A GaN rectifier device resistant to single particle burnout radiation effect and its preparation method

Abstract

The present invention provides a GaN rectifier device resistant to single-particle burning radiation effect and a preparation method thereof, belonging to the field of semiconductor technology. The GaN rectifier device includes a back cathode metal layer, an n+ gallium nitride substrate layer and an n-gallium nitride drift layer, the n-gallium nitride drift layer is provided with a plurality of annular groove structures and a p+ nickel oxide layer is grown inside, a Schottky contact metal layer is provided above the n-gallium nitride drift layer, an ohmic contact metal layer is provided above the p+ nickel oxide layer and an insulating passivation layer is provided for isolation. A first contact through hole and a second contact through hole are provided on the insulating passivation layer, and a mutually isolated front first anode metal layer and a front second anode metal layer are grown above, which are connected to the Schottky contact metal layer and the ohmic contact metal layer through the first contact through hole and the second contact through hole, respectively. It can solve the technical problem that the existing GaN rectifier is damaged by radiation or even single-particle burning due to the accumulation of holes near the anode.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a GaN rectifier device resistant to single particle burnout radiation effect and a preparation method thereof. Background Art

[0002] Wide bandgap GaN semiconductors are considered to be an ideal semiconductor material to replace traditional silicon materials and meet the application of aerospace power systems due to their superior electrical and radiation properties such as strong breakdown electric field, high electron mobility and high atomic threshold displacement energy. They can be used to make power semiconductor devices with high breakdown voltage, low on-resistance, low switching loss and other characteristics. As the demand for miniaturized, low-loss, high-reliability, and radiation-resistant power devices in aerospace power systems becomes increasingly strong, and rectifier diodes play a key role in transferring energy in power systems, gallium nitride rectifier diodes have become a current research hotspot due to their excellent performance, and have broad application prospects in power systems such as mobile phone fast charging, 5G communications, and smart trams.

[0003] In the related art, the existing GaN rectifier devices mainly adopt the JBS structure in which the pin structure and the sbd structure are arranged alternately. When working at forward bias, it mainly relies on the sbd structure to generate a lower turn-on voltage, and relies on the large injection effect of the pin structure to provide a stable and reliable forward current; when working at reverse bias, it mainly relies on the pin depletion region to pinch off to achieve high withstand voltage. However, under space irradiation, the GaN rectifier works at a higher reverse bias, and the device is prone to single particle effect, which will instantly generate a large number of electron-hole pairs inside the device. At this time, the cathode ohmic contact metal layer of the device is under a higher positive voltage, which will attract the electrons generated by the single particle effect and discharge them out of the device with the current, while the p-type depletion layer region on the side of the anode ohmic contact metal layer will prevent the holes generated by the single particle effect from being discharged from the device, resulting in the accumulation of holes near the anode, and then irradiation damage or even single particle burnout, reducing the working life of the device. Summary of the invention

[0004] The embodiment of the present invention provides a GaN rectifier device resistant to single particle burnout radiation effect and a preparation method thereof. It can solve the technical problem in the prior art that holes accumulate near the anode due to structural defects of the conventional GaN rectifier under radiation, causing radiation damage or even single particle burnout, which affects the normal operation of the device. The technical solution is as follows:

[0005] In the first aspect, an embodiment of the present invention provides a GaN rectifier device resistant to single-particle burnout radiation effects, comprising a back cathode metal layer, an n+ gallium nitride substrate layer and an n-gallium nitride drift layer arranged from bottom to top, a plurality of annular groove structures are opened on the n-gallium nitride drift layer from the center to the outside, a p+ nickel oxide layer is grown in the plurality of annular groove structures and is mutually conductive, a Schottky contact metal layer is arranged above the n-gallium nitride drift layer, an ohmic contact metal layer is arranged above the p+ nickel oxide layer, the p+ nickel oxide layer and the n-gallium nitride drift layer are adjacent to each other, and the An insulating passivation layer is arranged above the Schottky contact metal layer and above the ohmic contact metal layer, and a first contact through-hole connected to the Schottky contact metal layer and a second contact through-hole connected to the ohmic contact metal layer are opened on the insulating passivation layer. A first front anode metal layer and a second front anode metal layer isolated from each other are grown above the insulating passivation layer, the first front anode metal layer is connected to the Schottky contact metal layer through the first contact through-hole, and the second front anode metal layer is connected to the ohmic contact metal layer through the second contact through-hole.

