A schottky barrier diode and a preparation method and application thereof

Abstract

The application discloses a Schottky barrier diode and a preparation method and application thereof. The Schottky barrier diode comprises a Si substrate, an AlN nucleation layer, a GaN buffer layer and an AlGaN barrier layer which are sequentially arranged in layers, and further comprises a first passivation layer, a second passivation layer, a cathode metal electrode, a first anode metal field plate, a third passivation layer, a second anode metal field plate and an anode metal electrode. The Schottky barrier diode has the advantages of high transient resistance, high voltage resistance and breakdown resistance, high reliability and the like, and is suitable for large-scale popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, in particular to a Schottky barrier diode and a preparation method and application thereof. BACKGROUND

[0002] The Schottky barrier diode, also known as the hot carrier diode, is an indispensable device in most power electronic products, which needs to have a lower opening voltage, a specific conduction resistance, a lower reverse leakage current and a higher breakdown voltage, so as to reduce the power loss in the use process. The gallium nitride (GaN) has a larger band gap and a higher electron mobility, and the performance of the AlGaN / GaN Schottky barrier diode (SBD) with sapphire or silicon carbide (SiC) as the substrate is significantly better than that of the Schottky barrier diode of other material systems, and the application prospect is more extensive. The Si / GaN-based Schottky barrier diode has good performance and low cost, and has good commercialization potential, which has attracted widespread attention. However, the existing Si / GaN-based Schottky barrier diode has poor transient resistance, poor voltage resistance and breakdown resistance, and the reliability needs to be improved, which is difficult to fully meet the increasing practical application requirements.

[0003] Therefore, it is of great significance to develop a Schottky barrier diode with high transient resistance, high voltage resistance and breakdown resistance, and high reliability. SUMMARY

[0004] The purpose of the present application is to provide a Schottky barrier diode and a preparation method and application thereof.

[0005] The technical scheme adopted by the present application is:

[0006] A Schottky barrier diode, which comprises a Si substrate, an AlN nucleation layer, a GaN buffer layer and an AlGaN barrier layer arranged in sequence, and further comprises a first passivation layer, a second passivation layer, a cathode metal electrode, a first anode metal field plate, a third passivation layer, a second anode metal field plate and an anode metal electrode;

[0007] The first passivation layer is arranged on the side of the AlN nucleation layer away from the Si substrate and in contact with the GaN buffer layer;

[0008] The second passivation layer is in the shape of L, one side of which covers the side of the AlGaN barrier layer away from the GaN buffer layer, and the other side of which is in contact with the GaN buffer layer;

[0009] The cathode metal electrode is arranged on the side of the AlGaN barrier layer away from the GaN buffer layer and in contact with the second passivation layer and the third passivation layer;

[0010] The first anode metal field plate is L-shaped, covers the corner of the second passivation layer, and contacts the GaN buffer layer;

[0011] The third passivation layer is L-shaped, covers the second passivation layer and the first anode metal field plate, and contacts the GaN buffer layer and the first passivation layer;

[0012] The second anode metal field plate is L-shaped, covers the corner of the third passivation layer, and contacts the first passivation layer;

[0013] The anode metal electrode penetrates the second anode metal field plate, the third passivation layer, the first anode metal field plate, the second passivation layer and the AlGaN barrier layer in sequence, and contacts the GaN buffer layer.

[0014] Preferably, the thickness of the AlN nucleation layer is 1nm-5nm.

[0015] Preferably, the thickness of the GaN buffer layer is 300nm-350nm.

[0016] Preferably, the thickness of the AlGaN barrier layer is 15nm-25nm.

[0017] Preferably, the composition of the AlGaN barrier layer comprises Al x GaN, wherein x is 0.2-0.3.

[0018] Preferably, the composition of the first passivation layer comprises at least one of SiO2, Si3N4, SiC, HfO2.

[0019] Preferably, the thickness of the first passivation layer is 50nm-100nm.

[0020] Preferably, the composition of the second passivation layer comprises at least one of SiO2, Si3N4, SiC, HfO2.

[0021] Preferably, the thickness of the second passivation layer is 50nm-100nm.

[0022] Preferably, the composition of the cathode metal electrode comprises at least one of Ti, Al, Ni, Au, Ag, TiN.

[0023] Preferably, the width of the cathode metal electrode is 5μm-10μm.

