Gallium nitride isotope-based battery transducer device and method of making same

Abstract

This invention provides a battery transducer based on gallium nitride isotopes, comprising: a sapphire substrate, a buffer layer, an epitaxial structure, a P-type electrode, and an N-type electrode. The epitaxial structure includes a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes adjacent first and second regions, with the second region located within the first region of the first N-type epitaxial layer. The second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. Therefore, this battery transducer has a large bandgap, resulting in improved energy conversion efficiency. Furthermore, due to the low density of aluminum gallium nitride, the reflectivity of the radiation source on the surface of the epitaxial layer is low.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices, and more particularly to a battery energy transducer based on gallium nitride isotopes and its fabrication method. Background Technology

[0002] With the rapid development of Micro-Electro-Mechanical Systems (MEMS) technology, radiation-volt-volt (RVV) batteries have become a research hotspot in the field of micro-energy. RVV batteries (also known as radioisotope batteries) utilize the energy-carrying particles (such as radioactive isotope cells) emitted by the decay of radioactive isotopes. particle, Particles or Radiation is a device that converts radiation into electrical energy. However, because radiation sources generally have high energy, first-generation and second-generation semiconductors, represented by silicon (Si), germanium (Ge), and gallium arsenide (GaAs), cannot withstand such radiation, leading to damage to their PN junctions and causing them to fail. Summary of the Invention

[0003] This invention provides a battery energy conversion device based on gallium nitride isotopes and its fabrication method, in order to improve the energy conversion efficiency of the energy conversion device.

[0004] According to a first aspect of the present invention, a battery transducer based on gallium nitride isotopes is provided, comprising: Sapphire substrate; A buffer layer is located on the surface of the sapphire substrate; An epitaxial structure is located on the surface of the buffer layer. The epitaxial structure includes a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes an adjacent first region and a second region. The second N-type epitaxial layer is located in the first region of the first N-type epitaxial layer, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. A plurality of independent P-type electrodes arranged in an array, wherein the P-type electrodes are located on the surface of the second P-type epitaxial layer; An N-type electrode is located on a second region of the first N-type epitaxial layer, the N-type electrode surrounds the second N-type epitaxial layer and there is a gap between the N-type electrode and the second N-type epitaxial layer.

[0005] Optionally, the buffer layer is made of aluminum nitride, and in any two adjacent epitaxial layers of the epitaxial structure, the aluminum content in the lower epitaxial layer is greater than or equal to the aluminum content in the upper epitaxial layer.

[0006] Optionally, the material of the first N-type epitaxial layer is , The material of the second N-type epitaxial layer is , The material of the first P-type epitaxial layer is , The material of the second P-type epitaxial layer is , .

[0007] Optionally, the thickness range of the first N-type epitaxial layer is: The thickness range of the second N-type epitaxial layer is The thickness range of the first P-type epitaxial layer is The thickness range of the second P-type epitaxial layer is The thickness range of the buffer layer is ; The N-type ion doping concentration of the first N-type epitaxial layer is greater than 8 × 10⁻⁶. 16 cm -3 The N-type ion doping concentration of the second N-type epitaxial layer ranges from 1×10⁻⁶. 14 cm -3 ~8×10 14 cm -3 The P-type ion doping concentration of the first P-type epitaxial layer ranges from 1×10⁻⁶. 15 cm -3 ~8×10 15 cm -3 The p-type ion doping concentration of the second p-type epitaxial layer is greater than 10. 19 cm -3 .

[0008] Optionally, the ratio between the sum of the upper surface areas of the plurality of P-type electrodes and the upper surface area of ​​the first P-type epitaxial layer is less than or equal to 70%, and the distance between two adjacent P-type electrodes is [missing information]. The minimum distance between the N-type electrode and the second N-type epitaxial layer is greater than or equal to .

[0009] Optionally, the P-type electrode includes a first nickel metal layer and a first gold metal layer stacked from bottom to top, and the N-type electrode includes a titanium metal layer, an aluminum metal layer, a second nickel metal layer, and a second gold metal layer stacked from bottom to top.

