Preparation method of wafer-level InSe thin film and semiconductor structure

Abstract

The embodiment of the invention provides a preparation method of a wafer-level InSe thin film, and the method comprises the steps: sputtering an In target material and an InSe compound target material on a substrate through a magnetron sputtering method, and generating an In and InSe compound mixed thin film on the substrate; and carrying out rapid annealing on the substrate with the mixed thin film to enable the mixed thin film to be crystallized, so as to firstly form an In4Se3 thin film on the substrate and finally form an InSe thin film. According to the preparation method of the wafer-level InSe thin film provided by the embodiment of the invention, the preparation of the wafer-level two-dimensional material InSe thin film is realized in a manner of combining magnetron sputtering and rapid annealing. The embodiment of the invention also provides a semiconductor structure.

Description

Technical Field

[0001] This application belongs to the field of semiconductor materials technology, and particularly relates to a method for preparing wafer-level InSe thin films and a semiconductor structure. Background Technology

[0002] InSe (indium selenide) is a typical two-dimensional semiconductor material, characterized by its high electron mobility (ranging from 300 to 1000 cm⁻¹). 2 ·V -1 ·s -1 With its outstanding comprehensive electrical properties, such as low resistivity and high carrier concentration, it is widely recognized by the scientific community as having great application potential in many fields such as high-speed transistors, high-frequency electronic devices, and optoelectronic devices.

[0003] However, current main methods for preparing InSe have significant drawbacks. Taking traditional methods such as chemical vapor deposition and liquid phase epitaxy as examples, these methods not only have complex processes requiring precise control of multiple parameters such as reaction temperature, gas flow rate, and solution concentration, but also place high demands on equipment, resulting in high preparation costs. In existing preparation methods, the crystallinity quality of InSe films is highly dependent on the degree of substrate lattice matching. This makes it impossible to obtain highly crystallinity InSe films on various substrates using the same preparation process, thus limiting its application flexibility.

[0004] Furthermore, existing methods are insufficient for achieving wafer-level, large-area, and high-quality InSe thin film preparation, failing to meet the stringent requirements of integrated circuits and large-scale electronic devices for material consistency and reliability, thus hindering the further promotion and application of InSe thin films in related fields. Summary of the Invention

[0005] To address the problems existing in the aforementioned related technologies, this application provides a method for preparing wafer-level InSe thin films and a semiconductor structure, which achieves the preparation of wafer-level two-dimensional InSe thin films by combining magnetron sputtering and rapid annealing.

[0006] In a first aspect, embodiments of this application propose a method for preparing wafer-level InSe thin films, comprising the following steps:

[0007] In a magnetron sputtering method, an In target and an InSe compound target are sputtered onto a substrate to form a mixed In and InSe compound thin film on the substrate; and

[0008] The substrate with the mixed film is subjected to rapid annealing to crystallize the mixed film, so that an In4Se3 film is first formed on the substrate and eventually becomes an InSe film.

[0009] Furthermore, the molar ratio of In to Se in the hybrid film is greater than 1:1.

[0010] Further, the InSe compound is In2Se3, and the process of sputtering an In target and an InSe compound target onto a substrate using magnetron sputtering to generate a mixed In and InSe compound thin film on the substrate includes:

[0011] The substrate is placed in a magnetron sputtering chamber for co-sputtering deposition of the In target and the In2Se3 target, wherein the sputtering power of the In target is 7W, the sputtering power of the In2Se3 target is 45W, the sputtering time is 100s, and the sputtering pressure is 2.5E-3Torr, so that the In / In2Se3 mixed film is uniformly deposited on the substrate.

[0012] Furthermore, the rapid annealing temperature is between 400°C and 500°C.

[0013] Further, the rapid annealing of the substrate with the mixed film to crystallize the mixed film, thereby first forming an In4Se3 film on the substrate and ultimately transforming it into an InSe film, includes:

[0014] The substrate with the In / In2Se3 mixed film was placed in a rapid annealing furnace and heated to 450°C at a heating rate of 20 K / s, held for 5 min, and then allowed to cool naturally to room temperature, so that an In4Se3 film was first formed on the substrate, and finally recrystallized from the In4Se3 film to become an InSe film.

