Epitaxial wafer and optoelectronic device
By using a combined structure of the first nitride buffer layer, a pattern structure layer and a nitride fill layer in the epitaxial sheet, the low efficiency and leakage current problems caused by dislocation during heteroepitaxy are solved by the use of a combined structure of the first nitride buffer layer, a pattern structure layer and a nitride filling layer in the epitaxial sheet, the problems of low efficiency and leakage current caused by dislocation in the heteroepitaxy process of the Group III nitride semiconductor material are solved. , achieving higher crystal quality and radiation recombination efficiency, extending device life and suitable for large-size applications.
Patent Information
- Application Number
- CN202420376274.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-28
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2034-02-28
AI Technical Summary
Group III nitride semiconductor materials are dislocations due to lattice constants and thermal mismatch during heteroepitaxy, resulting in low device efficiency and increased leakage current, affecting their application life.
Using an epitaxial sheet structure including a first nitride buffer layer, a pattern structure layer, a nitride fill layer and a second nitride buffer layer, dislocation extension is blocked through the first nanopore of the pattern structure layer, and through the nitride fill layer The lateral epitaxial and crystal quality of the second nitride buffer layer are improved, and the stress is adjusted to improve the radiation recombination efficiency of the luminescent layer.
Effectively block dislocation extension, improves the crystal quality of the epitaxial sheet and the radiation recombination efficiency of the luminescent layer, extends the device life and makes it more suitable for large-size applications.
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Figure CN222126569U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of semiconductor devices, and particularly relates to an epitaxial wafer and an optoelectronic device. Background Art
[0002] III-V group nitride semiconductor materials have been widely used in optoelectronic devices, optoelectronic integration, ultra-high-speed microelectronic devices, and ultra-high-frequency microwave devices and circuits, and have broad prospects. Since III-group nitrides are generally grown heteroepitaxially on heterogeneous substrates such as sapphire or SiC, the lattice constants and thermal mismatches between different materials will produce dislocations or defects, which will extend upward with the growth of the epitaxial layer. These dislocations will appear as non-radiative recombination centers when the device is working and affect the efficiency of the device. At the same time, they will act as leakage channels to increase the leakage current and cause the device to age rapidly, affecting the working efficiency and life of the device, which restricts its application in the field of semiconductor electronics. Utility Model Content
[0003] The main purpose of the utility model is to provide an epitaxial wafer and an optoelectronic device, thereby overcoming the deficiencies in the prior art.
[0004] In order to achieve the above-mentioned utility model purpose, the technical solution adopted by the utility model includes:
[0005] The utility model provides an epitaxial wafer, comprising a heterogeneous substrate, a buffer structure layer and an epitaxial layer stacked in sequence along a selected direction, wherein the buffer structure layer comprises:
[0006] A first nitride buffer layer is stacked on the foreign substrate along the selected direction;
[0007] A graphic structure layer, stacked on the first nitride buffer layer along the selected direction, the graphic structure layer having at least one first nanopore;
[0008] A nitride filling layer, wherein the nitride filling layer is disposed on the pattern structure layer, and a portion of the nitride filling layer is also disposed in the first nanopore and in contact with the first nitride buffer layer;
[0009] A covering structure layer, disposed on the graphic structure layer and the nitride filling layer;
[0010] The second nitride buffer layer is disposed on the cover structure layer.
[0011] The utility model provides an epitaxial wafer with nanopores, which blocks dislocation extension from a heterogeneous substrate through a first nanopore of a graphic structure layer, and a nitride filling layer arranged in the first nanopore of the graphic structure layer and on the graphic structure layer improves the lateral epitaxy of a second nitride buffer layer, thereby improving the crystal quality of the epitaxial wafer and alleviating the leakage problem of the epitaxial wafer.
[0012] Furthermore, the thickness of the first nitride buffer layer is 100 nm to 500 nm.
[0013] Furthermore, the graphic structure layer has a plurality of the first nanoholes, and the nitride filling layer includes a plurality of filling structures, the plurality of filling structures are distributed at intervals, a portion of each of the filling structures is correspondingly arranged in a first nanohole and in contact with the first nitride buffer layer, and the other portion is arranged on the graphic structure layer.
