CN108660417B - Self-supporting Ga2O3Film and preparation method thereof - Google Patents

Abstract

The present invention relates to a self-supporting Ga₂O₃The preparation method comprises the following steps: in thatGrowing a layer of Sr on the substrate₃Al₂O₆After being thinned, then the Sr is added₃Al₂O₆Growing a layer of Ga on the film₂O₃A film; putting the substrate coated with the two films into water until Sr₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃Film, i.e. self-supporting Ga₂O₃A film. The preparation method has strong process controllability and easy operation; the self-supporting Ga prepared by the invention₂O₃The film has compact surface, stable and uniform thickness, large-area preparation and good repeatability.

Description

Self-supporting Ga2O3Film and preparation method thereof

Technical Field

The invention relates to the technical field of semiconductor material preparation, in particular to self-supporting Ga₂O₃A film and a preparation method thereof.

Background

Ga₂O₃The energy gap of the semiconductor is about 4.9eV, and the semiconductor is a novel ultra-wide energy gap semiconductor material. Since Ga is₂O₃The forbidden band width of the solar blind ultraviolet communication band is just in the solar blind ultraviolet band (200-280nm), the solar blind ultraviolet communication band is not interfered by external sunlight, the detection sensitivity of the solar blind ultraviolet signal is extremely high, the solar blind ultraviolet communication working in the band has almost zero error, and the solar blind ultraviolet communication band has wide application in military, aerospace and aviation. Ga₂O₃The breakdown field of the transistor is strong (up to 8MV/cm), the Barre plus merit value is large, and the transistor is an ideal material of a field effect transistor. At the same time, Ga₂O₃And the material can also be used as a transparent conductive electrode, an information memory, a gas sensor, an LED substrate and other devices.

With the rise of wearable electronics in emerging electronics technologies, flexible, lightweight, flexible, and transparent 2D materials have been applied and developed in new electronics technologies, including wearable energy harvesting systems, foldable electronics, curved-screen electronics, soft-portable devices, and roll-to-roll displays. It will become a popular trend to combine flexible, bendable, retractable, sensitive solar blind areas with other bending devices. The flexible ultraviolet photodetector can be applied to portable electronic devices, display devices and the like.

To realize Ga₂O₃Application of film on flexible device, scientific research personnel directly grow Ga on flexible substrate at low temperature₂O₃The method obtains amorphous Ga₂O₃A flexible film. However, amorphous materials are prone to material property changes at high temperature or in other harsh environments (such as strong acidic or basic environments), which results in unstable device performance. If it is possible to obtain both flexible and free-standing Ga in one way₂O₃The film realizes the preparation of related flexible devices, can ensure high crystallinity and enables the devices to have stable performance in severe environment. Meanwhile, according to application requirements, Ga with high crystallinity is adopted₂O₃And shearing and further recombining the thin film, and assembling the thin film on a flexible substrate or a rigid substrate to realize the application of the thin film in a device.

Disclosure of Invention

The invention aims to provide a method for utilizing water-soluble material Sr₃Al₂O₆Preparation of self-supporting Ga₂O₃Method for thin film production of self-supporting Ga₂O₃A film.

The self-supporting Ga₂O₃The preparation method of the film comprises the following steps: growing a layer of Sr on the substrate₃Al₂O₆After being thinned, then the Sr is added₃Al₂O₆Growing a layer of Ga on the film₂O₃A film; putting the substrate coated with the two films into water until Sr₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃Film, i.e. self-supporting Ga₂O₃A film.

Preferably, said Sr₃Al₂O₆The thickness of the film being said Ga₂O₃The thickness of the film is 0.5-2 times that of the film; when said Sr is₃Al₂O₆The thickness of the film being said Ga₂O₃When the thickness of the film is 0.5-1 times, the dissolving time is easier to save, and the obtained self-supporting Ga₂O₃Film integrity and structural stability are superior.

The invention further adopts the following preparation method to prepare the self-supporting Ga₂O₃The film comprises the following specific steps:

1) the first time adopts the magnetron sputtering method to grow Sr on the substrate₃Al₂O₆A film;

2) in Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

3) putting the sample prepared in the step 2) into water, and soaking until Sr is achieved₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃Film, i.e. self-supporting Ga₂O₃A film.

The film prepared by the invention can independently exist without the support of a substrate. Optionally for self-supporting Ga₂O₃The film is sheared and reformed. Or further preparing Ga on a flexible substrate by transferring₂O₃A bendable device.