[0024] Preferably, one side of the first anode metal field plate has a length of 3μm-5μm and a thickness of 40nm-60nm, and the other side has a length of 3μm-5μm and a thickness of 500nm-800nm.

[0025] Preferably, the third passivation layer comprises at least one of SiO2, Si3N4, SiC, HfO2.

[0026] Preferably, the third passivation layer has a thickness of 200-300 nm.

[0027] Preferably, one side of the second anode metal field plate has a length of 5-7 μm and a thickness of 40-60 nm, and the other side has a length of 3-5 μm and a thickness of 1.2-1.5 μm.

[0028] Preferably, the anode metal electrode comprises at least one of Ti, Al, Ni, Au, Ag, and TiN.

[0029] Preferably, the anode metal electrode has a width of 5-10 μm.

[0030] Preferably, the distance between the cathode metal electrode and the anode metal electrode is 15-20 μm.

[0031] A method for preparing the Schottky barrier diode as described above comprises the following steps:

[0032] 1) sequentially epitaxially growing an AlN nucleation layer, a GaN buffer layer, and an AlGaN barrier layer on a Si substrate;

[0033] 2) performing photolithography to expose the cathode metal electrode preparation area, and then performing alloy evaporation and peeling to form the cathode metal electrode;

[0034] 3) performing photolithography to expose the first passivation layer and the second passivation layer preparation area, and then performing deposition to form the first passivation layer and the second passivation layer;

[0035] 4) performing photolithography to expose the anode metal electrode preparation area and the first anode metal field plate preparation area, and then performing alloy evaporation and peeling to form the anode metal electrode and the first anode metal field plate;

[0036] 5) performing deposition to form the third passivation layer;

[0037] 6) performing photolithography to expose the second anode metal field plate preparation area, and then performing alloy evaporation and peeling to form the second anode metal field plate, thereby obtaining the Schottky barrier diode.

[0038] An electronic device comprising the Schottky barrier diode as described above.

[0039] The principle of the present application: the present application reduces the peak electric field strength at the edge of the anode metal electrode by the transverse double anode field plate (the transverse part of the first and second anode metal field plates), and reduces the peak electric field at the channel by introducing the electric field at the channel into the underlying GaN buffer layer by the longitudinal double anode field plate (the longitudinal part of the first and second anode metal field plates), thereby improving the withstand voltage and anti-breakdown capability of the device and reducing the leakage current, which can significantly reduce the peak electric field strength at the edge of the device, thereby suppressing the current collapse effect, improving the reliability of the device, and being different from the traditional single-layer field plate, the transverse and longitudinal double-layer field plates make the electric field at the metal edge more uniform, thereby improving the breakdown voltage of the device.

[0040] The present application has the advantages that the Schottky barrier diode has high transient resistance, high withstand voltage and anti-breakdown performance, high reliability, and is suitable for large-scale popularization and application.

[0041] Specifically:

[0042] 1) The Schottky barrier diode of the present application adopts a transverse double field plate (the transverse part of the first and second anode metal field plates) design, which reduces the peak electric field strength at the edge of the anode metal electrode and the leakage current, and can effectively improve the reliability of the device.

[0043] 2) The Schottky barrier diode of the present application adopts a longitudinal double field plate (the longitudinal part of the first and second anode metal field plates) design, which introduces the electric field into the underlying GaN buffer layer, reduces the peak electric field at the channel, and can effectively improve the breakdown voltage of the device. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The structure of the Schottky barrier diode of the present application is shown in the figure.

[0045] The figure identification is as follows: 10, Si substrate; 20, AlN nucleation layer; 30, GaN buffer layer; 40, AlGaN barrier layer; 50, first passivation layer; 60, second passivation layer; 70, cathode metal electrode; 80, first anode metal field plate; 90, third passivation layer; 100, second anode metal field plate; 110, anode metal electrode. DETAILED DESCRIPTION

[0046] The present application will be further explained and described below in conjunction with specific embodiments.

