Groove type gallium oxide heterojunction barrier Schottky diode

Abstract

The invention relates to a trench-type gallium oxide heterojunction barrier Schottky diode, which adopts a trench structure design and is composed of cathode metal, an N + substrate layer, a first N-type buffer layer, a second N-type buffer layer, a third N-type buffer layer, a first lightly doped drift layer, an N-type field stop layer, a second lightly doped drift layer, a NiO protection ring and anode metal from bottom to top. Through a P-type NiO protection ring structure, an electric field near a Schottky junction is effectively dispersed and reduced. The groove structure reduces the influence of a single-particle burning effect by increasing the Schottky contact area; according to the buffer layer, a buffer area is introduced between the drift layer and the substrate, so that the risk of thermal failure of the device is remarkably improved; the N-type field stop layer reduces a strong electric field and a heat effect of a Schottky contact interface by accelerating extraction and recombination of holes. According to the Schottky diode, the capability of resisting the single event burnout effect is greatly improved, and the risk of device failure caused by the single event effect is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of power semiconductors, and in particular to a trench-type gallium oxide heterojunction barrier Schottky diode. Background Art

[0002] As a wide bandgap semiconductor material, gallium oxide not only has a large bandgap width, but also has high breakdown electric field, high thermal conductivity, high carrier saturation mobility and excellent radiation resistance. It is suitable for use in modern power electronic systems and can withstand harsh environments such as high temperature, high voltage, high current, and strong radiation. Its broad application prospects include rail transportation, new energy vehicles, and aerospace.

[0003] However, in the space environment, high-energy charged particles continuously irradiate electronic devices with high energy due to radiation sources such as cosmic rays and solar flares. When these particles pass through power semiconductor devices, they are prone to cause single event effects. This effect may cause the electrical performance of power chips to degrade or even burn out, seriously threatening the normal operation of spacecraft.

[0004] In space applications, gallium oxide Schottky diodes are susceptible to space radiation. When high-energy particles are incident, heavy ions hit the Schottky junction area of ​​the gallium oxide Schottky diode, generating a large number of electron-hole pairs, aggravating local heating and causing burning inside the device. Due to the low thermal conductivity of gallium oxide materials, heat accumulates more easily in local areas, further increasing the risk of single-particle burnout. Therefore, in order to improve the gallium oxide Schottky diode's ability to resist single-particle effects, its reinforcement design has become one of the important challenges in aerospace applications. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a trench-type gallium oxide heterojunction barrier Schottky diode, in which the trench structure effectively enhances the device's ability to resist single-particle effects under heavy ion impact, comprising a cathode metal layer, an N+ substrate layer, a first N-type buffer layer, a second N-type buffer layer, a third N-type buffer layer, a first lightly doped drift layer, an N-type field stop layer, a P-type NiO guard ring, a second lightly doped drift layer and an anode metal;

[0006] The p-type NiO guard ring and the second lightly doped drift layer are arranged on the upper surface of the N-type field stop layer, and the p-type NiO guard ring and the second lightly doped drift layer are arranged alternately, and the second lightly doped drift layer is thicker than the p-type NiO guard ring, and the p-type NiO guard ring and the second lightly doped drift layer are both square structures; the anode metal layer is arranged on the top layer, covering all the p-type NiO guard rings and the second lightly doped drift layer, and forming a groove structure with the contact part of the second lightly doped drift layer; the anode metal layer forms an ohmic contact with the top of the p-type NiO guard ring, and forms a Schottky contact with the top of the second lightly doped drift layer.

[0007] In one embodiment of the present invention, the second lightly doped drift layer is 1 μm to 3 μm thicker than the p-type NiO guard ring, and the p-type NiO guard ring is 2 μm to 3 μm thick and has a doping concentration of 1×10 19 cm -3 ~2×10 19 cm -3 The thickness of the second lightly doped drift layer is 3 μm to 6 μm, and the doping concentration is 3×10 15 cm -3 ~2×10 16 cm -3 .

[0008] In one embodiment of the present invention, the cathode metal layer (101) is horizontally arranged at the bottom layer; the N+ substrate layer (102) is arranged on the upper surface of the cathode metal layer (101); the first N-type buffer layer is arranged on the upper surface of the N+ substrate layer (102); the second N-type buffer layer is arranged on the upper surface of the first N-type buffer layer; the third N-type buffer layer is arranged on the upper surface of the second N-type buffer layer; the first lightly doped drift layer is arranged on the upper surface of the third N-type buffer layer; and the N-type field stop layer is arranged on the upper surface of the first lightly doped drift layer.

[0009] In one embodiment of the present invention, the N+ substrate layer is N-type doped, the doping element is silicon or tin, the thickness is 100 μm to 150 μm, and the doping concentration is 5×10 18 cm -3 ~2×10 19 cm -3 .

