Silver oxide / gallium oxide heterojunction diode, method for preparing same, and use thereof

Abstract

This invention provides a silver oxide / gallium oxide heterojunction diode, its fabrication method, and its application. The heterojunction diode comprises an n-type silver oxide layer and a p-type gallium oxide layer in contact with each other, wherein the n-type silver oxide layer has a (111) preferred orientation. The silver oxide / gallium oxide heterojunction diode provided by this invention uses silver oxide with a specific (111) preferred orientation to form a pn heterojunction with gallium oxide, exhibiting excellent characteristics of high withstand voltage and low leakage current. In addition, the Schottky barrier height of the interface of this heterojunction is increased to 2.41 eV, which is significantly better than that of traditional Ni anodes. The fabrication method provided by this invention has excellent process stability: the room temperature sputtering process avoids unstable phase decomposition caused by high temperature, obtains a high-purity Ag2O crystal phase, and through condition control, its dominant crystal orientation is (111), providing excellent high voltage withstand and low leakage current characteristics.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology, specifically relating to a silver oxide / gallium oxide heterojunction diode, its preparation method, and its application. Background Technology

[0002] With the development of modern electronic technology, gallium oxide (Ga2O3) has become a key material for next-generation power devices due to its ultra-wide bandgap and high breakdown field strength. However, p-type doping of gallium oxide is difficult to achieve, and existing NiO or Cu2O heterojunction schemes suffer from problems such as poor crystal quality and high leakage current. Furthermore, conventional silver oxide (AgO)... x The difficulty in obtaining a thermodynamically stable pure phase during the preparation process limits its application in high-voltage devices. Summary of the Invention

[0003] The main objective of this invention is to provide a silver oxide / gallium oxide heterojunction diode, its preparation method, and its application to overcome the shortcomings of the prior art.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-voltage, low-leakage silver oxide / gallium oxide heterojunction diode, comprising an n-type silver oxide layer and a p-type gallium oxide layer in contact with each other, wherein the n-type silver oxide layer has a (111) preferred orientation.

[0005] Secondly, the present invention also provides a method for preparing the above-mentioned silver oxide / gallium oxide heterojunction diode, comprising: A p-type gallium oxide layer is provided, and an n-type silver oxide layer is formed on the surface of the p-type gallium oxide layer by magnetron sputtering. The magnetron sputtering temperature is 15-35 °C, the atmosphere is a mixture of Ar and O2, the volume ratio of Ar to O2 in the mixture is 1:(1.5-3), and the pressure is 2-6 mTorr.

[0006] Thirdly, the present invention also provides the application of the above-mentioned silver oxide / gallium oxide heterojunction diode in the fabrication of high-voltage devices.

[0007] Compared with the prior art, the beneficial effects of the present invention include at least the following: The silver oxide / gallium oxide heterojunction diode provided by this invention uses a specific (111) preferred orientation of silver oxide and gallium oxide to form a pn heterojunction, exhibiting excellent characteristics of high withstand voltage and low leakage current. Thanks to the optimized interface quality, the device breakdown voltage reaches as high as 1520 V, and the leakage current is less than 10 V. -11 A / cm 2 Furthermore, the Schottky barrier height at the interface of this heterojunction is increased to 2.41 eV, which is significantly better than that of traditional Ni anodes.

[0008] The preparation method provided by this invention has excellent process stability: the room temperature sputtering process avoids the unstable phase decomposition caused by high temperature, obtains high purity Ag2O crystal phase, and through condition control, makes its dominant crystal orientation (111) orientation, providing excellent high voltage resistance and low leakage current characteristics.

