CN103745917B - A kind of electric field controls prepares the method for nanostructure on monocrystalline silicon substrate surface - Google Patents

Abstract

A method for preparing a nanostructure on the surface of a single crystal silicon substrate under electric field control, which belongs to the technical field of nanomaterials, and is carried out according to the following steps: (1) Select an n-type Si (111) silicon wafer and cut it into a rectangular single crystal silicon substrate; (2) fixed on the vacuum chamber sample stage of the molecular beam epitaxy chamber; heating and cleaning its surface under vacuum conditions; (3) depositing Au atoms on the surface to obtain surface structures with different reconstructions; (4) In is deposited on the center of the single crystal silicon substrate to obtain a rectangular thin film layer; (5) applying a DC electric field to drive electromigration, controlling electromigration diffusion, and obtaining a quasi-two-dimensional metal nanostructure. In the present invention, the heterogeneous metal film layer deposited on the silicon surface in advance will undergo directional migration and diffusion under the action of an electric field. As a result of the diffusion, the original film layer will be uniformly widened without destroying the surface morphology, effectively eliminating some structural defects. For example, the ubiquitous three-dimensional island structure on the surface of the film tends to be flattened to achieve atomic-level surface processing.

Description

A method for preparing nanostructures on the surface of a single crystal silicon substrate controlled by an electric field

technical field

The invention belongs to the technical field of nanomaterials, in particular to a method for preparing nanostructures on the surface of a single crystal silicon substrate under electric field control.

Background technique

The migration of atoms on a solid surface under the action of an external field is a basic problem with a wide range of applications. When a DC electric field parallel to the surface of the substrate is applied on the semiconductor silicon substrate, a series of electromigration and diffusion phenomena occurring on the surface is a typical example, which has very important physical significance. As we all know, as the most important material in the semiconductor industry, silicon and various silicon-based micro/nanostructure devices constitute the cornerstone of the modern electronics and information industry; and the deviceization and practical application of various nanostructures need to be based on the basis of nanomaterials. Based on the clarification of controlled growth and associated physical effects. Therefore, it has become the key to many nanotechnology applications to deeply explore the change rules of the nanoscale morphology and structural characteristics of the surface of materials under the action of external fields, and then realize the manipulation of nanostructures through macroscopic external forces. Using scanning tunneling microscopy (STM) as a tool, applying a longitudinal electric field to surface atoms or atomic clusters to manipulate and move them to form various tiny nanostructures is a representative and mature technology, but it is in the construction of more atoms (such as 10 ⁴ to 10 ⁶ atoms) is not suitable for large-scale nanostructures; and the self-assembly growth technology, which is also well known, is suitable for preparing nanostructures containing a large number of atoms, but it is difficult to achieve fine regulation of its local structure.

Contents of the invention

Aiming at the above-mentioned problems existing in the technology of preparing nanostructures by electric field control, the present invention provides a method for preparing nanostructures on the surface of a single crystal silicon substrate by electric field control, which makes the single crystal silicon substrate The film layer is uniformly expanded to form a nano-ordered structure.

A kind of electric field control of the present invention prepares the method for nanostructure on the surface of monocrystalline silicon substrate to carry out according to the following steps:

1. Select an n-type Si (111) silicon wafer with a mirror-polished resistivity of 50-100Ω·cm, cut along the long side parallel to the <1-10> direction, and make a rectangular single-crystal silicon substrate;

2. Fix the monocrystalline silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber; under the ultra-high vacuum condition of the vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the monocrystalline silicon substrate to 1473±10K And keep it for 2-6s to clean the surface;

3. Deposit 0.1 to 1 layer of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain gold-adsorbed single crystal silicon surface structures with different reconstructions on the surface of the single crystal silicon substrate; control the vacuum chamber during deposition Air pressure ≤ 1×10 ^-7 Pa, temperature of monocrystalline silicon substrate is 873±10K; the surface structure of different reconstructed gold-adsorbed monocrystalline silicon refers to 7×7, (7×7+5×2), 5×2, (5×2+α-√3×√3), α-√3×√3 or β-√3×√3 surface structure;

4. Evaporate and deposit metal In at room temperature through the slit window on the mask in the molecular beam epitaxy chamber to the center of the single crystal silicon substrate, and obtain a rectangular thin film layer on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0±0.2ML;

5. Apply a direct current electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, and control the electromigration diffusion of the rectangular thin film layer. The current intensity is 0.1-0.5A, and the applied current The time is 1-60 minutes, the temperature of the single-crystal silicon substrate is 630-763K when the electric field is applied, and a quasi-two-dimensional metal nanostructure is obtained on the surface of the single-crystal silicon substrate.

