Nitride PN junction Schottky diode and its fabrication method

Abstract

This invention discloses a nitride PN junction Schottky diode, mainly addressing the problem of low breakdown voltage in existing vertical nitride Schottky diodes. From bottom to top, it includes a cathode (5), a substrate (1), and an n-junction junction. + Al x Ga 1‑x The structure comprises an N-transport layer (2), a scandium-yttrium aluminum nitride / gallium nitride stacked structure (3), a scandium-yttrium aluminum nitride / aluminum nitride stacked structure (4), and an anode (6). The nitride and scandium-yttrium aluminum nitride materials in these two stacked structures (3, 4) are grown sequentially and periodically. Each scandium-yttrium aluminum nitride layer has a thickness of 3nm-50nm, with a constant composition. The total thickness and period of both layers may be the same or different, and the overall scandium composition is 0%-35%, while the yttrium composition is 0%-25%. This invention utilizes the polarization effect of nitride materials to form a vertical PN junction, and leverages the ferroelectric polarization effect of ScYAlN to improve reverse withstand voltage, reduce reverse leakage current, and increase breakdown voltage. It can be used in microwave rectification and power switching circuits.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology, and specifically relates to a vertical structure nitride PN junction Schottky diode, which can be used in microwave rectification and power switching circuits. Background Technology

[0002] Schottky diodes are electronic devices made by forming a metal-semiconductor junction through the contact between a metal and a semiconductor. They are characterized by low forward voltage and high switching frequency. Schottky diodes are classified into lateral and vertical structures. Improving the breakdown voltage of a lateral Schottky diode requires increasing the cathode-anode spacing, which consumes more chip area. In contrast, a vertical Schottky diode only needs to increase the drift layer thickness without increasing the lateral dimensions of the device to improve its breakdown characteristics. Furthermore, vertical Schottky diodes rely on the bulk material for conductivity, resulting in a wider conductive path, higher current density, less susceptibility to surface states, and better dynamic characteristics.

[0003] Group III nitride materials have been widely used in radio frequency microwave power devices and high voltage power switching devices due to their high breakdown field strength and high dielectric constant. Vertical Schottky diodes based on GaN materials have also received extensive research attention due to their excellent material properties and structural characteristics.

[0004] Traditional vertical GaN Schottky diode devices, such as Figure 1 As shown, the device comprises, from bottom to top, a cathode, a substrate, a transport layer, a drift layer, and an anode. When the device is in a reverse bias state, the electric field strength in the drift layer gradually decreases from top to bottom, with an extremely high electric field peak near the anode at the top of the drift layer, causing the device's breakdown voltage to be much lower than the theoretical value. To address the problem of low breakdown voltage in traditional GaN vertical structure Schottky diodes, which cannot meet the requirements of practical applications, existing technologies mainly solve this problem by adjusting the doping concentration of the GaN drift layer material, designing the anode field plate termination structure, and optimizing the interface.

[0005] In 2021, Xi'an University of Electronic Science and Technology disclosed a vertical GaN Schottky diode based on an in-situ grown MIS structure and its fabrication method in patent application CN202110658267. This device improves upon the traditional vertical GaN Schottky diode by inserting an in-situ grown dielectric layer between the drift layer and the anode of the traditional vertical GaN Schottky diode. By improving the interface quality, leakage current is reduced, thereby increasing the breakdown voltage. However, this method only changes the interface quality and does not improve the breakdown voltage capability of the drift layer itself, thus failing to achieve a higher breakdown voltage.

[0006] In 2020, Nanyang Technological University in Singapore reported a vertical structure Schottky diode with altered drift layer doping in their paper "Improved breakdown voltage invertical GaN Schottky barrier diodes on free-standing GaN with Mg-compensated drift layer". This device, based on a traditional vertical structure GaN Schottky diode, achieved a gallium nitride Schottky diode with a breakdown voltage of 1480V by compensating the drift layer with Mg. However, this method drastically increases the forward conduction resistance and fails to address the problem of uneven electric field in the drift layer. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the existing technology by proposing a vertical structure nitride PN junction Schottky diode and its fabrication method, so as to improve the reverse breakdown voltage of the drift layer and the reverse breakdown voltage of the device, thereby improving the device reliability.