[0009] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic cross-sectional view of a silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention. Figure 2 This is a schematic diagram of a method for fabricating a silver oxide / gallium oxide heterojunction diode according to a typical embodiment of the present invention; Figure 3 This is a schematic diagram of the intermediate product structure of a portion of the fabrication process of a silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention. Figure 4 This is a schematic diagram of the intermediate product structure of another part of the fabrication process of the silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention; Figure 5 This is a schematic diagram of the intermediate product structure of another part of the fabrication process of the silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention; Figure 6 This is a schematic diagram of the intermediate product structure of a further part of the fabrication process of the silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention; Figure 7 This is an XRD pattern of the n-type silver oxide layer of a silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention; Figure 8 This is a test diagram of the forward characteristics of the n-type silver oxide layer of a silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention; Figure 9This is a reverse characteristic test diagram of the n-type silver oxide layer of a silver oxide / gallium oxide heterojunction diode provided in a typical embodiment of the present invention. Detailed Implementation

[0012] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0013] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0014] The meanings of some of the technical terms involved in the following technical solutions are as follows.

[0015] Gallium oxide conductive substrate: made of β-phase gallium oxide (β-Ga2O2) single crystal material.

[0016] Magnetron sputtering: a physical vapor deposition technique that uses high-energy ions to bombard a target, causing target atoms to sputter onto the substrate surface to form a thin film.

[0017] Schottky barrier height (SBH): A key parameter determining the reverse leakage current level of a diode. In this invention, AgO is used. x The Ga2O3 interface properties significantly improved this value.

[0018] Lift-off process: A process that selectively removes excess metal or thin film using a photoresist mask.

[0019] The present invention aims to provide a heterojunction diode based on high-crystallinity p-type silver oxide (Ag₂O) and n-type gallium oxide. A stable Ag₂O phase with a (111) preferred orientation is fabricated using room-temperature magnetron sputtering, achieving a high breakdown voltage >1.5 kV and a voltage <10 kV. -11 A / cm 2 Ultra-low leakage current.

[0020] The embodiments of the present invention first provide a high-voltage, low-leakage silver oxide / gallium oxide heterojunction diode, which includes an n-type silver oxide layer and a p-type gallium oxide layer in contact with each other, wherein the n-type silver oxide layer has a (111) preferred orientation.

[0021] In some embodiments, the silver oxide / gallium oxide heterojunction diode further includes a first electrode and a second electrode, the first electrode being in ohmic contact with the n-type silver oxide layer and the second electrode being in ohmic contact with the p-type gallium oxide layer.

[0022] In some embodiments, the thickness of the n-type silver oxide layer is 500-900 nm.

[0023] In some implementations, the Schottky contact barrier height at the interface between the n-type silver oxide layer and the p-type gallium oxide layer is above 2.3 eV.

[0024] As a typical example, such as Figure 1 As shown, the main structure of the silver oxide / gallium oxide heterojunction diode provided by the present invention includes: ① Gallium oxide layer (conductive substrate): provides n-type conductive channels.

[0025] ② Silver oxide layer: Located on the upper surface of the substrate, mainly composed of Ag2O crystals with (111) orientation.

[0026] ③ Electrode: The upper surface is the top electrode (first electrode), and the lower surface is the bottom electrode (second electrode, which is an ohmic contact).

[0027] Embodiments of the present invention also provide a method for fabricating a silver oxide / gallium oxide heterojunction diode according to any of the above embodiments, which includes the following steps: A p-type gallium oxide layer is provided, and an n-type silver oxide layer is formed on the surface of the p-type gallium oxide layer by magnetron sputtering. The magnetron sputtering temperature is 15-35 °C, the atmosphere is a mixture of Ar and O2, the volume ratio of Ar to O2 in the mixture is 1:(1.5-3), and the pressure is 2-6 mTorr.

[0028] In some embodiments, the fabrication method may further include the step of forming a first electrode and a second electrode that are in ohmic contact with the n-type silver oxide layer and the p-type gallium oxide layer, respectively.

[0029] In some embodiments, the preparation method specifically includes the following process flow: The second electrode is formed on the first surface of the p-type gallium oxide layer by a metal deposition process; A photoresist layer is formed on the second side of the p-type gallium oxide layer; The photoresist layer is exposed and developed to form an opening region; The p-type gallium oxide layer is formed in the opening region and on the surface of the remaining photoresist layer; The first electrode is formed on the surface of the p-type gallium oxide layer by a metal deposition process; The remaining photoresist layer is stripped away to obtain a silver oxide / gallium oxide heterojunction diode.

[0030] In some implementation schemes, the following process flow is also included: After forming the second electrode, the combination of the second electrode and the p-type gallium oxide layer is annealed at 400-550°C.

