High-voltage-resistant gallium oxide heterojunction diode
By introducing JBS units and gradient JTE effects into gallium oxide heterojunction diodes, the electric field distribution is optimized, solving the problems of withstand voltage performance and reliability of gallium oxide diodes and achieving a high breakdown voltage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-07
AI Technical Summary
Existing gallium oxide diodes have shortcomings in terms of voltage withstand performance and reliability, especially in the problem of electric field concentration. They cannot fully utilize the high breakdown electric field characteristics of gallium oxide, and existing voltage withstand optimization methods are insufficient in their ability to control the electric field inside the junction region.
By introducing JBS units and gradient JTE effect into gallium oxide heterojunction diodes, the electric field distribution is optimized by setting protection units in the source and terminal regions within the cell trench. This includes setting p-type nickel oxide regions with doping concentration gradients in the source and terminal regions to form a gradient JTE effect and reduce the electric field peak.
This significantly improves the breakdown voltage and reliability of gallium oxide heterojunction diodes, meeting the withstand voltage requirements of high-voltage power electronics applications.
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Figure CN121815678A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a diode, in particular a high-voltage gallium oxide heterojunction diode. BACKGROUND
[0002] Wide bandgap semiconductor materials are the core driving force for the development of power electronic devices towards high voltage, high frequency, high efficiency, and miniaturization. Among them, gallium oxide has unique advantages such as ultra-high theoretical breakdown field (> 8 MV / cm), wide bandgap (about 4.8 eV), high Baliga merit (a key indicator of power device performance, the higher the value, the more suitable for high voltage applications), and has irreplaceable potential in high-voltage power electronics (such as high-voltage power transmission, new energy grid connection, electric vehicle high-voltage bus, etc.).
[0003] However, the characteristics of gallium oxide material itself make its p-type doping extremely challenging, and high-quality, high-concentration p-type gallium oxide has not yet been achieved. The contact between p-type nickel oxide and n-type gallium oxide can form a heterojunction, which can make up for the lack of p-type gallium oxide doping by using mature p-type high-doping technology (doping concentration up to 10 19 cm -3 The above), and has high matching degree with the band structure of gallium oxide, can form a stable heterojunction barrier, effectively support high-voltage blocking, and has good preparation process compatibility, so p-type nickel oxide material is used to form a heterojunction diode structure with gallium oxide, but the formed heterojunction still has many deficiencies, including: 1) The problem of electric field concentration is prominent. In the design of the heterojunction (such as a single-doping-concentration p-NiO / n-Ga2O3 junction), the electric field is easily concentrated in the edge of the junction region, the corner of the device (such as the corner of the interface between the dielectric layer and the semiconductor), and the surface state dense area. When the local electric field exceeds the material breakdown threshold, the device will break down prematurely, and the high breakdown field characteristics of gallium oxide cannot be fully utilized.
[0004] 2) Limitations of existing voltage optimization methods, such as surface passivation or field plate structure can be used to optimize voltage, wherein surface passivation can reduce surface states, but only partially alleviates surface leakage, and has limited effect on improving the internal electric field concentration of the junction region; when the field plate structure is used to optimize the voltage, the traditional field plate can disperse the surface electric field, but has insufficient ability to regulate the electric field in the vertical direction of the junction region.
[0005] In summary, the existing gallium oxide diode has deficiencies in voltage performance and reliability, and there is an urgent need for an innovative structure design of electric field regulation to optimize the electric field distribution in key areas such as the junction region, corner, and surface, fully release the high-voltage potential of gallium oxide material, and meet the stringent demands of high-voltage power electronic applications. SUMMARY
[0006] The present application aims to overcome the deficiencies in the prior art, and provide a high-voltage gallium oxide heterojunction diode which can optimize the electric field distribution of the gallium oxide heterojunction diode and improve the breakdown voltage of the gallium oxide heterojunction diode, thereby meeting the voltage withstand performance requirements of the diode in high-voltage power electronic application scenarios.
