A schottky barrier diode with a mixed anode and a mixed cathode, and a preparation method and application thereof

Abstract

The application discloses a Schottky barrier diode containing a mixed anode and a mixed cathode and a preparation method and application thereof. The Schottky barrier diode containing the mixed anode and the mixed cathode comprises a substrate, an AlN nucleation layer, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer and a passivation layer which are sequentially arranged in layers, and further comprises a first cathode metal electrode, a first anode metal electrode, a GaN cap layer, an anode field plate, a second cathode metal electrode and a second anode metal electrode. The Schottky barrier diode has the advantages of a large inflection point voltage, a small opening voltage and high reliability, and is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a Schottky barrier diode containing a hybrid anode and a hybrid cathode, its fabrication method, and its application. Background Technology

[0002] Schottky barrier diodes, also known as hot-carrier diodes, are indispensable devices in most power electronic products. They require low turn-on voltage, specific on-resistance, low reverse leakage current, and high breakdown voltage to reduce power loss during operation. Gallium nitride (GaN) has a large bandgap and high electron mobility, making it a promising semiconductor material with broad application prospects. Si / GaN-based Schottky barrier diodes combine good performance with low cost, showing great commercial potential and attracting widespread attention. However, existing Si / GaN-based Schottky barrier diodes generally suffer from low inflection point voltage and excessively high turn-on voltage, leading to easy failure and insufficient power in many applications, making it difficult to fully meet practical application requirements.

[0003] Therefore, it is of great significance to develop a Schottky barrier diode with a large inflection point voltage, a small turn-on voltage, and high reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a Schottky barrier diode containing a mixed anode and a mixed cathode, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A Schottky barrier diode comprising a hybrid anode and a hybrid cathode includes a substrate, an AlN nucleation layer, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer, and a passivation layer stacked sequentially. It also includes a first cathode metal electrode, a first anode metal electrode, a GaN capping layer, an anode field plate, a second cathode metal electrode, and a second anode metal electrode. The first cathode metal electrode is disposed on the side of the AlGaN barrier layer away from the GaN channel layer. The first anode metal electrode is disposed on the side of the GaN channel layer away from the GaN buffer layer and is in contact with the AlGaN barrier layer, the GaN capping layer, and the anode field plate. The GaN capping layer is disposed on the side of the AlGaN barrier layer away from the GaN channel layer and is in contact with the passivation layer. The anode field plate is disposed on the side of the GaN capping layer away from the AlGaN barrier layer. The second cathode metal electrode is disposed inside the first anode metal electrode and is in contact with the GaN channel layer. The second anode metal electrode is disposed on the side of the AlGaN barrier layer away from the GaN channel layer and is in contact with the first cathode metal electrode and the passivation layer.

[0007] Preferably, the substrate is one of a Si substrate, a GaAs substrate, or a sapphire substrate.

[0008] Preferably, the thickness of the AlN nucleation layer is 0.5 nm to 1.5 nm.

[0009] Preferably, the thickness of the GaN buffer layer is 200nm to 400nm.

[0010] Preferably, the thickness of the GaN channel layer is 100nm to 300nm.

[0011] Preferably, the thickness of the AlGaN barrier layer is 10 nm to 30 nm.

[0012] Preferably, the thickness of the passivation layer is 40 nm to 80 nm.

[0013] Preferably, the passivation layer comprises Si3N4.

[0014] Preferably, the width of the first cathode metal electrode is 3μm to 6μm.

[0015] Preferably, the first cathode metal electrode comprises Ti, Al, Ni, and Au.

[0016] Preferably, the width of the first anode metal electrode is 5μm to 8μm.

[0017] Preferably, the first anode metal electrode comprises Ni and Au.

[0018] Preferably, the distance between the first cathode metal electrode and the first anode metal electrode (the distance between the left edge of the first cathode metal electrode and the right edge of the first anode metal electrode, i.e., the minimum distance between the two) is 15μm to 25μm.

[0019] Preferably, the thickness of the GaN capping layer is 10 nm to 30 nm.

[0020] Preferably, the thickness of the anode field plate is 30 nm to 50 nm.