[0008] The technical solution of this invention is implemented as follows:

[0009] 1. A nitride PN junction Schottky diode, comprising, from bottom to top, a cathode, a substrate, and an n-type junction. + Al x Ga 1-x The N-transport layer and anode are characterized by:

[0010] The n + Al x Ga 1-x A Sc layer is sequentially disposed between the N transport layer and the anode. w Y y Al z N / GaN stacked structure and Sc w Y y Al z The N / AlN stacked structure relies on the polarization properties of nitride materials to form a PN junction in the vertical direction, thereby increasing the reverse breakdown voltage of the device.

[0011] The Sc w Y y Al z N / GaN stacked structure and Sc w Y y Al z In the N / AlN stacked structure, nitride materials and scandium-yttrium aluminum nitrogen materials are grown sequentially and periodically, with each Sc layer... w Y y Al z The N thickness is 3nm-50nm, and the composition remains unchanged. This Scw Y y Al z The total thickness of the N / GaN stacked structure is 936 nm-10 μm. w Y y Al z The total thickness of the N / AlN stacked structure is 936 nm-11 μm, where 0 ≤ w ≤ 0.35, 0 ≤ y ≤ 0.25, and 0 ≤ y ≤ 0.35. <z<1。

[0012] Furthermore, the Sc w Y y Al z In the N / GaN stacked structure, the GaN layer thickness within each stack is 10nm-50nm. w Y y Al z In the N / AlN stacked structure, the thickness of the AlN layer in each stack is 3nm-5nm, which is achieved by controlling the thickness of the single Sc layer in each layer. w Y y Al z The thickness of N, monolayer GaN, and monolayer AlN is used to control the forward conduction resistance and reverse breakdown voltage of the device.

[0013] Furthermore, the substrate is made of n-type GaN, n-type AlN, or n-type SiC.

[0014] Furthermore, the n + Al x Ga 1-x The thickness of the N-transport layer is 0.2 μm-5 μm, and the doping concentration is 1 × 10⁻⁶. 19 cm -3 ~5×10 20 cm -3 For the Al component, 0 ≤ x ≤ 1.

[0015] Furthermore, the cathode metal material is any one or any combination of several of Ni, Ti, Al, W, Cr, Ta, Mo, TiC, TiN, and TiW.

[0016] Furthermore, the metal material of the anode is any one or any combination of Ni, Pt, Pd, Au, and W.

[0017] 2. A method for fabricating a nitride PN junction Schottky diode, characterized by comprising the following steps:

[0018] 1) On the upper part of the substrate, metal-organic chemical vapor deposition or molecular beam epitaxy is used to deposit a layer with a thickness of 0.2μm-5μm and a doping concentration of 1×10⁻⁶. 19 cm -3 ~5×1020 cm -3 n + Al x Ga 1-x N transport layer;

[0019] 2) Using metal-organic chemical vapor deposition or molecular beam epitaxy, in n + Al x Ga 1-x GaN monolayers with thicknesses ranging from 10 nm to 50 nm and Sc layers with thicknesses ranging from 3 nm to 50 nm are sequentially and periodically grown on the N-transport layer. w Y y Al z A single layer of N constitutes a Sc layer with a total thickness of 936 nm-10 μm. w Y y Al z N / GaN stacked structure, where 0≤w≤0.35, 0≤y≤0.25, 0 <z<1;

[0020] 3) Using metal-organic chemical vapor deposition or molecular beam epitaxy, on Sc w Y y Al z On the N / GaN stacked structure, AlN monolayers with a thickness of 3nm-5nm and Sc with a thickness of 3nm-50nm are periodically grown sequentially. w Y y Al z A single layer of N forms a Sc layer with a total thickness of 936 nm-11 μm. w Y y Al z N / AlN stacked structure, where 0≤w≤0.35, 0≤y≤0.25, 0 <z<1;

[0021] 4) On the lower part of the substrate, cathode metal is deposited using electron beam evaporation, and annealed at 800℃-1200℃ for 30s-5min according to the cathode metal material to form ohmic contact and obtain the cathode.