[0007] According to the technical scheme provided by the present application, a high-voltage gallium oxide heterojunction diode comprises: a gallium oxide substrate comprising at least an N-type gallium oxide drift layer; an active region distributed in a central region of the N-type gallium oxide drift layer and comprising at least one JBS unit, wherein, the JBS unit comprises a cell trench prepared in the N-type gallium oxide drift layer and an anode metal located in the cell trench and electrically connected with a source region gallium oxide heterojunction; the source region gallium oxide heterojunction comprises at least a source region first doped p-type nickel oxide region distributed below a bottom of the cell trench and in contact with the N-type gallium oxide drift layer; on a cross section of the diode, a source region protection unit is arranged to at least cover a corner region of the source region first doped p-type nickel oxide region and form a gradient JTE effect with the source region first doped p-type nickel oxide region, and the corner region of the source region first doped p-type nickel oxide region is spaced from the N-type gallium oxide drift layer by the source region protection unit.
[0008] the source region protection unit comprises a source region second doped p-type nickel oxide region, wherein, on the cross section of the diode, the source region second doped p-type nickel oxide region corresponds to at least a corner of the bottom of the cell trench; a doping concentration of the source region second doped p-type nickel oxide region is lower than a corresponding doping concentration of the source region first doped p-type nickel oxide region.
[0009] a doping concentration range of the source region first doped p-type nickel oxide region is 5×10 18 cm -3 ~2×10 20 cm -3 , and a doping concentration range of the source region second doped p-type nickel oxide region is 5×10 16 cm -3 ~5×10 18 cm -3 .
[0010] on the cross section of the diode, a width of the anode metal is less than a groove width of the cell trench; in the cell trench, an end portion of the anode metal adjacent to a corner of the cell trench is insulated and separated from the source region first doped p-type nickel oxide region by a source region dielectric layer.
[0011] In the active region, the anode metal is also in a basic Schottky contact with the gallium oxide outside the cell trench.
[0012] The diode further comprises a terminal region distributed outside the gallium oxide substrate, wherein, The terminal region surrounds the active region, and the terminal region comprises at least one guard ring surrounding the active region; In the cross section of the diode, the guard ring comprises a terminal trench, and a terminal dielectric layer and a terminal passivation layer filled in the terminal trench; The terminal passivation layer is separated from the inner wall of the terminal trench by the terminal dielectric layer.
[0013] The depth of the terminal trench is greater than the depth of the cell trench.
[0014] In the terminal region, a terminal gallium oxide heterojunction is further provided, wherein, The terminal gallium oxide heterojunction comprises a terminal first doped p-type nickel oxide region covering the outer wall of the terminal trench, and the terminal first doped p-type nickel oxide region is in contact with the N-type gallium oxide drift layer.
[0015] In the terminal region, a terminal protection unit is further provided for contact matching of the terminal first doped p-type nickel oxide region and forming a gradient JTE effect, wherein, The terminal protection unit comprises a terminal second doped p-type nickel oxide region, and the terminal first doped p-type nickel oxide region is separated from the N-type gallium oxide drift layer by the terminal second doped p-type nickel oxide region. The doping concentration of the terminal second doped p-type nickel oxide region is lower than the corresponding doping concentration of the terminal first doped p-type nickel oxide region.
[0016] The gallium oxide substrate further comprises an N-type gallium oxide substrate adjacent to the N-type gallium oxide drift layer, wherein, A cathode metal is provided on the N-type gallium oxide substrate, and the cathode metal is in ohmic contact with the N-type gallium oxide substrate.
[0017] Advantages of the present application: the active region comprises at least one JBS unit, the JBS unit comprises a cell trench, and an anode metal is provided in the cell trench, the anode metal is electrically connected with the source region gallium oxide heterojunction, the source region protection unit is in contact with the source region first doped p-type nickel oxide region in the source region gallium oxide heterojunction to form a gradient JTE effect, and the peak electric field of the corresponding corner region of the source region first doped p-type nickel oxide region can be reduced by the formed gradient JTE effect.