[0010] In one embodiment of the present invention, the first N-type buffer layer is N-type doped, disposed on the upper surface of the N+ substrate layer (102), and the doping element is silicon or tin, with a thickness of 2 μm to 5 μm and a doping concentration of 5×10 17 cm -3 ~6×10 17 cm -3 , which is used to control the electric field distribution.

[0011] In one embodiment of the present invention, the second N-type buffer layer is disposed on the upper surface of the first N-type buffer layer, and the doping element is silicon or tin, the thickness is 2 μm to 5 μm, and the doping concentration is 3×10 17 cm -3 ~5×10 17 cm -3 , which is used to further control the electric field distribution.

[0012] In one embodiment of the present invention, the third N-type buffer layer is disposed on the upper surface of the second N-type buffer layer, and the doping element is silicon or tin, the thickness is 2 μm to 5 μm, and the doping concentration is 1×10 17 cm -3 ~3×10 17 cm -3 , which is used to further control the electric field distribution.

[0013] In one embodiment of the present invention, the first lightly doped drift layer is disposed on the upper surface of the third N-type buffer layer, and has a thickness of 10 μm to 15 μm and a doping concentration of 3×10 15 cm -3 ~2×10 16 cm -3 , used to achieve the device's withstand voltage characteristics.

[0014] In one embodiment of the present invention, the N-type field stop layer is disposed above the first lightly doped drift layer and has a thickness of 1 μm to 2 μm and a doping concentration of 1×10 17 cm -3 ~5×10 17 cm -3 , used to accelerate the extraction and recombination of holes.

[0015] The above technical solution of the present invention has the following advantages over the prior art: The Schottky diode structure described in the present invention solves the problems of increased leakage current and single particle burnout effect caused by high-energy charged particle radiation in space applications. The structure effectively enhances the device's ability to resist single particle effects under heavy ion impact by integrating a buffer layer, an N-type field stop layer, a trench structure, and a P-type NiO guard ring. The trench-type gallium oxide heterojunction barrier Schottky diode of the present invention exhibits excellent performance in high voltage and high-energy particle radiation environments, significantly improving the device's ability to resist single particle effects while ensuring its long-term stability and reliability. Compared with traditional structures, the diode can maintain lower leakage current, excellent voltage resistance, and stronger radiation resistance under extreme space conditions, and is suitable for key applications in high-energy particle radiation environments such as spacecraft and satellites. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the trench-type gallium oxide heterojunction barrier Schottky diode of the present invention;

[0018] Figure 2 It is a process flow chart of the trench-type gallium oxide heterojunction barrier Schottky diode of the present invention;

[0019] Figure 3 It is a temperature data simulation comparison diagram of the device when the single particle effect occurs in the present invention;

[0020] Figure 4 It is a density diagram comparing the hole current simulation experiment results in the present invention.

[0021] As shown in the figure, 101 is a cathode metal layer; 102 is an N+ substrate layer; 103 is a first N-type buffer layer; 104 is a second N-type buffer layer; 105 is a third N-type buffer layer; 106 is a first lightly doped drift layer; 107 is an N-type field stop layer; 108 is a P-type NiO guard ring; 109 is a second lightly doped drift layer; and 110 is an anode metal layer. DETAILED DESCRIPTION

[0022] like Figure 1 and Figure 2 As shown, this embodiment provides a trench-type gallium oxide heterojunction barrier Schottky diode structure, which adopts a staggered layout of a single-layer P-type NiO guard ring and a lightly doped drift layer. Through a reasonable trench structure design, the local electric field strength is effectively reduced, the single-particle radiation resistance of the diode is improved, and a high voltage resistance performance is maintained.

[0023] Furthermore, if Figure 1 As shown, a trench-type gallium oxide heterojunction barrier Schottky diode structure specifically includes a cathode metal layer 101, an N+ substrate layer 102, a first N-type buffer layer 103, a second N-type buffer layer 104, a third N-type buffer layer 105, a first lightly doped drift layer 106, an N-type field stop layer 107, a P-type NiO guard ring 108, a second lightly doped drift layer 109 and an anode metal layer 110.

[0024] Among them, the cathode metal layer 101 is horizontally arranged at the bottom layer; the N+ substrate layer 102 is located on the upper surface of the cathode metal layer 101; the first N-type buffer layer 103 is located on the upper surface of the N+ substrate layer 102; the second N-type buffer layer 104 is located on the upper surface of the first N-type buffer layer 103; the third N-type buffer layer 105 is located on the upper surface of the second N-type buffer layer 104; the first lightly doped drift layer 106 is located on the upper surface of the third N-type buffer layer 105.

