Heterogeneous substrate epitaxial growth method, heterogeneous epitaxial structure and its application

Abstract

The present invention discloses a heterogeneous substrate epitaxial growth method, a heteroepitaxial structure, and its application. The growth method comprises: forming a dielectric layer and a mask layer on the surface of the heterogeneous substrate, the mask layer having a first window; over-etching the dielectric layer to form a second window, the second window having a width greater than the first window; continuing to plasma-treat the heterogeneous substrate using the first window to form a conversion zone, forming a substrate exposure zone between the conversion zone and the edge of the second window; and using the substrate exposure zone to perform heteroepitaxial growth. The present invention can greatly suppress dislocation extension by using a very large mask / window duty cycle. In addition, it can also control the width of the remaining dielectric layer from being too wide while obtaining an extremely narrow substrate exposure zone, which is beneficial for lateral merging, improving preparation efficiency and the quality of the heteroepitaxial layer, and reducing the demand for high-precision lithography equipment, thereby facilitating the widespread application of heteroepitaxial technology.

Description

Technical Field

[0001] The present invention relates to the technical field of epitaxial growth, and in particular to a heterogeneous substrate epitaxial growth method, a heterogeneous epitaxial structure and applications thereof. Background Art

[0002] Wide bandgap semiconductor materials such as gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AlN) have emerged as third-generation semiconductor materials. They possess superior properties such as high frequency, high efficiency, high power, high temperature resistance, high voltage resistance, and strong radiation resistance. They are widely used in laser diodes, power electronic devices, Micro-LED full-color displays, new energy vehicles and other fields, and have become the focus of competition in the global semiconductor technology and industry.

[0003] The above-mentioned semiconductor materials are basically obtained by epitaxial growth using heterogeneous substrates. For example, GaN is basically obtained by heteroepitaxial growth on substrates such as Si, SiC, and sapphire. However, due to the different lattice constants and thermal expansion coefficients between the heterogeneous substrate and the epitaxial layer, large lattice mismatch and thermal mismatch are caused, which will directly affect the crystal quality of the epitaxial layer, such as higher dislocation density, greater stress in the epitaxial layer, warping of the epitaxial layer, and cracking.

[0004] In order to obtain high-quality heteroepitaxial substrates, researchers have explored a variety of methods, which can be roughly divided into three types: substrate pretreatment (such as beveled substrates, nitridation, patterned substrates, etc.), inserting buffer layer and intermediate layer technology (such as low-temperature buffer layer, dielectric mask layer, two-dimensional material intermediate layer, etc.), and regulating the crystal growth process (such as changing the growth mode, nucleation density, growth rate, etc.).

[0005] Among them, the lateral epitaxial growth of GaN using mask materials (ELOG, epitaxial lateral overgrowth: mask lateral epitaxial growth) technology is considered to be one of the most effective means to reduce dislocation density. Its main principle is to first prepare a periodic patterned mask on the substrate. Since GaN has a low viscosity coefficient on the mask and is difficult to nucleate, GaN will selectively nucleate and grow three-dimensionally on the substrate exposed in the window area during the initial growth. Then, by adjusting the growth parameters, the lateral growth rate of GaN is changed, and GaN undergoes lateral epitaxy on the mask, ultimately obtaining a merged GaN film (or a heterogeneous growth layer of other materials). In this process, the coverage of the patterned mask on the substrate blocks dislocations from the substrate, thereby improving the crystal quality of the epitaxial layer.

[0006] However, there are still many problems with this method of mask growth, including at least:

[0007] 1. Currently, the windows for lateral epitaxial III-nitrides are generally at the micron level. As a result, dislocations in the substrate will penetrate through the overly large windows, causing many dislocations to extend into the heteroepitaxial layer. Although this approach can effectively reduce the extension of dislocations through the window into the epitaxial layer by making the window at the nanometer level, the nanometer-level windows place extremely high demands on processes and equipment.

[0008] 2. The masks for traditional lateral epitaxial growth of group III nitrides are usually silicon oxide, graphene, etc., which will introduce impurities into the epitaxial growth.