[0018] A protection ring can be arranged in the terminal region, and a terminal trench is also arranged in the protection ring, and a terminal gallium oxide heterojunction and a terminal protection unit are arranged in the terminal region. The gradient JTE effect can be formed in the terminal region, the electric field distribution of the gallium oxide heterojunction diode is optimized in a double way, the electric field concentration is reduced, and thus the breakdown voltage and the reliability of the gallium oxide heterojunction diode are significantly improved, and the withstand voltage performance requirement of the diode in the high-voltage power electronic application scenario is met. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 An embodiment of a cross-sectional view of the gallium oxide heterojunction diode is shown.
[0020] Figure 2 An embodiment of an electric field distribution diagram of the gradient JTE effect is shown.
[0021] Figure 3 An embodiment of an electric field distribution diagram of the existing gallium oxide heterojunction is shown.
[0022] The reference signs are explained as follows: 1, cathode metal; 2, N-type gallium oxide substrate; 3, N-type gallium oxide drift layer; 4, terminal second doped p-type nickel oxide region; 5, terminal dielectric layer; 6, front passivation layer; 7, source region dielectric layer; 8, source region first doped p-type nickel oxide region; 9, source region second doped p-type nickel oxide region; 10, anode metal; and 11, terminal first doped p-type nickel oxide region. DETAILED DESCRIPTION
[0023] The application will be further described below in combination with specific drawings and embodiments.
[0024] In order to optimize the electric field distribution of the gallium oxide heterojunction diode, improve the breakdown voltage of the gallium oxide heterojunction diode, and meet the withstand voltage performance requirement of the diode in the high-voltage power electronic application scenario, the application provides a high-voltage gallium oxide heterojunction diode. Specifically, the diode comprises: a gallium oxide substrate, which at least comprises an N-type gallium oxide drift layer 3; an active region, which is distributed in a central region of the N-type gallium oxide drift layer 3 and comprises at least one JBS unit, wherein the JBS unit comprises a cell trench prepared in the N-type gallium oxide drift layer 3 and an anode metal 10 located in the cell trench and electrically connected with a source region gallium oxide heterojunction; the source region gallium oxide heterojunction comprises at least a source region first doped p-type nickel oxide region 8 distributed below a bottom of the cell trench and in contact with the N-type gallium oxide drift layer 3; On the cross section of the diode, a source region protection unit is arranged to at least cover the corner region of the source region first doped p-type nickel oxide region 8 and form a gradient JTE effect with the source region first doped p-type nickel oxide region 8. The corner region of the source region first doped p-type nickel oxide region 8 is spaced from the N-type gallium oxide drift layer through the source region protection unit.
[0025] The diode of the present application should include a gallium oxide substrate, which can adopt the form commonly used in the prior art, Figure 1 An embodiment of the gallium oxide substrate is shown in FIG. 1. As can be seen from the figure, the gallium oxide substrate should include an N-type gallium oxide drift layer 3, which is generally a low-doped gallium oxide layer. The N-type gallium oxide drift layer 3 is generally used to bear the reverse withstand voltage of the diode, and a high-voltage blocking is achieved by widening the depletion region, while the reverse leakage current level is controlled.
[0026] In order to form the functional region of the diode, an active region should be prepared in the central region of the N-type gallium oxide drift layer 3. In an embodiment of the present application, the active region includes at least one JBS (Junction Barrier Schottky) unit. Of course, the active region can also include multiple arrayed JBS units, each of which serves as a cell in the active region. Figure 1 An embodiment in which one JBS unit is arranged in the active region is shown in FIG. 1. When multiple JBS units are present, the multiple JBS units are connected in parallel to form an integral whole.
[0027] Unlike the prior art gallium oxide heterojunction diode, the JBS unit of the present application includes a cell trench and an anode metal 10 prepared in the cell trench, and Figure 1 As can be seen, the cell trench is prepared in the N-type gallium oxide drift layer 3, and the cell trench is vertically distributed in the N-type gallium oxide drift layer 3. The anode metal 10 can serve as the anode terminal of the diode. When multiple JBS units are present, the anode metals of all the JBS units are electrically connected to each other to connect all the JBS units in parallel to form an integral whole. It should be understood that the cell trench is not marked in the figure.