[0022] 5) In Sc w Y y Al z A mask is fabricated on an N / AlN stacked structure, and an anode metal is deposited on it using an electron beam evaporation process to obtain the anode, thus completing the device fabrication.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. This invention is in n + Al x Ga 1-xSc is sequentially arranged between the N transport layer and the anode. w Y y Al z N / GaN stacked structure and Sc w Y y Al z In the N / AlN stacked structure, due to the polarization effect of the nitride materials in these two layers, two-dimensional electron gas and two-dimensional hole gas can be generated on the surface of the GaN layer and the AlN layer, respectively. The lower Sc layer... w Y y Al z N / GaN stacked structure and upper Sc w Y y Al z The N / AlN stacked structure forms an integral reverse PN junction structure along the growth direction, which can improve the reverse breakdown voltage of the Schottky diode.

[0025] 2. This invention uses Sc w Y y Al z As a multilayer material, N exhibits high dielectric constant and strong critical field, allowing for increased reverse breakdown voltage while maintaining a constant drift layer thickness, thus achieving excellent breakdown characteristics. Furthermore, due to its ferroelectric polarization properties, N can increase the reverse breakdown voltage of Sc when a reverse voltage is applied. w Y y Al z The polarization direction of the N thin layer is reversed, which consumes electrons on the GaN layer surface, further improving the device's breakdown voltage and enhancing its reliability. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a traditional vertical GaN Schottky diode.

[0027] Figure 2 This is a schematic diagram of the structure of the nitride PN junction Schottky diode of the present invention;

[0028] Figure 3 This is a schematic diagram illustrating the implementation process of fabricating a nitride PN junction Schottky diode according to the present invention. Detailed Implementation

[0029] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings:

[0030] Reference Figure 2 The nitride PN junction Schottky diode of the present invention includes a cathode 5, a substrate 1, and an n + Al x Ga 1-x N Transport Layer 2, Sc w Y y Alz 3. N / GaN stacked structure, Sc w Y y Al z N / AlN stacked structure 4 and anode 6;

[0031] The substrate 1 is an n-type GaN substrate, an n-type AlN substrate, or an n-type SiC substrate;

[0032] The n + Al x Ga 1-x N-transport layer 2, located on substrate 1, has a thickness of 0.2 μm-5 μm and a doping concentration of 1 × 10⁻⁶. 19 cm -3 ~5×10 20 cm -3 Al component 0≤x≤1;

[0033] The Sc w Y y Al z The N / GaN stacked structure 3 is located in n + Al x Ga 1-x Above the N-transport layer 2, its total thickness is 936nm-10μm, with each GaN monolayer having a thickness of 10nm-50nm, and each Sc w Y y Al z The thickness of the N monolayer is 3nm-50nm, and the composition remains constant. Within each layer, the composition is 0≤w≤0.35, 0≤y≤0.25, and 0 <z<1;

[0034] The Sc w Y y Al z The N / AlN stacked structure 4 is located in Sc w Y y Al z Above the N / GaN stacked structure, the total thickness is 936nm-11μm, with each AlN layer having a thickness of 3nm-5nm, and each Sc... w Y y Al z The thickness of the N monolayer is 3nm-50nm, and the composition remains constant. Within each layer, the composition is 0≤w≤0.35, 0≤y≤0.25, and 0 <z<1;

[0035] The cathode 5 is located below the substrate 1 and is made of any one or a combination of several of the following materials: Ni, Ti, Al, W, Cr, Ta, Mo, TiC, TiN, and TiW.

[0036] The anode 6 is located in Sc w Yy Al z Above the N / AlN stacked structure 4, any one or any combination of Ni, Pt, Pd, Au, and W is used.

[0037] Reference Figure 3 The present invention provides three embodiments for fabricating nitride PN junction Schottky diodes.

[0038] Example 1: Fabrication of Sc w Y y Al z The N / GaN stacked structure uses ScAlN / GaN material with a total thickness of 10 μm. w Y y Al z The N / AlN stacked structure uses ScAlN / AlN material with a total thickness of 11 μm, and the substrate is an n-type GaN substrate. + Al x Ga 1-x The N transport layer uses n + GaN PN junction Schottky diode with Ni / Au anode metal and Ti cathode metal.