[0014] Furthermore, there is a gap between adjacent filling structures, and a portion of the graphic structure layer is exposed from the gap, and a portion of the covering structure layer is distributed in the gap and covered on the graphic structure layer, or a portion of the covering structure layer and a portion of the second nitride buffer layer are distributed in the gap and arranged on the graphic structure layer.
[0015] Furthermore, the filling structure includes a first part, a second part and a third part sequentially arranged along the selected direction, the first part is arranged in the first nanohole, the second part is arranged on the first part and the graphic structure layer, and the third part is arranged on the second part.
[0016] Furthermore, the area of the radial cross section of the second portion is greater than the area of the radial cross section of the first portion, and the area of the radial cross section of the third portion gradually decreases in a direction away from the second portion.
[0017] Furthermore, a surface of the nitride filling layer facing away from the first nitride buffer layer is a discontinuous concave-convex structure.
[0018] Furthermore, the covering structure layer is covered on the surfaces of the second part and the third part.
[0019] Furthermore, the first nanohole penetrates the graphic structure layer along the selected direction.
[0020] Furthermore, the thickness of the graphic structure layer is 50nm to 300nm.
[0021] Furthermore, the first nanopore is a cylindrical hole, and the pore diameter of the first nanopore is 100nm to 1000nm.
[0022] Furthermore, the pattern structure layer includes a patterned silicon oxide layer.
[0023] Furthermore, the thickness of the nitride filling layer is 0.5 μm to 1 μm.
[0024] Furthermore, the covering structure layer includes a plurality of second nanopores, the second nanopores penetrate the covering structure layer along the thickness direction of the covering structure layer, and a portion of the second nitride buffer layer is also disposed in the second nanopores and in contact with the filling structure layer.
[0025] Furthermore, the covering structure layer includes a porous silicon nitride layer, and the pore diameter of the second nanopore is 5 nm to 150 nm.
[0026] Furthermore, the epitaxial layer includes an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer stacked along the selected direction.
[0027] Furthermore, the covering structure layer arranged on the nitride filling layer utilizes its own second nanopores to strengthen the lateral epitaxy of the second nitride buffer layer, thereby improving the crystal quality of the second nitride buffer layer and blocking the dislocations from extending upward into the epitaxial layer (mainly the light-emitting layer); and the gap structure between the nitride filling layers also modulates the stress of the epitaxial wafer and improves the radiation recombination efficiency of the nitride light-emitting layer, thereby making it easier to obtain large-size epitaxial wafers.
[0028] Furthermore, the thickness of the covering structure layer is 2nm to 50nm.
[0029] Furthermore, the thickness of the first nitride buffer layer is 100 nm to 500 nm.
[0030] Furthermore, the thickness of the second nitride buffer layer is 1 μm to 5 μm.
[0031] Since the nitride filling layer includes a plurality of filling structures arranged at intervals, that is, the nitride filling layer has gaps, the setting of the gaps adjusts the stress of the epitaxial wafer, improves the radiation recombination efficiency of the light-emitting layer, and makes it easier to obtain a large-sized epitaxial wafer.
[0032] On the other hand, the utility model further provides an optoelectronic device, comprising the epitaxial wafer.
[0033] Compared with the prior art, the advantages of the utility model include:
[0034] The epitaxial wafer provided by the utility model blocks the dislocation extension from the heterogeneous substrate through the first nanopore of the graphic structure layer, and the nitride filling layer arranged in the first nanopore of the graphic structure layer and on the graphic structure layer improves the lateral epitaxy of the second nitride buffer layer, improves the crystal quality of the epitaxial wafer, and improves the leakage problem of the epitaxial wafer.