[0028] Like the prior art gallium oxide heterojunction diode, the anode metal 10 should be electrically connected to the source region gallium oxide heterojunction. The manner of forming the source region gallium oxide heterojunction can be consistent with the prior art, such as arranging a source region first doped p-type nickel oxide region 8 in the N-type gallium oxide drift layer 3 and making the source region first doped p-type nickel oxide region 8 contact the N-type gallium oxide drift layer 3. At this time, the anode metal 10 is electrically connected to the source region gallium oxide heterojunction, specifically, the anode metal 10 is in ohmic contact with the source region first doped p-type nickel oxide region 8. Therefore, when the anode metal 10 is prepared in the cell trench, the anode metal 10 should be in ohmic contact with the source region first doped p-type nickel oxide region 8.
[0029] As can be seen from the above description, the existing gallium oxide heterojunction may have a relatively insufficient withstand voltage. In order to further optimize the electric field distribution and improve the breakdown voltage of the gallium oxide heterojunction diode, in an embodiment of the present application, for each JBS unit, a source region protection unit capable of forming a gradient JTE effect with the source region first doped p-type nickel oxide region 8 is further arranged, and the source region protection unit at least covers the corner region of the source region first doped p-type nickel oxide region 8. At this time, the corner region of the source region first doped p-type nickel oxide region 8 is separated from the N-type gallium oxide drift layer 3 by the source region protection unit. It should be noted that when the source region protection unit is used to coat the source region first doped p-type nickel oxide region 8, a gradient JTE effect can be formed. Based on the characteristics of the gradient JTE effect, the peak electric field of the corresponding corner region of the source region first doped p-type nickel oxide region 9 can be reduced by using the formed gradient JTE (Junction Termination Extension) effect, thereby improving the withstand voltage of the gallium oxide heterojunction diode and meeting the withstand voltage performance requirements of the diode in high-voltage power electronic application scenarios.
[0030] In an embodiment of the present application, the source region protection unit includes a source region second doped p-type nickel oxide region 9. On the cross section of the diode, the source region second doped p-type nickel oxide region 9 at least corresponds to the corner of the cell trench bottom. The doping concentration of the source region second doped p-type nickel oxide region 9 is lower than the corresponding doping concentration of the source region first doped p-type nickel oxide region 8.
[0031] Figure 1 An embodiment of the source region protection unit is shown in FIG. 5. In the figure, the source region protection unit at least includes a source region second doped p-type nickel oxide region 9. In order to form a gradient JTE effect, the doping concentration of the source region second doped p-type nickel oxide region 9 is lower than the corresponding doping concentration of the source region first doped p-type nickel oxide region 8. In specific implementation, the source region first doped p-type nickel oxide region should at least coat the bottom of the cell trench, and the corner region of the source region first doped p-type nickel oxide region 8 is coated by the source region second doped p-type nickel oxide region 9 and corresponds to the corner of the bottom of the cell trench. At this time, the region located directly below the bottom of the cell trench of the source region first doped p-type nickel oxide region 8 is not completely coated by the source region second doped p-type nickel oxide region 9, that is, the heterojunction formed by the contact between the source region first doped p-type nickel oxide region 8 and the N-type gallium oxide drift layer 3 is not affected.
[0032] Figure 1In the embodiment shown in the figure, the source region first doped p-type nickel oxide region 8 covers not only the bottom of the cell trench but also the corresponding sidewall of the cell trench. In the figure, the source region second doped p-type nickel oxide region 9 covers not only the corner region of the source region first doped p-type nickel oxide region 8 but also the region between the source region first doped p-type nickel oxide region 8 and the corresponding sidewall of the cell trench. In addition, as can be known from the above description, the corner region of the source region first doped p-type nickel oxide region 8 generally includes at least the region corresponding to the corner of the bottom of the cell trench.