[0010] Optionally, the thickness of the first nickel metal layer ranges from 10 nm to 50 nm, the thickness of the first gold metal layer ranges from 1000 nm to 1500 nm, the thickness of the titanium metal layer ranges from 30 nm to 50 nm, the thickness of the aluminum metal layer ranges from 150 nm to 200 nm, the thickness of the second nickel metal layer ranges from 30 nm to 50 nm, and the thickness of the second gold metal layer ranges from 1000 nm to 1500 nm.

[0011] Optionally, it also includes: a passivation layer located on the surface of the second P-type epitaxial layer exposed by the P-type electrode, the surface of the first N-type epitaxial layer exposed by the N-type electrode, and the sidewalls of the exposed second N-type epitaxial layer, the first P-type epitaxial layer, and the second P-type epitaxial layer.

[0012] According to a second aspect of the present invention, a method for fabricating a battery transducer based on gallium nitride isotopes is provided, comprising: A buffer layer is formed on the surface of the sapphire substrate; An epitaxial structure is formed on the surface of the buffer layer. The epitaxial structure consists of a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes an adjacent first region and a second region. The second N-type epitaxial layer is located in the first region of the first N-type epitaxial layer, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. A plurality of independent P-type electrodes are formed on the surface of the second P-type epitaxial layer and arranged in an array, wherein the P-type electrodes are located on the surface of the second P-type epitaxial layer; An N-type electrode is formed on a second region of the second N-type epitaxial layer, the N-type electrode surrounding the second N rows of epitaxial layer and with a gap between the N-type electrode and the second N-type epitaxial layer.

[0013] Optionally, the method for forming the P-type electrode and the N-type electrode is electron beam evaporation, and after forming the P-type electrode and the N-type electrode, the preparation method further includes: performing rapid thermal annealing on the battery transducer under a nitrogen atmosphere.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: In the gallium nitride isotope-based battery transducer provided by this invention, from bottom to top, there is a sapphire substrate, a buffer layer, and an epitaxial structure. The epitaxial structure is made of aluminum gallium nitride. Therefore, the aluminum gallium nitride-based battery transducer has a large bandgap, enabling it to withstand the energy of a radiation source and achieve a high energy conversion efficiency. Furthermore, due to the low density of aluminum gallium nitride, the reflectivity of the radiation source on the surface of the epitaxial layer is low.

[0015] Furthermore, since the buffer layer is made of aluminum nitride, it minimizes the lattice fit problem between the sapphire substrate and the epitaxial structure. Based on this, because the aluminum content in the lower epitaxial layer is greater than or equal to the aluminum content in the upper epitaxial layer in any two adjacent epitaxial layers of the epitaxial structure, the aluminum content gradually decreases from bottom to top in the epitaxial structure. This gradually reduces the lattice fit between the epitaxial layers and the buffer layer in each epitaxial structure, resulting in better crystal quality of the epitaxial structure. In addition, the gradual decrease in aluminum content from bottom to top in the epitaxial structure allows for perfect activation of the P-type dopant ions in the second P-type epitaxial layer, leading to a significant reduction in the contact resistance between the second P-type epitaxial layer and the P-type electrode, thereby forming a good ohmic contact between the second P-type epitaxial layer and the P-type electrode. Attached Figure Description

[0016] Figures 1-10 This is a schematic cross-sectional view of each step in the fabrication method of a gallium nitride isotope-based battery transducer provided in the embodiments of the present invention. Figure 11 yes Figure 7 The corresponding top view.

[0017] Figure label: 1-Sapphire substrate; 2-Buffer layer; 3-First N-type epitaxial layer; 40 - Initial second N-type epitaxial layer; 4-Second N-type epitaxial layer; 50 - Initial first P-type epitaxial layer; 5-First P-type epitaxial layer; 60 - Initial second P-type epitaxial layer; 6-Second P-type epitaxial layer; 71 - First photoresist layer; 72 - Second photoresist layer; 73 - Third photoresist layer; 74 - Fourth photoresist layer; 8-P type electrode; 9-N type electrode; 100 - Initial passivation layer; 10-Passivation layer. Detailed Implementation

[0018] As described in the background section, since the energy of radiation sources is generally high, first-generation and second-generation semiconductors, represented by silicon (Si), germanium (Ge), and gallium arsenide (GaAs), cannot withstand such irradiation, resulting in damage to their PN junctions and thus failure.