[0021] Preferably, the anode field plate comprises Ni and Au.

[0022] Preferably, the width of the second cathode metal electrode is 2μm to 5μm.

[0023] Preferably, the composition of the second cathode metal electrode includes Ti, Al, Ni and Au.

[0024] Preferably, the width of the second anode metal electrode is 2μm to 6μm.

[0025] Preferably, the second anode metal electrode comprises Ni and Au.

[0026] A method for fabricating a Schottky barrier diode containing a mixed anode and a mixed cathode as described above includes the following steps:

[0027] 1) Sequentially deposit an AlN nucleation layer, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer, and a GaN capping layer on the substrate;

[0028] 2) Photolithography and CF4 etching source are performed on the surface of the GaN capping layer to expose part of the AlGaN barrier layer;

[0029] 3) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first cathode metal electrode preparation area and the second cathode metal electrode preparation area. After the electrode metal is deposited by evaporation, photoresist is stripped and annealed to form the first cathode metal electrode and the second cathode metal electrode.

[0030] 4) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first anode metal electrode fabrication area and the second anode metal electrode fabrication area. After the electrode metal is deposited by evaporation, the photoresist is stripped to form the first anode metal electrode and the second anode metal electrode.

[0031] 5) Electrode metal is deposited on the surface of the GaN capping layer to form an anode field plate;

[0032] 6) Photolithography is performed on the surface of the AlGaN barrier layer to form the passivation layer preparation area, and then the passivation layer material is deposited to form the passivation layer, thus obtaining a Schottky barrier diode containing a mixed anode and a mixed cathode.

[0033] An electronic product comprising the aforementioned Schottky barrier diode containing a mixed anode and a mixed cathode.

[0034] The beneficial effects of the present invention are: the Schottky barrier diode of the present invention is provided with a hybrid anode structure and a hybrid cathode structure, which has the advantages of large inflection point voltage, small turn-on voltage and high reliability, and is suitable for large-scale industrial production and application.

[0035] Specifically:

[0036] 1) The Schottky barrier diode of the present invention is provided with a hybrid anode structure. When the voltage is less than the threshold voltage of the Schottky barrier and greater than the threshold voltage of the ohmic contact of the cathode metal electrode in the hybrid anode structure, the device can be turned on, which greatly reduces the turn-on voltage of the device.

[0037] 2) The Schottky barrier diode of the present invention is provided with a hybrid cathode structure. When forward conduction is performed, the Schottky contact at the cathode can deplete electrons to a certain extent, thereby playing a role in current regulation and thus improving the inflection point voltage of the device. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the Schottky barrier diode containing a hybrid anode and a hybrid cathode, as described in Example 1.

[0039] Figure 2 This is a schematic diagram of a Schottky barrier diode for comparison.

[0040] Explanation of reference numerals in the attached figures: 10, Si substrate; 20, AlN nucleation layer; 30, GaN buffer layer; 40, GaN channel layer; 50, AlGaN barrier layer; 60, passivation layer; 70, first cathode metal electrode; 80, first anode metal electrode; 90, GaN capping layer; 100, anode field plate; 110, second cathode metal electrode; 120, second anode metal electrode.

[0041] Figure 3 The figures show the saturation current test results of the Schottky barrier diodes with mixed anodes and mixed cathodes in Examples 1-3 and the Schottky barrier diodes in the comparative example.

[0042] Figure 4 The diagram shows the breakdown voltage test results of the Schottky barrier diodes with mixed anodes and mixed cathodes in Examples 1-3 and the Schottky barrier diodes in the comparative example. Detailed Implementation

[0043] The present invention will be further explained and described below with reference to specific embodiments.

[0044] Example 1:

[0045] A Schottky barrier diode containing a hybrid anode and a hybrid cathode (structural schematic shown in figure) Figure 1 As shown, it consists of a Si substrate 10, an AlN nucleation layer 20, a GaN buffer layer 30, a GaN channel layer 40, an AlGaN barrier layer 50, a passivation layer 60, a first cathode metal electrode 70, a first anode metal electrode 80, a GaN capping layer 90, an anode field plate 100, a second cathode metal electrode 110, and a second anode metal electrode 120.