[0033] In order to form the required gradient JTE effect, in an embodiment of the present application, the doping concentration of the source region first doped p-type nickel oxide region 8 ranges from 5×10 18 cm -3 ~2×10 20 cm -3 , and the doping concentration of the source region second doped p-type nickel oxide region 9 ranges from 5×10 16 cm -3 ~5×10 18 cm -3 .
[0034] It should be noted that when the doping concentration of the source region first doped p-type nickel oxide region 8 ranges from 5×10 18 cm -3 ~2×10 20 cm -3 , on the one hand, ohmic contact between the anode metal and the source region first doped p-type nickel oxide region 8 can be ensured (the contact resistance is less than 1×10 -4 Ω·cm²), and on the other hand, sufficient hole injection can be provided to maintain the forward conduction capability (low conduction voltage drop). In a specific implementation, for the doping concentration of the source region second doped p-type nickel oxide region 9, if the doping concentration is too low (<10 17 cm -3 , the depletion region will be excessively expanded, and the forward resistance will be increased. If the doping concentration is greater than 5×10 18 cm -3 , the shielding effect will be weakened, and the breakdown voltage will not be significantly improved. Therefore, in order to form the gradient JTE effect and achieve a compromise between the breakdown voltage and the forward resistance, in an embodiment of the present application, the doping concentration of the source region second doped p-type nickel oxide region 9 ranges from 5×10 16 cm -3 ~5×10 18 cm -3 .
[0035] Figure 2 The upper figure in FIG. 1 shows an embodiment of the gallium oxide heterojunction cooperating with the source region second doped p-type nickel oxide region 9, Figure 2 The lower figure in FIG. 1 shows an embodiment of the corresponding electric field distribution, Figure 3The upper diagram of Fig. 1 shows an existing gallium oxide heterojunction embodiment, Figure 3 The lower diagram of Fig. 1 shows an embodiment of the corresponding electric field distribution, Figure 2 And Figure 3 In Fig. 2, the horizontal coordinate is the electric field distribution of the corresponding contact interface x direction.
[0036] As can be seen from the diagram, assuming that the doping is uniform doping, according to the electric neutrality condition, qN D xn=qN A xp, where q is the charge amount, N D is the donor doping concentration, xn is the extension width of the depletion region on the n side, N A is the donor doping concentration, xp is the extension width of the depletion region on the p side. When the doping concentration NA of the p-type nickel oxide region of the contact is reduced, the depletion region width xp will increase, which can be understood as the smaller the electric field slope |k|, therefore, the electric field distribution of the existing gallium oxide heterojunction can be obtained, and the corresponding battery distribution of the present application, specifically, the area surrounded by the electric field and the coordinate axis is the maximum withstand voltage, it can be seen that the present application uses the source region second doped p-type nickel oxide region 9 to cover the corner region of the source region first doped p-type nickel oxide region 8, so that a greater withstand voltage value can be achieved. Figure 2 And Figure 3 In Fig. 2, n-Ga2O3 is the N-type gallium oxide drift layer 3, p - -NiO is the source region second doped p-type nickel oxide region 9.
[0037] In an embodiment of the present application, on the cross section of the diode, the width of the anode metal 10 is less than the slot width of the cell trench; In the cell trench, the end of the anode metal 10 adjacent to the cell trench corner is insulated and separated from the source region first doped p-type nickel oxide region 8 by the source region dielectric layer 7.
[0038] In order to achieve the above-mentioned contact with the source region first doped p-type nickel oxide region 8, the anode metal 10 should generally be prepared and deposited in the cell trench. In specific implementation, the cell trench is generally first prepared in the N-type gallium oxide drift layer 3, then the source region second doped p-type nickel oxide region 9 and the source region first doped p-type nickel oxide region 8 are prepared by ion deposition or other methods, and the anode metal 10 is prepared after the source region first doped p-type nickel oxide region 8 is prepared, so as to satisfy the Schottky contact between the anode metal 10 and the source region first doped p-type nickel oxide region 8.
