Diode Module

Abstract

The present invention discloses a diode module, which includes: a substrate; a drift layer of a first conductivity type; an anode layer of a second conductivity type, the anode layer having a flow region and an edge region; an insulating layer; an anode metal layer; a field stop layer of a first conductivity type; a cathode metal layer; a blocking injection layer, the blocking injection layer is located between the field stop layer and the drift layer, and the blocking injection layer is extended from the terminal region to the active region; the projection of the blocking injection layer in the vertical direction and the projection of the anode layer in the vertical direction at least partially overlap with each other and form an overlap portion, and the width of the overlap portion is L1, and L1 satisfies the relationship: 10μm<L1<50μm. Therefore, by setting the blocking injection layer and setting the width of the overlap portion within a reasonable range, the carrier storage capacity of the drift layer in the terminal region can be effectively reduced, the electric field concentration in the edge region of the anode layer during reverse recovery can be avoided, and the dynamic avalanche during reverse recovery can be avoided to cause thermal damage to the diode module.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a diode module. Background Art

[0002] In a power diode element used in anti-parallel connection with a switching element such as an insulated gate bipolar transistor (IGBT) or an insulated gate field effect transistor (IGFET) such as a MOSFET, if the change over time (di / dt) of the current when switching from the forward state to the reverse state during recovery is too large, it may cause breakdown depending on the conditions of use.

[0003] In the related art, the structural design of the diode element is not reasonable enough. During reverse recovery, the base region carriers are prone to excess. When the reverse recovery di / dt is large, the edge of the anode layer is prone to electric field concentration, and dynamic avalanche is prone to occur at a reverse bias voltage much lower than the static avalanche voltage, reaching the critical electric field strength in advance to cause collision ionization, which reduces the dynamic robustness. In addition, severe dynamic avalanche will cause local temperature rise, and eventually cause the device to be damaged due to local overheating. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a diode module that can avoid dynamic avalanche during reverse recovery and has higher dynamic robustness.

[0005] According to an embodiment of the present invention, a diode module comprises: a substrate, the substrate having a first main surface and a second main surface on the opposite side of the first main surface, the first main surface and the second main surface being spaced apart in the vertical direction; a drift layer of a first conductivity type, the drift layer being arranged between the first main surface and the second main surface; an anode layer of a second conductivity type, the diode module having an active region and a terminal region, the terminal region being circumferentially arranged outside the active region, the anode layer being arranged on a side of the drift layer facing the first main surface and located in the active region, the side of the anode layer facing away from the drift layer constituting at least a portion of the first main surface, the anode layer having a flow region and an edge region, the edge region being circumferentially arranged at the outer edge of the flow region; an insulating layer, the insulating layer being arranged on the first main surface, the insulating layer being provided with a contact hole in a portion of the insulating layer corresponding to the flow region of the anode layer; an anode metal layer, the anode A cathode metal layer is at least partially arranged in the contact hole and contacts the current-passing area of ​​the anode layer; a field stop layer of the first conductivity type is arranged on the side of the drift layer facing the second main surface, and the side of the field stop layer away from the drift layer constitutes at least a part of the second main surface; a cathode metal layer is arranged on the second main surface; a blocking injection layer is arranged on the side of the drift layer facing the second main surface and is located between the field stop layer and the drift layer, and the blocking injection layer extends from the terminal area to the active area; the projection of the blocking injection layer in the vertical direction and the projection of the anode layer in the vertical direction at least partially overlap with each other and form an overlapping portion, the width of the overlapping portion extends from the terminal area to the active area in the horizontal direction, and the width of the overlapping portion is L1, and L1 satisfies the relationship: 10μm<L1<50μm.

[0006] Therefore, by locating the blocking injection layer between the field stop layer and the drift layer, the blocking injection layer is extended from the terminal area to the active area, and the projection of the blocking injection layer in the vertical direction and the projection of the anode layer in the vertical direction are at least partially overlapped with each other and the overlapping portion is arranged within a reasonable range, so that the carrier storage capacity of the drift layer in the terminal area can be effectively reduced, the electric field concentration in the edge area of ​​the anode layer during reverse recovery can be avoided, and the dynamic avalanche during reverse recovery can be avoided to cause thermal damage to the diode module, thereby further improving the dynamic robustness of the diode module and improving the reliability of the diode module.

[0007] In some examples of the present invention, the projection of the blocking injection layer in the vertical direction coincides with the projection of the edge area of ​​the anode layer in the vertical direction, and the projection of the blocking injection layer in the vertical direction coincides with at least part of the projection of the flow area of ​​the anode layer in the vertical direction.

[0008] In some examples of the present invention, the thickness of the blocking injection layer is extended in the vertical direction, and the thickness of the blocking injection layer is D1, and D1 satisfies the relationship: 0.1 μm<D1<2 μm.