[0009] 3. The mask area of ​​traditional lateral epitaxial III-nitride is still relatively small compared to the window area, generally 7 / 3. Such a duty ratio can theoretically only reduce about 3 / 7 of the nitride substrate dislocations, and cannot significantly reduce the dislocation density.

[0010] 4. The substrate window size for traditional lateral epitaxial III-nitride is controlled by factors such as the lithography machine's exposure and development time. This often limits the precision of many lithography machines, especially for sizes below the micron level. For example, the MA6 series can only achieve 1 μm precision, and steppers can only achieve 500 nm precision, making practical application difficult. Summary of the Invention

[0011] In view of the deficiencies in the prior art, the present invention aims to provide a heterogeneous substrate epitaxial growth method, a heterogeneous epitaxial structure and applications thereof.

[0012] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0013] In a first aspect, the present invention provides a method for epitaxial growth on a heterogeneous substrate, comprising:

[0014] forming a dielectric layer and a mask layer on a surface of a foreign substrate, wherein the mask layer has a first window, and the first window exposes the surface of the dielectric layer;

[0015] Over-etching the dielectric layer using the first window to form a second window in the dielectric layer, wherein the second window is wider than the first window and exposes the surface of the foreign substrate;

[0016] Continue to perform plasma treatment on the foreign substrate using the first window, so that the surface material of the foreign substrate in the corresponding area of ​​the first window is transformed to form a transformed area, and a substrate exposed area is formed between the transformed area and the edge of the second window;

[0017] The mask layer is removed and the exposed area of ​​the substrate is used for heteroepitaxial growth (including a vertical nucleation growth stage and a lateral merging growth stage, which belongs to the existing growth process in this field) to obtain a heteroepitaxial layer.

[0018] In a second aspect, the present invention also provides a heteroepitaxial structure obtained by the above-mentioned heterogeneous substrate epitaxial growth method, which includes a heterogeneous substrate, a dislocation blocking structure and a heteroepitaxial layer arranged in sequence along the thickness direction, the dislocation blocking structure includes a dielectric layer covering the surface of the heterogeneous substrate and a transformation zone embedded in the surface of the heterogeneous substrate, the dielectric layer has a second window, the transformation zone is within the second window, and the heteroepitaxial layer is formed by heteroepitaxial growth based on the substrate exposed area between the edge of the transformation zone and the second window.

[0019] In a third aspect, the present invention also provides applications of the above-mentioned heteroepitaxial structure in the fields of laser diodes, power electronic devices, Micro-LED full-color displays, and new energy vehicles.

[0020] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least:

[0021] The heterogeneous substrate epitaxial growth method provided by the present invention involves, after a first window is formed in a mask layer, overetching the dielectric layer through the first window, causing simultaneous longitudinal and lateral etching of the dielectric layer. By adjusting the overetching conditions, the width of the second window in the dielectric layer relative to the first window can be adjusted. Plasma treatment is then continued through the first window to transform the substrate material in the region corresponding to the first window, forming a conversion zone. This creates a substrate exposure region with controllable width, easily reaching the nanometer level, between the conversion zone and the edge of the second window. Heteroepitaxial growth is performed using this substrate exposure region. This significantly increases the mask duty cycle (total area of ​​the conversion zone and the remaining dielectric layer / area of ​​the substrate exposure region) to significantly suppress dislocation extension. Furthermore, while achieving an extremely narrow substrate exposure region, the width of the remaining dielectric layer can be controlled to be less than excessive, facilitating lateral merging, improving fabrication efficiency and the quality of the heteroepitaxial layer. This also reduces the need for high-precision lithography equipment, facilitating widespread application of heteroepitaxial technology.