[0006] Optionally, the annular groove structure is a square annular structure arranged around the center of the n-gallium nitride drift layer.

[0007] Optionally, the inner side lengths and outer side lengths of the plurality of annular groove structures are arranged in equal distances from the inside to the outside.

[0008] Optionally, a conducting channel penetrating the plurality of annular groove structures is provided on the n-gallium nitride drift layer, and the p+ nickel oxide layer in the plurality of annular groove structures is conducted through the conducting channel.

[0009] Optionally, a plurality of the conducting channels are spaced around the center of the n-gallium nitride drift layer.

[0010] Optionally, the depth of the conduction channel is the same as the thickness of the p+ nickel oxide layer, and the width of the conduction channel is 10 μm.

[0011] Optionally, a contour shape of the first contact through hole is the same as a contour shape of the Schottky contact metal layer.

[0012] Optionally, a contour shape of the second contact through hole is the same as a contour shape of the ohmic contact metal layer located above the p+ nickel oxide layer in the annular groove structure of the outermost circle.

[0013] In a second aspect, an embodiment of the present invention provides a preparation method for manufacturing a GaN rectifier device resistant to single particle burnout radiation effect as described in the first aspect, comprising:

[0014] Step 1: depositing and growing the back cathode metal layer, the n+ gallium nitride epitaxial layer and the n- gallium nitride drift layer on an epitaxial wafer, etching and removing a portion of the n- gallium nitride drift layer to form the multiple annular groove structures, depositing and growing the p+ nickel oxide layer in the multiple annular groove structures, and growing the insulating passivation layer adjacent to the p+ nickel oxide layer and the n- gallium nitride drift layer;

[0015] Step 2: depositing the Schottky contact metal layer on the n-gallium nitride drift layer, and depositing the ohmic contact metal layer on the p+ nickel oxide layer;

[0016] Step 3: depositing another layer of the insulating passivation layer on the Schottky contact metal layer and the ohmic contact metal layer, etching a first contact through hole in a corresponding area above the Schottky contact metal layer, etching a second contact through hole in a corresponding area above the ohmic contact metal layer, and depositing contact metal in the first contact through hole and the second contact through hole;

[0017] Step 4: deposit the front first anode metal layer above the first contact hole, deposit the front second anode metal layer above the second contact hole, and deposit another layer of the insulating passivation layer between the front first anode metal layer and the front second anode metal layer to achieve electrical isolation.

[0018] Optionally, step 1 further includes etching a conducting channel on the n-gallium nitride drift layer that penetrates the plurality of annular groove structures in a transverse direction, so as to make the p+ nickel oxide layer within the plurality of annular groove structures conductive.

[0019] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0020] The GaN rectifier device with resistance to single particle burnout radiation effect provided by the embodiment of the present invention is compared with the single anode configuration structure in the traditional device structure of the related art. By distributing the p+ nickel oxide layer and the n-gallium nitride drift layer in a ring-shaped interval, the overall distribution area of ​​the p+ nickel oxide layer, that is, the pn junction contact area in the rectifier device, is expanded, which is beneficial to increase the radiation resistance of the device and maintain a good forward conductivity modulation capability. At the same time, when the device is in a high reverse voltage bias and single particle irradiation environment, the positive first anode metal layer corresponding to the Schottky contact metal layer above the n-gallium nitride drift layer is normally set to 0V, and a negative voltage can be applied to the positive second anode metal layer of the ohmic contact metal layer corresponding to the p+ nickel oxide layer. In this case, the holes generated by the single particle effect will be attracted by the negative voltage of the positive second anode metal layer and can be dissipated to the outside of the device more quickly, thereby effectively solving the technical problem that the conventional GaN rectifier in the prior art accumulates holes near the anode due to structural defects of the device under irradiation, causing irradiation damage or even single particle burning, which affects the normal operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a schematic diagram of the arrangement structure of the p+ nickel oxide layer and the n- gallium nitride drift layer in the conventional GaN rectifier device structure in the related art;