[0039] Step 1: Deposit a GaN transport layer, such as... Figure 3 (a).

[0040] Metal-organic chemical vapor deposition was used to deposit a 5 μm thick layer of doped GaN with a doping concentration of 5 × 10⁻⁶ on an n-type GaN substrate 1. 20 cm -3 GaN transport layer 2;

[0041] The deposition process conditions were as follows: temperature 1000℃, pressure 40 Torr, ammonia flow rate 5000 sccm, hydrogen flow rate 3500 sccm, and gallium source flow rate 200 sccm.

[0042] Step 2: Deposit ScAlN / GaN stacked structure, such as Figure 3 (b)

[0043] On the GaN transport layer 2, GaN monolayers and ScAlN monolayers are sequentially and periodically deposited using metal-organic chemical vapor deposition (MOCVD). Each GaN monolayer has a thickness of 50 nm, and each ScAlN monolayer has a thickness of 50 nm. The deposition period is 100, resulting in a ScAlN / GaN stacked structure 3 with a total thickness of 10 μm.

[0044] The deposition process conditions were as follows: temperature 1000℃, pressure 200 Torr, ammonia flow rate 5000 sccm, hydrogen flow rate 3500 sccm, aluminum source flow rate 50 sccm, scandium source flow rate 5000 sccm, and gallium source flow rate 200 sccm.

[0045] Step 3: Deposit the ScAlN / AlN stacked structure, such as... Figure 3 (c)

[0046] On the ScAlN / GaN stack structure 3, AlN monolayers and ScAlN monolayers were sequentially and periodically deposited using metal-organic chemical vapor deposition (MOCVD). The thickness of each AlN monolayer was 5 nm and the thickness of each ScAlN monolayer was 50 nm. The deposition period was 200, resulting in a ScAlN / AlN stack structure 4 with a total thickness of 11 μm.

[0047] The deposition process conditions were as follows: temperature 1000℃, pressure 200 Torr, ammonia flow rate 5000 sccm, hydrogen flow rate 3500 sccm, aluminum source flow rate 50 sccm, and scandium source flow rate 5000 sccm.

[0048] Step four: Prepare the cathode metal and perform annealing treatment, such as... Figure 3 (d)

[0049] Using electron beam evaporation, a 100nm thick Ti layer is deposited on the underside of an n-type GaN substrate as the cathode metal. The prepared cathode metal is then annealed using rapid annealing technology to form an ohmic contact, thus completing the fabrication of cathode 5.

[0050] The process conditions for electron beam evaporation are: vacuum degree less than 1.2 × 10⁻⁶. -3 Pa, power is 400W, evaporation rate is

[0051] The annealing process conditions were: nitrogen atmosphere, temperature 800℃, and annealing time 5 min.

[0052] Step 5: Form an anode on the ScAlN / AlN stacked structure, such as... Figure 3 (e).

[0053] A photolithography process was used to define the anode pattern on the ScAlN / AlN stacked structure 4. An electron beam evaporation process was used to deposit 50 / 100nm Ni / Au as the anode metal on the ScAlN / AlN stacked structure to form the anode 6, thus completing the device fabrication.

[0054] The process conditions for electron beam evaporation are: vacuum degree less than 1.2 × 10⁻⁶. -3 Pa, power is 400W, evaporation rate is

[0055] Example 2: Fabrication of Sc w Y y Al z The N / GaN stacked structure uses YAlN / GaN material with a total thickness of 936 nm. w Y y Al z The N / AlN stacked structure uses YAlN / AlN material with a total thickness of 936 nm, and the substrate is an n-type AlN substrate. + Al x Ga 1-x The N transport layer uses n + AlN, a nitride PN junction Schottky diode with Ni / Au / Ni anode metal and Ti / Al / Ni / Au cathode metal.

[0056] Step 1: Epitaxially grow an AlN transport layer using molecular beam epitaxy (MBE), such as... Figure 3 (a).

[0057] The set temperature is 750℃, the nitrogen flow rate is 3.2 sccm, and the aluminum beam equilibrium vapor pressure is 3.5 × 10⁻⁶. -7 Torr, with a nitrogen RF source power of 380W, and an epitaxial layer thickness of 0.2μm on an n-type AlN substrate 1, with a doping concentration of 1×10⁻⁶. 19 cm -3 AlN transport layer 2.