[0015] Furthermore, the InSe compound is In2Se. 2.5 Target material or InSe target material.

[0016] Furthermore, the substrate is a p+-silicon / silicon oxide substrate, a silicon substrate, or a sapphire substrate.

[0017] Secondly, embodiments of this application also provide a semiconductor structure, the semiconductor structure including an InSe thin film, the InSe thin film being made by the method described in any of the above-mentioned methods.

[0018] The wafer-level InSe thin film preparation method provided in this application utilizes the interaction of a magnetic field and an electric field to bombard the surface of an In target and an InSe compound target with ions generated by the ionization of, for example, argon gas, sputtering In atoms and InSe molecules / clusters. These particles deposit on the substrate surface to form a mixed In and InSe compound thin film. Furthermore, by heating the substrate to a high temperature for a short period and holding it therefore, the atoms in the mixed film gain sufficient energy to migrate and rearrange, thereby crystallizing to first form an In4Se3 thin film on the substrate, and finally transforming it into an InSe thin film with a specific crystal structure. The wafer-level InSe thin film preparation method provided in this application has advantages such as high deposition rate, good film uniformity, and large-area fabrication capability, making it suitable for wafer-level thin film preparation. Moreover, rapid annealing effectively reduces impurities and defects that may be introduced during annealing, improving film quality. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart illustrating the wafer-level InSe thin film preparation method provided in the embodiments of this application.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. Those skilled in the art will be able to understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] Reference Figure 1 This application provides a method for preparing a wafer-level InSe thin film, comprising the following steps:

[0026] S101: An In target and an InSe compound target are sputtered onto a substrate using magnetron sputtering to generate a mixed In and InSe compound thin film on the substrate; and

[0027] S102: The substrate with the mixed film is rapidly annealed to allow the mixed film to crystallize, so that an In4Se3 film is first formed on the substrate and eventually becomes an InSe film.

[0028] In other words, the wafer-level InSe thin film preparation method provided in this application utilizes the interaction of a magnetic field and an electric field to bombard the surface of an In target and an InSe compound target with ions generated by, for example, argon ionization, sputtering In atoms and InSe molecules / clusters. These particles deposit on the substrate surface to form a mixed In and InSe compound thin film. Furthermore, by heating the substrate to a high temperature for a short time and holding it therefore, the atoms in the mixed film gain sufficient energy to migrate and rearrange, thereby crystallizing to first form an In4Se3 thin film on the substrate, and finally transforming it into an InSe thin film with a specific crystal structure. The wafer-level InSe thin film preparation method provided in this application has advantages such as high deposition rate, good film uniformity, and the ability to prepare large areas, making it suitable for wafer-level thin film preparation. Moreover, rapid annealing effectively reduces impurities and defects that may be introduced during the annealing process, improving film quality.

[0029] Furthermore, in some embodiments of this application, the molar ratio of In to Se in the mixed film is greater than 1:1.

[0030] Specifically, in the wafer-level InSe thin film preparation method provided in this application embodiment, the molar ratio of In to Se in the mixed film is set to be greater than 1:1, which is based on the stoichiometric ratio of the In4Se3 compound. This ratio provides an ideal elemental composition basis for subsequent rapid annealing and crystallization to first form In4Se3, and then recrystallizing In4Se3 to form a high-quality InSe thin film. This helps to obtain InSe thin films with stable crystal structures and excellent photoelectric properties, meeting the application requirements in optoelectronic devices and other fields.

[0031] In practice, the molar ratio of In to Se in the mixed film is slightly greater than 1:1, for example, between 1.3:1 and 1.4:1, and the specific ratio depends on the actual situation.