In the above method, the window of the mask is rectangular or slit, with a width of 50-200 μm, and the material of the mask is metal tantalum.

In the above method, the number of monoatomic layers (monolayer, ML) of the deposited metal represents the coverage of the metal, and one monoatomic layer (ML) corresponds to 7.8×10 ¹⁴ atoms per square centimeter on the surface.

Traditional electromigration is used to prepare nano-gap structures by using its destructiveness, while the method provided by the present invention belongs to semiconductor surface heterogeneous electromigration, which is to form a nano-ordered structure by uniformly expanding the film layer through the action of a direct current electric field in the horizontal direction. Different from the traditional electromigration that occurs in the tiny interconnection wires of integrated circuits and leads to the destruction and failure of metal or alloy thin film materials, electromigration on the surface of semiconductors is a unique type of material transport phenomenon, which is caused by the directional movement of surface atoms and has a significant impact on surface morphology. have an important influence. According to the characteristics of the migratory substances, they can be divided into two categories: first, for the clean silicon adjacent crystal surface, that is, when there are only homogeneous silicon adatoms on the surface, the DC electric field and current will form complex transitions depending on the direction of action. The surface morphology (including regular step structure, step bundle and step meander structure); since A.V.Latyshev first reported the step structure instability caused by direct current on the adjacent crystal Si(111) surface, a lot of work in the world Mainly focus on the phenomenological research and theoretical modeling of this phenomenon, the purpose of which is to find the controlling factors of these surface step structures, expecting that these specific scale and orderly arranged steps can be used as the preferential nucleation center during the epitaxial growth of thin film materials Or as a template for synthesizing nanostructures; some people have used this characteristic to grow quantum wires and quantum dots on adjacent crystal planes. However, due to the irregular shape of single-atom steps, it is difficult to obtain ordered quantum wires and quantum dots. Quantum dots; the second is surface heterogeneous electromigration, which means that when a horizontal DC electric field is applied to a clean semiconductor silicon substrate, the heterogeneous metal film layer deposited on the silicon surface in advance will undergo directional migration under the action of the electric field Diffusion, the result of diffusion is that the original film layer is uniformly expanded without destroying the surface morphology, and through the migration of atoms on the surface, it can also effectively eliminate some structural defects, such as the tendency of the three-dimensional island structure that commonly exists on the surface of the film. In planarization, to achieve atomic level surface processing.

The method for preparing nanostructures on the surface of a single crystal silicon substrate by controlling the electric field of the present invention can directly deposit a thin film through a mask on a clean single crystal silicon substrate, or deposit a certain metal on the entire surface of a single crystal silicon substrate (such as gold, silver or copper), and then use mask deposition to form a laminated film,

By fixing both ends of the silicon substrate with tantalum metal clamps (also used as electrodes), the DC electric field applied on the silicon substrate to drive the electromigration diffusion is along the horizontal direction, which makes the film deposited in a regular shape possible. It evolves into different sizes, shapes and surface structures as required; through the regulation of electromigration parameters, single metal, alloy or silicide nanostructures with a certain composition can also be obtained.

Under the condition of knowing the properties of the substrate material and coating material, precisely control the current magnitude, orientation and time of the applied surface DC electric field, and use the characteristics of electromigration and diffusion to achieve the purpose of moving on demand; deposit 0.1 to 1 monolayer in advance The gold atoms constitute different surface mobile platforms on which the migration and diffusion rates of other metals deposited can be precisely controlled.

The present invention utilizes a field emission scanning electron microscope and a reflection high-energy electron diffraction device integrated with molecular beam epitaxy equipment to continuously observe and measure changes in the surface morphology and surface structure of samples while electrifying and driving electromigration diffusion, and record them . After the nanostructure is formed, in-situ or ex-situ chemical composition, valence state and electronic structure analysis and characterization of the nanostructure can be performed according to the equipped electron spectrometer.