[0031] like Figure 2 As shown, as a typical example, the preparation process of the preparation method provided by the present invention mainly includes the following steps: ① Provide a gallium oxide conductive substrate; ② Deposit the bottom electrode and anneal it to form an ohmic contact; ③ Photolithography defines the anode region; ④ Key steps: At room temperature, a silver oxide layer was deposited by magnetron sputtering using an Ar:O2 (1:2) mixture, 200W power, and 4 mTorr gas pressure; ⑤ Deposit the top electrode metal; ⑥ Remove the photoresist to form the final device.

[0032] Finally, embodiments of the present invention also provide the application of the silver oxide / gallium oxide heterojunction diode provided in any of the above embodiments in the fabrication of high-voltage devices.

[0033] In some implementations, the high-voltage device operates at a voltage of 1000-1500 V.

[0034] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0035] Example 1 This embodiment illustrates the fabrication process of the above-mentioned silver oxide / gallium oxide heterojunction diode, as detailed below: like Figure 3 As shown, a gallium oxide substrate is provided, a Ti / Au bottom electrode is deposited on the back side, and rapid thermal annealing is performed at 470°C.

[0036] like Figure 4 As shown, a photolithography process is performed on the front side to expose the anode region.

[0037] like Figure 5 As shown, silver oxide was grown on a patterned substrate by magnetron sputtering. The process parameters were: room temperature (around 25°C), power 200 W, gas pressure 4 mTorr, atmosphere Ar:O2 = 1:2 (deposition time 60 min, final thickness 700 nm).

[0038] like Figure 6 As shown, a Ni / Au / Ni top electrode is deposited and a stripping process is performed to complete the device fabrication.

[0039] The silver oxide thin film prepared by the above method was subjected to XRD test, and the results are as follows: Figure 7 As shown, it exhibits obvious cubic Ag2O (111) diffraction peaks.

[0040] For device performance testing, electrical tests were performed on the fabricated Ag₂O / Ga₂O₃ diodes. Forward characteristics are as follows: Figure 8 As shown, the device exhibits excellent rectification characteristics, with a turn-on voltage of approximately 2.21 V and a rectification ratio exceeding 10. 13 Reverse characteristics such as Figure 9 As shown, the device did not experience hard breakdown at -1500 V, and the final breakdown voltage reached 1520 V. Compared with existing β-Ni devices, both forward and reverse performance have been significantly improved.

[0041] Comparative Example 1 This comparative example is largely the same as Example 1, with the main difference being: The preparation conditions of the silver oxide layer were changed, with the temperature adjusted to 100℃ while keeping other conditions unchanged.

[0042] The resulting silver oxide layer is (200) oriented. The final device performance is as follows: turn-on voltage is 1.85 V, breakdown voltage is 980 V, and leakage current is 10 V / V. -9 Compared to Example 1, the breakdown voltage was reduced by 35.5% and the leakage current increased by two orders of magnitude (A / cm²).

[0043] Comparative Example 2 This comparative example is largely the same as Example 1, with the main difference being: The preparation conditions of the silver oxide layer were changed by adjusting the volume ratio of Ar to O2 to 1:1, while keeping other conditions unchanged.

[0044] The obtained silver oxide layer has a (110) crystal orientation. The final device performance is as follows: turn-on voltage is 1.92 V, breakdown voltage is 1050 V, and leakage current is 5 × 10⁻⁶. -10 Compared to Example 1, the breakdown voltage was reduced by 31.0% and the leakage current increased by one order of magnitude (A / cm²).

[0045] Comparative Example 3 This comparative example is largely the same as Example 1, with the main difference being: The preparation conditions of the silver oxide layer were changed by adjusting the volume ratio of Ar to O2 to 1:4, while keeping other conditions unchanged.

[0046] The resulting silver oxide layer was amorphous. The final device performance was as follows: turn-on voltage of 1.65 V, breakdown voltage of 720 V, and leakage current of 10 V / V. -8Compared to Example 1, the breakdown voltage was reduced by 52.6% and the leakage current increased by 3 orders of magnitude (A / cm²).