[0022] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of this application and implement them according to the contents of the specification, the following is an explanation of the preferred embodiments of the present invention with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for epitaxial growth on a heterogeneous substrate provided by a typical embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the process of a heterogeneous substrate epitaxial growth method provided by a typical embodiment of the present invention;

[0025] Figure 3 This is a surface electron microscope photograph of a heterogeneous substrate having a dislocation barrier layer obtained by the heterogeneous substrate epitaxial growth method provided in a typical embodiment of the present invention;

[0026] Figure 4 This is an electron microscope photograph of the surface of a semi-finished product having an epitaxial nucleation layer obtained by the heterogeneous substrate epitaxial growth method provided in a typical embodiment of the present invention;

[0027] Figure 5 These are transmission and synchronous EDS images of a semi-finished product having an epitaxial nucleation layer obtained by the heterogeneous substrate epitaxial growth method provided in a typical embodiment of the present invention;

[0028] Figure 6 This is a CL test image of a heteroepitaxial layer obtained by the heterogeneous substrate epitaxial growth method provided in a typical embodiment of the present invention;

[0029] Figure 7 This is a CL test image of a heteroepitaxial layer obtained by the heterogeneous substrate epitaxial growth method provided in a typical control case of the present invention.

[0030] Explanation of the accompanying symbols: 1. Heterogeneous substrate, 2. Dielectric layer, 3. Mask layer, 4. Mask pattern, 5. Dielectric pattern, 6. Conversion region, 7. Epitaxial nucleation layer. DETAILED DESCRIPTION

[0031] In combination with the above background technology, some existing technologies related to the present invention are as follows:

[0032] Chinese utility model patent publication number CN220079259U, "A Structure for Growing Gallium Nitride Thin Films Using a Graphene Mask," discloses a structure for growing gallium nitride thin films using a graphene mask, belonging to the field of semiconductor technology. The structure comprises a gallium nitride thin film layer, a mask layer, and a substrate layer. The exposed substrate layer serves as a window region, while the graphene-covered region serves as a mask region. The gallium nitride layer nucleates and grows in the window region of the substrate layer, covering the mask layer surface. The mask layer comprises a hexagonal graphene mask layer structure. The window region widths range from 3 to 5 microns, and the mask region widths range from 15 to 25 microns. This mask layer structure effectively reduces the high dislocation density generated by heteroepitaxial growth in gallium nitride thin films. The weak van der Waals forces of the graphene mask material help gallium nitride overcome mismatch issues, significantly reducing stress in the gallium nitride film. The hexagonal mask structure, with its six window regions, effectively accelerates the merging time of the gallium nitride film. Due to the inherent anisotropy of gallium nitride, gallium nitride films grown using the hexagonal mask layer exhibit improved uniformity.

[0033] This technical solution uses photolithography to obtain a 3 μm growth window and a 20 μm mask. By increasing the width of the mask, a large mask window duty cycle is achieved, but the window size cannot be effectively reduced. Therefore, it is still difficult to reduce the dislocations extending from the window. Moreover, the excessive width of the mask will make it difficult for lateral growth to merge into a complete film.

[0034] Chinese invention patent publication number CN119230391A, "A method for lateral epitaxial growth of a gallium nitride layer and a gallium nitride structure," discloses a method for lateral epitaxial growth of a gallium nitride layer and a gallium nitride structure. The method comprises the following steps: providing a substrate structure comprising a stacked substrate and a graphene layer; etching the graphene layer to form a first window and a first graphene mask structure spaced apart; the bottom of the first window contacts the upper surface of the substrate, and an oxide mask structure is provided at the bottom; etching the first graphene mask structure to form a second window to obtain a second graphene mask structure; the bottom of the second window contacts the upper surface of the substrate, and the second window is located around the second graphene mask structure; and nucleating and growing a gallium nitride layer on the substrate located at the boundary of the second graphene mask structure.

[0035] This technical solution uses ammonia to etch graphene to obtain nanoscale windows, but it is impossible to accurately control the size of the window.

[0036] In addition, both of the above technical solutions use graphene as a mask, which will introduce C impurity contamination.

[0037] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The following will further explain this technical solution, its implementation process and principles.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0039] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component or method step from another with the same name, but do not necessarily require or imply any actual relationship or order between these components or method steps.

[0040] The purpose of the present invention is to provide a new method for preparing nano-patterned windows, by shrinking the growth window to obtain a high mask-to-window duty ratio, thereby greatly reducing the probability of dislocations in the substrate penetrating into the epitaxial layer, and ultimately obtaining an epitaxial layer with low dislocation density.