[0047] Example 1:

[0048] A Schottky barrier diode (structure schematic diagram as shown in the figure) Figure 1The structure comprises a Si substrate 10, an AlN nucleation layer 20, a GaN buffer layer 30, and an AlGaN barrier layer 40, which are sequentially stacked, and further comprises a first passivation layer 50, a second passivation layer 60, a cathode metal electrode 70, a first anode metal field plate 80, a third passivation layer 90, a second anode metal field plate 100, and an anode metal electrode 110;

[0049] The first passivation layer 50 is arranged on the side of the AlN nucleation layer 20 away from the Si substrate 10 and in contact with the GaN buffer layer 30;

[0050] The second passivation layer 60 is L-shaped, with one side covering the side of the AlGaN barrier layer 40 away from the GaN buffer layer 30 and the other side in contact with the GaN buffer layer 30;

[0051] The cathode metal electrode 70 is arranged on the side of the AlGaN barrier layer 40 away from the GaN buffer layer 30 and in contact with both the second passivation layer 60 and the third passivation layer 90;

[0052] The first anode metal field plate 80 is L-shaped, covering the corner of the second passivation layer 60 and in contact with the GaN buffer layer 30;

[0053] The third passivation layer 90 is L-shaped, covering the second passivation layer 60 and the first anode metal field plate 80 and in contact with both the GaN buffer layer 30 and the first passivation layer 50;

[0054] The second anode metal field plate 100 is L-shaped, covering the corner of the third passivation layer 90 and in contact with the first passivation layer 50;

[0055] The anode metal electrode 110 sequentially penetrates the second anode metal field plate 100, the third passivation layer 90, the first anode metal field plate 80, the second passivation layer 60, and the AlGaN barrier layer 40 and is in contact with the GaN buffer layer 30.

[0056] The preparation method of the Schottky barrier diode comprises the following steps:

[0057] 1) An AlN nucleation layer with a thickness of 1 nm, a GaN buffer layer with a thickness of 300 nm, and an AlGaN barrier layer with a thickness of 20 nm (Al 0.2 GaN) are sequentially epitaxially grown on a Si substrate by metal organic chemical vapor deposition (MOCVD);

[0058] 2) Photolithography is performed to expose the cathode metal electrode preparation area, and Ti / Al / Ni / Au alloy evaporation is performed by electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3Pa, and then stripping by using acetone to form the anode metal electrode and the first anode metal field plate, the width of the anode metal electrode is 5 μm, the distance between the anode metal electrode and the cathode metal electrode is 20 μm, the length of the horizontal side of the first anode metal field plate is 4 μm and the thickness is 60 nm, and the length of the vertical side of the first anode metal field plate is 5 μm and the thickness is 500 nm;

[0059] 3) performing photolithography and controllable CF4 etching source etching to expose the first passivation layer and the second passivation layer preparation area, and then depositing Si3N4 with a thickness of 60 nm by using low pressure chemical vapor deposition (LPCVD) to form the first passivation layer and the second passivation layer;

[0060] 4) performing photolithography and controllable CF4 etching source etching to expose the anode metal electrode preparation area and the first anode metal field plate preparation area, and then performing Ni / Au alloy evaporation by using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3 Pa, and then stripping by using acetone to form the anode metal electrode and the first anode metal field plate, the width of the anode metal electrode is 5 μm, the distance between the anode metal electrode and the cathode metal electrode is 20 μm, the length of the horizontal side of the first anode metal field plate is 4 μm and the thickness is 60 nm, and the length of the vertical side of the first anode metal field plate is 5 μm and the thickness is 500 nm;

[0061] 5) depositing SiO2 with a thickness of 300 nm by using low pressure chemical vapor deposition (LPCVD) to form the third passivation layer;

[0062] 6) performing photolithography to expose the second anode metal field plate preparation area, and then performing Ni / Au alloy evaporation by using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3 Pa, and then stripping by using acetone to form the second anode metal field plate, the length of one side of the second anode metal field plate is 6 μm and the thickness is 40 nm, and the length of the other side of the second anode metal field plate is 3 μm and the thickness is 1.2 μm, thereby obtaining the Schottky barrier diode.

[0063] Example 2:

[0064] A Schottky barrier diode has the same structure as the Schottky barrier diode of Example 1, and the preparation method thereof comprises the following steps:

[0065] 1) sequentially epitaxially growing an AlN nucleation layer with a thickness of 1 nm, a GaN buffer layer with a thickness of 300 nm, and an AlGaN barrier layer (Al 0.2 GaN) with a thickness of 20 nm on a Si substrate by using metal organic chemical vapor deposition (MOCVD);

[0066] 2) performing photolithography to expose the cathode metal electrode preparation area, and then performing Ti / Al / Ni / Au alloy evaporation by using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3Pa, and then peeled off with acetone, and then placed in N2 atmosphere for annealing to form a cathode metal electrode, the width of the cathode metal electrode is 5μm;