[0023] Figure 2 It is a schematic diagram of the overall structure of a conventional GaN rectifier device in the related art;

[0024] Figure 3 It is a schematic diagram of the steps of manufacturing a back cathode metal layer, an n+ gallium nitride substrate layer, an n- gallium nitride drift layer, a p+ nickel oxide layer and an insulating passivation layer of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of the steps of manufacturing a conducting channel of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0026] Figure 5 It is a schematic diagram of the steps of manufacturing a Schottky contact metal layer and an ohmic contact metal layer of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0027] Figure 6It is a schematic diagram of the steps of making a first contact through hole in a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0028] Figure 7 It is a schematic diagram of the steps of making a second contact through hole in a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0029] Figure 8 It is a schematic diagram of the overall structure of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention;

[0030] Fig. 9 It is a flow chart of the preparation method provided in an embodiment of the present invention.

[0031] In the figure: 1-back cathode metal layer; 2-n+ gallium nitride substrate layer; 3-n-gallium nitride drift layer; 4-p+ nickel oxide layer; 5-Schottky contact metal layer; 6-ohmic contact metal layer; 7-insulating passivation layer; 8-front first anode metal layer; 9-front second anode metal layer; 31-annular groove structure; 32-conduction channel; 71-first contact through hole; 72-second contact through hole. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] Figure 1 It is a schematic diagram of the arrangement structure of a p+ nickel oxide layer and an n- gallium nitride drift layer in a conventional GaN rectifier device structure in the related art; Figure 2 Schematic diagram of the overall structure of a conventional GaN rectifier device in the related art. Figure 1 to Figure 2 As shown, in the related art, the structure of the p+ nickel oxide layer (the region marked 20 in the figure) and the n- gallium nitride drift layer (the region marked 30 in the figure) in the existing GaN rectifier device is as follows Figure 1 As shown, reference Figure 2 In the overall structure, the ohmic contact metal layer above the p+ nickel oxide layer (the area marked as 40 in the figure) and the Schottky contact metal layer above the n-gallium nitride drift layer (the area marked as 40 in the figure) are a layer of metal grown at the same time, and then a layer of metal is deposited and grown on top as an anode metal layer (the area marked as 50 in the figure).

[0034] The GaN rectifier device with the above structure is susceptible to the irradiation effect, especially the single particle effect, when in extreme working conditions, causing a large number of electron-hole pairs to be generated inside the device. For example, when in a reverse bias state, the electrons generated by the irradiation are attracted by the positive voltage of the cathode and will flow out of the device from the conventional cathode ohmic contact metal layer. However, since one side of the conventional anode ohmic contact metal layer is in a zero bias state, the depletion layer generated by the conventional p+ nickel oxide layer in the reverse bias state hinders the dissipation of holes, which in turn causes holes to gather at the anode, thereby causing single particle burnout in the rectifier device and affecting the normal operation of the device.