[0035] The epitaxial wafer provided by the utility model, the covering structure layer arranged on the nitride filling layer utilizes its own first nanopores to further strengthen the lateral epitaxy of the second nitride buffer layer, further improves the crystal quality of the second nitride buffer layer, and blocks the dislocations from extending upward into the epitaxial layer (mainly the light-emitting layer); and the gap structure between the nitride filling layers also adjusts the stress of the epitaxial wafer, improves the radiation recombination efficiency of the nitride light-emitting layer, thereby making it easier to obtain large-sized epitaxial wafers. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0037] Figure 1 It is a structural schematic diagram of an epitaxial wafer provided by the utility model;
[0038] Figure 2 It is a top view of a graphic structure layer in an epitaxial wafer provided by the utility model;
[0039] Figure 3 It is a partial structural schematic diagram of an epitaxial wafer provided by the utility model;
[0040] Figure 4 It is a partial structural schematic diagram of another epitaxial wafer provided by the utility model;
[0041] Figure 5 It is a structural schematic diagram of another epitaxial wafer provided by the utility model. DETAILED DESCRIPTION
[0042] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the utility model after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.
[0043] See also Figure 1 , Figure 1 It is a structural schematic diagram of an epitaxial wafer provided by the utility model, which comprises a heterogeneous substrate 100, a buffer structure layer 200 and an epitaxial layer 300 which are sequentially stacked along a selected direction, wherein the selected direction can be understood as the longitudinal direction or thickness direction of the epitaxial wafer, etc.
[0044] The foreign substrate 100 may be a sapphire substrate, a silicon substrate, a silicon carbide substrate, or the like.
[0045] The buffer structure layer 200 includes a first nitride buffer layer 210, a graphic structure layer 220, a nitride filling layer 230, a covering structure layer 240 and a second nitride buffer layer 250. The first nitride buffer layer 210 and the second nitride buffer layer 250 are arranged along a selected direction, and the graphic structure layer 220, the nitride filling layer 230 and the covering structure layer 240 are arranged between the first nitride buffer layer 210 and the second nitride buffer layer 250.
[0046] For further information, please also refer to Figure 1 and Figure 2 A first nitride buffer layer 210 is stacked on a foreign substrate 100 along a selected direction, a graphic structure layer 220 is stacked on the first nitride buffer layer 210 along a selected direction, and the graphic structure layer 220 has a plurality of first nanoholes 221 distributed at intervals; a nitride filling layer 230 is disposed on the graphic structure layer 220, and a portion of the nitride filling layer 230 is also disposed in the first nanoholes 221 and in contact with the first nitride buffer layer 210, a covering structure layer 240 is disposed on the graphic structure layer 220 and the nitride filling layer 230, and a second nitride buffer layer 250 is disposed on the graphic structure layer 220 and the covering structure layer 240.
[0047] The utility model blocks the dislocation extension from the heterogeneous substrate through the first nanopore of the graphic structure layer, and the nitride filling layer arranged in the first nanopore of the graphic structure layer and on the graphic structure layer improves the lateral epitaxy of the second nitride buffer layer, improves the crystal quality of the epitaxial wafer, and improves the leakage problem of the epitaxial wafer.
[0048] In a specific embodiment, the first nitride buffer layer 210 is a group III nitride buffer layer, such as a GaN buffer layer or an AlGaN buffer layer. The thickness of the first nitride buffer layer 210 is 100 nm to 500 nm.
[0049] In a specific embodiment, the thickness of the graphic structure layer 220 is 50nm to 300nm; the graphic structure layer 220 has a plurality of first nanopores 221, each of which penetrates the graphic structure layer 220 along the thickness direction of the graphic structure layer 220, and the first nanopore 221 can be a cylindrical hole, and the pore size of the first nanopore 221 is 100nm to 1000nm. Specifically, the graphic structure layer 220 can be a patterned silicon oxide layer, and the plurality of first nanopores 221 can be distributed in an array.
[0050] In a specific implementation, please refer to Figure 1 and Figure 3The nitride filling layer 230 includes a plurality of filling structures, and the plurality of filling structures are distributed at intervals. A portion of each filling structure is correspondingly arranged in a first nanohole 221 and in contact with the first nitride buffer layer 210, and another portion is arranged on the graphic structure layer 220; and there are gaps between adjacent filling structures, and a portion of the graphic structure layer 220 is exposed from the gap. Correspondingly, the covering structure layer 240 is a non-continuous structure, and the covering structure layer 240 includes a plurality of covering structures 241, and each covering structure 241 is correspondingly covered with a filling structure. Part of the covering structure layer 240 and part of the second nitride buffer layer 250 are distributed in the gap and arranged on the graphic structure layer 220.