[0067] 3) performing photolithography and etching with a controllable CF4 etching source to expose the preparation areas of the first passivation layer and the second passivation layer, and then depositing Si3N4 with a thickness of 60 nm by low-pressure chemical vapor deposition (LPCVD) to form the first passivation layer and the second passivation layer;

[0068] 4) Perform photolithography and controllable CF4 etching source etching to expose the anode metal electrode preparation area and the first anode metal field plate preparation area, and then perform Ni / Au alloy evaporation using electron beam evaporation with an electron beam energy of 3kV and a vacuum degree of P≤10 -3 Pa, and then peeled off with acetone to form an anode metal electrode and a first anode metal field plate, the width of the anode metal electrode is 5 μm, the distance between the anode metal electrode and the cathode metal electrode is 20 μm, the length of the horizontal side of the first anode metal field plate is 4 μm, the thickness is 60 nm, the length of the vertical side is 5 μm, and the thickness is 600 nm;

[0069] 5) using low pressure chemical vapor deposition (LPCVD) to deposit SiO2 with a thickness of 300 nm to form a third passivation layer;

[0070] 6) Perform photolithography to expose the second anode metal field plate preparation area, and then perform Ni / Au alloy evaporation using electron beam evaporation with an electron beam energy of 3kV and a vacuum degree of P≤10 -3 Pa, and then acetone is used for peeling to form a second anode metal field plate, wherein one side of the second anode metal field plate has a length of 6 μm and a thickness of 50 nm, and the other side has a length of 4 μm and a thickness of 1.3 μm, thereby obtaining a Schottky barrier diode.

[0071] Example 3:

[0072] A Schottky barrier diode having the same structure as the Schottky barrier diode of Example 1, wherein the preparation method thereof comprises the following steps:

[0073] 1) Using metal organic chemical vapor deposition (MOCVD) method, a 1nm thick AlN nucleation layer, a 300nm thick GaN buffer layer and a 20nm thick AlGaN barrier layer (Al 0.2 GaN);

[0074] 2) Perform photolithography to expose the cathode metal electrode preparation area, and then perform Ti / Al / Ni / Au alloy evaporation using electron beam evaporation with an electron beam energy of 3kV and a vacuum degree of P≤10 -3Pa, and then stripping by using acetone, and then annealing in N2 atmosphere to form a cathode metal electrode, wherein the width of the cathode metal electrode is 5 μm;

[0075] 3) performing photolithography and controllable CF4 etching source etching to expose a first passivation layer and a second passivation layer preparation area, and then depositing Si3N4 with a thickness of 60 nm by using low pressure chemical vapor deposition (LPCVD) to form the first passivation layer and the second passivation layer;

[0076] 4) performing photolithography and controllable CF4 etching source etching to expose an anode metal electrode preparation area and a first anode metal field plate preparation area, and then performing Ni / Au alloy evaporation by using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3 Pa, and then stripping by using acetone to form an anode metal electrode and a first anode metal field plate, wherein the width of the anode metal electrode is 5 μm, the distance between the anode metal electrode and the cathode metal electrode is 20 μm, the length of a horizontal side of the first anode metal field plate is 4 μm and the thickness thereof is 60 nm, and the length of a vertical side of the first anode metal field plate is 5 μm and the thickness thereof is 700 nm;

[0077] 5) depositing SiO2 with a thickness of 300 nm by using low pressure chemical vapor deposition (LPCVD) to form a third passivation layer;

[0078] 6) performing photolithography to expose a second anode metal field plate preparation area, and then performing Ni / Au alloy evaporation by using electron beam evaporation with an electron beam energy of 3 kV and a vacuum degree of P≤10 -3 Pa, and then stripping by using acetone to form a second anode metal field plate, wherein the length of one side of the second anode metal field plate is 6 μm and the thickness thereof is 60 nm, and the length of the other side of the second anode metal field plate is 5 μm and the thickness thereof is 1.4 μm, thereby obtaining a Schottky barrier diode.

[0079] Comparative Example:

[0080] A Schottky barrier diode is the same as the Schottky barrier diode of Example 1 except that the first anode metal field plate and the second anode metal field plate only have horizontal parts (without vertical parts).

[0081] It is tested that the Schottky barrier diodes of Examples 1-3 have the advantages of high transient resistance, strong withstand voltage and breakdown resistance, and high reliability, and the performance of the above several aspects is significantly better than that of the Schottky barrier diode of the comparative example.

