape and area size of a carbon ion beam used for carbon ion implantation according to the regional requirement of the nano porous carbon oxygen silicon film to be prepared;

performing ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, wherein before the carbon-oxygen-silicon mixed layer containing nano-track pores is formed on the silicon substrate, the method further comprises the following steps:

and determining the dose value of the ion beam used for ion transmission irradiation according to the aperture requirement of the nano-track pores in the nano-porous carbon oxygen silicon film to be prepared.

10. A nanoporous carbon-oxygen-silicon thin film, prepared by the method of any one of claims 1 to 9; wherein the diameter range of the nanometer track pores in the nanometer porous carbon-oxygen-silicon film is 1 nm-10 nm; the thickness of the nano porous carbon-oxygen-silicon film ranges from 500nm to 600 nm.

Technical Field

The invention belongs to the technical field of nano materials, and particularly relates to a preparation method of a nano porous carbon-oxygen-silicon film and the film.

Background

Due to the characteristics of small size, large specific surface area, high surface energy and the like, the nano porous material has unique electric conduction, heat conduction and quantum effect and is favored by material researchers, and the porous carbon oxygen silicon low dielectric constant film material is widely applied to the semiconductor manufacturing industry and is considered to have great potential application value in the research and preparation of future nano devices. Therefore, many methods are applied to the synthesis and preparation of the carbon-oxygen-silicon nano film material.

Disclosure of Invention

The invention provides a preparation method of a nano porous carbon-oxygen-silicon film and the film, which are used for realizing the controllable preparation of the nano porous carbon-oxygen-silicon film.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to an aspect of the embodiments of the present invention, there is provided a method for preparing a nanoporous carbon-oxygen-silicon thin film, including:

processing the surface of a silicon substrate by using an oxidation method, and forming an amorphous silicon oxide layer on the silicon substrate;

injecting carbon ions into the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate;

carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate; wherein the energy of the ion transmission irradiation is higher than that of the carbon ion implantation.

In some embodiments, the oxidation process is a dry-wet combined oxidation process.

In some embodiments, the carbon ion implantation is performed on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and a carbon-oxygen-silicon mixed layer is formed on the silicon substrate, including:

performing carbon ion implantation on the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer buried under the silicon oxide layer on the silicon substrate;

performing ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano-track pores on the silicon substrate, wherein the method comprises the following steps:

and carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores between the silicon substrate and the silicon oxide layer.

In some embodiments, performing ion transmission irradiation on the surface of the silicon substrate on which the silicon-carbon-oxygen mixed layer is formed to form the silicon-carbon-oxygen mixed layer containing nano-track pores on the silicon substrate comprises:

and carrying out lead ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate.

In some embodiments, the carbon ion implantation is performed on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and a carbon-oxygen-silicon mixed layer is formed on the silicon substrate, including:

and under the condition of normal temperature, injecting carbon ions into the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate.

In some embodiments, performing ion transmission irradiation on the surface of the silicon substrate on which the silicon-carbon-oxygen mixed layer is formed to form the silicon-carbon-oxygen mixed layer containing nano-track pores on the silicon substrate comprises:

and under the normal temperature condition, carrying out ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate.

In some embodiments, the energy range of the carbon ion implantation is 60KeV to 120 KeV; the dosage range of carbon ion implantation is 2 x 10¹⁷～1.2×10¹⁸。

In some embodiments, the energy range of the ion transmission irradiation is 700MeV to 900 MeV; the irradiation dose range of ion transmission irradiation is 5 × 10¹¹～5×10¹²。

In some embodiments, treating a surface of a silicon substrate on which an amorphous silicon oxide layer is formed using an oxidation process includes:

putting a silicon substrate into a quartz tube with sealing plugs at two ends;

introducing oxygen from the first conduit to a position below the water level in the first container, and then introducing the oxygen above the water level in the first container into the quartz tube through the second conduit passing through the sealing plug at one end of the quartz tube; oxygen enters the second container through a third conduit passing through a sealing plug at the other end of the quartz tube, and then the oxygen in the second container enters the liquid in the third container through a fourth conduit;

heating the quartz tube to a first temperature and the first container to a second temperature under the condition that oxygen passes through the quartz tube, and forming an amorphous silicon oxide layer on the silicon substrate after keeping for a set time; wherein the first temperature range is 1000-1200 deg.C, and the second temperature range is 60-100 deg.C.

In some embodiments, the silicon substrate is a silicon wafer.

