A method for preparing silicon nanostructures by combining alternating electric field and ultrasound

Abstract

The present invention discloses a method for preparing silicon nanostructures using an alternating electric field combined with ultrasound. Two pairs of ultrasonic generators form a standing wave field within a reactor, causing charged metal particles to stagnate at various standing wave nodes within the standing wave field. Alternating current is passed through two graphite electrodes to generate an alternating electric field within the reactor, causing the charged metal particles to drive acid in a corrosive solution to etch a silicon wafer along the direction of the alternating electric field force. The positions of the standing wave nodes within the standing wave field are altered by varying the frequency and amplitude of the ultrasonic wave, thereby changing the locations where the charged metal particles catalyze the etching reaction. The depth of the etching of the silicon wafer surface microstructure is altered by varying the frequency and amplitude of the alternating current. The inclination of the silicon wafer surface microstructure is altered by varying the direction of the alternating electric field force. By adjusting the frequency and amplitude of the ultrasonic wave and the alternating current, the present invention can achieve etching of the silicon wafer surface according to a preset pattern, thereby improving the etching efficiency and accuracy of the silicon wafer.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing silicon nanowire structure materials, and in particular relates to a method for preparing silicon nanostructures by combining alternating electric field with ultrasound. Background Art

[0002] Silicon, with its low price, excellent performance, and sophisticated manufacturing processes, has become one of the most widely used semiconductor materials. It is the core and foundation of integrated circuits and electronic components. The booming development of the computer, internet, and electronics industries is closely related to the improvement of semiconductor processing technology. In addition, silicon materials are widely used in biomedicine, aerospace, and new energy fields. Especially in today's coal and oil energy shortages, research on silicon materials to improve energy conversion efficiency and energy storage per unit volume has important and positive significance. However, the current manufacturing process for silicon nanomaterials is relatively low and has many problems, such as cumbersome control processes, low silicon nanostructure preparation precision, low preparation efficiency, and high cost. Therefore, to solve these problems, there is an urgent need for a simple process, high-precision, and high-efficiency silicon nanostructure preparation method. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the present invention proposes a method for preparing silicon nanostructures by combining alternating electric field and ultrasonic waves.

[0004] The technical solutions adopted in the present invention are as follows:

[0005] The present invention provides a method for preparing silicon nanostructures by combining an alternating electric field with ultrasound, which is specifically as follows:

[0006] Step 1: An ultrasonic generator is installed in each of groove 1 at the bottom of the reactor and two grooves 2 on both sides of the reactor, and the silicon wafer to be processed is clamped on the three ultrasonic generators; the etching liquid is injected into the reactor, an ultrasonic generator is installed in groove 1 at the bottom of the end cover of the reactor, the end cover of the reactor is covered on the reactor, and the ultrasonic generator on the end cover is also clamped on the silicon wafer; the ultrasonic generator at the bottom of the reactor and the ultrasonic generator at the bottom of the end cover form a pair, and the two ultrasonic generators on both sides of the reactor form a pair; then, two graphite electrodes are placed in the etching liquid and connected to an alternating current power supply; finally, the two pairs of ultrasonic generators are turned on, and the frequency and amplitude of the two pairs of ultrasonic generators are adjusted so that the ultrasonic waves emitted by the two pairs of ultrasonic generators form a standing wave field on the surface of the silicon wafer, and each standing wave node of the standing wave field is located on a pattern consistent with the shape and position of the preset silicon nanostructure; the standing wave field causes the charged metal particles in the etching liquid to stagnate at each standing wave node in the standing wave field;

[0007] Step 2: An alternating power source is applied to the two graphite electrodes, generating an alternating electric field between the two graphite electrodes. Charged metal particles in the etching solution that are stagnant at the standing wave nodes are affected by the alternating electric field force, moving in the direction of the alternating electric field force and colliding with the silicon wafer. The acid in the etching solution that is aggregated around the charged metal particles reacts with the surface of the silicon wafer under the influence of the charged metal particles. After colliding with the silicon wafer, the charged metal particles rebound and return to the respective standing wave nodes. After the rebound, the charged metal particles are affected by the alternating electric field force and collide with the silicon wafer again. After a preset time, a portion of the preset silicon nanostructure is formed on the surface of the silicon wafer.