[0082] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

1. A Schottky barrier diode, characterized in that: The composition includes a Si substrate, an AlN nucleation layer, a GaN buffer layer and an AlGaN barrier layer stacked in sequence, and also includes a first passivation layer, a second passivation layer, a cathode metal electrode, a first anode metal field plate, a third passivation layer, a second anode metal field plate and an anode metal electrode; The first passivation layer is arranged on the side of the AlN nucleation layer away from the Si substrate and in contact with the GaN buffer layer; The second passivation layer is L-shaped, with one side covering the side of the AlGaN barrier layer away from the GaN buffer layer, and the other side contacting the GaN buffer layer; The cathode metal electrode is arranged on the side of the AlGaN barrier layer away from the GaN buffer layer, and is in contact with both the second passivation layer and the third passivation layer; The first anode metal field plate is L-shaped, covers the corner of the second passivation layer, and contacts the GaN buffer layer; The third passivation layer is L-shaped, covers the second passivation layer and the first anode metal field plate, and is in contact with both the GaN buffer layer and the first passivation layer; The second anode metal field plate is L-shaped, covers the corner of the third passivation layer, and contacts the first passivation layer; The anode metal electrode sequentially penetrates the second anode metal field plate, the third passivation layer, the first anode metal field plate, the second passivation layer and the AlGaN barrier layer, and contacts the GaN buffer layer.

2. The Schottky barrier diode according to claim 1, wherein: The thickness of the AlN nucleation layer is 1 nm to 5 nm.

3. The Schottky barrier diode according to claim 1, wherein: The thickness of the GaN buffer layer is 300nm-350nm.

4. The Schottky barrier diode according to claim 1, wherein: The thickness of the AlGaN barrier layer is 15nm to 25nm; the components of the AlGaN barrier layer include Al x GaN, where x is 0.2 to 0.

3.

5. The Schottky barrier diode according to any one of claims 1 to 4, characterized in that: The components of the first passivation layer include at least one of SiO2, Si3N4, SiC, and HfO2; the thickness of the first passivation layer is 50nm~100nm; the components of the second passivation layer include at least one of SiO2, Si3N4, SiC, and HfO2; the thickness of the second passivation layer is 50nm~100nm; the components of the third passivation layer include at least one of SiO2, Si3N4, SiC, and HfO2; the thickness of the third passivation layer is 200nm~300nm.

6. The Schottky barrier diode according to any one of claims 1 to 4, characterized in that: The length of one side of the first anode metal field plate is 3μm~5μm and the thickness is 40nm~60nm, and the length of the other side is 3μm~5μm and the thickness is 500nm~800nm; the length of one side of the second anode metal field plate is 5μm~7μm and the thickness is 40nm~60nm, and the length of the other side is 3μm~5μm and the thickness is 1.2μm~1.5μm.

7. The Schottky barrier diode according to any one of claims 1 to 4, characterized in that: The components of the cathode metal electrode include at least one of Ti, Al, Ni, Au, Ag, and TiN; the width of the cathode metal electrode is 5μm to 10μm; the components of the anode metal electrode include at least one of Ti, Al, Ni, Au, Ag, and TiN; the width of the anode metal electrode is 5μm to 10μm.

8. The Schottky barrier diode according to any one of claims 1 to 4, characterized in that: The distance between the cathode metal electrode and the anode metal electrode is 15 μm to 20 μm.

9. A method for preparing a Schottky barrier diode according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) epitaxially growing an AlN nucleation layer, a GaN buffer layer, and an AlGaN barrier layer on a Si substrate; 2) performing photolithography to expose the cathode metal electrode preparation area, and then performing alloy evaporation and stripping to form the cathode metal electrode; 3) performing photolithography to expose the preparation areas of the first passivation layer and the second passivation layer, and then performing deposition to form the first passivation layer and the second passivation layer; 4) performing photolithography to expose the anode metal electrode preparation area and the first anode metal field plate preparation area, and then performing alloy evaporation and stripping to form the anode metal electrode and the first anode metal field plate; 5) performing deposition to form a third passivation layer; 6) Perform photolithography to expose the second anode metal field plate preparation area, and then perform alloy evaporation and lift-off to form the second anode metal field plate, thereby obtaining a Schottky barrier diode.

10. An electronic device, characterized in that: The composition includes the Schottky barrier diode according to any one of claims 1 to 8.

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