Description of drawings

Figure 1 is a graph showing the relationship between Au atomic coverage and temperature (different reconstructed surface structures);

2 is a schematic diagram of the structure of a nanostructure device prepared on the surface of a single crystal silicon substrate by electric field control in an embodiment of the present invention;

In the figure, 1. Vacuum chamber, 2. Electron gun system, 3. Monocrystalline silicon substrate, 4. Secondary electron detector, 5. Linear motion control mechanism, 6. Baffle plate, 7. Evaporation source, 8. Observation, Control and recording system, 9. Optical fiber, 10. Diffraction electron beam, 11. Mask;

Fig. 3 is a schematic diagram of a monocrystalline silicon substrate and electrode layout in an embodiment of the present invention;

In the figure, 3, single crystal silicon substrate, 12, mask window, 13, tantalum electrode;

Fig. 4 is a scanning electron microscope observation diagram of the structure evolution process of metal indium (In) with two monoatomic layer thicknesses (2.0ML) on a clean Si(111) silicon surface driven by a DC electric field in Example 1 of the present invention; in the figure, (a) initial film, (b) apply 0.1A current for 1min, substrate temperature 630K, (c) apply 0.1A current for 10min, (d) apply 0.1A current for 30min, (e) apply 0.3A current for 3min , substrate temperature 763K, (f) apply 0.3A current for 10min, (g) apply 0.3A current for 20min;

Fig. 5 is the Si(111)-β-√3× √ Electron micrograph of the structural evolution process of the 3-Au surface driven by a DC electric field; the preparation method of the initial film is exactly the same as that in Example 1 (a), (m) apply a 0.1A current for 1min, and the substrate temperature is 630K , (n) Apply a 0.1A current for 4min.

Figure 6 shows the Si(111)-5×2-Au covered with 0.5 monoatomic layer gold (Au) covered with two monoatomic layers (2.0ML) of metal indium (In) in Example 3 of the present invention. Electron micrograph of the surface structure evolution process driven by a DC electric field; the preparation method of the initial film is exactly the same as that in Example 1 (a), (x) 0.1A current is applied for 1 min, and the substrate temperature is 630K, (y) Apply 0.1A current for 10min, 630K, (z) continue to apply 0.2A current for 10min, substrate temperature 763K.

Fig. 7 is the Si(111)-(5×2+ Electron micrograph of the structure evolution process of the α-√3×√3)-Au surface driven by a DC electric field; the preparation method of the initial film is exactly the same as that in (a) in Example 1, (u) applying a 0.1A current 5min, substrate temperature 630K, (v) apply 0.1A current for 10min, 630K, (w) apply 0.1A current for 30min, 630K.

detailed description

The molecular beam epitaxy chamber used in the embodiment of the present invention is a molecular beam epitaxy chamber manufactured by Japan Vacuum (ULVAC).

The observation equipment used in the embodiment of the present invention is a Hitachi S-4200 field emission scanning electron microscope (FE-SEM) and a microprobe reflection high-energy electron diffraction (μ-probeRHEED) device.

The linear motion control mechanism used in the embodiment of the present invention is a linear motion control mechanism used in conjunction with the molecular beam epitaxy chamber manufactured by ULVAC.

The weight purity of the metal In evaporation source used in the embodiment of the present invention is 99.9999%.

The weight purity of the Au evaporation source used in the embodiment of the present invention is 99.9999%.

The weight purity of metal tantalum in the embodiment of the present invention is 99.9999%.

Example 1

The electric field control in the embodiment of the present invention prepares a nanostructure device on the surface of a single crystal silicon substrate as shown in Figure 2, including a vacuum chamber 1, an electron gun system 2, a secondary electron detector 4, a linear motion manipulation mechanism 5, and a baffle 6 , evaporation source 7, observation, control and recording system 8, optical fiber 9, diffracted electron beam 10, mask 11;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 2s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 150μm, and the mask material is tantalum; when evaporating indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a DC electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration and diffusion of the rectangular thin film layer, the current intensity is 0.1-0.3A, and the time for applying the current is 1 to 20 minutes, when the electric field is applied, the temperature of the single crystal silicon substrate is 630K to 763K, and a quasi-two-dimensional metal nanostructure is obtained on the surface of the single crystal silicon substrate; the structure evolution process driven by the DC electric field is shown in Figure 4.