[0019] In view of this, the present invention creatively proposes a battery energy transducer based on gallium nitride isotopes, comprising: Sapphire substrate; A buffer layer is located on the surface of the sapphire substrate; An epitaxial structure is located on the surface of the buffer layer. The epitaxial structure includes a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes an adjacent first region and a second region. The second N-type epitaxial layer is located in the first region of the first N-type epitaxial layer, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. A plurality of independent P-type electrodes arranged in an array, wherein the P-type electrodes are located on the surface of the second P-type epitaxial layer; An N-type electrode is located on a second region of the first N-type epitaxial layer, the N-type electrode surrounds the second N-type epitaxial layer and there is a gap between the N-type electrode and the second N-type epitaxial layer.

[0020] The battery transducer based on aluminum gallium nitride has a large bandgap, enabling it to withstand the energy of a radiation source and achieve a high energy conversion efficiency. Furthermore, the low density of aluminum gallium nitride results in low reflectivity of the radiation source on the epitaxial layer surface.

[0021] To make the above-mentioned objects, features, and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The terms "second," "first," "second," etc., in the specification, claims, and accompanying drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Please combine Figures 1-10 This invention provides a method for fabricating a battery transducer based on gallium nitride isotopes.

[0023] Please refer to Figure 1 A buffer layer 2 is formed on the surface of the sapphire substrate 1.

[0024] The sapphire substrate 1 can be 2-8 inches in size, on which several chips with identical structures can be formed. The size of a single chip can be, for example, 10mm × 10mm. It should be noted that... Figures 1-10 All of them show the structure of a single chip.

[0025] In this embodiment, the material of the buffer layer 2 is aluminum nitride, and the thickness range of the buffer layer 2 is [missing information]. Therefore, it can minimize the lattice compatibility problem between the sapphire substrate 1 and the subsequent aluminum gallium nitride epitaxial structure formed on the surface of the buffer layer 2.

[0026] Please continue to refer to this. Figure 3 An epitaxial structure is formed on the surface of the buffer layer 2. The epitaxial structure consists of a first N-type epitaxial layer 3, a second N-type epitaxial layer 4, a first P-type epitaxial layer 5, and a second P-type epitaxial layer 6, which are stacked sequentially from bottom to top. The second N-type epitaxial layer 4 includes an adjacent first region and a second region. The second N-type epitaxial layer 4 is located in the first region of the first N-type epitaxial layer 3, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride.

[0027] For details, please refer to Figures 1-3 Methods for forming an epitaxial structure on the surface of buffer layer 2 include: Please refer to Figure 1 A first N-type epitaxial layer 3, an initial second N-type epitaxial layer 40, an initial first P-type epitaxial layer 50, and an initial second P-type epitaxial layer 60 are sequentially stacked on the surface of buffer layer 2; please refer to... Figure 2 A patterned first photoresist layer 71 is formed on the surface of the second P-type epitaxial layer 6; please refer to... Figure 3 Using the first photoresist layer 71 as a mask, the second N-type epitaxial layer 4, the first P-type epitaxial layer 5, and the second P-type epitaxial layer 6 on the second region are etched away to form the second N-type epitaxial layer 4, the first P-type epitaxial layer 5, and the second P-type epitaxial layer 6; the first photoresist layer 71 is then removed.

[0028] In this embodiment, the etching depth for removing the second N-type epitaxial layer 4, the first P-type epitaxial layer 5, and the second P-type epitaxial layer 6 on the second region is: .

[0029] In this embodiment, before forming the patterned first photoresist layer 71 on the surface of the second P-type epitaxial layer 6, the surface of the formed epitaxial layer needs to be cleaned using standard RCA cleaning. The specific RCA cleaning process includes: cleaning with sulfuric acid-hydrogen peroxide mixture (SPM) for 300 seconds, cleaning with buffered oxide etchant (BOE) for 80-180 seconds, and organic cleaning with acetone, methanol, isopropanol, and deionized water, and rinsing and drying are performed after cleaning.