[0051] In another specific embodiment, please refer to Figure 1 and Figure 4 The covering structure layer 240 is a continuous thin film structure. The covering structure layer 240 is continuously covered on the graphic structure layer 220 and the nitride filling layer 230 . The second nitride buffer layer 250 is disposed on the covering structure layer 240 .
[0052] Furthermore, each filling structure includes a first part 231, a second part 232 and a third part 233 arranged in sequence along a selected direction, the first part 231 is arranged in the first nanohole 221, the second part 232 is arranged on the first part 231 and the graphic structure layer 220, and the third part 233 is arranged on the second part 232.
[0053] Furthermore, the area of the radial cross section of the second portion 232 is greater than the area of the radial cross section of the first portion 231 , and the area of the radial cross section of the third portion 233 gradually decreases in a direction away from the second portion 232 .
[0054] As mentioned above, the nitride filling layer 230 is composed of a plurality of filling structures distributed at intervals. Therefore, the surface of the nitride filling layer 230 facing away from the first nitride buffer layer 210 is a non-continuous concave-convex structure, which can also be understood as a graphic structure.
[0055] The nitride filling layer 230 is a group III nitride filling layer, for example, a GaN filling layer or an AlGaN filling layer. Specifically, the thickness of the nitride filling layer 230 is 0.5-1 μm.
[0056] In a specific embodiment, the covering structural layer 240 is covered on the surface of the second part 232 and the third part 233, and the covering structural layer 240 has a contoured structure that matches the second part 232 and the third part 233 of the nitride filling layer 230 as a whole. It can be understood that the covering structural layer 240 as a whole is a non-continuous structural layer.
[0057] Furthermore, the covering structure layer 240 has a plurality of second nanopores, and the second nanopores penetrate the covering structure layer 240 along its thickness direction. The second nitride buffer layer 250 is continuously covered on the graphic structure layer 220 and the covering structure layer 240, and a part of the second nitride buffer layer 250 is also provided with second nanopores in the covering structure layer 240, and the surface of the second nitride buffer layer 250 facing away from the covering structure layer 240 is a continuous and flat surface.
[0058] The thickness of the covering structure layer 240 is 2nm~50nm, and the pore size of the second nanopores contained in the porous silicon nitride layer is 5nm~150nm. Exemplarily, the covering structure layer 240 can be a porous silicon nitride layer; the second nitride buffer layer 250 is a group III nitride buffer layer, for example, it can be a GaN buffer layer or an AlGaN buffer layer, and the thickness of the second nitride buffer layer 250 is 1μm~5μm.
[0059] In a specific implementation, please refer to Figure 1 and Figure 5 The epitaxial layer 300 is a group III nitride epitaxial layer, and the epitaxial layer 300 includes an n-type semiconductor layer 310, a light emitting layer 320, and a p-type semiconductor layer 330 stacked on the second nitride buffer layer 250 along a selected direction.
[0060] The n-type semiconductor layer 310 may be an n-type Al x Ga 1-x N layer, 0≤x≤1; the n-type semiconductor layer may be Si-doped, and the Si doping concentration of the n-type semiconductor layer 310 is 1×10 18 cm -3 ~8×10 18 cm -3 ; The thickness of the n-type semiconductor layer 310 is 2μm to 10μm.
[0061] The light-emitting layer 320 may include 2 to 10 periodic cycles of overlapping growth of a quantum well layer with a thickness of 1 to 6 nm and a quantum barrier layer with a thickness of 6 to 25 nm; the quantum well layer and the quantum barrier layer are both group III nitride structure layers, and illustratively, the quantum well layer may be an InGaN well layer, a GaN well layer or an AlGaN well layer, and the quantum barrier layer may be an InGaN barrier layer, a GaN barrier layer or an AlGaN barrier layer.
[0062] The p-type semiconductor layer 330 may be a p-type Al y Ga 1-y N layer, 0≤y≤1; the p-type semiconductor layer 330 may be Mg-doped, and the Mg doping concentration of the p-type semiconductor layer 330 is 1×10 19 cm -3 ~1×10 21 cm-3 ; The thickness of the p-type semiconductor layer 330 is 20nm to 300nm.