Example 2

The nanostructure device prepared on the surface of a single crystal silicon substrate by electric field control is the same as that in Example 1;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 2s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Deposit 1.0 layer of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain a β-√3×√3 gold adsorption single crystal silicon surface structure on the surface of the single crystal silicon substrate; control the vacuum chamber pressure ≤ during deposition 1×10 ^-7 Pa, the temperature of single crystal silicon substrate is 873±10K;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 150μm, and the mask material is tantalum; when evaporating indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a DC electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration and diffusion of the rectangular thin film layer, the current intensity is 0.1A, and the time of applying the current is 1～ For 4 minutes, the temperature of the single crystal silicon substrate was 630K when the electric field was applied, and a quasi-two-dimensional metal nanostructure was obtained on the surface of the single crystal silicon substrate; the structure evolution process driven by the DC electric field is shown in Figure 5.

Example 3

The preparation of nanostructure devices on the surface of a single crystal silicon substrate by electric field control is the same as in Example 1;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 2s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Deposit 0.5 layers of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain a 5×2 gold adsorption single crystal silicon surface structure on the surface of the single crystal silicon substrate; control the vacuum chamber pressure ≤ 1×10 ^{- 7} Pa, the temperature of the single crystal silicon substrate is 873±10K;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 150μm, and the mask material is tantalum; when evaporating indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a direct current electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration and diffusion of the rectangular thin film layer, the current intensity is 0.1-0.2A, and the time for applying the current is 1 to 10 minutes, when the electric field is applied, the temperature of the single crystal silicon substrate is 630K to 763K, and a quasi-two-dimensional metal nanostructure is obtained on the surface of the single crystal silicon substrate; the structure evolution process driven by the DC electric field is shown in Figure 6.

Example 4

The nanostructure device prepared on the surface of a single crystal silicon substrate by electric field control is the same as that in Example 1;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of the vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 4s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Deposit 0.7 layers of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain (5X2+α-√3X√3) gold adsorption single crystal silicon surface structure on the surface of the single crystal silicon substrate; vacuum is controlled during deposition Chamber pressure ≤1×10 ^-7 Pa, single crystal silicon substrate temperature 873±10K;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 150μm, and the mask material is tantalum; when evaporating indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a direct current electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration and diffusion of the rectangular thin film layer, the current intensity is 0.1A, and the time of applying the current is 5～ After 30 minutes, the temperature of the single crystal silicon substrate was 630K when the electric field was applied, and a quasi-two-dimensional metal nanostructure was obtained on the surface of the single crystal silicon substrate. The structure evolution process driven by the DC electric field is shown in Figure 7.

Example 5

The preparation of nanostructure devices on the surface of a single crystal silicon substrate by electric field control is the same as in Example 1;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of the vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 4s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Deposit 0.1 layer of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain (7×7+5×2) gold adsorption single crystal silicon surface structure on the surface of the single crystal silicon substrate; control the vacuum chamber during deposition Air pressure ≤1×10 ^-7 Pa, single crystal silicon substrate temperature is 873±10K;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 200μm, and the material of the mask is tantalum; when evaporating the indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a DC electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration diffusion of the rectangular thin film layer, the current intensity is 0.1-0.5A, and the time for applying the current is 1-60min, when the electric field is applied, the temperature of the single crystal silicon substrate is 763K, and a quasi-two-dimensional metal nanostructure is obtained on the surface of the single crystal silicon substrate.