Wherein, step 2) grows Ga₂O₃Film and final product self-supporting Ga₂O₃The thickness of the film is consistent.

The invention can control the Ga according to the actual requirement₂O₃The thickness of the film.

The invention selects a substance which does not participate in the reaction and has a stable structure as the substrate, such as SrTiO₃、Al₂O₃Single crystal Si, etc.; particularly, single crystal Si is preferably used.

To effectively ensure the Sr₃Al₂O₆Thin film and Ga₂O₃Thickness of thin film, and Sr₃Al₂O₆Solubility of film and Ga₂O₃The combination of properties of the film. The invention further optimizes the sputtering condition and sputtering time of magnetron sputtering.

Wherein the specific conditions of the magnetron sputtering in the step 1) are that the back bottom is vacuumized to 0.1 × 10^-4～1×10^{- 3}Pa, adjusting the temperature of the substrate to 400-800 ℃, introducing argon at a flow rate of 20-25 sccm, keeping the pressure of 0.2-0.45 Pa, and sputtering for 0.5-3 h at a sputtering power of 70-100W.

When the air pressure is 0.3 to 0.4Pa, Sr is more favorable₃Al₂O₆Subsequent dissolution of the film; when the air pressure is 0.35Pa, Sr₃Al₂O₆The water solubility of the film is optimal.

Preferably, the backing is evacuated to a vacuum of 0.1 × 10^-4～1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing argon at a flow rate of 22-24 sccm, keeping the pressure at 0.3-0.4 Pa, and sputtering for 1.8-2.2 h at a sputtering power of 85-95W.

More preferably, the magnetron sputtering is carried out under the specific condition that the back bottom is vacuumized to 1 × 10^-4Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing argon at the flow rate of 25sccm, keeping the gas pressure at 0.35Pa, and sputtering for 2 hours at the sputtering power of 90W.

Wherein the specific conditions of the magnetron sputtering in the step 2) are that the back bottom is vacuumized to 0.1 × 10^-4～1×10^{- 3}Pa, adjusting the temperature of the substrate to 400-800 ℃, introducing argon at a flow rate of 20-25 sccm, keeping the air pressure at 0.6-1 Pa, and sputtering for 0.5-3 h at a sputtering power of 70-100W;

preferably, the backing is evacuated to a vacuum of 0.1 × 10^-4～1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing argon at a flow rate of 22-24 sccm, keeping the air pressure at 0.7-0.9 Pa, and sputtering for 1.8-2.2 h at a sputtering power of 85-95W;

most preferably, the magnetron sputtering is carried out under the specific condition that the vacuum pumping of the back substrate is 1 × 10^-4Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing argon at the flow of 25sccm, keeping the gas pressure at 0.8Pa, and sputtering for 2 hours at the sputtering power of 80W.

Under the adaptive air pressure, Ar ions are formed in the magnetic control by the argon, the Ar ions impact the gallium oxide target material in the magnetic field environment, and gallium oxide molecules are sputtered to deposit on the substrate to form the gallium oxide film.

Wherein the separation is specifically: will be coated with Ga₂O₃Taking the substrate of the film out of the water surface to treat Ga₂O₃The upper surface of the film is free of moisture, Ga₂O₃When water is still present between the film and the substrate, the film is slowly and obliquely put back into the water to separate the substrate from Ga₂O₃A film.

The water is water commonly used in the art that does not affect the reaction, such as deionized water.

Wherein the substrate further comprises cleaning prior to use;

preferably, the cleaning is in particular: and sequentially soaking the substrate in acetone, ethanol and deionized water, performing ultrasonic treatment for 10-20 minutes respectively, taking out the substrate, fully washing the substrate with the deionized water, and drying the substrate for later use.

The invention provides a preferable scheme, and the preparation method comprises the following steps:

1) taking single crystal Si as a substrate, and growing Sr on the substrate by adopting a magnetron sputtering method for the first time₃Al₂O₆A film;

the specific condition of the first magnetron sputtering is that the back bottom is vacuumized to 0.1 × 10^-4～1 ×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.3-0.4 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

2) in Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

the specific conditions of the second magnetron sputtering are that the back bottom is vacuumized to 0.1 × 10^-4～1 ×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.7-0.9 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

3) putting the sample prepared in the step 2) into water, and soaking until Sr is achieved₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃And (5) film forming.

The preparation process is simple, and the used substrate is a commercial product; in the preparation process, the water-soluble layer Sr is grown by adopting a commercial preparation method through magnetron sputtering₃Al₂O₆Thin film and Ga₂O₃The film has strong process controllability and easy operation, and the obtained film has compact surface, stable and uniform thickness, large-area preparation and good repeatability.

Self-supporting Ga prepared by the invention₂O₃The film has the advantages of large area, good flexibility, convenient shearing and recombination, capability of integrally preparing novel devices such as a high-frequency high-power field effect transistor, a solar blind ultraviolet detector, a transparent conductive electrode, an information memory, a gas sensor and the like on portable, flexible and wearable equipment, and huge potential application value.

Drawings

FIG. 1 is a schematic representation of the preparation of free-standing Ga₂O₃A flow diagram of a thin film;

FIG. 2 is a view of the self-supporting Ga obtained in example 2₂O₃A film;

FIG. 3 is a view of the self-supporting Ga obtained in example 2₂O₃Physical images of the films transferred on the flexible substrate PET and the alumina substrate respectively;

FIG. 4 is a view of the self-supporting Ga obtained in example 2₂O₃The ultraviolet absorption spectrum of the film, and the inset in the figure is a calculated forbidden band width figure;

FIG. 5 is a view of the self-supporting Ga obtained in example 2₂O₃An STM map of the film;

FIG. 6 shows self-supporting Ga obtained in example 2₂O₃Ga obtained by X-ray photoelectron spectroscopy test of film₂O₃XPS spectra of (a);

FIG. 7 shows Sr growth in comparative examples 1 to 2₃Al₂O₆Film and Ga₂O₃Comparing before and after the Si substrate of the film is placed in alcohol or acetone;

FIG. 8 is a graph showing the comparison of the dissolution effects of the samples prepared in comparative examples 4 to 9;

FIG. 9 is a graph showing the comparison of the effects of the samples prepared in example 2 and comparative examples 5 to 9 when put in water for 30 seconds.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The following examples are provided by using Si, which is available from Soy-Fei-Yuan-Jing materials Co., Ltd, and has a size of 10mm × 12mm, 12mm × 0.5mm and 0.5 mm.

Before use, Si needs to be cleaned specifically, and specifically: sequentially soaking the substrate in acetone, ethanol and deionized water, performing ultrasonic treatment for 15 minutes respectively, taking out, washing with deionized water, and drying with dry N₂And (5) drying the mixture by air for later use.

Example 1

This example provides a self-supporting Ga₂O₃The preparation method of the film comprises the following steps:

1) taking single crystal Si as a substrate, putting the substrate into a deposition chamber, and growing Sr on the substrate by adopting a magnetron sputtering method for the first time₃Al₂O₆A film;

the specific condition of the first magnetron sputtering is that the back bottom is vacuumized to 1 × 10^-4Pa, adjusting the substrate temperature to 500 ℃, introducing argon at a flow rate of 24sccm, and maintaining the gas pressure P_ArSputtering is carried out for 2h under the sputtering power of 90W under the pressure of 0.35 Pa.

2) In Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

the specific conditions of the second magnetron sputtering are that the back bottom is vacuumized to 1 × 10^-4Pa, adjusting the temperature of the substrate to 500 ℃, and introducing argon at the flow rate of 24sccm to ensure that the air pressure is P_ArSputtering is carried out for 2h under the sputtering power of 80W under the pressure of 0.8 Pa.

3) Putting the sample prepared in the step 2) into deionized water, standing for 6h, taking out the sample by using a forceps in an inclined manner until Ga is obtained₂O₃The upper surface of the film is free of moisture, Ga₂O₃Water is still remained between the film and the substrate, and the film is slowly put back into the deionized water in an inclined way, Ga₂O₃The film can separate from the Si substrate and float on the water surface, namely the self-supporting Ga₂O₃An amorphous film.

Self-supporting Ga prepared in this example₂O₃The film is amorphous.

As shown in figure 1 of the drawings, in the figure,preparation of self-supporting Ga₂O₃Flow chart of the film.