[0041] Based on the above technical ideas, an embodiment of the present invention provides a method for epitaxial growth on a heterogeneous substrate, which includes the following steps:

[0042] forming a dielectric layer and a mask layer on a surface of a foreign substrate, wherein the mask layer has a first window, and the first window exposes the surface of the dielectric layer;

[0043] Over-etching the dielectric layer using the first window to form a second window in the dielectric layer, wherein the second window is wider than the first window and exposes the surface of the foreign substrate;

[0044] Continue to perform plasma treatment on the foreign substrate using the first window, so that the surface material of the foreign substrate in the corresponding area of ​​the first window is transformed to form a transformed area, and a substrate exposed area is formed between the transformed area and the edge of the second window;

[0045] The mask layer is removed and the exposed area of ​​the substrate is used for heteroepitaxial growth to obtain a heteroepitaxial layer.

[0046] The key technical means of the technical solution provided by the present invention lies in forming a second window with controllable lateral expansion by over-etching the dielectric layer, and utilizing the phenomenon that the mask layer blocks the laterally over-etched part so that it cannot be processed by plasma to form a conversion zone smaller than the second window, thereby obtaining an extremely narrow growth window between the conversion zone and the edge of the second window. Ultimately, a gallium nitride epitaxial layer with a low dislocation density is obtained through a high mask-to-window ratio, and the method of increasing the mask-to-window ratio by increasing the mask width is avoided.

[0047] Specifically, the heterogeneous substrate epitaxial growth method provided by the present invention easily controls the width of the second window of the dielectric layer by adjusting the over-etching conditions of the dielectric layer (such as temperature, etching concentration, and etching time). The difference between the widths of the first and second windows substantially corresponds to the width of the substrate exposure region. Therefore, a very narrow substrate exposure region can be obtained without the use of high-precision photolithography equipment, thereby preventing the extension of dislocations. Through this method, the growth window (the remaining dielectric layer on both sides of the second window is considered the first mask, the conversion region is considered the second mask, and the substrate exposure region between the two masks is considered the growth window) is reduced to the nanometer level, while the mask width can be maintained at the micron level. For example, the growth window width is 100 nm and the mask width is 5 μm. This theoretically reduces substrate dislocations by 1 / 50. Moreover, because the mask width can be freely controlled, for example, it can be easily controlled to a mask width of only 5 μm, lateral merging growth is more likely to occur than with a traditional mask width of 7 μm.

[0048] Regarding the specific process, in some embodiments, the dielectric layer is over-etched by wet etching.

[0049] In some embodiments, the dielectric layer is made of SiO 2 , and the wet etching solution is a BOE solution.

[0050] In some embodiments, the wet etching time is 10-120 seconds.

[0051] As a preferred example, controlling the BOE wet overetching time for silicon oxide can yield a precisely controllable and uniform nanoscale growth window. For example, the BOE (7:1) etch rate for silicon oxide in a typical ALD film is 5 nm / s. Controlling the etching time to around 10 s yields a growth window of approximately 50 nm. Extending the time can widen the window, while shortening it can narrow it. However, the typical range is within the time range shown above.

[0052] Of course, the above embodiment is only a specific example. Those skilled in the art can replace it with a dielectric layer of other materials and cooperate with other wet etching processes (or even replace it with any other etching process that can produce controllable lateral etching). As long as a second window with a controllable width that is larger than the first window can be formed and the heterogeneous substrate at the bottom is exposed, the same purpose can be achieved.

[0053] For example, in some embodiments, the dielectric layer material can be replaced with silicon nitride and matched with an etching solution capable of etching silicon nitride. Of course, in general, the matching principle of the foreign substrate, dielectric layer, mask layer and corresponding etching solution (or other over-etching means) should be: the etching effect of the etching solution (or other over-etching means) on the foreign substrate and mask layer is small (or even no etching reaction occurs at all), while the etching effect on the dielectric layer is strong, and sufficient lateral etching reaction can occur in the dielectric layer.