In some embodiments, the carbon ion implantation is performed on the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and before the formation of the carbon-oxygen-silicon mixed layer on the silicon substrate, the preparation method further includes:

determining the energy value of a carbon ion beam used for carbon ion implantation according to the depth requirement of the nano porous carbon oxygen silicon film to be prepared in the silicon substrate; and/or

Determining the dosage value of a carbon ion beam used for carbon ion implantation according to the thickness requirement of the nano porous carbon-oxygen-silicon film to be prepared or the track length requirement of nano track pores in the nano porous carbon-oxygen-silicon film; and/or

According to the regional requirement of the nano porous carbon oxygen silicon film to be prepared, the beam spot shape and the area size of the carbon ion beam used for carbon ion implantation are determined.

In some embodiments, before the step of forming the hybrid layer of silicon carbon-oxygen-containing pores on the silicon substrate by performing ion transmission irradiation on the surface of the silicon substrate on which the hybrid layer of silicon carbon-oxygen-containing pores is formed, the preparation method further includes: and determining the dose value of the ion beam used for ion transmission irradiation according to the aperture requirement of the nano-track pores in the nano-porous carbon oxygen silicon film to be prepared.

According to another aspect of the embodiment of the invention, a nano porous carbon oxygen silicon film is provided, which is prepared by the method of the embodiment; wherein the diameter range of the nanometer track pores in the nanometer porous carbon-oxygen-silicon film is 1 nm-10 nm; the thickness of the nano porous carbon-oxygen-silicon film ranges from 500nm to 600 nm.

According to the preparation method of the nano porous carbon oxygen silicon film and the film, an amorphous silicon oxide layer is formed on a silicon substrate by using an oxidation method, carbon ions are injected into the surface of the silicon substrate with the amorphous silicon oxide layer, a carbon oxygen silicon mixed layer is formed on the silicon substrate, then ion transmission irradiation is carried out on the surface of the silicon substrate with the carbon oxygen silicon mixed layer, and the carbon oxygen silicon mixed layer containing nano track pores is formed on the silicon substrate, so that the preparation of the nano porous carbon oxygen silicon film can be realized. Moreover, the size of the pore in the carbon-oxygen-silicon film can be well regulated and controlled by changing the implantation condition of carbon ions and the condition of ion transmission irradiation.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

FIG. 1 is a schematic flow chart of a method for preparing a nanoporous carbon-oxygen-silicon thin film according to an embodiment of the invention;

FIG. 2 is a schematic diagram of an apparatus for dry-wet combined oxidation in accordance with an embodiment of the present invention;

FIG. 3 is a schematic flow chart of a process for preparing a nanoporous carbon-oxygen-silicon thin film according to an embodiment of the invention;

FIG. 4 is a transmission electron microscope image of the thin film preparation result obtained by the preparation method according to one embodiment of the present invention.

Description of the symbols:

1: a first conduit; 2: a first container; 3: a second conduit; 4: a third conduit; 5: a second container; 6: a fourth conduit; 7: a third container; 8: an annealing furnace; 9: a quartz tube; 21: a silicon substrate; 22: a silicon oxide layer; 23: a carbon-oxygen-silicon mixed layer; 24: a carbon-silicon mixed layer; 25: and (4) nano-tracks.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

FIG. 1 is a schematic flow chart of a method for preparing a nanoporous carbon-oxygen-silicon thin film according to an embodiment of the invention. As shown in fig. 1, the method for preparing a nanoporous carbon-oxygen-silicon thin film according to some embodiments may include the following steps S110 to S130.

Specific embodiments of steps S110 to S130 will be described in detail below.

Step S110: processing the surface of a silicon substrate by using an oxidation method, and forming an amorphous silicon oxide layer on the silicon substrate to be used as a nano porous carbon silicon oxide film; wherein the energy of the ion transmission irradiation is higher than that of the carbon ion implantation.

In step S110, the silicon substrate may be a silicon wafer, which may be single crystal silicon or polycrystalline silicon, may be crystalline silicon preferentially grown along various crystal directions, may be pure silicon or doped silicon, and may be P-type crystalline silicon or N-type crystalline silicon. For example, the silicon substrate is boron-doped P-type single crystal silicon grown in the 100 crystal direction.

Before this step S110, a desired silicon wafer may be prepared as a silicon substrate, and the prepared silicon substrate may be cleaned and then used to form a silicon oxide layer. For example, a boron-doped P-type single crystal silicon wafer preferentially grown along the 100 crystal direction may be selected, and may have a thickness of 0.5mm and a surface polish level of 1 sp; the silicon wafer may then be cut into 2X 4cm pieces²The rectangular small piece of (a) as a silicon substrate; then, the silicon substrate may be soaked in alcohol for about 1 hour, and then, may be ultrasonically washed with deionized water for 30 minutes, and finally, may be blow-dried by room-temperature air for forming a silicon oxide layer.

The oxidation method may be any of various methods capable of oxidizing silicon on the surface of a silicon substrate to form a silicon oxide layer on the silicon substrate. For example, a wet oxidation method, a dry-wet combined oxidation method, or the like may be used. Among them, the dry-wet combined oxidation method may be a method of oxidizing silicon on the surface of a silicon substrate with wet oxygen.