Example 2

This example provides a self-supporting Ga₂O₃The preparation method of the film comprises the following steps:

1) taking single crystal Si as a substrate, putting the substrate into a deposition chamber, and growing Sr on the substrate by adopting a magnetron sputtering method for the first time₃Al₂O₆A film;

the specific condition of the first magnetron sputtering is that the back bottom is vacuumized to 1 × 10^-4Pa, adjusting the substrate temperature to 750 ℃, introducing argon at the flow rate of 24sccm, and maintaining the gas pressure P_ArSputtering is carried out for 2h under the sputtering power of 90W under the pressure of 0.35 Pa.

2) In Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

the specific conditions of the second magnetron sputtering are that the back bottom is vacuumized to 1 × 10^-4Pa, adjusting the substrate temperature to 750 ℃, introducing argon at the flow rate of 25sccm, and maintaining the gas pressure P_ArSputtering is carried out for 2h under the sputtering power of 80W under the pressure of 0.8 Pa.

3) Putting the sample prepared in the step 2) into deionized water, standing for 6h, taking out the sample by using a forceps in an inclined manner until Ga is obtained₂O₃The upper surface of the film is free of moisture, Ga₂O₃Water is still remained between the film and the substrate, and the film is slowly put back into the deionized water in an inclined way, Ga₂O₃The film can separate from the Si substrate and float on the water surface, namely the self-supporting Ga₂O₃An amorphous film.

FIG. 2 shows the self-supporting Ga obtained in this example₂O₃A film.

FIG. 3 is a view of separately prepared self-supporting Ga₂O₃Physical picture of film transfer on flexible substrates PET and alumina substrates.

FIG. 4 shows the self-supporting Ga obtained in the present embodiment₂O₃The ultraviolet absorption spectrum of the film, and the inset in the figure is a calculated forbidden band width figure;

FIG. 5 shows the exampleExample prepared self-supporting Ga₂O₃An STM map of the film;

FIG. 6 shows a self-supporting Ga obtained in the present example₂O₃Ga obtained by X-ray photoelectron spectroscopy test of film₂O₃XPS spectra of (a);

comparative examples 1 to 2

This comparative example provides Ga₂O₃A method for preparing a thin film, which is different from example 2 only in that water is replaced with alcohol and acetone in step 3), respectively;

as shown in FIG. 7, step 3) will grow Sr₃Al₂O₆Film and Ga₂O₃Comparing before and after the Si substrate of the film is placed in alcohol or acetone; can see Sr₃Al₂O₆The film is not changed at all, Sr₃Al₂O₆Insolubilization of the film, substrate and Ga₂O₃The film could not be separated.

Comparative example 3

This comparative example provides Ga₂O₃A film preparation method, which is different from the method of example 2 only in that water is replaced by ethanol with the volume percentage of 70% in the step 3);

sr in step 3)₃Al₂O₆The film dissolves very slowly; sr₃Al₂O₆The film did not dissolve completely.

Comparative examples 4 to 9

This comparative example provides Ga₂O₃The preparation method of the thin film is different from the preparation method of the embodiment 2 only in that in the step 1), the substrate temperature and the argon gas pressure are different;

1) the substrate temperature was 750 ℃, and argon gas was introduced to maintain the pressure at P_Ar＝0.5Pa；

2) The substrate temperature was 750 ℃, and argon gas was introduced to maintain the pressure at P_Ar＝0.6Pa；

3) The substrate temperature is 800 ℃, argon is introduced to keep the pressure of the substrate at P_Ar＝0.5Pa；

4) The substrate temperature is 750 ℃, and argon is introducedAir pressure of the air is respectively kept at P_Ar＝0.8Pa；

5) The substrate temperature is 800 ℃, argon is introduced to keep the pressure of the substrate at P_Ar＝0.8Pa；

Putting the samples prepared in the comparative examples 4-9 into deionized water for full dissolution, and then comparing; as shown in fig. 8, the sequence from the right to the left is: a blank single crystal Si substrate, comparative examples 4 to 9; as can be seen from the figure, Sr in comparative examples 4 to 9₃Al₂O₆Only comparative example 4 of the film was partially dissolved and none of the remaining comparative examples were dissolved.