[0032] To achieve a molar ratio slightly greater than 1:1, precise control of the sputtering rates of the In target and the InSe compound target is required. This necessitates meticulous adjustment and optimization of parameters such as sputtering power, working gas pressure, and target-substrate distance to ensure that the sputtering yield ratio of the two targets meets the requirements. This, in turn, ensures that the In and InSe compound mixed film deposited on the substrate achieves the desired elemental ratio and facilitates more efficient atomic migration and rearrangement during annealing, promoting the formation of a well-crystallized InSe film with fewer defects. Deviations in the ratio may lead to the appearance of impurity phases or incomplete crystallization in the film, affecting its performance.

[0033] Furthermore, in some embodiments of this application, the InSe compound is In2Se3, and the step of sputtering an In target and an InSe compound target onto a substrate by magnetron sputtering to generate a mixed In and InSe compound film on the substrate includes:

[0034] The substrate is placed in a magnetron sputtering chamber for co-sputtering deposition of the In target and the In2Se3 target, wherein the sputtering power of the In target is 7W, the sputtering power of the In2Se3 target is 45W, the sputtering time is 100s, and the sputtering pressure is 2.5E-3Torr, so that the In / In2Se3 mixed film is uniformly deposited on the substrate.

[0035] Specifically, in some embodiments of this application, In₂Se₃ is used as the InSe compound. A mixed In and InSe compound thin film is generated on a substrate by co-sputtering In and In₂Se₃ targets using magnetron sputtering. Specifically, the substrate is placed in a magnetron sputtering chamber, and under specific electric and magnetic fields, ions generated by the ionization of argon gas bombard the In and In₂Se₃ targets, causing In atoms and In₂Se₃ molecules / clusters to be sputtered from the target surfaces, thereby depositing a mixed thin film on the substrate.

[0036] The sputtering power is 7W for the In target and 45W for the In₂Se₃ target. This power setting adjusts the sputtering yield of both targets, affecting the ratio of In to In₂Se₃ in the mixed film, which is crucial for forming an InSe film with a stoichiometric ratio. The sputtering time is set to 100s, working in conjunction with the sputtering power to determine the film thickness, ensuring a uniform deposition of a suitable thickness of mixed film on the substrate. The sputtering pressure is maintained at 2.5E-3 Torr, which provides a stable plasma environment, ensuring a stable sputtering process and preventing improper pressure from affecting film quality and deposition rate.

[0037] Furthermore, in some embodiments of this application, the rapid annealing temperature is between 400°C and 500°C.

[0038] Specifically, rapid annealing is a key step in the preparation of wafer-level InSe thin films. The above temperature range is set to allow sufficient physical and chemical changes to occur in the In and In2Se3 mixed thin films formed by magnetron sputtering in the early stage, promoting atomic migration and rearrangement, and finally crystallizing to form high-quality InSe thin films.

[0039] Furthermore, in some embodiments of this application, the rapid annealing of the substrate with the mixed film to crystallize the mixed film, thereby first forming an In4Se3 film on the substrate and ultimately transforming it into an InSe film, includes:

[0040] The substrate with the In / In2Se3 mixed film was placed in a rapid annealing furnace and heated to 450°C at a heating rate of 20 K / s, held for 5 min, and then allowed to cool naturally to room temperature, so that an In4Se3 film was first formed on the substrate, and finally recrystallized from the In4Se3 film to become an InSe film.

[0041] In other words, a substrate with an In / In2Se3 mixed film is placed in a rapid annealing furnace, heated to a target temperature at a specific heating rate, held at that temperature for a period of time, and finally allowed to cool naturally to room temperature. This process first forms an In4Se3 film on the substrate, which eventually becomes an InSe film. The heating rate is set to 20 K / s, which allows the substrate to reach the target temperature quickly, preventing film decomposition during heating and ensuring uniform heating of the mixed film, creating favorable conditions for subsequent crystallization. The target annealing temperature is chosen to be 450℃, which falls within the reasonable range of 400℃ to 500℃. This provides sufficient energy to the In and In2Se3 mixed film, promoting sufficient atomic migration and rearrangement for effective crystallization of the InSe film, while avoiding problems such as element volatilization and InSe decomposition caused by excessively high temperatures. The holding time is set to 5 minutes to ensure sufficient time for the mixed film to complete the crystallization process at 450℃, resulting in a more perfect crystal structure, reduced defects, and improved film quality.