Illustratively, this step S110 may be performed using an apparatus for a dry-wet combined oxidation process shown in fig. 2. Referring to fig. 2, the step S110 may specifically include the steps of: s111, placing the silicon substrate into a quartz tube 9 with sealing plugs at two ends; s112, introducing oxygen from the first conduit 1 to a position below the liquid level of the water in the first container 2, and then introducing the oxygen above the liquid level of the water in the first container 2 into the quartz tube 9 through the second conduit 3 passing through a sealing plug at one end of the quartz tube 9; oxygen enters the second container 5 through the third conduit 4 passing through the sealing plug at the other end of the quartz tube 9, and then the oxygen in the second container 5 enters the liquid in the third container 7 through the fourth conduit 6; s113, in the case where oxygen passes through the quartz tube 9, the quartz tube 9 is heated to a first temperature, the first container 2 is heated to a second temperature, and after a predetermined time, an amorphous silicon oxide layer is formed on the silicon substrate. The above steps S112 and S113 may be performed under normal pressure.

In this step S112, the water in the first container 2 may be deionized water. After the oxygen is filtered by the water, a small amount of water can be carried into the quartz tube 9 so as to form an atmosphere filled with humid oxygen in the quartz tube. The introduction of oxygen into the quartz tube in the above step S112 may be continued for a period of time to exhaust the air originally in the quartz tube. The oxygen discharged from the quartz tube is not directly discharged to the air, but is discharged after passing through the liquid in the second container 5 and the third container 7, so that the gas at the outlet end of the quartz tube can be sucked back into the quartz tube through the liquid in the third container 7.

In step S113, oxygen is continuously introduced into the quartz tube in the manner of step S112, so that oxygen is continuously introduced into the quartz tube. By heating the first container 2, the liquid water in the first container 2 can be heated, so that more moisture can be let into the quartz tube. In addition, the first temperature may range from 1000 ℃ to 1200 ℃, for example, the first temperature may be 1000 ℃, 1050 ℃, 1100 ℃, or 1150 ℃. The second temperature may range from 60 ℃ to 100 ℃, specifically the second temperature may range from 70 ℃ to 90 ℃, for example, the second temperature is 75 ℃, 80 ℃ or 85 ℃. The set time for holding may be determined as needed, and may be, for example, 2 hours, 3 hours, 5 hours, or the like.

In addition, in the step S113, the quartz tube 9 is heated to the first temperature, and the first container 2 is heated to the second temperature, after the set time is maintained, the heating of the first container 2 may be stopped first, and then the heating of the quartz tube 9 may be stopped, for example, after the first temperature and the second temperature are maintained and the state where the water vapor and the oxygen are simultaneously introduced is 3 hours, the heating of the first container 2 (beaker) is stopped first, and after 30 minutes, the power supply of the annealing furnace for heating the quartz tube 9 is cut off, and during this period, the introduction of the oxygen may be continued until the quartz tube and the silicon substrate are naturally cooled to the room temperature. The film prepared by the method is purple with naked eyes, and the thickness of the silicon oxide film is between 500nm and 600 nm.

Step S120: and performing carbon ion implantation on the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate.

In this step S120, "ion implantation" may refer to irradiating a material with a low energy ion beam having an energy of an keV order (e.g., 100keV order) under a certain vacuum condition. After the ion beam is incident into the material, a series of physical and/or chemical interactions occur with atoms or molecules in the material, and the incident ions gradually lose energy and finally stay in the material, so that the surface composition of the material is changed. If the ion beam used for ion implantation is a carbon ion beam, carbon ion implantation is performed. By performing carbon ion implantation on the side of the silicon substrate on which the amorphous silicon oxide layer is formed, carbon can be doped into the silicon oxide layer (forming a carbon-oxygen-silicon mixed layer), and carbon can also be doped into the silicon substrate below the silicon oxide layer.

Illustratively, the grown silicon oxide layer has a thickness of 500nm, the peak depth of the implanted carbon ions may be 350nm, and the ion implantation distribution region may vary with the implantation dose, for example, the distribution region may have a thickness of 100nm to 480nm at a low dose, the distribution region may have a thickness of 40nm to 500nm at a medium dose, and the distribution region may have a thickness of 20nm to 520nm at a high dose, and at least a portion of the silicon oxycarbide region may be located below the silicon oxide layer.