[0054] In particular, in some embodiments, by controlling the above time range, the width of the exposed area of ​​the substrate can be controlled to be in the nanometer level.

[0055] Furthermore, in some embodiments, the thickness of the dielectric layer is typically controlled to be 10-100 nm. Controlling the thickness of the dielectric layer is critical. A dielectric layer that is too thin often results in uneven morphology and may even lead to film discontinuity. A thickness of at least 10 nm is generally required to avoid these issues. Furthermore, an overly thick dielectric layer also has negative consequences, as it can affect the consistency of the lateral corrosion rate, making it difficult to accurately control the width of the second window. Furthermore, an overly thick dielectric layer requires a longer etching time, often resulting in an excessively large lateral etching width and making it difficult to obtain a nanoscale growth window.

[0056] In some embodiments, the width of the first window is typically controlled to be 2-10 μm. The width of the first window generally determines the width of the conversion zone (the two are substantially equal or have a certain relationship, subject to experimental results). Generally, it is necessary to control the width not to be too wide to prevent lateral merging growth.

[0057] Regarding the specific process of plasma treatment, in some embodiments, the foreign substrate is selected from metal nitride substrates, and the plasma treatment is selected from O plasma treatment.

[0058] In some embodiments, the power of the O plasma treatment is 200-800 W, the O 2 flow rate is 100-400 sccm, and the treatment time is 1-5 min.

[0059] As a typical application example of the above technical solution, a preferred embodiment of the present invention oxidizes a heterogeneous substrate of group III nitrides by an O plasma method to form an amorphous oxide layer (NXO, where X represents various metal elements), thereby acting as a traditional silicon oxide mask during the epitaxial growth process. Moreover, such an oxide layer does not introduce impurity contamination to the substrate.

[0060] Of course, if the main body of the foreign substrate is oxide, such as a sapphire substrate, and material conversion cannot be achieved through O plasma treatment, then it is necessary to grow a layer of other materials that can be oxidized on the surface of the sapphire substrate as a surface layer, such as metal nitrides or carbides, etc., specifically GaN, AlN, SiC, etc., so that these materials can be transformed into a conversion zone under the conditions of O plasma treatment.

[0061] Similarly, the feasible scope is not limited to this. The preferred embodiment of the present invention is to use oxygen plasma treatment to form metal nitride oxide as a conversion zone. However, in fact, if a heterogeneous substrate made of other materials is used, the corresponding plasma treatment method may be different (for example, it may include nitrogen plasma treatment of an oxide substrate, which is also within the theoretical feasible scope of the present invention). The key is that through plasma treatment, a conversion zone can be formed whose surface material is different from that of the heterogeneous substrate and which will not produce the desired epitaxial growth of the heteroepitaxial layer on its surface.

[0062] In addition, regarding other specific processes, in some embodiments, the material of the mask layer is photoresist, and the method of removing the mask layer includes cleaning with an organic solvent.

[0063] Of course, it is not limited to this, and the mask layer may be replaced with other forms, such as a hard mask, as long as it can form the first window and can be removed more thoroughly.

[0064] An embodiment of the present invention also provides a heteroepitaxial structure produced by the heterogeneous substrate epitaxial growth method provided in any of the above-mentioned embodiments, which includes a heterogeneous substrate, a dislocation blocking structure and a heteroepitaxial layer arranged in sequence along the thickness direction, the dislocation blocking structure includes a dielectric layer covering the surface of the heterogeneous substrate and a transformation zone embedded in the surface of the heterogeneous substrate, the dielectric layer has a second window, the transformation zone is within the second window, and the heteroepitaxial layer is formed by heteroepitaxial growth based on the substrate exposed area between the transformation zone and the edge of the second window.

[0065] The embodiments of the present invention also provide applications of the above-mentioned heteroepitaxial structure in the fields of laser diodes, power electronic devices, Micro-LED full-color displays, and new energy vehicles.