[0042] Furthermore, in some embodiments of this application, the InSe compound is In2Se. 2.5 Target material or InSe target material.

[0043] In other words, the wafer-level InSe thin film preparation method provided in this application embodiment can also use magnetron sputtering to co-sputter In target and In2Se. 2.5 Using a target material or InSe target material, an In and In2Se layer is formed on the substrate. 2.5 / InSe mixed thin film. The substrate with the mixed film is placed in a rapid annealing furnace, and rapid annealing causes the mixed film to crystallize, ultimately forming an InSe thin film. In target and In2Se 2.5 The sputtering power of InSe needs to be controlled separately to ensure that the molar ratio of In to Se in the resulting mixed film is maintained at slightly greater than 1:1.

[0044] It should be noted that in some embodiments of this application, if In2Se is used... 2.5 The target material (stoichiometric ratio corresponding to In:Se = 1:1.25) or InSe target material (stoichiometric ratio corresponding to In:Se = 1:1) needs to be adjusted according to its characteristics to achieve high-quality InSe thin film preparation. Of course, other phases of InSe compounds can also be used as InSe target materials, depending on the actual situation.

[0045] Furthermore, in some embodiments of this application, the substrate is a p+-silicon / silicon oxide substrate, a silicon substrate, or a sapphire substrate.

[0046] Due to the characteristics of magnetron sputtering, the wafer-level InSe thin film preparation method provided in this application embodiment is applicable to substrates of various materials, such as p+-silicon / silicon oxide substrates, silicon substrates or sapphire substrates, and has high flexibility and application prospects.

[0047] Furthermore, this application also provides a semiconductor structure comprising an InSe thin film, which is fabricated using the methods described above. The specific preparation method of this InSe thin film is the same as described in the above embodiments. Since the specific preparation method of the InSe thin film adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0048] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a wafer-level InSe thin film, characterized in that, Includes the following steps: In a magnetron sputtering method, an In target and an InSe compound target are sputtered onto a substrate to generate a mixed film of In and InSe compounds on the substrate. and The substrate with the mixed film is subjected to rapid annealing to crystallize the mixed film, so that an In4Se3 film is first formed on the substrate and eventually becomes an InSe film.

2. The method as described in claim 1, characterized in that, The molar ratio of In to Se in the hybrid film is greater than 1:

1.

3. The method as described in claim 2, characterized in that, The InSe compound is In2Se3. The process involves sputtering an In target and an InSe compound target onto a substrate using magnetron sputtering to generate a mixed In and InSe compound thin film on the substrate, including: The substrate is placed in a magnetron sputtering chamber for co-sputtering deposition of the In target and the In2Se3 target, wherein the sputtering power of the In target is 7W, the sputtering power of the In2Se3 target is 45W, the sputtering time is 100s, and the sputtering pressure is 2.5E-3Torr, so that the In / In2Se3 mixed film is uniformly deposited on the substrate.

4. The method as described in claim 3, characterized in that, The rapid annealing temperature is between 400°C and 500°C.

5. The method as described in claim 4, characterized in that, The step of rapidly annealing the substrate with the mixed film to crystallize the mixed film, thereby first forming an In4Se3 film on the substrate and ultimately transforming it into an InSe film, includes: The substrate with the In / In2Se3 mixed film was placed in a rapid annealing furnace and heated to 450°C at a heating rate of 20 K / s, held for 5 min, and then allowed to cool naturally to room temperature, so that an In4Se3 film was first formed on the substrate, and finally recrystallized from the In4Se3 film to become an InSe film.

6. The method as described in claim 2, characterized in that, The InSe compound is In2Se. 2.5 Target material.

7. The method as described in claim 2, characterized in that, The InSe compound is an InSe target.

8. The method as described in claim 1, characterized in that, The substrate is a p+-silicon / silicon oxide substrate, a silicon substrate, or a sapphire substrate.

9. A semiconductor structure, characterized in that, The semiconductor structure includes an InSe thin film, which is made by the method according to any one of claims 1 to 8.

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