[0058] Step 2: Use molecular beam epitaxy (MBE) to epitaxially grow a YAlN / GaN stacked structure, such as... Figure 3 (b)

[0059] The set temperature is 600℃, the nitrogen flow rate is 0.6 sccm, and the aluminum beam equilibrium vapor pressure is 0.6 × 10⁻⁶. -7 Torr, the equilibrium vapor pressure of the gallium beam is 3.2 × 10⁻⁶. -7 Torr, the equilibrium vapor pressure of the yttrium beam is 0.6 × 10⁻⁶. -8 Under the process conditions of a nitrogen RF source power of 320W, a GaN monolayer with a thickness of 10nm and a YAlN monolayer with a thickness of 3nm were sequentially and periodically epitaxially grown on the n-type AlN transport layer 2, with an epitaxial period of 72, resulting in a YAlN / GaN stacked structure 3 with a total thickness of 936nm.

[0060] Step 3: Use molecular beam epitaxy to epitaxially grow a YAlN / AlN stacked structure, such as... Figure 3 (c)

[0061] The set temperature is 600℃, the nitrogen flow rate is 0.6 sccm, and the aluminum beam equilibrium vapor pressure is 0.6 × 10⁻⁶. -7 Torr, the equilibrium vapor pressure of the yttrium beam is 1.8 × 10⁻⁶. -8 Under the process conditions of a nitrogen RF source power of 320W, a GaN monolayer with a thickness of 3nm and a YAlN monolayer with a thickness of 3nm were sequentially epitaxially grown on the YAlN / GaN stacked structure 3, with an epitaxial period of 156, resulting in a YAlN / AlN stacked structure 4 with a total thickness of 936nm.

[0062] Step 4: Deposit cathode metal on the back side of the substrate and perform annealing treatment, such as... Figure 3 (d)

[0063] Set the vacuum level to less than 1.2 × 10⁻⁶. -3 Pa, power is 600W, evaporation rate is Under the specified process conditions, Ti / Al / Ni / Au metal with a thickness of 30 / 150 / 55 / 45nm was deposited on the underside of n-type AlN substrate 1 as cathode 5;

[0064] The cathode metal was annealed for 30 seconds at a temperature of 850°C in a nitrogen atmosphere to form an ohmic contact.

[0065] Step 5: Form an anode on the YAlN / AlN stacked structure using electron beam evaporation technology, such as... Figure 3 (e).

[0066] A mask is fabricated on the YAlN / AlN stacked structure 4 using photolithography to form an anode window;

[0067] Electron beam evaporation was used at a vacuum level of less than 1.2 × 10⁻⁶. -3 Pa, power is 600W, evaporation rate is Under the specified process conditions, Ni / Au / Ni metal with a thickness of 50 / 90 / 150nm is deposited in the anode window as anode 6 to complete the device fabrication.

[0068] Example 3: Fabrication of Sc w Y y Al z The N / GaN stacked structure adopts a ScYAlN / GaN stacked structure with a total thickness of 6μm. w Y y Al z The N / AlN stacked structure adopts a ScYAlN / AlN stacked structure with a total thickness of 4μm, and the substrate is an n-type SiC substrate. + Al x Ga 1-x The N transport layer uses n + Al0.2 Ga 0.8 A Schottky diode with a nitride PN junction, N, anode metal of W / Au, and cathode metal of Ti / Al.

[0069] Step A, Al deposition 0.2 Ga 0.8 N transport layer, such as Figure 3 (a).

[0070] Using metal-organic chemical vapor deposition (MOCVD), under the following conditions: temperature 1300℃, pressure 60 Torr, ammonia flow rate 5000 sccm, hydrogen flow rate 3500 sccm, gallium source flow rate 100 sccm, and aluminum source flow rate 20 sccm, a 0.5 μm thick layer of 1×10⁻⁶ doped material was deposited on an n-type SiC substrate 1. 20 cm -3 Al 0.2 Ga 0.8 N Transport Layer 2.