[0066] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0067] Example 1

[0068] This embodiment proposes a method for preparing a patterned substrate for lateral epitaxial growth of Group III nitrides. BOE (Boiling Etching) is used to overetch a silicon oxide film, achieving lateral etching. Through a first window in the photoresist layer, O plasma in a plasma stripper is used to oxidize the portion of the nitride substrate not blocked by the photoresist, forming an amorphous oxide layer (NXO, where X represents various metals) on the nitride surface. Ultimately, the combined action of the amorphous oxide mask and the silicon oxide mask results in a patterned substrate with nanometer-scale windows. Finally, this substrate is used for lateral epitaxial growth of a gallium nitride thin film using MOCVD.

[0069] Figure 1 This is the process flow chart of this embodiment, Figure 2 The specific process of this embodiment is shown in FIG.

[0070] The specific steps are as follows:

[0071] S1: A thin layer (1μm to 5μm) of GaN is grown on sapphire by MOCVD as the heterogeneous substrate 1.

[0072] S2: A 30 nm thick silicon oxide layer is deposited on the foreign substrate 1 using an ALD process as the dielectric layer 2.

[0073] S3: The coated substrate is subjected to photoresist coating to form a mask layer 3, and then a periodic stripe structure with a first window width of 5 μm and a mask width of 5 μm is obtained by photolithography and development to form a mask pattern 4.

[0074] S4: Immerse in BOE (7:1) solution for over-etching for 20 seconds, then take out and clean the remaining BOE solution with ultrapure water. At this time, a second window with a width greater than the first window is formed in the dielectric layer 2, that is, Figure 2 The window formed by the dielectric pattern 5 is shown.

[0075] S5: The cleaned substrate is placed in a debonding machine, and the surface of the nitride substrate not blocked by the photoresist in the first window is oxidized for 2 min using an O plasma with parameters set to 400 W and an oxygen flow rate of 200 sccm to form a conversion zone 6.

[0076] The surface morphology of the product obtained in step S5 is as follows: Figure 3 As shown, the darkest color is the silicon oxide mask (mask pattern 4), the second darkest is the oxide layer mask (conversion area 6), and the brightest white area between the two is the substrate exposure area, that is, the area of ​​the defined growth window.

[0077] S6: Finally, the photoresist layer is removed by cleaning with acetone, isopropyl alcohol and water, and then the conventional GaN epitaxial growth process is used to form an epitaxial nucleation layer first, and the following is obtained: Figure 4 The epitaxial structure shown in the figure has a bright stripe, which is the epitaxial nucleation layer. The process conditions are then adjusted to allow for lateral merging growth, ultimately resulting in a GaN epitaxial growth layer.

[0078] Figure 5 The TEM and EDX images of the epitaxial nucleation layer of gallium nitride material grown by MOCVD are shown, showing obvious element distribution and regular arrangement of extremely narrow stripes.

[0079] The GaN epitaxial growth layer obtained by the preparation method provided in this embodiment is shown in FIG. Figure 6 As shown, its dislocation density is characterized as 5×10 7 / cm 2 , as a comparison, see Figure 7 As shown in the figure, the dislocation density of the GaN epitaxial growth layer obtained by using a patterned mask with a micron-scale window (i.e., a window with a width of 5 microns) is generally around 5×10 8 / cm 2 The difference is almost an order of magnitude.

[0080] Example 2

[0081] This embodiment is substantially the same as embodiment 1, with the main differences being:

[0082] The thickness of the dielectric layer was adjusted to 10 nm, the width of the first window was adjusted to 2 μm, the wet etching time was adjusted to 10 s, the power of the O plasma treatment was 200 W, the O2 flow rate was 100 sccm, and the treatment time was 1 min.

[0083] Example 3

[0084] This embodiment is substantially the same as embodiment 1, with the main differences being:

[0085] The thickness of the dielectric layer was adjusted to 100 nm, the width of the first window was adjusted to 10 μm, the wet etching time was adjusted to 120 s, the power of the O plasma treatment was 800 W, the O2 flow rate was 400 sccm, and the treatment time was 5 min.

[0086] Both of the above-mentioned embodiments 2 and 3 can realize a growth window with an extremely narrow width, and at the same time can control the width of the mask not to be too wide, and ultimately obtain a heteroepitaxial growth layer with an extremely low dislocation density. The only difference is the specific structural size.