[0046] A Si substrate 10, an AlN nucleation layer 20, a GaN buffer layer 30, a GaN channel layer 40, an AlGaN barrier layer 50, and a passivation layer 60 are stacked sequentially.

[0047] The first cathode metal electrode 70 is disposed on the side of the AlGaN barrier layer 50 that is away from the GaN channel layer 40.

[0048] The first anode metal electrode 80 is disposed on the side of the GaN channel layer 40 away from the GaN buffer layer 30, and is in contact with the AlGaN barrier layer 50, the GaN capping layer 90 and the anode field plate 100.

[0049] The GaN capping layer 90 is disposed on the side of the AlGaN barrier layer 50 away from the GaN channel layer 40 and is in contact with the passivation layer 60.

[0050] The anode field plate 100 is disposed on the side of the GaN capping layer 90 that is away from the AlGaN barrier layer 50;

[0051] The second cathode metal electrode 110 is disposed inside the first anode metal electrode 80 and is in contact with the GaN channel layer 40;

[0052] The second anode metal electrode 120 is disposed on the side of the AlGaN barrier layer 50 away from the GaN channel layer 40, and is in contact with the first cathode metal electrode 70 and the passivation layer 60.

[0053] The fabrication method of the Schottky barrier diode containing a mixed anode and a mixed cathode is as follows:

[0054] 1) Metal-organic chemical vapor deposition (MOCVD) was used to sequentially epitaxially grow an AlN nucleation layer with a thickness of 1 nm, a GaN buffer layer with a thickness of 300 nm, a GaN channel layer with a thickness of 200 nm, an AlGaN barrier layer with a thickness of 20 nm, and a GaN capping layer with a thickness of 20 nm on a Si substrate.

[0055] 2) Photolithography and CF4 etching source are performed on the surface of the GaN capping layer to expose part of the AlGaN barrier layer;

[0056] 3) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first and second cathode metal electrode fabrication areas. Then, Ti-Al-Ni-Au alloy is deposited using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree P ≤ 10. -3 Pa, then acetone is used to remove the photoresist and annealing is performed in a nitrogen atmosphere to form a first cathode metal electrode with a width of 3μm and a second cathode metal electrode with a width of 3μm;

[0057] 4) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first and second anode metal electrode fabrication areas. Then, Ni-Au alloy is deposited using electron beam evaporation with an electron beam energy of 3kV and a vacuum degree P≤10.-3 Pa, then acetone is used to remove the photoresist to form a first anode metal electrode with a width of 8μm and a distance of 20μm from the first cathode metal electrode, and a second anode metal electrode with a width of 2μm;

[0058] 5) Ni-Au alloy was deposited on the surface of the GaN capping layer using electron beam evaporation. The electron beam energy was 3kV, and the vacuum degree P≤10. -3 Pa forms an anode field plate with a thickness of 40 nm;

[0059] 6) Photolithography is performed on the surface of the AlGaN barrier layer to form the passivation layer preparation area. Then, a Si3N4 layer with a thickness of 60nm is deposited by low-pressure chemical vapor deposition to form the passivation layer, thus obtaining a Schottky barrier diode containing a mixed anode and a mixed cathode.

[0060] Example 2:

[0061] A Schottky barrier diode containing a mixed anode and a mixed cathode is identical to the Schottky barrier diode containing a mixed anode and a mixed cathode in Example 1, except that the width of the second cathode metal electrode is adjusted from "3μm" to "5μm".

[0062] Example 3:

[0063] A Schottky barrier diode containing a mixed anode and a mixed cathode is identical to the Schottky barrier diode containing a mixed anode and a mixed cathode in Example 1, except that the width of the second cathode metal electrode is adjusted from "3μm" to "4μm".

[0064] Comparative example: (without hybrid anode and hybrid cathode structures)

[0065] A Schottky barrier diode (structural schematic shown) Figure 2 As shown, it consists of a Si substrate 10, an AlN nucleation layer 20, a GaN buffer layer 30, a GaN channel layer 40, an AlGaN barrier layer 50, a passivation layer 60, a first cathode metal electrode 70, a first anode metal electrode 80, a GaN capping layer 90, and an anode field plate 100.