[0071] Step B, deposit the ScYAlN / GaN stacked structure, such as Figure 3 (b)

[0072] Using metal-organic chemical vapor deposition (MOCVD), under the following conditions: temperature 1100℃, pressure 180 Torr, ammonia flow rate 5000 sccm, hydrogen flow rate 3500 sccm, gallium source flow rate 100 sccm, aluminum source flow rate 20 sccm, scandium source flow rate 3000 sccm, and yttrium source flow rate 3000 sccm, in Al... 0.2 Ga 0.8 On the N-transport layer 2, a GaN monolayer with a thickness of 30 nm and a ScYAlN monolayer with a thickness of 20 nm are periodically deposited sequentially, with a deposition period of 120, to obtain a ScYAlN / GaN stacked structure 3 with a total thickness of 6 μm.

[0073] Step C, deposit the ScYAlN / AlN stacked structure, such as Figure 3 (c)

[0074] Using metal-organic chemical vapor deposition (MOCVD), under conditions of 1100℃, 180 Torr, ammonia flow rate of 5000 sccm, hydrogen flow rate of 3500 sccm, aluminum source flow rate of 4 sccm, scandium source flow rate of 2000 sccm, and yttrium source flow rate of 1000 sccm, a 4 nm thick AlN monolayer and a 16 nm thick ScYAlN monolayer were sequentially and periodically deposited on the ScYAlN / GaN stack structure 3, with a deposition cycle of 200, to obtain a ScYAlN / GaN stack structure 4 with a total thickness of 4 μm.

[0075] Step D: Deposit cathode metal and perform annealing treatment, such as... Figure 3 (d)

[0076] Electron beam evaporation technology was used in an environment with a vacuum level of less than 1.2 × 10⁻⁶. -3 Pa, power 500W, evaporation rate is Under the process conditions, a Ti / Al metal with a thickness of 50 / 150 nm is deposited on the underside of an n-type SiC substrate 1 as a cathode 5;

[0077] Using rapid annealing technology, the cathode metal is annealed for 30 seconds at 1200°C in a nitrogen atmosphere to form an ohmic contact.

[0078] Step E: Forming an anode on the ScYAlN / GaN stacked structure, such as... Figure 3 (e).

[0079] A mask was fabricated on the ScYAlN / AlN stacked structure 4 using photolithography to form an anode window;

[0080] Electron beam evaporation technology was used in an environment with a vacuum level of less than 1.2 × 10⁻⁶. -3 Pa, power is 500W, evaporation rate is Under the specified process conditions, a 50 / 150 nm thick W / Au metal layer was deposited in the anode window as anode 6 to complete the device fabrication.

[0081] The above descriptions are merely three specific examples of the present invention and do not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention. For example, in addition to the metals used above, the cathode metal material may also use any one or any combination of Ni, Ti, Al, W, Cr, Ta, Mo, TiC, TiN, and TiW; and in addition to the metals used above, the anode metal material may also use any one or any combination of Ni, Pt, Pd, Au, and W. However, these modifications and changes based on the concept of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A nitride PN junction Schottky diode comprising, from bottom to top, a cathode (5), a substrate (1), an n + Al x Ga 1-x N transport layer (2) and an anode (6), characterized in that: The n + Al x Ga 1-x N transmission layer (2) and anode (6) are sequentially provided with Sc w Y y Al z N / GaN stack structure (3) and Sc w Y y Al z N / AlN stack structure (4), both of which form PN junction in the vertical direction by virtue of the polarization characteristics of nitride materials to increase the reverse breakdown voltage of the device; The Sc w Y y Al z N / GaN stack (3) and Sc w Y y Al z N / AlN stack (4) are grown periodically, each layer of Sc w Y y Al z N has a thickness of 3 nm - 50 nm, the composition remains unchanged, the Sc w Y y Al z N / GaN stack (3) has a total thickness of 936 nm - 10 μm, the Sc w Y y Al z N / AlN stack (4) has a total thickness of 936 nm - 11 μm, where 0 ≤ w ≤ 0.35, 0 ≤ y ≤ 0.25, 0 < z < 1. The Sc w Y y Al z The thickness of the GaN layer in each stack in the N / GaN stack structure (3) is 10 nm-50 nm, the Sc w Y y Al z The thickness of the AlN layer in each stack in the N / AlN stack structure (4) is 3 nm-5 nm, the Sc w Y y Al z The thickness of the N, single-layer GaN, and single-layer AlN is controlled to regulate the forward conduction resistance and reverse breakdown voltage of the device. The n + Al x Ga 1-x The thickness of the N transport layer (2) is 0.2 μm - 5 μm, the doping concentration is 1 x 10 19 cm -3 ~ 5 x 10 20 cm -3 , the Al component 0 ≤ x ≤ 1.