[0030] Specifically, in any two adjacent epitaxial layers of the epitaxial structure, the aluminum content in the lower epitaxial layer is greater than or equal to the aluminum content in the upper epitaxial layer. Therefore, the aluminum content in the epitaxial layers gradually decreases from bottom to top, resulting in a gradual decrease in the lattice fit between the epitaxial layers and the buffer layer 2, thus improving the crystal quality of the epitaxial structure. Furthermore, the gradual decrease in aluminum content from bottom to top allows for perfect activation of the P-type doped ions in the second P-type epitaxial layer 6, leading to a significant reduction in the contact resistance between the second P-type epitaxial layer 6 and the P-type electrode 8, thereby forming a good ohmic contact between them.

[0031] In this embodiment, the material of the first N-type epitaxial layer 3 is , The material of the second N-type epitaxial layer 4 is , The material of the first P-type epitaxial layer 5 is , The material of the second P-type epitaxial layer 6 is , .

[0032] In this embodiment, the thickness range of the first N-type epitaxial layer 3 is: The thickness range of the second N-type epitaxial layer 4 is The thickness range of the first P-type epitaxial layer 5 is... The thickness range of the second P-type epitaxial layer 6 is... .

[0033] In this embodiment, the N-type ion doping concentration of the first N-type epitaxial layer 3 is greater than 8 × 10⁻⁶. 16 cm -3 The N-type ion doping concentration of the second N-type epitaxial layer 4 ranges from 1×10⁻⁶. 14 cm -3 ~8×10 14 cm -3 The p-type ion doping concentration of the first p-type epitaxial layer 5 ranges from 1 × 10⁻⁶. 15 cm -3 ~8×10 15 cm-3 The p-type ion doping concentration of the second p-type epitaxial layer 6 is greater than 10. 19 cm -3 .

[0034] In this embodiment, the method for forming the epitaxial structure may be, for example, chemical vapor deposition.

[0035] Please refer to Figure 5 A plurality of independent P-type electrodes 8 are formed on the surface of the second P-type epitaxial layer 6 in an array, and the P-type electrodes 8 are located on the surface of the second P-type epitaxial layer 6.

[0036] In this embodiment, please refer to Figure 4 and Figure 5 The specific methods for forming the P-type electrode 8 include: Please refer to... Figure 4 A patterned second photoresist layer 72 is formed on the exposed upper surface of the epitaxial structure; using the second photoresist layer 72 as a mask, a P-type electrode 8 material layer (not shown) is formed; please refer to... Figure 5 Remove the P-type electrode 8 material layer on the second photoresist layer 72 to form the P-type electrode 8.

[0037] The ratio of the sum of the upper surface areas of several P-type electrodes 8 to the upper surface area of ​​the first P-type epitaxial layer 5 is less than or equal to 70%, and the distance between two adjacent P-type electrodes 8 is... Therefore, it can ensure that the radioactive source can smoothly enter the second P-type epitaxial layer 6 through the area not covered by the P-type electrode 8, that is, enter the transducer.

[0038] In this embodiment, the P-type electrode 8 includes a first nickel metal layer and a first gold metal layer stacked from bottom to top.

[0039] In this embodiment, the thickness of the first nickel metal layer ranges from 10 nm to 50 nm, and the thickness of the first gold metal layer ranges from 1000 nm to 1500 nm.

[0040] Please refer to Figure 7 An N-type electrode 9 is formed on the second region of the second N-type epitaxial layer 4, the N-type electrode 9 surrounds the second N-type epitaxial layer 4 and there is a gap between the N-type electrode 9 and the second N-type epitaxial layer 4.

[0041] In this embodiment, please refer to Figure 6 and Figure 7 The specific methods for forming the N-type electrode 9 include: Please refer to... Figure 6 A patterned third photoresist layer 73 is formed on the surface of the epitaxial structure and the P-type electrode 8; using the third photoresist layer 73 as a mask, an N-type electrode 9 material layer (not shown) is formed; please refer to... Figure 6Remove the third photoresist layer 73 and the N-type electrode 9 material layer on the third photoresist layer 73 to form the N-type electrode 9.