[0025] The N-type field stop layer 107 is arranged on the upper surface of the first lightly doped drift layer 106, and the P-type NiO guard ring 108 and the second lightly doped drift layer 109 are arranged alternately on the upper surface of the N-type field stop layer 107, and the thickness of the P-type NiO guard ring 108 is less than that of the second lightly doped drift layer 109, forming a trench structure. This design can effectively avoid local electric field concentration and reduce the sudden increase of the local electric field of the device caused by single particle incidence. The anode metal layer 110 is arranged on the top layer, covering all the P-type NiO guard rings 108 and the second lightly doped drift layer 109, forming an ohmic contact with the top of the P-type NiO guard ring, and forming a Schottky contact with the top of the second lightly doped drift layer.

[0026] The detailed design of each layer in the present invention is as follows:

[0027] N+ substrate layer 102: N-type doping, doping element is silicon or tin, thickness is 100μm~150μm, doping concentration is 5×10 18 cm -3 ~2×10 19 cm -3 .

[0028] The first N-type buffer layer 103 is N-type doped with silicon or tin as the doping element, with a thickness of 2 μm to 5 μm and a doping concentration of 5×10 17 cm -3 ~6×10 17 cm -3 , which is used to control the electric field distribution.

[0029] The second N-type buffer layer 104 is located on the upper surface of the first N-type buffer layer 103, with a thickness of 2 μm to 5 μm and a doping concentration of 3×10 17 cm -3 ~5×10 17 cm -3 , which is used to further control the electric field distribution.

[0030] The third N-type buffer layer 105 is located on the upper surface of the second N-type buffer layer 104, has a thickness of 2 μm to 5 μm, and a doping concentration of 1×10 17 cm -3 ~3×10 17 cm-3 , further optimize the electric field distribution.

[0031] The first lightly doped drift layer 106 is lightly doped N-type with a thickness of 12 μm to 20 μm and a doping concentration of 1×10 16 cm -3 ~2×10 16 cm -3 , providing the voltage resistance of Schottky diode.

[0032] P-type NiO guard ring 108: thickness 1μm to 3μm, doping concentration 1.5×10 18 cm -3 ~2.5×10 18 cm -3 , avoiding the electric field concentration phenomenon near the Schottky junction.

[0033] The second lightly doped drift layer 109 has a thickness of 3 μm to 6 μm and a doping concentration of 1×10 16 cm -3 ~2×10 16 cm -3 , can be staggered with the P-type NiO guard ring 108 to form a Schottky contact with the anode.

[0034] The trench structure significantly improves the hole extraction efficiency by increasing the Schottky contact area, reduces the accumulation of holes in the Schottky area, reduces the electric field strength and thermal power, and improves the device's ability to resist single-particle burnout. The P-type NiO guard ring avoids excessive concentration of the electric field in the Schottky contact area by moving the voltage-resistant area from the Schottky interface to the contact part of the P-type guard ring and the substrate, further improving the device's voltage-resistant performance and stability. In addition, the N-type field stop layer accelerates the extraction and recombination of holes, reduces the accumulation of holes under high-energy particle radiation or current stress, reduces local strong electric fields and high temperatures, and enhances the stability of the device in irradiated environments. The buffer layer further optimizes the electric field distribution, prevents excessive concentration of the electric field in key areas, and significantly reduces the risk of thermal failure.

[0035] In summary, the trench-type gallium oxide heterojunction barrier Schottky diode structure of the present invention significantly improves the device's ability to resist single-particle radiation, and is very suitable for use in space and other harsh environments with high-energy particle radiation.

[0036] In the Schottky diode described in this embodiment, the trench structure increases the effective Schottky contact area and improves the hole extraction efficiency: the trench structure significantly improves the hole extraction efficiency by increasing the Schottky contact area on the sidewall. Compared with the traditional planar structure, the trench structure can accelerate the discharge of holes generated by radiation from the device, reduce the hole accumulation in the top Schottky area, and improve the device's ability to resist single-particle burnout effects. The simulation experiment results are shown in Figure 2. Figure 4 As shown, compared with the conventional structure I, in the embodiment II, a clear hole migration channel is formed in the groove area, thereby improving the effective hole extraction capability.

[0037] The N-type field stop layer accelerates hole extraction and recombination, reducing heat accumulation: By accelerating hole extraction and recombination, hole accumulation under radiation or current stress is reduced, thereby reducing the strong electric field and high temperature effects of the Schottky interface. This not only reduces the formation of local hot spots, but also expands the energy dispersion area, significantly reduces the temperature peak, and enhances the stability of the device under irradiation.

[0038] The buffer layer optimizes the distribution of the electric field by introducing a multi-layer buffer between the drift region and the substrate, avoiding excessive concentration of the electric field in certain areas, especially at the Schottky interface. This effectively reduces local hot spots and electric field spikes in the device under high bias voltage, reducing the risk of thermal failure.