[0063] The utility model provides an epitaxial wafer with a nanopore structure, in which a covering structure layer arranged on a nitride filling layer utilizes its own second nanopores to further strengthen the lateral epitaxy of the second nitride buffer layer, further improves the crystal quality of the second nitride buffer layer, blocks dislocations from extending upward into the epitaxial layer (mainly the light-emitting layer), and the gap structure between the nitride filling layers also modulates the stress of the epitaxial wafer, improves the radiation recombination efficiency of the light-emitting layer, thereby making it easier to obtain large-sized epitaxial wafers.
[0064] It should be understood that the above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.
Claims
1. An epitaxial wafer, comprising a heterogeneous substrate, a buffer structure layer and an epitaxial layer stacked in sequence along a selected direction, characterized in that: The buffer structure layer comprises: A first nitride buffer layer is stacked on the foreign substrate along the selected direction; A graphic structure layer, stacked on the first nitride buffer layer along the selected direction, the graphic structure layer having a first nanopore; A nitride filling layer, wherein the nitride filling layer is disposed on the pattern structure layer, and a portion of the nitride filling layer is also disposed in the first nanopore and in contact with the first nitride buffer layer; A covering structure layer, disposed on the graphic structure layer and the nitride filling layer; The second nitride buffer layer is disposed on the cover structure layer.
2. The epitaxial wafer according to claim 1, characterized in that: The graphic structure layer has a plurality of the first nanoholes, and the nitride filling layer includes a plurality of filling structures. A portion of each of the filling structures is correspondingly arranged in a first nanohole and in contact with the first nitride buffer layer, and another portion is arranged on the graphic structure layer.
3. The epitaxial wafer according to claim 2, characterized in that: There is a gap between adjacent filling structures, part of the graphic structure layer is exposed from the gap, part of the covering structure layer is distributed in the gap and covered on the graphic structure layer, or part of the covering structure layer and part of the second nitride buffer layer are distributed in the gap and arranged on the graphic structure layer.
4. The epitaxial wafer according to claim 3, characterized in that: The filling structure includes a first part, a second part and a third part sequentially arranged along the selected direction, the first part is arranged in the first nanohole, the second part is arranged on the first part and the graphic structure layer, and the third part is arranged on the second part.
5. The epitaxial wafer according to claim 4, characterized in that: The area of the radial cross section of the second portion is greater than that of the radial cross section of the first portion, and the area of the radial cross section of the third portion gradually decreases in a direction away from the second portion.
6. The epitaxial wafer according to claim 4 or 5, characterized in that: The surface of the nitride filling layer facing away from the first nitride buffer layer is a discontinuous concave-convex structure.
7. The epitaxial wafer according to claim 4 or 5, characterized in that: The covering structure layer is covered on the surfaces of the second portion and the third portion.
8. The epitaxial wafer according to claim 1 or 3, characterized in that: The first nanohole penetrates the pattern structure layer along the selected direction.
9. The epitaxial wafer according to claim 1 or 3, characterized in that: The thickness of the graphic structure layer is 50nm to 300nm.
10. The epitaxial wafer according to claim 1 or 3, characterized in that: The pore diameter of the first nanopore is 100 nm to 1000 nm.
11. The epitaxial wafer according to claim 1 or 3, characterized in that: The thickness of the first nitride buffer layer is 100 nm to 500 nm.
12. The epitaxial wafer according to claim 1 or 3, characterized in that: The thickness of the nitride filling layer is 0.5 μm to 1 μm.
13. The epitaxial wafer according to claim 1 or 3, characterized in that: The thickness of the second nitride buffer layer is 1 μm to 5 μm.
14. The epitaxial wafer according to claim 2, characterized in that: The covering structure layer includes a plurality of second nanopores, wherein the second nanopores penetrate the covering structure layer along a thickness direction of the covering structure layer, and a portion of the second nitride buffer layer is also disposed within the second nanopores and in contact with the nitride filling layer.
15. The epitaxial wafer according to claim 14, characterized in that: The pore diameter of the second nanopore is 5 nm to 150 nm.
16. The epitaxial wafer according to claim 2, characterized in that: The thickness of the covering structure layer is 2nm-50nm.
17. An optoelectronic device, characterized in that: include: The epitaxial wafer according to any one of claims 1 to 16.