[0039] In order to further improve the withstand voltage of the gallium oxide heterojunction diode, the present application can also prepare a source region dielectric layer 7 in the cell trench. The source region dielectric layer 7 should generally cover at most the inner wall where the cell trench corner is located, so as not to affect the contact connection between the anode metal 10 and the source region first doped p-type nickel oxide region 8.Figure 1 When the source region dielectric layer 7 is arranged in the cell trench, the end of the anode metal 10 adjacent to the cell trench corner can be located on the source region dielectric layer 7, so that the end of the anode metal 10 can be insulated and separated from the source region first doped p-type nickel oxide region 9 by the source region dielectric layer 7, and both ends of the anode metal 10 form field plates to suppress the edge electric field concentration, thereby further improving the voltage reliability of the gallium oxide heterojunction diode.
[0040] In an embodiment of the present application, in the active region, the anode metal 10 also has a Schottky contact with the gallium oxide substrate outside the cell trench.
[0041] Figure 1 In the illustrated embodiment, in the cell trench, in order to achieve insulation and separation of the anode metal 10 and the source region first doped p-type nickel oxide region 8, the source region dielectric layer 7 covers part of the bottom of the cell trench and also covers the corresponding sidewall of the cell trench, in addition, the anode metal 10 is also located outside the cell trench and has a Schottky contact with the corresponding gallium oxide substrate, that is, the anode metal 10 should have a Schottky contact with the corresponding surface of the N-type gallium oxide drift layer.
[0042] It should be noted that the source region dielectric layer 7 can use existing commonly used dielectric materials and passivation materials, and the type of material used by the source region dielectric layer 7 and the corresponding preparation process can be compatible with the process, which will not be described here.
[0043] In an embodiment of the present application, the diode further comprises a terminal region distributed on the outer ring of the gallium oxide substrate, wherein, The terminal region surrounds the active region, and the terminal region at least comprises a guard ring surrounding the active region; On the cross section of the diode, the guard ring comprises a terminal trench, and a terminal dielectric layer 5 and a terminal passivation layer filled in the terminal trench; The terminal passivation layer is insulated from the inner wall of the terminal trench by the terminal dielectric layer 5.
[0044] The same as the existing diode, the gallium oxide diode generally also comprises a terminal region, the terminal region is generally distributed on the outer ring of the gallium oxide substrate and surrounds the active region, and the terminal region can further improve the voltage of the active region, and the distribution position of the terminal region and the voltage mechanism between the active region are consistent with the prior art. In specific implementation, the terminal region generally comprises a guard ring, the guard ring is annular and surrounds the active region.
[0045] Figure 1 An embodiment of the terminal region provided with a guard ring is shown in the figure, and it can be seen from the figure that the guard ring can comprise a terminal trench, and the depth of the terminal trench is greater than the depth of the cell trench. It can be understood that the relationship between the terminal trench and the cell trench can achieve the voltage of the gallium oxide heterojunction diode when it is turned off in reverse.Figure 1 In the terminal trench, a terminal dielectric layer 5 and a terminal passivation layer are filled, and it should be noted that the terminal dielectric layer 5 is generally prepared by the same process step as the source region dielectric layer 7, and the terminal passivation layer is prepared by the same process step as the source region passivation layer. Figure 1 An embodiment in which the terminal passivation layer and the source region passivation layer are connected to form a front passivation layer 6 is shown.
[0046] In order to improve the withstand voltage of the guard ring, in an embodiment of the present application, a terminal gallium oxide heterojunction is further arranged in the terminal region, wherein, The terminal gallium oxide heterojunction includes a terminal first doped p-type nickel oxide region 11 covering the outer wall of the terminal trench, and the terminal first doped p-type nickel oxide region 11 is in contact with the N-type gallium oxide drift layer 3.