[0035] Figure 3 It is a schematic diagram of the steps of manufacturing a back cathode metal layer, an n+ gallium nitride substrate layer, an n- gallium nitride drift layer, a p+ nickel oxide layer and an insulating passivation layer of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the steps of manufacturing a conducting channel of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention; Figure 5 It is a schematic diagram of the steps of manufacturing a Schottky contact metal layer and an ohmic contact metal layer of a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention; Figure 6 It is a schematic diagram of the steps of making a first contact through hole in a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of the steps of making a second contact through hole in a GaN rectifier device resistant to single particle burnout radiation effect provided by an embodiment of the present invention; Figure 8 Schematic diagram of the overall structure of a GaN rectifier device resistant to single particle burnout irradiation effect provided by an embodiment of the present invention. Figures 3 to 8As shown, based on the above defects, an embodiment of the present invention provides a GaN rectifier device resistant to single particle burnout radiation effect, including a back cathode metal layer 1, an n+ gallium nitride substrate layer 2 and an n-gallium nitride drift layer 3 arranged from bottom to top. A plurality of annular groove structures 31 are opened on the n-gallium nitride drift layer 3 from the center to the outside, and a p+ nickel oxide layer 4 is grown in the plurality of annular groove structures 31 and is mutually conductive. A Schottky contact metal layer 5 is arranged above the n-gallium nitride drift layer 3, an ohmic contact metal layer 6 is arranged above the p+ nickel oxide layer 4, and an insulating passivation layer 7 is arranged adjacent to the p+ nickel oxide layer 4 and the n-gallium nitride drift layer 3, above the Schottky contact metal layer 5 and above the ohmic contact metal layer 6. A first contact through hole 71 connected to the Schottky contact metal layer 5 and a second contact through hole 72 connected to the ohmic contact metal layer 6 are provided on the insulating passivation layer 7. A first front anode metal layer 8 and a second front anode metal layer 9 isolated from each other are grown above the insulating passivation layer 7. The first front anode metal layer 8 is connected to the Schottky contact metal layer 5 through the first contact through hole 71, and the second front anode metal layer 9 is connected to the ohmic contact metal layer 6 through the second contact through hole 72.

[0036] In the embodiment of the present invention, when manufacturing the GaN rectifier device resistant to single particle burnout radiation effect, refer to Figure 3 The epitaxial wafer is sequentially grown from bottom to top to form a back cathode metal layer 1, an n+ gallium nitride substrate layer 2 and an n- gallium nitride drift layer 3, and a portion of the n- gallium nitride drift layer 3 is removed by inductively coupled plasma dry etching to form a plurality of annular groove structures 31, and then an insulating passivation layer 7 is grown along the edge of the annular groove structure 31 by plasma enhanced chemical vapor deposition, and then a p+ nickel oxide layer 4 is deposited and grown in the plurality of annular groove structures 31 to obtain the four regions 3A, 3B, 3C, and 3D of the n- gallium nitride drift layer 3 and the four regions 4a, 4b, 4c, and 4d of the p+ nickel oxide layer 4 in the embodiment of the present invention.

[0037] Further, refer to Figure 4 , the inductively coupled plasma dry etching method is used again to etch away part of the n-gallium nitride drift layer 3 and the insulating passivation layer 7 to form a conductive channel 32 that runs through multiple annular groove structures 31 in the transverse direction, and the p+ nickel oxide layer 4 is deposited and grown again in the conductive channel 32 area to form the overall conduction of the four areas 4a, 4b, 4c, and 4d in the p+ nickel oxide layer 4 in the embodiment of the present invention.

[0038] Further, refer to Figure 5, using a photolithography lift-off method, a Schottky contact metal layer 5 is deposited and grown on the n-gallium nitride drift layer 3, and an ohmic contact metal layer 6 is deposited and grown on the p+ nickel oxide layer 4, to form regions 5A, 5B, 5C, 5D of the Schottky contact metal layer 5 and regions 6a, 6b, 6c, 6d of the ohmic contact metal layer 6 in the embodiment of the present invention.

[0039] Further, refer to Figure 6 , a plasma enhanced chemical vapor deposition method is used again to grow an insulating passivation layer 7 on the entire device, and then a first contact through hole 71 is etched above the 5A, 5B, 5C, and 5D regions of the Schottky contact metal layer 5 using an inductively coupled plasma dry etching method, and an ohmic contact metal is deposited and grown in the first contact through hole 71 using a photolithography lift-off method for further connection with the upper structure.

[0040] Further, refer to Figure 7 The second contact hole 72 is etched above the outermost circle 6d in the ohmic contact metal layer 6 by inductively coupled plasma dry etching, and the ohmic contact metal is deposited and grown in the second contact hole 72 by photolithography lift-off method for further connection with the upper structure.