[0047] Comparative Example 4 This comparative example is largely the same as Example 1, with the main difference being: The silver oxide layer was deposited by laser sputtering under the following conditions: laser power 3 J / cm², frequency 10 Hz, and oxygen partial pressure 10 mTorr.

[0048] The resulting silver oxide layer was polycrystalline with a mixed orientation. The final device performance was as follows: turn-on voltage of 1.78 V, breakdown voltage of 850 V, and leakage current of 10 V / V. -9 Compared to Example 1, the breakdown voltage was reduced by 44.1% and the leakage current increased by two orders of magnitude (A / cm²).

[0049] Example 2 This embodiment is largely the same as Example 1, except that the preparation conditions for the silver oxide layer are different: The process parameters are as follows: the magnetron sputtering temperature is 15 °C, the atmosphere is a mixture of Ar and O2 with a volume ratio of Ar to O2 of 1:1.5, the gas pressure is 6 mTorr, and the final deposition thickness is 500 nm.

[0050] Example 3 This embodiment is largely the same as Example 1, except that the preparation conditions for the silver oxide layer are different: The process parameters are as follows: the magnetron sputtering temperature is 35 °C, the atmosphere is a mixture of Ar and O2 with a volume ratio of Ar to O2 of 1:3, the gas pressure is 2 mTorr, and the final deposition thickness is 900 nm.

[0051] The above Examples 2-3 can all form a silver oxide layer with a preferred orientation of 111, and the device performance obtained is similar to that of Example 1, all having excellent high voltage resistance and low leakage current characteristics, which will not be described in detail here.

[0052] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-voltage, low-leakage silver oxide / gallium oxide heterojunction diode, characterized in that, It includes an n-type silver oxide layer and a p-type gallium oxide layer in contact with each other, wherein the n-type silver oxide layer has a (111) preferred orientation.

2. The silver oxide / gallium oxide heterojunction diode according to claim 1, characterized in that, It also includes a first electrode and a second electrode, wherein the first electrode is in ohmic contact with the n-type silver oxide layer and the second electrode is in ohmic contact with the p-type gallium oxide layer.

3. The silver oxide / gallium oxide heterojunction diode according to claim 1, characterized in that, The thickness of the n-type silver oxide layer is 500-900 nm.

4. The silver oxide / gallium oxide heterojunction diode according to claim 1, characterized in that, The Schottky contact barrier height at the interface between the n-type silver oxide layer and the p-type gallium oxide layer is above 2.3 eV.

5. The method for fabricating the silver oxide / gallium oxide heterojunction diode according to any one of claims 1-4, characterized in that, include: A p-type gallium oxide layer is provided, and an n-type silver oxide layer is formed on the surface of the p-type gallium oxide layer by magnetron sputtering. The magnetron sputtering temperature is 15-35 °C, the atmosphere is a mixture of Ar and O2, the volume ratio of Ar to O2 in the mixture is 1:(1.5-3), and the pressure is 2-6 mTorr.

6. The preparation method according to claim 5, characterized in that, It also includes the steps of forming a first electrode and a second electrode that are in ohmic contact with the n-type silver oxide layer and the p-type gallium oxide layer, respectively.

7. The preparation method according to claim 6, characterized in that, Specifically, it includes: The second electrode is formed on the first surface of the p-type gallium oxide layer by a metal deposition process; A photoresist layer is formed on the second side of the p-type gallium oxide layer; The photoresist layer is exposed and developed to form an opening region; The p-type gallium oxide layer is formed in the opening region and on the surface of the remaining photoresist layer; The first electrode is formed on the surface of the p-type gallium oxide layer by a metal deposition process; The remaining photoresist layer is stripped away to obtain a silver oxide / gallium oxide heterojunction diode.

8. The preparation method according to claim 7, characterized in that, Also includes: After forming the second electrode, the combination of the second electrode and the p-type gallium oxide layer is annealed at 400-550°C.

9. The application of the silver oxide / gallium oxide heterojunction diode according to any one of claims 1-4 in the fabrication of high-voltage devices.

10. The application according to claim 9, characterized in that, The operating voltage of the high-voltage device is 1000-1500V.

Images