[0066] A Si substrate 10, an AlN nucleation layer 20, a GaN buffer layer 30, a GaN channel layer 40, an AlGaN barrier layer 50, and a passivation layer 60 are stacked sequentially.

[0067] The first cathode metal electrode 70 is disposed on the side of the AlGaN barrier layer 50 away from the GaN channel layer 40 and is in contact with the passivation layer 60.

[0068] The first anode metal electrode 80 is disposed on the side of the GaN channel layer 40 away from the GaN buffer layer 30, and is in contact with the AlGaN barrier layer 50, the GaN capping layer 90 and the anode field plate 100.

[0069] The GaN capping layer 90 is disposed on the side of the AlGaN barrier layer 50 away from the GaN channel layer 40 and is in contact with the passivation layer 60.

[0070] The anode field plate 100 is disposed on the side of the GaN capping layer 90 that is away from the AlGaN barrier layer 50.

[0071] The fabrication method of the above Schottky barrier diode is as follows:

[0072] 1) Metal-organic chemical vapor deposition (MOCVD) was used to sequentially epitaxially grow an AlN nucleation layer with a thickness of 1 nm, a GaN buffer layer with a thickness of 300 nm, a GaN channel layer with a thickness of 200 nm, an AlGaN barrier layer with a thickness of 20 nm, and a GaN capping layer with a thickness of 20 nm on a Si substrate.

[0073] 2) Photolithography and CF4 etching source are performed on the surface of the GaN capping layer to expose part of the AlGaN barrier layer;

[0074] 3) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first cathode metal electrode fabrication area. Then, Ti-Al-Ni-Au alloy is deposited by electron beam evaporation with an electron beam energy of 3kV and a vacuum degree P≤10. - 3 Pa, then acetone is used to remove the photoresist and annealing is performed in a nitrogen atmosphere to form a first cathode metal electrode with a width of 3μm;

[0075] 4) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first anode metal electrode fabrication area. Then, Ni-Au alloy is deposited by electron beam evaporation with an electron beam energy of 3kV and a vacuum degree P≤10. -3 Pa, and then acetone is used to remove the photoresist to form a first anode metal electrode with a width of 8μm and a distance of 20μm from the first cathode metal electrode;

[0076] 5) Ni-Au alloy was deposited on the surface of the GaN capping layer using electron beam evaporation. The electron beam energy was 3kV, and the vacuum degree P≤10. -3 Pa forms an anode field plate with a thickness of 40 nm;

[0077] 6) Photolithography is performed on the surface of the AlGaN barrier layer to form the passivation layer preparation area. Then, a Si3N4 layer with a thickness of 60nm is deposited by low-pressure chemical vapor deposition to form the passivation layer, thus obtaining the Schottky barrier diode.

[0078] Performance testing:

[0079] The saturation current test results of the Schottky barrier diodes with mixed anodes and mixed cathodes in Examples 1-3 and the comparative Schottky barrier diode are as follows: Figure 3 As shown, the breakdown voltage test results are as follows: Figure 4 As shown.

[0080] Depend on Figure 3 It can be seen that the inflection point voltages of the Schottky barrier diodes with mixed anodes and mixed cathodes in Examples 1 to 3 reach 1.2V, 1.4V and 1.1V respectively, while the inflection point voltage of the Schottky barrier diode in the comparative example (without mixed anode and mixed cathode structures) is 0.8V. The breakdown voltage of the Schottky barrier diode with mixed anodes and mixed cathodes in Example 1 is as high as 50% higher than that of the Schottky barrier diode in the comparative example, indicating that setting mixed anode and mixed cathode structures can indeed significantly improve the inflection point voltage of Schottky barrier diode devices.

[0081] Depend on Figure 4 It can be seen that the turn-on voltages of the Schottky barrier diodes with mixed anodes and mixed cathodes in Examples 1 to 3 are 0.35V, 0.40V, and 0.30V, respectively, while the turn-on voltage of the Schottky barrier diode in the comparative example (without the mixed anode and mixed cathode structures) is 0.60V. The Schottky barrier diode with mixed anodes and mixed cathodes in Example 1 has a turn-on voltage reduction of up to 42% compared with the Schottky barrier diode in the comparative example, indicating that setting the mixed anode and mixed cathode structures can indeed significantly reduce the turn-on voltage of the Schottky barrier diode device.