[0041] Finally, reference Figure 8 , a first front anode metal layer 8 is deposited and grown on the ohmic contact metal in the first contact hole 71 by using a photolithography lift-off method to cover the entire area above the Schottky contact metal layer 5; a second front anode metal layer 9 is deposited and grown on the ohmic contact metal in the second contact hole 72 to cover the entire corresponding area above the ohmic contact metal layer 6, and an insulating passivation layer 7 is deposited and grown between the first front anode metal layer 8 and the second front anode metal layer 9 to achieve electrical isolation, thereby completing the manufacture of the GaN rectifier device.

[0042] Compared with the single anode configuration structure in the conventional device structure of the related art, the GaN rectifier device resistant to single particle burnout radiation effect provided by the embodiment of the present invention expands the overall distribution area of ​​the p+ nickel oxide layer 4, that is, the pn junction contact area in the rectifier device, by distributing the p+ nickel oxide layer 4 and the n-gallium nitride drift layer 3 in a ring shape, which is beneficial to increasing the radiation resistance of the device while maintaining a good forward conductivity modulation capability. At the same time, when the device is in a high reverse voltage bias and single-particle irradiation environment, the front first anode metal layer 8 corresponding to the Schottky contact metal layer 5 above the n-gallium nitride drift layer 3 is normally set to 0V, and a negative voltage can be applied separately to the front second anode metal layer 9 corresponding to the ohmic contact metal layer 6 of the p+ nickel oxide layer 4. In this case, the holes generated by the single-particle effect will be attracted by the negative voltage of the front second anode metal layer 9 and can be dissipated to the outside of the device more quickly, thereby effectively solving the technical problem in the prior art that holes accumulate near the anode due to structural defects of the device under irradiation, resulting in radiation damage or even single-particle burning, which affects the normal operation of the device.

[0043] Preferably, the annular groove structure 31 is a square annular structure arranged around the center of the n-gallium nitride drift layer 3. Figure 1 The distribution of the p+ nickel oxide layer and the n-gallium nitride drift layer in the conventional GaN rectifier device in the embodiment of the present invention is different. In the embodiment of the present invention, the n-gallium nitride drift layer 3 and the p+ nickel oxide layer 4 are distributed in a square ring shape, which can increase the area proportion of the p+ nickel oxide layer 4 in the same pattern area, thereby expanding the pn junction contact area in the rectifier device, and further increasing the device's radiation resistance and forward conductivity modulation capability.

[0044] Preferably, the inner side lengths and outer side lengths of the plurality of annular groove structures 31 are arranged equidistantly from the inside to the outside. For example, in the embodiment of the present invention, the 3A region of the n-gallium nitride drift layer 3 located at the center is a square, and 3B, 3C, and 3D are all square annular structures. A p+ nickel oxide layer 4 which is also a square annular is provided on the outer layer of each n-gallium nitride drift layer 3 region, that is, four regions 4a, 4b, 4c, and 4d. Among them, the side length of 3A is 25μm, the inner and outer side lengths of 4a are 25μm and 50μm, the inner and outer side lengths of 3B are 50μm and 75μm, the inner and outer side lengths of 4b are 75μm and 100μm, the inner and outer side lengths of 3C are 100μm and 125μm, the inner and outer side lengths of 4c are 125μm and 150μm, the inner and outer lengths of 3D are 150μm and 175μm, and the inner and outer side lengths of 4d are 175μm and 200μm. The above-mentioned arrangement of side lengths in arithmetic steps is conducive to weakening the electric field of the Schottky contact interface layer and reducing the leakage current in the device.

[0045] The GaN drift layer 3 is provided with a conducting channel 32 penetrating a plurality of annular groove structures 31, and the p+ nickel oxide layer 4 in the plurality of annular groove structures 31 is conducted through the conducting channel 32. By way of example, in an embodiment of the present invention, according to the conduction requirement, a plurality of conducting channels 32 can be evenly spaced in the four sides of the square ring around the center of the n-GaN drift layer 3, that is, the 3a region, to flexibly adjust the conductivity of the conducting channel 32. By way of example, in an embodiment of the present invention, the depth of the conducting channel 32 is the same as the thickness of the p+ nickel oxide layer 4, and the width of the conducting channel 32 is 10 μm.