In addition, when carbon ion implantation is performed on the side of the silicon substrate on which the amorphous silicon oxide layer is formed, the ion beam may penetrate a part of the thickness of the silicon oxide layer (carbon ions are not doped in the part of the thickness of the silicon oxide layer) and dope carbon ions in the part of the silicon oxide layer below the part of the thickness of the silicon oxide layer, so that the carbon-oxygen-silicon mixed layer formed by the carbon ion implantation is a layer of carbon-oxygen-silicon buried below the part of the thickness of the silicon oxide layer. In this case, for example, the specific implementation of step S120 may include the steps of: and S121, performing carbon ion implantation on the surface of the silicon substrate with the amorphous silicon oxide layer, and forming a carbon-oxygen-silicon mixed layer buried under the silicon oxide layer on the silicon substrate.

In this embodiment, the carbon-oxygen-silicon mixed layer is a buried layer, so that the obtained nanoporous carbon-oxygen-silicon thin film can also be a buried layer. And the depth of the buried layer can be adjusted by adjusting the energy of the implanted carbon ions, and the defect that the buried depth cannot be adjusted by the conventional preparation method of the nano porous film is overcome, so that the nano porous carbon-oxygen-silicon film obtained by the invention has wider application.

In other embodiments, the carbon-oxygen-silicon mixed layer directly exposed outside can be obtained by adjusting the ion beam energy during carbon ion implantation, or by treating the surface of the silicon substrate by chemical etching or the like after carbon ion implantation, in other words, the obtained carbon-oxygen-silicon mixed layer may not be a buried layer.

In step S120, the inventors have experimentally found that, due to the limited thickness of the silicon oxide film, if the energy of the carbon ion beam is too high, most of the implanted carbon may be distributed in the single crystal silicon layer, and thus the carbon-oxygen-silicon mixed layer may not be formed, and thus a porous structure may not be formed. The energy value of the carbon ion beam can be determined appropriately according to the thickness of the silicon oxide film. Illustratively, the energy range of the carbon ion implantation may be 60KeV to 120KeV, for example, 60KeV, 80KeV, 100KeV, or 120 KeV. The dosage range of the carbon ion implantation can be 2 x 10¹⁷～1.2×10¹⁸For example, it may be 5 × 10¹⁷、8×10¹⁷、1×10¹⁸Or 1.1X 10¹⁸. The degree of vacuum of the implantation chamber during the carbon ion implantation may be high vacuum or ultra high vacuum, and the degree of vacuum may be in the range of 5 × 10^-5Pa～5×10^-7Pa, for example, may be 1X 10^-6Pa or 5X 10^-6Pa. In addition, the beam intensity of the carbon ion beam may be in the range of 1 × 10¹³ions/cm²/s～5×10¹⁴ions/cm²S, e.g. 5X 10¹³ions/cm²/s。

This step S120 may be performed at a normal temperature, i.e., without additionally adjusting the ion implantation temperature. In this case, the specific implementation of step S120 may include: and under the condition of normal temperature, injecting carbon ions into the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, and forming a carbon-oxygen-silicon mixed layer on the silicon substrate. In this embodiment, the carbon ion implantation is performed at normal temperature, so that the silicon-oxygen-carbon mixed layer has good stability.

In other embodiments, the temperature of the implantation chamber during the carbon ion implantation can be adjusted according to the temperature of the application environment of the nanoporous carbon-oxygen-silicon thin film, so that the carbon-oxygen-silicon mixed layer has better stability in the application environment.

In other embodiments, before the step S120, the method for preparing the nanoporous carbon-oxygen-silicon thin film shown in fig. 1 may further include the steps of: determining the energy value of a carbon ion beam used for carbon ion implantation according to the depth requirement of the nano porous carbon oxygen silicon film to be prepared in the silicon substrate; and/or determining the dosage value of the carbon ion beam used for carbon ion implantation according to the thickness requirement of the nano porous carbon oxygen silicon film to be prepared or the track length requirement of nano track pores in the nano porous carbon oxygen silicon film; and/or determining the beam spot shape and the area size of the carbon ion beam for carbon ion implantation according to the regional requirement of the nano porous carbon oxygen silicon film to be prepared.

The nano porous carbon-oxygen-silicon film refers to a carbon-oxygen-silicon mixed layer containing nano track pores. The depth requirement of the nano porous carbon oxygen silicon film to be prepared in the silicon substrate can refer to the depth of the surface of one side, facing the silicon substrate, of the carbon oxygen silicon mixed layer in the silicon substrate, or the depth of the middle position in the thickness direction of the carbon oxygen silicon mixed layer in the silicon substrate; in the case where the silicon-carbon mixed layer is a buried layer, this depth requirement may be referred to as a buried depth.

In the embodiment, corresponding film preparation parameters can be determined according to one or more of the depth requirement, the thickness requirement or the track length requirement and the region requirement of the nano porous carbon-oxygen-silicon film to be prepared, so that the accurate regulation and control of the nano porous structure in the nano porous carbon-oxygen-silicon film can be realized.