[0047] In specific implementation, a terminal gallium oxide heterojunction can be arranged in the terminal region, and similar to the source region gallium oxide heterojunction, the terminal gallium oxide heterojunction can include a terminal first doped p-type nickel oxide region 11, Figure 1 An embodiment in which the terminal first doped p-type nickel oxide region 11 covers the terminal trench is shown, and after the terminal first doped p-type nickel oxide region 11 is in contact with the N-type gallium oxide drift layer 3, a heterojunction can be formed. It should be noted that the terminal first doped p-type nickel oxide region 11 can be prepared by the same process step as the source region first doped p-type nickel oxide region 8, of course, different processes can also be used to prepare and form, and specific selection can be made according to needs.
[0048] In an embodiment of the present application, a terminal protection unit for the terminal first doped p-type nickel oxide region 11 to cooperate and form a gradient JTE effect is further arranged in the terminal region, wherein, The terminal protection unit includes a terminal second doped p-type nickel oxide region 4, and the terminal first doped p-type nickel oxide region 11 is spaced from the N-type gallium oxide drift layer 3 through the terminal second doped p-type nickel oxide region 4. The doping concentration of the terminal second doped p-type nickel oxide region 4 is lower than the corresponding doping concentration of the terminal first doped p-type nickel oxide region 11.
[0049] Figure 1The illustration shows an embodiment in which a terminal protection unit is also provided in the terminal region. As can be seen from the illustration, the terminal protection unit and the source region protection unit can adopt the same form. Therefore, the situation where the terminal second doped p-type nickel oxide region 4 and the terminal first doped p-type nickel oxide region 11 cooperate to form a gradient JTE effect can be referred to the corresponding description of the source region protection unit above, and will not be repeated here. In specific implementation, the terminal second doped p-type nickel oxide region 4 can be prepared by the same process step as the source region second doped p-type nickel oxide region 9. Of course, it can also be formed by different process steps. The corresponding doping concentrations of the terminal second doped p-type nickel oxide region 4 and the terminal first doped p-type nickel oxide region 11 can be referred to the corresponding descriptions of the source region second doped p-type nickel oxide region 9 and the source region first doped p-type nickel oxide region 8 above, and the specific concentration should be based on the requirement to form a gradient JTE effect transistor.
[0050] It should be noted that when the guard ring adopts the above-mentioned structural form, on the one hand, by setting a terminal trench and setting the depth of the terminal trench to be greater than the depth of the cell trench, the electric field concentration characteristics of the planar junction can be broken from a three-dimensional perspective, so that the depletion region in the region where the terminal trench is located can be widened in both the longitudinal and transverse directions; on the other hand, by using the terminal gallium oxide heterojunction and the terminal protection unit formed by using the terminal second doped p-type nickel oxide region, the potential barrier distribution at the corner of the terminal trench is made more gentle, which can further alleviate the electric field concentration caused by the abrupt change in potential barrier.
[0051] In one embodiment of the present invention, the gallium oxide substrate further includes an N-type gallium oxide substrate 2 adjacent to the N-type gallium oxide drift layer 3, wherein, A cathode metal 1 is disposed on the N-type gallium oxide substrate 2, and the cathode metal 1 is in ohmic contact with the N-type gallium oxide substrate 2.
[0052] Figure 1 In the embodiment shown, the gallium oxide substrate also includes an N-type gallium oxide substrate 1. Compared with the N-type gallium oxide drift layer 3, the N-type gallium oxide substrate 1 has a higher doping concentration and is the core carrier for the mechanical support and longitudinal current transmission of the diode.
[0053] To form the cathode of the gallium oxide heterojunction diode, a cathode metal 1 should be disposed on the N-type gallium oxide substrate 2, and the cathode metal 1 should be in ohmic contact with the N-type gallium oxide substrate 2. It is understood that the working mechanism of the gallium oxide heterojunction diode formed by this invention is consistent with the working mechanism of existing gallium oxide heterojunction diodes, and will not be elaborated further here.