[0046] Preferably, the contour shape of the first contact through hole 71 is the same as the contour shape of the Schottky contact metal layer 5. The contour shape of the second contact through hole 72 is the same as the contour shape of the ohmic contact metal layer 6 located above the p+ nickel oxide layer 4 in the annular groove structure 31 of the outermost circle. Exemplarily, in an embodiment of the present invention, in order to form a good contact between the first anode metal layer 8 on the front side and the Schottky contact metal layer 5, the number and shape of the first contact through holes 71 are variable; in order to form a good contact between the second anode metal layer 9 on the front side and the ohmic contact metal layer 6, the number and shape of the second contact through holes 72 are variable. In an embodiment of the present invention, the first contact through holes 71 with the same contour shape are arranged above the 3A, 3B, 3C and 3D regions, that is, above all the Schottky contact metal layer 5 regions, and the second contact through holes 72 with the same contour shape are arranged only above the 4d with a relatively larger overall area, so as to reduce the process difficulty and save costs while ensuring the conductive performance.

[0047] Fig. 9 Schematic diagram of the preparation method provided in the embodiment of the present invention. Fig. 9 As shown, the embodiment of the present invention also provides a preparation method for preparing Figures 3 to 8 The GaN rectifier device resistant to single particle burnout radiation effect shown in the figure comprises the following steps:

[0048] S1: depositing and growing a back cathode metal layer 1, an n+ gallium nitride epitaxial layer and an n- gallium nitride drift layer 3 on an epitaxial wafer, etching and removing a portion of the n- gallium nitride drift layer 3 to form a plurality of annular groove structures 31, and depositing and growing a p+ nickel oxide layer 4 in the plurality of annular groove structures 31, and growing an insulating passivation layer 7 adjacent to the p+ nickel oxide layer 4 and the n- gallium nitride drift layer 3;

[0049] Specifically, a back cathode metal layer 1, an n+ gallium nitride substrate layer 2 and an n- gallium nitride drift layer 3 are grown on the epitaxial wafer in sequence from bottom to top, a portion of the n- gallium nitride drift layer 3 is removed by inductively coupled plasma dry etching to form a plurality of annular groove structures 31, and then an insulating passivation layer 7 is grown along the edge of the annular groove structure 31 by plasma enhanced chemical vapor deposition, and then a p+ nickel oxide layer 4 is deposited and grown in the plurality of annular groove structures 31 to obtain the four regions 3A, 3B, 3C, and 3D of the n- gallium nitride drift layer 3 and the four regions 4a, 4b, 4c, and 4d of the p+ nickel oxide layer 4 in the embodiment of the present invention. In addition, by using an inductively coupled plasma dry etching method, a portion of the n-gallium nitride drift layer 3 and the insulating passivation layer 7 are etched away to form a conductive channel 32 that runs through multiple annular groove structures 31 in the transverse direction, and a p+ nickel oxide layer 4 is deposited and grown again in the conductive channel 32 area to form an overall conduction of the four areas 4a, 4b, 4c, and 4d in the p+ nickel oxide layer 4 in the embodiment of the present invention.

[0050] S2 : depositing a Schottky contact metal layer 5 on the n-gallium nitride drift layer 3 , and depositing an ohmic contact metal layer 6 on the p+ nickel oxide layer 4 .

[0051] Specifically, a Schottky contact metal layer 5 made of Ni / Al is deposited and grown on the n-gallium nitride drift layer 3, and an ohmic contact metal layer 6 made of Ti / Al is deposited and grown on the p+ nickel oxide layer 4 by a photolithography lift-off method, to form regions 5A, 5B, 5C, 5D of the Schottky contact metal layer 5 and regions 6a, 6b, 6c, 6d of the ohmic contact metal layer 6 in the embodiment of the present invention.