Step S130: carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate; wherein the energy of the ion transmission irradiation is higher than that of the carbon ion implantation.

In step S130, the nano-track pores included in the silicon carbon oxygen mixed layer means that a plurality of nano-pores are formed in the silicon carbon oxygen mixed layer, and the nano-pores extend for a certain length in the thickness direction of the silicon carbon oxygen mixed layer. The pore diameter and the extension length of the nanometer track pores are in a nanometer level, and the nanometer level mainly represents a microscopic scale which can be as small as tens of angstroms and as large as hundreds of microns. In addition, the extension direction of the nanopore may be determined according to the direction in which the ion beam of the ion transmission irradiation is irradiated toward the silicon substrate, for example, may be perpendicular to the silicon substrate.

The "ion transmission irradiation" may refer to irradiating a material with a high-energy ion beam with energy of hundreds of MeV under a certain vacuum condition, wherein the high-energy ion penetrates through the material and causes a change in the surface structure of the material. The energy of the ion transmission irradiation is higher than that of the carbon ion implantation, and the ion transmission irradiation is high-energy irradiation at least relative to the carbon ion implantation, and specifically, the energy of the two ion beams may be different by several orders of magnitude in electron volts. More specifically, the ions used for ion transmission irradiation are high-energy heavy ions, the energy of which is high enough to easily penetrate through the carbon-oxygen-silicon mixed layer and simultaneously deposit high-density energy, and a porous structure is formed after physicochemical change is caused.

The ions used for ion transmissive irradiation may be heavy ions, for example, lead ions. In this case, the specific implementation of step S130 may include: and carrying out lead ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate.

If the carbon-oxygen-silicon mixed layer is a carbon-oxygen-silicon mixed layer buried under a silicon oxide layer, that is, if the embodiment of the step S120 includes the step S121, the carbon-oxygen-silicon mixed layer containing the nano-track pores (the nano-porous carbon-oxygen-silicon thin film) may also be a buried layer, in other words, the embodiment of the step S130 may include: and carrying out ion transmission irradiation on the surface of the silicon substrate with the carbon-oxygen-silicon mixed layer, and forming the carbon-oxygen-silicon mixed layer containing nano track pores between the silicon substrate and the silicon oxide layer. In this case, depending on the irradiation conditions, the silicon oxide layer above the silicon-carbon-oxygen mixed layer and the portion below the silicon-carbon-oxygen mixed layer may also contain nanopores.

In other embodiments, the nanoporous carbon-oxygen-silicon thin film directly exposed outside can be obtained by adjusting the ion beam energy during carbon ion implantation, or by treating the surface of the silicon substrate by chemical etching or the like after ion transmission irradiation, in other words, the obtained nanoporous carbon-oxygen-silicon thin film may not be a buried layer.

In step S130, the inventors have experimentally found that, when performing the ion transmission irradiation, if the energy of the ions is too high, the energy deposition density may be reduced, and the formation of the porous structure may be further unfavorable. The energy loss condition of the ions used for transmission irradiation can be simulated by software before the ion transmission irradiation is carried out, and the energy of the ion beams used for transmission irradiation can be determined according to the requirements of the porous structure. For example, if the lead ion beam is irradiated in transmission, the energy of the lead ion irradiation may be in the range of 700MeV to 900MeV, for example, 750MeV, 785MeV, 800MeV, or 900 MeV. The irradiation dose range of the lead ion transmission irradiation can be 5 multiplied by 10¹¹～5×10¹²The amount of the solvent to be used is, for example,can be 8 multiplied by 10¹¹、1×10¹²Or 3X 10¹². The vacuum degree of the irradiation chamber during ion transmission irradiation can be high vacuum or ultrahigh vacuum, and the vacuum degree range can be 5 × 10^-5Pa～5×10^-7Pa, for example, may be 1X 10^-6Pa or 5X 10^-6Pa. Further, the beam intensity of the ion beam used for the ion transmission irradiation may be in the range of 1 × 10¹³ions/cm²/s～5×10¹⁴ions/cm²S, e.g. 5X 10¹³ions/cm²/s。

The energy required may vary depending on the type of ion used for the ion transmission irradiation. For example, when the ion used for the ion transmission irradiation may be a xenon ion, the energy of the xenon ion may be, for example, 300 MeV. Of course, the pore diameter and the track length of the nano porous carbon oxygen silicon film finally prepared can be different.

In some embodiments, the carbon ion implant dose is 1.2 × 10¹⁸And the dose of lead ion irradiation is 1X 10¹². The continuity of the tracking voids in the silicon-on-carbon film obtained under the conditions of this example was good.