Dissolving the samples prepared in the example 2 and the comparative examples 5-9 in deionized water for 30s, and taking out and comparing; as shown in fig. 9, only example 2 showed significant evidence of dissolution.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (13)

1. Self-supporting Ga₂O₃A method for producing a film, characterized by comprising the steps of:

1) the first time adopts the magnetron sputtering method to grow Sr on the substrate₃Al₂O₆A film;

2) in Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

3) putting the sample prepared in the step 2) into water, and soaking until Sr is achieved₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃Film, i.e. self-supporting Ga₂O₃A film;

wherein the specific conditions of the magnetron sputtering in the step 1) are that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3PaAnd adjusting the temperature of the substrate to 500-750 ℃, introducing argon at a flow rate of 22-24 sccm, keeping the pressure of 0.3-0.4 Pa, and sputtering for 1.8-2.2 h at a sputtering power of 85-95W.

2. The method of claim 1, wherein the substrate is selected from SrTiO₃、Al₂O₃And single crystal Si.

3. The production method according to claim 1 or 2, wherein the Sr is₃Al₂O₆The thickness of the film being said Ga₂O₃The thickness of the film is 0.5 to 2 times.

4. The production method according to claim 1 or 2, wherein the Sr is₃Al₂O₆The thickness of the film being said Ga₂O₃The thickness of the film is 0.5 to 1 time.

5. The preparation method according to claim 1 or 2, wherein the specific conditions of the magnetron sputtering in the step 2) are that the back substrate is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 400-800 ℃, introducing inert gas at a flow rate of 20-25 sccm, keeping the gas pressure at 0.6-1 Pa, and sputtering for 0.5-3 h at a sputtering power of 70-100W.

6. The preparation method of claim 3, wherein the specific conditions of the magnetron sputtering in the step 2) are that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 400-800 ℃, introducing inert gas at a flow rate of 20-25 sccm, keeping the gas pressure at 0.6-1 Pa, and sputtering for 0.5-3 h at a sputtering power of 70-100W.

7. The preparation method according to claim 1 or 2, wherein the specific conditions of the magnetron sputtering in the step 2) are that the back substrate is vacuumized to 0.1 × 10^-4~1×10^-3Pa, and adjustingThe temperature of the substrate is 500-750 ℃, inert gas is introduced at the flow rate of 22-24 sccm, the pressure is kept at 0.7-0.9 Pa, and sputtering is carried out for 1.8-2.2 h at the sputtering power of 85-95W.

8. The preparation method according to claim 1 or 2, characterized in that the separation is in particular: will be coated with Ga₂O₃Taking the substrate of the film out of the water surface to treat Ga₂O₃The upper surface of the film is free of moisture, Ga₂O₃Water is still remained between the film and the substrate, and the film and the substrate are slowly put back into the water in an inclined way, so that the substrate and the Ga can be separated₂O₃A film.

9. A method of manufacturing as claimed in claim 1 or 2, wherein the substrate further comprises cleaning prior to use.

10. The method for preparing according to claim 9, wherein the cleaning is specifically: and sequentially soaking the substrate in acetone, ethanol and deionized water, performing ultrasonic treatment for 10-20 minutes respectively, taking out the substrate, fully washing the substrate with the deionized water, and drying the substrate for later use.

11. The method of claim 1, comprising the steps of:

1) taking single crystal Si as a substrate, and growing Sr on the substrate by adopting a magnetron sputtering method for the first time₃Al₂O₆A film;

the specific condition of the first magnetron sputtering is that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.3-0.4 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

2) in Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

the specific conditions of the second magnetron sputtering are that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.7-0.9 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

3) putting the sample prepared in the step 2) into water, and soaking until Sr is achieved₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃And (5) film forming.

12. The method of claim 3, comprising the steps of:

1) taking single crystal Si as a substrate, and growing Sr on the substrate by adopting a magnetron sputtering method for the first time₃Al₂O₆A film;

the specific condition of the first magnetron sputtering is that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.3-0.4 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

2) in Sr₃Al₂O₆On the film, Ga grows by adopting a magnetron sputtering method for the second time₂O₃A film;

the specific conditions of the second magnetron sputtering are that the back bottom is vacuumized to 0.1 × 10^-4~1×10^-3Pa, adjusting the temperature of the substrate to 500-750 ℃, introducing inert gas at the flow rate of 22-24 sccm, keeping the gas pressure at 0.7-0.9 Pa, and sputtering for 1.8-2.2 h at the sputtering power of 85-95W;

3) putting the sample prepared in the step 2) into water, and soaking until Sr is achieved₃Al₂O₆After the film is dissolved, the substrate and Ga are separated₂O₃And (5) film forming.

13. Self-supporting Ga obtainable by the process according to any one of claims 1 to 12₂O₃A film.

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