[0052] S3: Deposit another insulating passivation layer 7 on the Schottky contact metal layer 5 and the ohmic contact metal layer 6, etch a first contact through hole 71 in the corresponding area above the Schottky contact metal layer 5, etch a second contact through hole 72 in the corresponding area above the ohmic contact metal layer 6, and deposit contact metal in the first contact through hole 71 and the second contact through hole 72.

[0053] Specifically, a plasma enhanced chemical vapor deposition method is used to grow an insulating passivation layer 7 on the entire device, and then a first contact hole 71 is etched above the 5A, 5B, 5C, and 5D regions of the Schottky contact metal layer 5 by an inductively coupled plasma dry etching method, and an ohmic contact metal is deposited and grown in the first contact hole 71 by a photolithography stripping method for further connection with the upper structure; a second contact hole 72 is etched above 6d located in the outermost circle in the ohmic contact metal layer 6 by an inductively coupled plasma dry etching method, and an ohmic contact metal is deposited and grown in the second contact hole 72 by a photolithography stripping method for further connection with the upper structure.

[0054] S4: deposit a first front anode metal layer 8 above the first contact through hole 71, deposit a second front anode metal layer 9 above the second contact through hole 72, and deposit an insulating passivation layer 7 between the first front anode metal layer 8 and the second front anode metal layer 9 to achieve electrical isolation.

[0055] Specifically, a first front anode metal layer 8 is deposited and grown on the ohmic contact metal in the first contact hole 71 by using a photolithography lift-off method to cover the entire area above the Schottky contact metal layer 5; a second front anode metal layer 9 is deposited and grown on the ohmic contact metal in the second contact hole 72 to cover the entire corresponding area above the ohmic contact metal layer 6, and an insulating passivation layer 7 is deposited and grown between the first front anode metal layer 8 and the second front anode metal layer 9 to achieve electrical isolation, thereby completing the manufacture of the GaN rectifier device.

[0056] The GaN rectifier device resistant to single particle burnout radiation effect manufactured by the above-mentioned preparation method, compared with the single anode configuration structure in the traditional device structure of the related technology, expands the overall distribution area of ​​the p+ nickel oxide layer 4, that is, the pn junction contact area in the rectifier device, by distributing the p+ nickel oxide layer 4 and the n-gallium nitride drift layer 3 in a ring-shaped interval, which is beneficial to increase the device's radiation resistance while maintaining a good forward conductivity modulation capability. At the same time, when the device is in a high reverse voltage bias and single-particle irradiation environment, the front first anode metal layer 8 corresponding to the Schottky contact metal layer 5 above the n-gallium nitride drift layer 3 is normally set to 0V, and a negative voltage can be applied separately to the front second anode metal layer 9 corresponding to the ohmic contact metal layer 6 of the p+ nickel oxide layer 4. In this case, the holes generated by the single-particle effect will be attracted by the negative voltage of the front second anode metal layer 9 and can be dissipated to the outside of the device more quickly, thereby effectively solving the technical problem in the prior art that holes accumulate near the anode due to structural defects of the device under irradiation, resulting in radiation damage or even single-particle burning, which affects the normal operation of the device.