This step S130 may be performed at normal temperature, i.e., without additionally regulating the ion transmission irradiation temperature. In this case, the specific implementation of step S130 may include: and under the normal temperature condition, carrying out ion transmission irradiation on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, and forming the carbon-oxygen-silicon mixed layer containing nano track pores on the silicon substrate. In the embodiment, the nano porous carbon-oxygen-silicon film has good stability by carrying out ion transmission irradiation at normal temperature.

In other embodiments, the temperature of the irradiation chamber during ion transmission irradiation can be adjusted according to the temperature of the application environment of the nanoporous carbon-oxygen-silicon thin film, so that the nanoporous carbon-oxygen-silicon thin film has better stability in the application environment.

In other embodiments, before the step S130, the method for preparing the nanoporous carbon-oxygen-silicon thin film shown in fig. 1 may further include the steps of: and determining the dose value of the ion beam used for ion transmission irradiation according to the aperture requirement of the nano-track pores in the nano-porous carbon oxygen silicon film to be prepared.

In the embodiment, corresponding film preparation parameters can be determined according to the aperture requirement of the nano porous carbon-oxygen-silicon film to be prepared, so that the accurate regulation and control of the size of the nano aperture in the nano porous carbon-oxygen-silicon film can be realized.

The embodiment of the invention also provides a nano porous carbon-oxygen-silicon film which is prepared by the method in each embodiment; wherein the diameter range of the nanometer track pores in the nanometer porous carbon-oxygen-silicon film is 1 nm-10 nm; the thickness of the nano porous carbon-oxygen-silicon film ranges from 500nm to 600 nm.

In order that those skilled in the art will better understand the present invention, embodiments of the present invention will be described below with reference to specific examples.

In one embodiment, the preparation method of the nano porous carbon oxygen silicon composite film material comprises the following steps: 1) forming an amorphous silicon oxide layer on the silicon substrate by an oxidation method; 2) forming a carbon-oxygen-silicon buried layer on the near surface of the material by a low-energy carbon ion implantation method; 3) carrying out transmission irradiation treatment on the film by high-energy lead ions; 4) and observing by an electron microscope photo, and forming the carbon-oxygen-silicon buried layer with the nanometer track pores in the film.

In the step 1), the preparation method of the silicon oxide layer is a dry-wet combination method, as shown in fig. 2, the furnace temperature is 1050 ℃, the reaction time is 3 hours, and the thickness of the obtained silicon oxide layer is 500 nm-600 nm; in step 2), the implantation of carbon ions is performed at room temperature, the ion energy is 100KeV, and the implantation dose is 2X 10¹⁷～1.2×10¹⁸In the meantime. In step 3), the irradiation of lead ions is carried out at room temperature, the ion energy is 850MeV, and the irradiation dose is 5X 10¹¹～5×10¹²In the meantime. In the step 4), the observed length of the nano-track pores is between 200nm and 500nm, the edges of the nano-track pores are neat at the positions close to the substrate, and the diameters of the pores are less than 10 nm.

Specifically, in the step 1), the temperature is maintained at 1050 ℃, heating is stopped after 3 hours, and oxygen is continuously introduced until the temperature is cooled to room temperature; step 2)In the method, carbon ions are implanted at room temperature, and the vacuum degree of an implantation chamber reaches 1 × 10^-6Pa, beam intensity of 5 × 10¹³ions/cm²The ion energy is 100KeV, and the ion current is strong to inject the dose at 2X 10¹⁷～1.2×10¹⁸To (c) to (d); in step 3), the irradiation of lead ions is carried out at room temperature, the vertical irradiation is carried out on the sample, and the vacuum degree of an irradiation chamber reaches 1 multiplied by 10^-6Pa, beam intensity of 1 × 10⁹ions/cm²S, radiation dose at 5X 10¹¹～5×10¹²In the meantime. The prepared silicon oxide film is purple and has a thickness of 500-600 nm. The diameter of the nanometer pore in the prepared film is less than 10 nm. The length of the nano-pores in the prepared film is adjustable between 200nm and 500nm, and carbon ions are implanted into the film by 1.2 multiplied by 10¹⁸Dose and lead ion irradiation 1X 10¹²Experimental conditions for best track continuity at dose.

In another embodiment, the method for preparing the nanoporous carbon-oxygen-silicon film can comprise the following steps: s1, forming a silicon oxide layer 22 on the silicon substrate 21 by a dry-wet combined oxidation method; s2, the carbon ions are injected to form a carbon-oxygen-silicon mixed layer 23 and a silicon-carbon mixed layer 24; s3, the irradiation of the high-energy lead ions rapidly deposits high-density energy in the thin film.