[0082] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A Schottky barrier diode comprising a hybrid anode and a hybrid cathode, characterized in that, The device comprises a substrate, an AlN nucleation layer, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer, and a passivation layer, stacked sequentially. It also includes a first cathode metal electrode, a first anode metal electrode, a GaN capping layer, an anode field plate, a second cathode metal electrode, and a second anode metal electrode. The first cathode metal electrode is disposed on the side of the AlGaN barrier layer away from the GaN channel layer. The first anode metal electrode is disposed on the side of the GaN channel layer away from the GaN buffer layer and is in contact with the AlGaN barrier layer, the GaN capping layer, and the anode field plate. The GaN capping layer is disposed on the side of the AlGaN barrier layer away from the GaN channel layer and is in contact with the passivation layer. The anode field plate is disposed on the side of the GaN capping layer away from the AlGaN barrier layer; the second cathode metal electrode is disposed inside the first anode metal electrode and is in contact with the GaN channel layer; the second anode metal electrode is disposed on the side of the AlGaN barrier layer away from the GaN channel layer and is in contact with the first cathode metal electrode and the passivation layer; the width of the second anode metal electrode is 2μm to 6μm; the composition of the second anode metal electrode includes Ni and Au.

2. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1, characterized in that: The thickness of the AlN nucleation layer is 0.5 nm to 1.5 nm; the thickness of the GaN buffer layer is 200 nm to 400 nm; the thickness of the GaN channel layer is 100 nm to 300 nm; and the thickness of the AlGaN barrier layer is 10 nm to 30 nm.

3. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The thickness of the passivation layer is 40 nm to 80 nm.

4. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The passivation layer is composed of Si3N4.

5. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The thickness of the GaN capping layer is 10 nm to 30 nm.

6. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The width of the first cathode metal electrode is 3μm to 6μm; the width of the first anode metal electrode is 5μm to 8μm; the thickness of the anode field plate is 30nm to 50nm; the width of the second cathode metal electrode is 2μm to 5μm; and the distance between the first cathode metal electrode and the first anode metal electrode is 15μm to 25μm.

7. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The first cathode metal electrode is composed of Ti, Al, Ni and Au; the first anode metal electrode is composed of Ni and Au; the anode field plate is composed of Ni and Au; and the second cathode metal electrode is composed of Ti, Al, Ni and Au.

8. The Schottky barrier diode containing a mixed anode and a mixed cathode according to claim 1 or 2, characterized in that: The substrate is one of Si substrate, GaAs substrate, or sapphire substrate.

9. A method for fabricating a Schottky barrier diode containing a mixed anode and a mixed cathode as described in any one of claims 1 to 8, characterized in that, Includes the following steps: 1) Sequentially deposit an AlN nucleation layer, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer, and a GaN capping layer on the substrate; 2) Photolithography and CF4 etching source are performed on the surface of the GaN capping layer to expose part of the AlGaN barrier layer; 3) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first cathode metal electrode preparation area and the second cathode metal electrode preparation area. After the electrode metal is deposited by evaporation, photoresist is stripped and annealed to form the first cathode metal electrode and the second cathode metal electrode. 4) Photolithography and CF4 etching are performed on the surface of the AlGaN barrier layer to form the first anode metal electrode fabrication area and the second anode metal electrode fabrication area. After the electrode metal is deposited by evaporation, the photoresist is stripped to form the first anode metal electrode and the second anode metal electrode. 5) Electrode metal is deposited on the surface of the GaN capping layer to form an anode field plate; 6) Photolithography is performed on the surface of the AlGaN barrier layer to form the passivation layer preparation area, and then the passivation layer material is deposited to form the passivation layer, thus obtaining a Schottky barrier diode containing a mixed anode and a mixed cathode.

10. An electronic product, characterized in that, The Schottky barrier diode comprising a hybrid anode and a hybrid cathode as described in any one of claims 1 to 8.

Images