[0057] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0058] The above descriptions are merely optional embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A GaN rectifier device resistant to single particle burnout radiation effect, characterized in that: The invention comprises a back cathode metal layer (1), an n+ gallium nitride substrate layer (2) and an n- gallium nitride drift layer (3) arranged from bottom to top, a plurality of annular groove structures (31) are provided on the n- gallium nitride drift layer (3) from the center outward, a p+ nickel oxide layer (4) is grown in the plurality of annular groove structures (31) and is mutually conductive, a Schottky contact metal layer (5) is provided above the n- gallium nitride drift layer (3), an ohmic contact metal layer (6) is provided above the p+ nickel oxide layer (4), an insulating passivation layer (7) is provided adjacent to the p+ nickel oxide layer (4) and the n- gallium nitride drift layer (3), above the Schottky contact metal layer (5) and above the ohmic contact metal layer (6), a first contact layer (5) is provided on the insulating passivation layer (7) and is connected to the Schottky contact metal layer (5). A contact through hole (71) and a second contact through hole (72) connected to the ohmic contact metal layer (6); a first front anode metal layer (8) and a second front anode metal layer (9) isolated from each other are grown above the insulating passivation layer (7); the first front anode metal layer (8) is connected to the Schottky contact metal layer (5) through the first contact through hole (71); the second front anode metal layer (9) is connected to the ohmic contact metal layer (6) through the second contact through hole (72); the first front anode metal layer (8) corresponding to the Schottky contact metal layer (5) above the n-gallium nitride drift layer (3) is normally set to 0V, and a negative voltage is applied separately to the second front anode metal layer (9) corresponding to the ohmic contact metal layer (6) of the p+ nickel oxide layer (4).

2. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 1, characterized in that: The annular groove structure (31) is a square annular structure arranged around the center of the n-gallium nitride drift layer (3).

3. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 2, characterized in that: The inner side lengths and outer side lengths of the plurality of annular groove structures (31) are arranged in equal differences from the inside to the outside.

4. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 2, characterized in that: A conducting channel (32) penetrating the plurality of annular groove structures (31) is provided on the n-gallium nitride drift layer (3), and the p+ nickel oxide layer (4) in the plurality of annular groove structures (31) is conducted through the conducting channel (32).

5. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 4, characterized in that: A plurality of the conducting channels (32) are arranged at intervals around the center of the n-gallium nitride drift layer (3).

6. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 4, characterized in that: The depth of the conducting channel (32) is the same as the thickness of the p+ nickel oxide layer (4), and the width of the conducting channel (32) is 10 μm.

7. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 1, characterized in that: The contour shape of the first contact through hole (71) is the same as the contour shape of the Schottky contact metal layer (5).

8. The GaN rectifier device resistant to single-particle burnout radiation effect according to claim 7, characterized in that: The contour shape of the second contact through hole (72) is the same as the contour shape of the ohmic contact metal layer (6) located above the p+ nickel oxide layer (4) in the outermost annular groove structure (31).

9. A preparation method for manufacturing a GaN rectifier device resistant to single particle burnout radiation effect as claimed in any one of claims 1 to 8, characterized in that: include: Step 1: depositing and growing the back cathode metal layer (1), the n+ gallium nitride epitaxial layer and the n-gallium nitride drift layer (3) on an epitaxial wafer, etching and removing a portion of the n-gallium nitride drift layer (3) to form the plurality of annular groove structures (31), depositing and growing the p+ nickel oxide layer (4) in the plurality of annular groove structures (31), and growing the insulating passivation layer (7) adjacent to the p+ nickel oxide layer (4) and the n-gallium nitride drift layer (3); Step 2: depositing the Schottky contact metal layer (5) on the n-gallium nitride drift layer (3), and depositing the ohmic contact metal layer (6) on the p+ nickel oxide layer (4); Step 3: depositing another layer of the insulating passivation layer (7) above the Schottky contact metal layer (5) and the ohmic contact metal layer (6), etching a first contact through hole (71) in a corresponding area above the ohmic contact metal layer (6), etching a second contact through hole (72) in a corresponding area above the ohmic contact metal layer (6), and depositing contact metal in the first contact through hole (71) and the second contact through hole (72); Step 4: Depositing the first front anode metal layer (8) above the first contact hole (71), depositing the second front anode metal layer (9) above the second contact hole (72), and depositing another layer of the insulating passivation layer (7) between the first front anode metal layer (8) and the second front anode metal layer (9) to achieve electrical isolation.

10. The preparation method according to claim 9, characterized in that: The step 1 also includes etching a conducting channel (32) on the n-gallium nitride drift layer (3) that penetrates the multiple annular groove structures (31) in a transverse direction, so as to make the p+ nickel oxide layer (4) in the multiple annular groove structures (31) conductive.

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