In the above step S1, referring to fig. 2, the method for preparing the silicon oxide layer may include the following three steps:

s11: selecting boron-doped P-type monocrystalline silicon grown preferentially along 100 crystal direction, thickness of 0.5mm, surface polishing level of 1sp, and cutting the silicon wafer into 2 × 4cm²Soaking the selected silicon wafer for about 1 hour by using alcohol, then cleaning the selected silicon wafer for 30 minutes by using deionized water and ultrasonic oscillation, and blowing the silicon wafer to dry at room temperature for later use;

s12: putting a pure Si sheet into the middle of a quartz tube 9 with the front side upward, then sealing two ends of the quartz tube 9 by using plugs with guide tubes, starting to continuously feed oxygen into the quartz tube 9, filtering gas by water in a first container 2 (flask) through a first guide tube 1, then feeding the gas into the quartz tube 9 through a second guide tube 3, feeding the gas into a second container 5 (flask) through a third guide tube 4 after the gas flows through a sample, then feeding the gas into a third container 7 (flask) through a fourth guide tube 6, filtering the gas and discharging the gas, wherein the second container 5 can play a role in preventing suck-back; switching on a power supply of an annealing furnace to heat the quartz tube 9, keeping the temperature of the annealing furnace 8 constant after reaching 1050 ℃, starting to heat the flask at the vent port to ensure that the water temperature is basically kept between 70 and 90 ℃, introducing oxygen to enable part of water vapor to enter the quartz tube 9 in a high-temperature state to reach the surface of a silicon wafer, and enabling the water vapor to react with silicon to generate silicon oxide, wherein the graph (a) in fig. 3 shows that;

s13: keeping the furnace temperature at 1050 ℃, simultaneously introducing water vapor and oxygen for 3 hours, stopping heating the beaker, cutting off the power supply of the annealing furnace after 30 minutes, and continuously introducing oxygen until the temperature is naturally cooled to room temperature. The prepared film is purple with naked eyes, and the thickness of the film is about 500 nm-600 nm.

In step S2, carbon ions are implanted at room temperature, and the degree of vacuum in the implantation chamber reaches 1 × 10^-6Pa, beam intensity of 5 × 10¹³ions/cm²The ion energy is 100KeV, and the ion current is strong to inject the dose at 2X 10¹⁷～1.2×10¹⁸To (c) to (d); the carbon ion implantation results are shown in (b) of fig. 3;

in the above step S3, the irradiation of lead ions was performed at room temperature, and the sample was irradiated vertically with the degree of vacuum of the irradiation chamber reaching 1X 10^-6Pa, beam intensity of 1 × 10⁹ions/cm²S, radiation dose at 5X 10¹¹～5×10¹²To (c) to (d); the ion irradiation process is shown in (c) of fig. 3, and the ion irradiation result is shown in (d) of fig. 3.

Based on the production methods of the above examples, various films were obtained by adjusting the production conditions, and the corresponding transmission electron micrographs are shown in (a) to (f) of FIG. 4. FIG. 4 (a) is a view showing a silicon oxide layer not implanted with carbon ions passing through 1X 10¹²Pb-ions/cm²As can be seen from the transmission electron microscope photograph of the lead ion beam irradiated, if no carbon ion is implanted into the silicon oxide layer, no track hole is formed even after irradiation. FIG. 4 (b) is a graph using 5X 10¹⁷C-ions/cm²Ion implantation of carbon ion beam into silicon oxide layer, and reuse of 1 × 10¹²Pb-ions/cm²Lead ion beam radiationAccording to a transmission electron microscope picture obtained after the carbon-oxygen-silicon mixed layer, a carbon-oxygen-silicon layer containing nano porous tracks is formed, and the aperture is only a few nanometers. FIG. 4 (c) is a graph using 5X 10¹⁷C-ions/cm²Ion implantation of carbon ion beam into silicon oxide layer, and reuse by 5 × 10¹²Pb-ions/cm²As can be seen from the transmission electron microscope image obtained after the carbon-oxygen-silicon mixed layer is irradiated with the lead ion beam (with an increased irradiation dose relative to the irradiation dose used in the graph (b) in fig. 4), a carbon-oxygen-silicon layer containing nanoporous tracks is formed, and the track pore size is larger than that shown in the graph (b) in fig. 4. FIG. 4 (d) is a graph using 1.2X 10¹⁸C-ions/cm²(the ion beam intensity is increased compared with the ion implantation beam intensity used in the graph (b) in FIG. 4) the carbon ion beam is used to implant ions into the silicon oxide layer, and then 1X 10 is used¹²Pb-ions/cm²As can be seen from the transmission electron microscope image obtained by irradiating the carbon-oxygen-silicon mixed layer with the lead ion beam, a carbon-oxygen-silicon layer containing a nanoporous track is formed, and the track length is longer than that shown in (b) of fig. 4. FIG. 4 (e) is a graph using 1.2X 10¹⁸C-ions/cm²(increased ion implantation dose relative to that used in the graph (b) of FIG. 4) the silicon oxide layer was ion-implanted with a carbon ion beam, and then 5X 10 was used¹²Pb-ions/cm²In the transmission electron microscope image obtained after the carbon-oxygen-silicon mixed layer is irradiated with the lead ion beam (with respect to the increase in the irradiation dose used in the graph (b) in fig. 4), the graph (f) in fig. 4 is an enlarged view of the graph (e), and it can be seen from the graph that the carbon-oxygen-silicon layer including the nanoporous track is formed, the pore diameter is, for example, only 3.19 nm, and the track pore diameter is larger than the track pore diameter shown in the graph (b) in fig. 4, and the track length is larger than the track length shown in the graph (b) in fig. 4. The diameters of the nano-pores shown in these figures are generally pores smaller than 10nm, and no pore structure is observed in the silicon-carbon mixed layer.