[0042] In this embodiment, the N-type electrode 9 includes a titanium metal layer, an aluminum metal layer, a second nickel metal layer, and a second gold metal layer stacked from bottom to top.

[0043] In this embodiment, the thickness of the titanium metal layer ranges from 30nm to 50nm, the thickness of the aluminum metal layer ranges from 150nm to 200nm, the thickness of the second nickel metal layer ranges from 30nm to 50nm, and the thickness of the second gold metal layer ranges from 1000nm to 1500nm.

[0044] In this embodiment, the method for forming the P-type electrode 8 and the N-type electrode 9 may be, for example, electron beam evaporation.

[0045] In this embodiment, after forming the P-type electrode 8 and the N-type electrode 9, the battery transducer needs to undergo rapid thermal annealing in a nitrogen atmosphere to ensure good ohmic contact between the P-type electrode 8 and the second P-type epitaxial layer 6, and between the N-type electrode 9 and the first N-type epitaxial layer 3. Specifically, the rapid thermal annealing method includes: raising the temperature of the chamber to 600°C in a nitrogen atmosphere at a heating rate of 30~50°C / s, holding at 600°C for 240s, and then rapidly cooling.

[0046] Next, please refer to Figures 8-10 The preparation method further includes forming a passivation layer 10 on the surface of the second P-type epitaxial layer 6 exposed by the P-type electrode 8, the surface of the first N-type epitaxial layer 3 exposed by the N-type electrode 9, and the sidewall surfaces of the exposed second N-type epitaxial layer 4, first P-type epitaxial layer 5, and second P-type epitaxial layer 6.

[0047] In this embodiment, the minimum distance between the N-type electrode and the second N-type epitaxial layer is greater than or equal to... .

[0048] In this embodiment, the specific method for forming the passivation layer 10 includes: Please refer to... Figure 8 An initial passivation layer 100 is deposited on the surface of the epitaxial structure, the surface of the P-type electrode 8, and the surface of the N-type electrode 9; please refer to... Figure 9 A patterned third photoresist layer 73 is formed on the surface of the passivation layer 10; please refer to... Figure 10 Using the third photoresist layer 73 as a mask, the initial passivation layer 100 is etched to form the passivation layer 10; the fourth photoresist layer 74 is removed.

[0049] In this embodiment, the material of the passivation layer 10 may be, for example, silicon nitride, and the thickness of the initial passivation layer 100 is in the range of 80 nm to 100 nm.

[0050] Please refer to Figure 7 and Figure 11 This embodiment also provides a battery transducer based on gallium nitride isotopes, including: a sapphire substrate 1, a buffer layer 2, an epitaxial structure, a P-type electrode 8, and an N-type electrode 9.

[0051] The buffer layer 2 is located on the surface of the sapphire substrate 1.

[0052] In this embodiment, the material of the buffer layer 2 is aluminum nitride, and the thickness range of the buffer layer 2 is [missing information]. .

[0053] The epitaxial structure is located on the surface of the buffer layer 2. The epitaxial structure includes a first N-type epitaxial layer 3, a second N-type epitaxial layer 4, a first P-type epitaxial layer 5, and a second P-type epitaxial layer 6 stacked sequentially from bottom to top. The second N-type epitaxial layer 4 includes an adjacent first region and a second region. The second N-type epitaxial layer 4 is located in the first region of the first N-type epitaxial layer 3, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride.

[0054] In this embodiment, the material of the first N-type epitaxial layer 3 is , The material of the second N-type epitaxial layer 4 is , The material of the first P-type epitaxial layer 5 is , The material of the second P-type epitaxial layer 6 is , .

[0055] In this embodiment, the thickness range of the first N-type epitaxial layer 3 is: The thickness range of the second N-type epitaxial layer 4 is The thickness range of the first P-type epitaxial layer 5 is... The thickness range of the second P-type epitaxial layer 6 is... .

[0056] In this embodiment, the N-type ion doping concentration of the first N-type epitaxial layer 3 is greater than 8 × 10⁻⁶. 16 cm -3 The N-type ion doping concentration of the second N-type epitaxial layer 4 ranges from 1×10⁻⁶. 14 cm -3 ~8×10 14 cm -3 The p-type ion doping concentration of the first p-type epitaxial layer 5 ranges from 1 × 10⁻⁶. 15 cm -3 ~8×10 15 cm -3 The p-type ion doping concentration of the second p-type epitaxial layer 6 is greater than 10.19 cm -3 .