2. The diode of claim 1, wherein: The substrate (1) is n-type GaN or n-type AlN or n-type SiC.

3. The diode according to claim 1, wherein: The metal material of the cathode (5) is any one or any combination of Ni, Ti, Al, W, Cr, Ta, Mo, TiC, TiN, TiW; The metal material of the anode (6) is any one or any combination of Ni, Pt, Pd, Au, W.

4. The method of fabricating a nitride PN-junction Schottky diode as claimed in claim 1, wherein, The method comprises the following steps: 1) On the upper portion of the substrate (1), a n-AlGaN transport layer (2) with a thickness of 0.2 μm to 5 μm and a doping concentration of 1 x 1018 cm-3 to 5 x 1018 cm-3 is deposited using metal organic chemical vapor deposition or molecular beam epitaxy. 19 cm -3 ~5 x 10 20 cm -3 + x 1-x -3​​​ 2) using metal organic chemical vapor deposition or molecular beam epitaxy technique, on the n + Al x Ga 1-x N transmission layer (2) sequentially and periodically grow GaN monolayer with thickness of 10 nm-50 nm and Sc w Y y Al z N monolayer with thickness of 3 nm-50 nm, forming Sc w Y y Al z N / GaN stack structure (3) with total thickness of 936 nm-10 μm, wherein 0≤w≤0.35, 0≤y≤0.25, 0 3) using metal organic chemical vapor deposition or molecular beam epitaxy techniques, on the Sc w Y y Al z N / GaN stack (3) sequentially and periodically grow AlN monolayers of thickness 3 nm - 5 nm and Sc w Y y Al z N monolayers of thickness 3 nm - 50 nm, constituting a Sc w Y y Al z N / AlN stack (4) of total thickness 936 nm - 11 μm, where 0≤w≤0.35, 0≤y≤0.25, 0<z<1. 4) On the lower part of the substrate (1), cathode metal is deposited by electron beam evaporation process and annealed at 800 o C-1200 o C for 30 s to 5 min to form an ohmic contact to obtain the cathode (5); 5) in Sc w Y y Al z A mask is made on the N / AlN stack structure (4), an anode (6) is obtained by depositing an anode metal on the mask using an electron beam evaporation process, and the device is completed.

5. The method of claim 4, wherein: The process conditions of the metal organic chemical vapor deposition method in the steps 1) - 3) are as follows: temperature is 1000 o C-1300 o C; The pressure is 40 Torr - 200 Torr; The ammonia flow is 5000 sccm; The hydrogen flow is 3500 sccm; The aluminum source flow is 4 sccm - 50 sccm; The gallium source flow is 50 sccm - 200 sccm; The scandium source flow is 2000 sccm - 5000 sccm; The yttrium source flow is 1000 sccm - 3000 sccm.

6. The method of claim 4, wherein: The process conditions of the molecular beam epitaxy method in the steps 1) - 3) are as follows: temperature is 600 o C-750 o C; The nitrogen flow is 0.6 sccm - 3.2 sccm; The gallium beam current was balanced at a vapor pressure of 3.2 x 10 -7 Torr-9.5 x 10 -7 Torr; The aluminum beam was balanced at a vapor pressure of 0.6 x 10 -7 Torr-3.5 x 10 -7 Torr; The scandium beam current was balanced at a vapor pressure of 0.9 x 10 -8 Torr-2.8 x 10 -8 Torr; The yttrium beam current is balanced at a vapor pressure of 0.6 x 10 -8 Torr-1.8 x 10 -8 Torr; The nitrogen radio frequency source power is 320 W - 380 W.

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