The above experimental data show that the higher the implantation dose of carbon ions, the larger the track length formed in the sample, and the larger the irradiation dose of lead ions, the larger the pore diameter. Further, as shown in FIG. 4 (d), when carbon ions are implanted, the carbon ions are implanted at 1.2X 10¹⁸Dose and lead ion irradiation 1X 10¹²Dosage formThe continuity of the tracking pores is better.

The length of the pore space of the nano porous structure material is closely related to the implantation dosage and energy of carbon ions and the irradiation energy of high-energy heavy ions, namely the implantation dosage value of the carbon ions can be changed by changing the implantation energy of the carbon ions, further changing the depth of the concentration peak value of the carbon ions in a silicon oxide layer, further accurately adjusting the depth of the porous carbon-oxygen silicon layer, further changing the implantation dosage value of the carbon ions, changing the size of a high-concentration area of the carbon ions, further accurately adjusting the thickness of the porous carbon-oxygen silicon layer, and in addition, by changing the irradiation dosage of lead ions, accurately adjusting the diameter of a nano gap. Means that technicians can purposefully prepare required special nano porous buried layer materials by finely adjusting experimental parameters to realize some special applications.

The method of the embodiment of the invention has the advantages that: (1) the depth of the carbon ion concentration peak value in the silicon oxide layer can be changed by changing the implantation energy value of the carbon ions, so that the depth of the porous silicon oxide buried layer can be accurately adjusted. (2) The size of the high-concentration area of the carbon ions can be changed by changing the injection dosage value of the carbon ions, so that the thickness of the porous carbon-oxygen-silicon layer or the length of the nano track can be accurately adjusted. (3) The diameter of the nanometer pore can be accurately adjusted by changing the irradiation dose of the lead ions. (4) The shape and the area of the beam spot of the carbon ion beam can be accurately controlled, so that the formation of the porous carbon-oxygen-silicon layer in a specific area of the material is realized, and the method has great application value particularly in the preparation aspect of precise special nano devices in the technical field of high precision. (5) The ion beam technology has good uniformity, which determines that the uniformity of the porous carbon-oxygen-silicon layer is good, and in addition, the irradiation preparation technology at room temperature ensures that the film has good stability at room temperature.

In summary, in the preparation method of the nanoporous carbon-oxygen-silicon thin film according to the embodiment of the invention, the amorphous silicon oxide layer is formed on the silicon substrate by using an oxidation method, carbon ions are implanted into the surface of the silicon substrate on which the amorphous silicon oxide layer is formed, so as to form the carbon-oxygen-silicon mixed layer on the silicon substrate, and then ion transmission irradiation is performed on the surface of the silicon substrate on which the carbon-oxygen-silicon mixed layer is formed, so as to form the carbon-oxygen-silicon mixed layer containing the nano-track pores on the silicon substrate, so that the preparation of the nanoporous carbon-oxygen-silicon thin film can be realized. Moreover, the size of the pore in the carbon-oxygen-silicon film can be well regulated and controlled by changing the implantation condition of carbon ions and the condition of ion transmission irradiation. Specifically, the thickness of the porous carbon-oxygen-silicon layer can be accurately adjusted by changing the injection dosage value of carbon ions and the size of a high-concentration area; the diameter of the nanometer gap can be accurately adjusted by changing the irradiation dose of the lead ions. Therefore, the method provided by the embodiment of the invention can overcome the problems of difficulty in preparation, complex process, poor controllability and the like of the nano porous carbon-oxygen-silicon film in the prior art, and can purposefully prepare the required special nano porous buried layer material by finely adjusting experimental parameters, thereby conveniently realizing some special applications.

In the description herein, reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," "an example," "a particular example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The sequence of steps involved in the various embodiments is provided to schematically illustrate the practice of the invention, and the sequence of steps is not limited and can be suitably adjusted as desired. Furthermore, the terms "above," "below," "over," and "under" are used merely as terms of description and should not be construed as limiting the orientation.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.