Example 6

The nanostructure device prepared on the surface of a single crystal silicon substrate by electric field control is the same as that in Example 1;

Choose mirror-polished n-type Si (111) silicon wafers with a resistivity of 50-100Ω·cm, and cut along the long side parallel to the <1-10> direction to make rectangular single-crystal silicon substrates;

Fix the single crystal silicon substrate on the vacuum chamber sample stage of the molecular beam epitaxy chamber, under the condition of vacuum chamber pressure ≤ 2×10 ^-8 Pa, heat the single crystal silicon substrate to 1473±10K and keep it for 6s, clean it surface; at this point a clean Si(111)7×7 surface is obtained;

Deposit a layer of Au atoms on the surface of the cleaned single crystal silicon substrate through the evaporation source, and obtain an α-√3×√3 gold adsorption single crystal silicon surface structure on the surface of the single crystal silicon substrate; control the vacuum chamber pressure ≤ during deposition 1×10 ^-7 Pa, the temperature of single crystal silicon substrate is 873±10K;

Metal In is evaporated and deposited on the center of the single crystal silicon substrate through the slit window on the mask in the molecular beam epitaxy chamber at room temperature, and a rectangular thin film layer is obtained on the single crystal silicon substrate. The thickness of the rectangular thin film layer is 2.0 ±0.2ML; the window of the mask is rectangular or slit, the width is 50μm, and the mask material is tantalum; when evaporating indium film, use the reflective high-energy electron diffraction device to monitor the diffraction spot pattern at any time, when √3× √3 The surface reconstructed diffraction pattern shows that the coverage of indium is just 1/3ML (one-third monoatomic layer), and this time is recorded; the deposition of indium film can be accurately controlled according to the rate and time of evaporation indium When the evaporation rate is the same and the evaporation time is 6 times that of the coverage of 1/3ML, an indium film with a coverage of 2.0ML is obtained;

Apply a DC electric field to the rectangular thin film layer on the single crystal silicon substrate along the <1-10> direction to start driving electromigration, control the electromigration diffusion of the rectangular thin film layer, the current intensity is 0.1-0.5A, and the time for applying the current is 1-60min, when the electric field is applied, the temperature of the single crystal silicon substrate is 630K, and a quasi-two-dimensional metal nanostructure is obtained on the surface of the single crystal silicon substrate.

Claims (2)

1. electric field controls prepares a method for nanostructure on monocrystalline silicon substrate surface, it is characterized in that carrying out according to the following steps:

(1) select bright finished resistivity to be N-shaped Si (111) the silicon circular wafer of 50 ~ 100 Ω cm, be parallel to <1-10> direction along long limit and cut, make rectangular monocrystalline silicon substrate;

(2) monocrystalline silicon substrate is fixed on the vacuum chamber sample stage of MBE chamber; In gas pressure in vacuum≤2 × 10 ^-8under the UHV condition of Pa, monocrystalline silicon substrate is heated to 1473 ± 10K and keeps 2 ~ 6s, its surface clean;

(3) pass through clean monocrystalline silicon substrate surface deposition 0.1 ~ 1 layer of Au atom by evaporation source to surface, obtain on monocrystalline silicon substrate surface and there is the different gold absorption monocrystalline silicon surface structure reconstructed; Gas pressure in vacuum≤1 × 10 are controlled during deposition ^-7pa, monocrystalline silicon substrate temperature is 873 ± 10K; The gold absorption monocrystalline silicon surface structure of described difference reconstruct refers to 7 × 7, (7 × 7+5 × 2), 5 × 2, (5 × 2+ α-√, 3 × √ 3), α-√ 3 × √ 3 or β-√ 3 × √ 3 surface texture; The monatomic number of plies of plated metal represents the coverage of metal, monoatomic layer correspond on the surface every square centimeter comprise 7.8 × 10 ¹⁴individual atom;

(4) by metal In at room temperature by the slit window hydatogenesis on the mask of molecular beam epitaxy indoor to monocrystalline silicon substrate center, monocrystalline silicon substrate obtains rectangular film lamella, and the thickness of rectangular film lamella is 2.0 ± 0.2ML;

(5) apply DC electric field along <1-10> direction to the rectangular film lamella on monocrystalline silicon substrate to start to drive electromigration, the Electromigration dispersion of control rectangle film lamina, current strength is 0.1 ~ 0.5A, the time applying electric current is 1 ~ 60min, the temperature applying monocrystalline silicon substrate during electric field is 630 ~ 763K, obtains accurate two-dimensional metallic nanostructure on monocrystalline silicon substrate surface.

2. a kind of electric field controls according to claim 1 prepares the method for nanostructure on monocrystalline silicon substrate surface, and it is characterized in that the window of described mask is rectangle or slit, width is 50 ~ 200 μm, mask material selection metal tantalum.