[0057] Several independent P-type electrodes 8 are arranged in an array on the surface of the second P-type epitaxial layer 6.

[0058] In this embodiment, the P-type electrode 8 includes a first nickel metal layer and a first gold metal layer stacked from bottom to top.

[0059] In this embodiment, the thickness of the first nickel metal layer ranges from 10 nm to 50 nm, and the thickness of the first gold metal layer ranges from 1000 nm to 1500 nm.

[0060] The N-type electrode 9 is located on the second region of the first N-type epitaxial layer 3. The N-type electrode 9 surrounds the second N-type epitaxial layer 4 and there is a gap between the N-type electrode 9 and the second N-type epitaxial layer 4.

[0061] In this embodiment, the N-type electrode 9 includes a titanium metal layer, an aluminum metal layer, a second nickel metal layer, and a second gold metal layer stacked from bottom to top.

[0062] In this embodiment, the thickness of the titanium metal layer ranges from 30nm to 50nm, the thickness of the aluminum metal layer ranges from 150nm to 200nm, the thickness of the second nickel metal layer ranges from 30nm to 50nm, and the thickness of the second gold metal layer ranges from 1000nm to 1500nm.

[0063] In this embodiment, please refer to Figure 10 The transducer also includes a passivation layer 10. The passivation layer 10 is located on the surface of the second P-type epitaxial layer 6 exposed by the P-type electrode 8, the surface of the first N-type epitaxial layer 3 exposed by the N-type electrode 9, and the sidewalls of the exposed second N-type epitaxial layer 4, first P-type epitaxial layer 5, and second P-type epitaxial layer 6.

[0064] In summary, in the gallium nitride isotope-based battery transducer provided in this embodiment of the invention, from bottom to top, there is a sapphire substrate 1, a buffer layer 2, and an epitaxial structure. The epitaxial structure is made of aluminum gallium nitride. Therefore, the aluminum gallium nitride-based battery transducer has a large bandgap, enabling it to withstand the energy of a radiation source and achieve a high energy conversion efficiency. Furthermore, due to the low density of aluminum gallium nitride, the reflectivity of the radiation source on the surface of the epitaxial layer is low.

[0065] Furthermore, since the buffer layer 2 is made of aluminum nitride, it minimizes the lattice fit problem between the sapphire substrate 1 and the epitaxial structure. Based on this, because the aluminum content in the lower epitaxial layer is greater than or equal to the aluminum content in the upper epitaxial layer in any two adjacent epitaxial layers, the aluminum content gradually decreases from bottom to top in the epitaxial structure. This gradually reduces the lattice fit between the epitaxial layers and the buffer layer 2, resulting in better crystal quality of the epitaxial structure. In addition, the gradual decrease in aluminum content from bottom to top in the epitaxial structure allows for perfect activation of the P-type doped ions in the second P-type epitaxial layer 6, leading to a significant reduction in the contact resistance between the second P-type epitaxial layer 6 and the P-type electrode 8, thus forming a good ohmic contact between them.

[0066] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A battery energy transducer based on gallium nitride isotopes, characterized in that, include: Sapphire substrate; A buffer layer is located on the surface of the sapphire substrate; An epitaxial structure is located on the surface of the buffer layer. The epitaxial structure includes a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes an adjacent first region and a second region. The second N-type epitaxial layer is located in the first region of the first N-type epitaxial layer, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. A plurality of independent P-type electrodes arranged in an array, wherein the P-type electrodes are located on the surface of the second P-type epitaxial layer; An N-type electrode is located on a second region of the first N-type epitaxial layer, the N-type electrode surrounds the second N-type epitaxial layer and there is a gap between the N-type electrode and the second N-type epitaxial layer.

2. The battery power conversion device based on gallium nitride isotopes according to claim 1, characterized in that, The buffer layer is made of aluminum nitride, and in any two adjacent epitaxial layers of the epitaxial structure, the aluminum content in the lower epitaxial layer is greater than or equal to the aluminum content in the upper epitaxial layer.