[0008] Step 3: Stop the alternating current power supply to the two graphite electrodes and change the frequency and amplitude of the two pairs of ultrasonic generators, so that the standing wave nodes in the standing wave field on the surface of the silicon wafer move along a pattern consistent with the shape and position of the preset silicon nanostructure to the next location where the preset silicon nanostructure is not formed, and the charged metal particles also move along with the standing wave nodes; then, repeat step 2 to form the next portion of the preset silicon nanostructure on the surface of the silicon wafer;

[0009] Step 4: Repeat step 3 to gradually etch the entire silicon nanostructure on the surface of the silicon wafer.

[0010] Preferably, the graphite electrode is installed on the optical axis, and the connecting rod is driven by a motor, which drives the two optical axes to change the positions of the two graphite electrodes, thereby changing the direction of the alternating electric field force, so that the charged metal particles move along the direction of the alternating electric field force that is not perpendicular to the surface of the silicon wafer, thereby forming a preset silicon nanostructure with inclined walls on the surface of the silicon wafer.

[0011] Preferably, the magnitude of the alternating electric field force is changed by changing the frequency and amplitude of the alternating power supply, and the etching depth of the silicon wafer surface increases with the increase of the alternating electric field force.

[0012] Preferably, the etching solution is prepared by hydrofluoric acid with a mass concentration of 40%, hydrogen peroxide with a mass concentration of 30%, silver nitrate solution with a molar concentration of 0.01 mol / L, and deionized water in a volume ratio of 5:12:1:28.

[0013] Preferably, the silicon wafer has a resistivity of 0.001-5Ω / cm 2 N-type silicon wafer or P-type silicon wafer; the crystal orientation index of the silicon wafer is 100.

[0014] The present invention has the following beneficial effects:

[0015] The present invention forms a standing wave field on the surface of a silicon wafer in a reactor by using two pairs of ultrasonic generators. Each standing wave node of the standing wave field is located on a pattern consistent with the shape and position of a preset silicon nanostructure, so that charged metal particles are stationary at each standing wave node in the standing wave field. An alternating current is passed through two graphite electrodes to generate an alternating electric field in the reactor, so that the charged metal particles drive acid in a corrosive solution that is aggregated around the charged metal particles to collide with the silicon wafer along the direction of the alternating electric field force, thereby generating an etching reaction. The positions of the standing wave nodes in the standing wave field are changed by changing the frequency and amplitude of the ultrasonic wave, thereby changing the positions where the charged metal particles collide with the silicon wafer. The etching depth of the microstructure on the surface of the silicon wafer is changed by changing the frequency and amplitude of the alternating current. The inclination of the microstructure on the surface of the silicon wafer is changed by changing the direction of the alternating electric field force. Therefore, the present invention can achieve etching of the silicon wafer surface according to the preset silicon nanostructure by adjusting the frequency and amplitude of the ultrasonic wave and the alternating current, thereby improving the etching efficiency and accuracy of the silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A structural perspective diagram of the device used to prepare silicon nanostructures in the present invention;

[0017] Figure 2 This is a cross-sectional view of the device used to prepare silicon nanostructures in the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] The present invention provides a method for preparing silicon nanostructures by combining an alternating electric field with ultrasound, which is specifically as follows:

[0020] Step 1: Install an ultrasonic generator 8 (which can be made of piezoelectric material) in the groove 1 9 at the bottom of the reactor 1 and the two grooves 2 on both sides of the reactor, and clamp the silicon wafer to be processed on the three ultrasonic generators 8; inject the corrosive liquid into the reactor, install an ultrasonic generator 8 in the groove 1 9 at the bottom of the end cover 2 of the reactor 1, cover the end cover 2 of the reactor 1 on the reactor 1, and make the ultrasonic generator 8 on the end cover 2 also clamp the silicon wafer; the ultrasonic generator 8 at the bottom of the reactor 1 and the ultrasonic generator at the bottom of the end cover 2 8 is a pair, and the two ultrasonic generators 8 on both sides of the reactor 1 are a pair; then, the two graphite electrodes 6 are placed in the etching solution and connected to the alternating power supply 7; finally, the two pairs of ultrasonic generators 8 are turned on, and the frequency and amplitude of the two pairs of ultrasonic generators 8 are adjusted so that the ultrasonic waves emitted by the two pairs of ultrasonic generators 8 form a standing wave field on the surface of the silicon wafer, and each standing wave node of the standing wave field is located on a pattern consistent with the shape and position of the preset silicon nanostructure; the standing wave field causes the charged metal particles in the etching solution to stagnate at each standing wave node in the standing wave field.

[0021] In step 2, the alternating power supply 7 supplies power to the two graphite electrodes 6, generating an alternating electric field between the two graphite electrodes 6. The charged metal particles in the etching solution that are stagnant at the standing wave nodes are affected by the alternating electric field force, move in the direction of the alternating electric field force, and collide with the silicon wafer. The acid in the etching solution that is aggregated around the charged metal particles reacts with the surface of the silicon wafer under the influence of the charged metal particles. After colliding with the silicon wafer, the charged metal particles rebound, and the rebounded charged metal particles return to each standing wave node and are affected by the alternating electric field force, colliding with the silicon wafer again. After a preset time, a portion of the preset silicon nanostructure is formed on the surface of the silicon wafer.

[0022] Step 3: The alternating power supply 7 stops supplying power to the two graphite electrodes 6, and the frequency and amplitude of the two pairs of ultrasonic generators 8 are changed, so that the standing wave nodes in the standing wave field on the surface of the silicon wafer move along a pattern consistent with the shape and position of the preset silicon nanostructure to the next position where the preset silicon nanostructure is not formed, and the charged metal particles also move along the standing wave nodes; then, step 2 is repeated to form the next part of the preset silicon nanostructure on the surface of the silicon wafer.

[0023] Step 4: Repeat step 3 to gradually etch the entire silicon nanostructure on the surface of the silicon wafer.

[0024] As a preferred embodiment, the graphite electrode 6 is installed on the optical axis, and the connecting rod 4 is driven by the motor 3. The connecting rod 4 drives the two optical axes 5 to change the position of the two graphite electrodes to change the direction of the alternating electric field force, so that the charged metal particles move along the direction of the alternating electric field force that is not perpendicular to the surface of the silicon wafer, thereby forming a preset silicon nanostructure with inclined walls on the surface of the silicon wafer.

[0025] As a preferred embodiment, by changing the frequency and amplitude of the alternating power supply 7, the magnitude of the alternating electric field force is changed, so that the etching depth of the silicon wafer surface increases with the increase of the alternating electric field force.

[0026] As a preferred embodiment, the etching solution is composed of hydrofluoric acid with a mass concentration of 40%, hydrogen peroxide with a mass concentration of 30%, silver nitrate solution with a molar concentration of 0.01 mol / L, and deionized water in a volume ratio of 5:12:1:28; charged silver particles are formed in the etching solution.

[0027] As a preferred embodiment, the silicon wafer has a resistivity of 0.001-5Ω / cm 2 N-type silicon wafer or P-type silicon wafer; the crystal orientation index of the silicon wafer is 100.