[0009] In some examples of the present invention, the blocking injection layer is a buried layer of the second conductivity type; and / or the blocking injection layer is a silicon dioxide layer.

[0010] In some examples of the present invention, the diode module further includes a semiconductor region of the first conductivity type, the semiconductor region is disposed in the anode layer and is located at one end of the anode layer adjacent to the terminal region, and the semiconductor region is in contact with the anode metal layer.

[0011] In some examples of the present invention, the length of the semiconductor region is circumferentially extended in the horizontal direction, the width of the semiconductor region is horizontally extended from the active area toward the terminal area, and the width of the semiconductor region is L2, and L2 satisfies the relationship: L2>50μm.

[0012] In some examples of the present invention, a distance between an end of the semiconductor region close to the terminal region and an end of the anode layer close to the terminal region is L3, and L3 satisfies the relationship: L3>2μm.

[0013] In some examples of the present invention, the diode module also includes a high-barrier metal layer, and a avoidance hole is provided on the side of the anode metal layer facing the first main surface, the avoidance hole is located at one end of the anode metal layer adjacent to the terminal area, the high-barrier metal layer is arranged in the avoidance hole and is in contact with the flow-through area of ​​the anode layer, and the barrier height of the high-barrier metal layer is higher than the barrier height of the anode metal layer.

[0014] In some examples of the present invention, the high barrier metal layer is at least one of a titanium metal layer and a platinum metal layer.

[0015] In some examples of the present invention, the thickness of the high barrier metal layer in the vertical direction is D2, and D2 satisfies the relationship: 0.015 μm≤D2≤0.025 μm.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1is a partial cross-sectional view of a diode module according to an embodiment of the present invention;

[0019] Figure 2 is a partial cross-sectional view of a diode module according to another embodiment of the present invention;

[0020] Figure 3 is a partial cross-sectional view of a diode module according to yet another embodiment of the present invention.

[0021] Reference numerals:

[0022] 100, diode module; 110, active region; 120, terminal region;

[0023] 10. substrate; 101. first main surface; 102. second main surface; 11. drift layer; 12. anode layer; 121. flow region; 122. edge region; 13. field stop layer; 14. blocking injection layer; 141. overlap portion; 15. semiconductor region;

[0024] 20. Insulating layer; 21. Contact hole;

[0025] 30. Anode metal layer; 31. Avoidance hole; 40. Cathode metal layer; 50. High barrier metal layer. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0027] Reference below Figure 1-Figure 3 The diode module 100 according to an embodiment of the present invention is described. The diode module 100 includes but is not limited to a fast recovery diode. In the following description, N and P represent the conductivity type of the semiconductor. In the present invention, the first conductivity type is set to N type and the second conductivity type is set to P type for description.

[0028] Combination Figure 1-Figure 3 As shown, the diode module 100 according to the present invention may mainly include: a substrate 10, a drift layer 11 of a first conductivity type, an anode layer 12 of a second conductivity type, a field stop layer 13 of a first conductivity type, an insulating layer 20, an anode metal layer 30, a cathode metal layer 40 and a blocking injection layer 14.

[0029] Among them, the substrate 10 has a first main surface 101 and a second main surface 102 on the opposite side of the first main surface 101, the first main surface 101 and the second main surface 102 are arranged at intervals, the drift layer 11 is arranged between the first main surface 101 and the second main surface 102, the anode layer 12 is arranged on the side of the drift layer 11 facing the first main surface 101, and the side of the anode layer 12 away from the drift layer 11 constitutes at least a part of the first main surface 101.

[0030] The insulating layer 20 is arranged on the first main surface 101, and the anode layer 12 has a flow area 121 and an edge area 122. The edge area 122 is arranged around the outer edge of the flow area 121. The contact hole 21 is provided in the portion of the insulating layer 20 corresponding to the flow area 121 of the anode layer 12, and the anode metal layer 30 is arranged in the contact hole 21 and in contact with the flow area 121 of the anode layer 12. In this way, a good ohmic contact can be formed between the anode metal layer 30 and the anode layer 12 to reduce the contact resistance, and the insulating layer 20 can prevent edge breakdown.

[0031] In addition, a field stop layer 13 is arranged on the side of the drift layer 11 facing the second main surface 102, and the side of the field stop layer 13 facing away from the drift layer 11 constitutes at least a part of the second main surface 102. A cathode metal layer 40 is arranged on the second main surface 102, so that the field stop layer 13 and the cathode metal layer 40 form a good ohmic contact to reduce the contact resistance.

[0032] In this way, the basic structure of the diode module 100 can be formed. It should be noted that the diode module 100 includes an active region 110 and a terminal region 120 , the terminal region 120 is disposed around the periphery of the active region 110 , the anode layer 12 is disposed in the active region 110 , and the edge region 122 of the anode layer 12 is disposed adjacent to the terminal region 120 .