Claims
1. A high-voltage gallium oxide heterojunction diode, characterized in that, The diode includes: Gallium oxide substrate, including at least an N-type gallium oxide drift layer; The active region, located in the central region of the N-type gallium oxide drift layer, includes at least one JBS unit, wherein... The JBS unit includes a cell trench fabricated in the N-type gallium oxide drift layer and an anode metal located in the cell trench and electrically connected to the source region gallium oxide heterojunction. The source region gallium oxide heterojunction includes at least a first doped p-type nickel oxide region distributed below the bottom of the cell trench and in contact with the N-type gallium oxide drift layer. On the cross-section of the diode, a source protection unit is provided that at least covers the corner region of the first doped p-type nickel oxide region of the source region and forms a gradient JTE effect with the first doped p-type nickel oxide region of the source region. The corner region of the first doped p-type nickel oxide region of the source region is separated from the N-type gallium oxide drift layer by the source protection unit.
2. The high-voltage gallium oxide heterojunction diode according to claim 1, characterized in that: The source region protection unit includes a second doped p-type nickel oxide region in the source region, wherein, On the cross-section of the diode, the second doped p-type nickel oxide region of the source region corresponds at least to the corner of the bottom of the cell trench; The doping concentration of the second doped p-type nickel oxide region in the source region is lower than the corresponding doping concentration of the first doped p-type nickel oxide region in the source region.
3. The high-voltage gallium oxide heterojunction diode according to claim 2, characterized in that: The doping concentration range of the first doped p-type nickel oxide region in the source region is 5 × 10⁻⁶. 18 cm -3 ~2×10 20 cm -3 The doping concentration range of the second doped p-type nickel oxide region in the source region is 5 × 10⁻⁶. 16 cm -3 ~5×10 18 cm -3 .
4. The high-voltage gallium oxide heterojunction diode according to claim 1, characterized in that: in On the cross-section of the diode, the width of the anode metal is smaller than the width of the cell trench; Within the cell trench, the end of the anode metal adjacent to the corner of the cell trench is insulated and isolated from the first doped p-type nickel oxide region of the source region through the source region dielectric layer.
5. The high-voltage gallium oxide heterojunction diode according to claim 4, characterized in that: Within the active region, the anode metal also contacts the gallium oxide basic Schottky layer outside the cell trench.
6. The high-voltage gallium oxide heterojunction diode according to any one of claims 1 to 5, characterized in that: The diode further includes a terminal region distributed on the outer edge of the gallium oxide substrate, wherein, The terminal area surrounds the active area, and the terminal area includes at least one protective ring surrounding the active area. On the cross-section of the diode, the guard ring includes a termination trench and a termination dielectric layer and a termination passivation layer filled in the termination trench; The terminal passivation layer is isolated from the inner wall of the terminal trench through the terminal dielectric layer.
7. The high-voltage gallium oxide heterojunction diode according to claim 6, characterized in that: The depth of the terminal trench is greater than the depth of the cell trench.
8. The high-voltage gallium oxide heterojunction diode according to claim 6, characterized in that: in The terminal region is also provided with a terminal gallium oxide heterojunction, wherein... The terminal gallium oxide heterojunction includes a terminal first doped p-type nickel oxide region covering the outer wall of the terminal trench, and the terminal first doped p-type nickel oxide region is in contact with the N-type gallium oxide drift layer.
9. The high-voltage gallium oxide heterojunction diode according to claim 8, characterized in that: A terminal protection unit is also provided in the terminal region for contact coordination of the first doped p-type nickel oxide region and for forming a gradient JTE effect. The terminal protection unit includes a second doped p-type nickel oxide region, and the first doped p-type nickel oxide region is separated from the N-type gallium oxide drift layer by the second doped p-type nickel oxide region. The doping concentration of the second doped p-type nickel oxide region at the terminal is lower than the corresponding doping concentration of the first doped p-type nickel oxide region at the terminal.
10. The high-voltage gallium oxide heterojunction diode according to any one of claims 1 to 5, characterized in that: The gallium oxide substrate further includes an N-type gallium oxide substrate adjacent to the N-type gallium oxide drift layer, wherein, A cathode metal is disposed on the N-type gallium oxide substrate, and the cathode metal is in ohmic contact with the N-type gallium oxide substrate.