3. The battery power transducer based on gallium nitride isotopes according to claim 2, characterized in that, The material of the first N-type epitaxial layer is , The material of the second N-type epitaxial layer is , The material of the first P-type epitaxial layer is , The material of the second P-type epitaxial layer is , .

4. The battery power transducer based on gallium nitride isotopes according to claim 1, characterized in that, The thickness range of the first N-type epitaxial layer is The thickness range of the second N-type epitaxial layer is The thickness range of the first P-type epitaxial layer is The thickness range of the second P-type epitaxial layer is The thickness range of the buffer layer is ; The N-type ion doping concentration of the first N-type epitaxial layer is greater than 8 × 10⁻⁶. 16 cm -3 The N-type ion doping concentration of the second N-type epitaxial layer ranges from 1×10⁻⁶. 14 cm -3 ~8×10 14 cm -3 The P-type ion doping concentration of the first P-type epitaxial layer ranges from 1×10⁻⁶. 15 cm -3 ~8×10 15 cm -3 The p-type ion doping concentration of the second p-type epitaxial layer is greater than 10. 19 cm -3 .

5. The battery power transducer based on gallium nitride isotopes according to claim 1, characterized in that, The ratio between the sum of the upper surface areas of the plurality of P-type electrodes and the upper surface area of ​​the first P-type epitaxial layer is less than or equal to 70%, and the distance between two adjacent P-type electrodes is [missing information]. The minimum distance between the N-type electrode and the second N-type epitaxial layer is greater than or equal to .

6. The battery power transducer based on gallium nitride isotopes according to claim 1, characterized in that, The P-type electrode includes a first nickel metal layer and a first gold metal layer stacked from bottom to top, and the N-type electrode includes a titanium metal layer, an aluminum metal layer, a second nickel metal layer and a second gold metal layer stacked from bottom to top.

7. The battery power transducer based on gallium nitride isotopes according to claim 6, characterized in that, The thickness of the first nickel metal layer ranges from 10 nm to 50 nm, the thickness of the first gold metal layer ranges from 1000 nm to 1500 nm, the thickness of the titanium metal layer ranges from 30 nm to 50 nm, the thickness of the aluminum metal layer ranges from 150 nm to 200 nm, the thickness of the second nickel metal layer ranges from 30 nm to 50 nm, and the thickness of the second gold metal layer ranges from 1000 nm to 1500 nm.

8. The battery power transducer based on gallium nitride isotopes according to claim 1, characterized in that, Also includes: The passivation layer is located on the surface of the second P-type epitaxial layer exposed by the P-type electrode, the surface of the first N-type epitaxial layer exposed by the N-type electrode, and the sidewalls of the exposed second N-type epitaxial layer, first P-type epitaxial layer, and second P-type epitaxial layer.

9. A method for fabricating a battery energy transducer based on gallium nitride isotopes, characterized in that, include: A buffer layer is formed on the surface of the sapphire substrate; An epitaxial structure is formed on the surface of the buffer layer. The epitaxial structure consists of a first N-type epitaxial layer, a second N-type epitaxial layer, a first P-type epitaxial layer, and a second P-type epitaxial layer stacked sequentially from bottom to top. The second N-type epitaxial layer includes an adjacent first region and a second region. The second N-type epitaxial layer is located in the first region of the first N-type epitaxial layer, and the second region surrounds the first region. The material of the epitaxial structure is aluminum gallium nitride. A plurality of independent P-type electrodes are formed on the surface of the second P-type epitaxial layer and arranged in an array, wherein the P-type electrodes are located on the surface of the second P-type epitaxial layer; An N-type electrode is formed on a second region of the second N-type epitaxial layer, the N-type electrode surrounding the second N rows of epitaxial layer and with a gap between the N-type electrode and the second N-type epitaxial layer.

10. The method for fabricating a battery transducer based on gallium nitride isotopes according to claim 9, characterized in that, The method for forming the P-type electrode and the N-type electrode is electron beam evaporation, and after forming the P-type electrode and the N-type electrode, the preparation method further includes: performing rapid thermal annealing on the battery transducer under a nitrogen atmosphere.

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