Claims

1. A method for preparing silicon nanostructures by combining an alternating electric field with ultrasound, characterized in that: The details are as follows: Step 1: An ultrasonic generator is installed in each of groove 1 at the bottom of the reactor and two grooves 2 on both sides of the reactor, and the silicon wafer to be processed is clamped on the three ultrasonic generators; the etching liquid is injected into the reactor, an ultrasonic generator is installed in groove 1 at the bottom of the end cover of the reactor, the end cover of the reactor is covered on the reactor, and the ultrasonic generator on the end cover is also clamped on the silicon wafer; the ultrasonic generator at the bottom of the reactor and the ultrasonic generator at the bottom of the end cover form a pair, and the two ultrasonic generators on both sides of the reactor form a pair; then, two graphite electrodes are placed in the etching liquid and connected to an alternating current power supply; finally, the two pairs of ultrasonic generators are turned on, and the frequency and amplitude of the two pairs of ultrasonic generators are adjusted so that the ultrasonic waves emitted by the two pairs of ultrasonic generators form a standing wave field on the surface of the silicon wafer, and each standing wave node of the standing wave field is located on a pattern consistent with the shape and position of the preset silicon nanostructure; the standing wave field causes the charged metal particles in the etching liquid to stagnate at each standing wave node in the standing wave field; Step 2: An alternating power source is applied to the two graphite electrodes, generating an alternating electric field between the two graphite electrodes. Charged metal particles in the etching solution that are stagnant at the standing wave nodes are affected by the alternating electric field force, moving in the direction of the alternating electric field force and colliding with the silicon wafer. The acid in the etching solution that is aggregated around the charged metal particles reacts with the surface of the silicon wafer under the influence of the charged metal particles. After colliding with the silicon wafer, the charged metal particles rebound and return to the respective standing wave nodes. After the rebound, the charged metal particles are affected by the alternating electric field force and collide with the silicon wafer again. After a preset time, a portion of the preset silicon nanostructure is formed on the surface of the silicon wafer. Step 3: Stopping the alternating current power supply to the two graphite electrodes and changing the frequency and amplitude of the two pairs of ultrasonic generators so that the standing wave nodes in the standing wave field on the surface of the silicon wafer move along a pattern consistent with the shape and position of the preset silicon nanostructure to the next location where the preset silicon nanostructure is not formed, and the charged metal particles also move along with the standing wave nodes; Then, repeat step 2 to form the next portion of the preset silicon nanostructure on the surface of the silicon wafer; Step 4: Repeat step 3 to gradually etch the entire silicon nanostructure on the surface of the silicon wafer.

2. The method for preparing silicon nanostructures by combining alternating electric field and ultrasound according to claim 1, characterized in that: The graphite electrode is installed on the optical axis. The connecting rod is driven by a motor, which drives the two optical axes to change the position of the two graphite electrodes, thereby changing the direction of the alternating electric field force, causing the charged metal particles to move along the direction of the alternating electric field force that is not perpendicular to the surface of the silicon wafer, thereby forming a preset silicon nanostructure with inclined walls on the surface of the silicon wafer.

3. The method for preparing silicon nanostructures by combining alternating electric field and ultrasound according to claim 1, characterized in that: By changing the frequency and amplitude of the alternating power supply, the magnitude of the alternating electric field force is changed, and the etching depth of the silicon wafer surface deepens as the alternating electric field force increases.

4. The method for preparing silicon nanostructures by combining alternating electric field and ultrasound according to claim 1, characterized in that: The etching solution is prepared by hydrofluoric acid with a mass concentration of 40%, hydrogen peroxide with a mass concentration of 30%, silver nitrate solution with a molar concentration of 0.01 mol / L, and deionized water in a volume ratio of 5:12:1:

28.

5. The method for preparing silicon nanostructures by combining alternating electric field and ultrasound according to claim 1, characterized in that: The resistivity of silicon wafer is 0.001-5Ω / cm 2 N-type silicon wafer or P-type silicon wafer; the crystal orientation index of the silicon wafer is 100.

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