[0039] The present invention effectively utilizes the buffer layer, N-type blocking layer and trench structure to optimize the electric field distribution without affecting the normal working characteristics of the device, reduces the hole accumulation and local heat accumulation, and reduces the temperature of the device when the single particle effect occurs. Figure 3 As shown, compared with the conventional structure, the reinforced structure reduces the maximum temperature of the device by about 62%, significantly improving the ability of the gallium oxide trench heterojunction barrier Schottky diode to resist single-event burnout effects.

[0040] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A trench-type gallium oxide heterojunction barrier Schottky diode, wherein the trench structure in the diode effectively enhances the device's ability to resist single event effects under heavy ion impact, characterized in that: It comprises a cathode metal layer (101), an N+ substrate layer (102), a first N-type buffer layer (103), a second N-type buffer layer (104), a third N-type buffer layer (105), a first lightly doped drift layer (106), an N-type field stop layer (107), a P-type NiO protection ring (108), a second lightly doped drift layer (109) and an anode metal (110); The p-type NiO protection ring (108) and the second lightly doped drift layer (109) are arranged on the upper surface of the N-type field stop layer (107), and the p-type NiO protection ring (108) and the second lightly doped drift layer (109) are arranged in a staggered manner, and the second lightly doped drift layer (109) is thicker than the p-type NiO protection ring (108), and the p-type NiO protection ring (108) and the second lightly doped drift layer (109) are both square structures; the anode metal layer (110) is arranged on the top layer, covers all the p-type NiO protection ring (108) and the second lightly doped drift layer (109), and forms a groove structure with the contact part of the second lightly doped drift layer (109); the anode metal layer (110) forms an ohmic contact with the top of the p-type NiO protection ring (108), and forms a Schottky contact with the top of the second lightly doped drift layer (109).

2. The Schottky diode according to claim 1, characterized in that: The second lightly doped drift layer (109) is 1 μm to 3 μm thicker than the p-type NiO guard ring (108). The p-type NiO guard ring (108) is 2 μm to 3 μm thick and has a doping concentration of 1×10 19 cm -3 ~2×10 19 cm -3 The second lightly doped drift layer (109) has a thickness of 3 μm to 6 μm and a doping concentration of 3×10 15 cm -3 ~2×10 16 cm -3 .

3. The Schottky diode according to claim 1, characterized in that: in, The cathode metal layer (101) is horizontally arranged at the bottom layer; the N+ substrate layer (102) is arranged on the upper surface of the cathode metal layer (101); the first N-type buffer layer (103) is arranged on the upper surface of the N+ substrate layer (102); the second N-type buffer layer (104) is arranged on the upper surface of the first N-type buffer layer (103); the third N-type buffer layer (105) is arranged on the upper surface of the second N-type buffer layer (104); the first lightly doped drift layer (106) is arranged on the upper surface of the third N-type buffer layer (105); and the N-type field stop layer (107) is arranged on the upper surface of the first lightly doped drift layer (106).

4. The Schottky diode according to claim 3, characterized in that: The N+ substrate layer (102) is N-type doped, with a thickness of 100 μm to 150 μm and a doping concentration of 5×10 18 cm -3 ~2×10 19 cm -3 .

5. The Schottky diode according to claim 3, characterized in that: The first N-type buffer layer (103) is arranged on the upper surface of the N+ substrate layer (102), wherein the first N-type buffer layer (103) has a thickness of 2 μm to 5 μm and a doping concentration of 3×10 17 cm -3 ~6×10 17 cm -3 .

6. The Schottky diode according to claim 3, characterized in that: The second N-type buffer layer (104) is disposed on the upper surface of the first N-type buffer layer (103), wherein the second N-type buffer layer (104) has a thickness of 2 μm to 5 μm and a doping concentration of 1×10 17 cm -3 ~2×10 17 cm -3 .

7. The Schottky diode according to claim 3, characterized in that: The third N-type buffer layer (105) is arranged on the upper surface of the second N-type buffer layer (104), wherein the thickness of the third N-type buffer layer (105) is 2 μm to 5 μm, and the doping concentration is 8×10 16 cm -3 ~1×10 17 cm -3 .

8. The Schottky diode according to claim 3, characterized in that: The first lightly doped drift layer (106) is arranged on the upper surface of the third N-type buffer layer (105), wherein the first lightly doped drift layer (106) has a thickness of 10 μm to 15 μm and a doping concentration of 3×10 15 cm -3 ~2×10 16 cm -3 .

9. The Schottky diode according to claim 3, characterized in that: The N-type field stop layer (107) is arranged above the first lightly doped drift layer (106), wherein the N-type field stop layer (107) has a thickness of 1 μm to 2 μm and a doping concentration of 1×10 17 cm -3 ~5×10 17 cm -3 .

Images