[0087] Example 4

[0088] This embodiment is substantially the same as embodiment 1, with the main differences being:

[0089] The substrate material is replaced with AlN, the dielectric layer material is replaced with silicon nitride, and the epitaxial growth material is GaN.

[0090] Example 5

[0091] This embodiment is substantially the same as embodiment 1, with the main differences being:

[0092] The substrate material is replaced with silicon carbide, and the dielectric layer material is replaced with silicon nitride.

[0093] The above-mentioned embodiments 4-5 can also achieve technical effects equivalent to those of embodiments 1-3, which will not be repeated here. However, the plasma treatment processes used in the above-mentioned embodiments are all O plasma treatments to ensure that the formed transformation zone is not prone to nucleation epitaxial growth.

[0094] Based on the above embodiments, it can be clearly seen that the embodiments provided by the present invention can obtain a size-controllable nanoscale window by controlling the time of BOE wet etching, without the need for advanced high-precision nanoscale lithography equipment and greatly saving costs; through the obtained nanoscale window, a high mask-to-window ratio can be achieved, which can greatly reduce the dislocations of the substrate penetrating into the epitaxial layer and make them easier to merge; the oxide layer acts as a mask during the epitaxial growth process, and the oxide layer will not introduce impurity contamination to the substrate.

[0095] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A method for epitaxial growth on a heterogeneous substrate, characterized in that: include: forming a dielectric layer and a mask layer on a surface of a foreign substrate, wherein the mask layer has a first window, and the first window exposes the surface of the dielectric layer; Over-etching the dielectric layer using the first window to form a second window in the dielectric layer, wherein the second window is wider than the first window and exposes the surface of the foreign substrate; Continue to perform plasma treatment on the foreign substrate using the first window, so that the surface material of the foreign substrate in the corresponding area of ​​the first window is transformed to form a transformed area, and a substrate exposed area is formed between the transformed area and the edge of the second window; The mask layer is removed and the exposed area of ​​the substrate is used for heteroepitaxial growth to obtain a heteroepitaxial layer.

2. The method for epitaxial growth on a heterogeneous substrate according to claim 1, wherein: The dielectric layer is over-etched by wet etching.

3. The method for epitaxial growth on a heterogeneous substrate according to claim 2, wherein: The dielectric layer is made of SiO 2 , and the wet etching solution is BOE solution.

4. The heterogeneous substrate epitaxial growth method according to claim 3, characterized in that: The wet etching time is 10-120s.

5. The method for epitaxial growth on a heterogeneous substrate according to claim 4, wherein: The width of the substrate exposed area is nanometer-scale; And / or, the thickness of the dielectric layer is 10-100 nm; And / or, the width of the first window is 2-10 μm.

6. The method for epitaxial growth on a heterogeneous substrate according to claim 1, wherein: The foreign substrate is selected from metal nitride substrates, and the plasma treatment is selected from O plasma treatment.

7. The method for epitaxial growth on a heterogeneous substrate according to claim 6, wherein: The power of the O plasma treatment is 200-800W, the O2 flow rate is 100-400sccm, and the treatment time is 1-5min.

8. The method for epitaxial growth on a heterogeneous substrate according to claim 1, wherein: The mask layer is made of photoresist, and a method for removing the mask layer includes cleaning with an organic solvent.

9. The heteroepitaxial structure obtained by the heterogeneous substrate epitaxial growth method according to any one of claims 1 to 8, characterized in that: The invention comprises a heterogeneous substrate, a dislocation blocking structure and a heteroepitaxial layer arranged in sequence along the thickness direction. The dislocation blocking structure comprises a dielectric layer covering the surface of the heterogeneous substrate and a transformation zone embedded in the surface of the heterogeneous substrate. The dielectric layer has a second window, the transformation zone is within the second window, and the heteroepitaxial layer is formed by heteroepitaxial growth based on the substrate exposed area between the transformation zone and the edge of the second window.

10. Application of the heteroepitaxial structure according to claim 9 in the fields of laser diodes, power electronic devices, Micro-LED full-color displays, and new energy vehicles.

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