[0033] When the diode module 100 is forward-conducted, holes are injected from the anode layer 12 into the drift layer 11, and electrons are injected from the field stop layer 13 into the drift layer 11, and the two together constitute a forward current from the anode to the cathode. The injection effect of the anode layer 12 and the field stop layer 13 in the active region 110 will accumulate a large number of holes and electrons in the drift layer 11 in the active region 110, and these carriers will diffuse laterally to the drift layer 11 in the terminal region 120 due to the concentration difference. In addition, the edge region 122 of the anode layer 12 and the field stop layer 13 in the terminal region 120 will also inject carriers into the drift layer 11 in the terminal region 120. Therefore, the drift layer 11 below the terminal region 120 will also store a large number of carriers.

[0034] During the reverse recovery process, since the terminal area 120 cannot pass current, the carriers in the terminal area 120 will concentrate on flowing to the edge area 122 of the anode layer 12, resulting in a large current density and a large electric field gradient there. Compared with other positions, under the same withstand voltage, the electric field strength at this position is large and the electric field is concentrated, which makes it easy for dynamic avalanche to occur, causing thermal damage to the diode module 100.

[0035] By arranging the blocking injection layer 14 on the side of the drift layer 11 facing the second main surface 102, and making the blocking injection layer 14 between the field stop layer 13 and the drift layer 11, the blocking injection layer 14 is extended from the terminal area 120 to the active area 110, so that the blocking injection layer 14 can block the field stop layer 13 from injecting electrons into the drift layer 11, thereby reducing the carrier storage capacity of the drift layer 11 in the terminal area 120, and further avoiding the electric field concentration in the edge area 122 of the anode layer 12 during reverse recovery, which can effectively improve the dynamic robustness of the diode module 100 and avoid dynamic avalanche during reverse recovery to cause thermal damage to the diode module 100.

[0036] Furthermore, the projection of the blocking injection layer 14 in the vertical direction and the projection of the anode layer 12 in the vertical direction at least partially overlap with each other and form an overlapping portion 141. The width of the overlapping portion 141 extends horizontally from the terminal area 120 to the active area 110. The width of the overlapping portion 141 is L1, and L1 satisfies the relationship: 10μm<L1<50μm.

[0037] Specifically, when the width of the overlapping portion 141 is no more than 10 μm, the portion of the blocking injection layer 14 extending into the active region 110 is too short, and the blocking injection layer 14 has a low blocking effect on the injection efficiency of the field stop layer 13. The field stop layer 13 can still inject a large amount of electrons into the drift layer 11, resulting in an excessively large carrier storage capacity of the drift layer 11 in the terminal region 120.

[0038] When the width of the overlapping portion 141 is not less than 50 μm, the portion of the blocking injection layer 14 extending into the active region 110 is too long, which will cause the injection efficiency of the field stop layer 13 into the drift layer 11 to be too low, which will not only affect the forward conduction performance of the diode module 100, but also make it easy for electric field concentration to occur near the blocking injection layer 14, resulting in thermal damage to the diode module 100.

[0039] By setting the width of the overlapping portion 141 to be greater than 10 μm and the width of the overlapping portion 141 to be less than 50 μm, the width of the overlapping portion 141 can be set within a reasonable range. Without affecting or slightly affecting the forward conduction performance of the diode module 100, and avoiding electric field concentration near the flow area 121, the carrier storage capacity of the drift layer 11 in the terminal area 120 is reduced, the electric field concentration in the edge area 122 of the anode layer 12 during reverse recovery is avoided, and dynamic avalanche during reverse recovery is avoided to cause thermal damage to the diode module 100, thereby further improving the dynamic robustness of the diode module 100 and improving the reliability of the diode module 100.

[0040] Therefore, by locating the blocking injection layer 14 between the field stop layer 13 and the drift layer 11, the blocking injection layer 14 is extended from the terminal area 120 to the active area 110, and the projection of the blocking injection layer 14 in the vertical direction and the projection of the anode layer 12 in the vertical direction are at least partially overlapped with each other to form an overlapping portion 141 arranged within a reasonable range, so that the carrier storage capacity of the drift layer 11 in the terminal area 120 can be effectively reduced, and the electric field concentration in the edge area 122 of the anode layer 12 during reverse recovery can be avoided, and the dynamic avalanche during reverse recovery can be avoided to cause thermal damage to the diode module 100, thereby further improving the dynamic robustness of the diode module 100 and improving the reliability of the diode module 100.

[0041] Combination Figure 1-Figure 3 As shown, the projection of the blocking injection layer 14 in the vertical direction coincides with the projection of the edge area 122 of the anode layer 12 in the vertical direction, that is, the projection of the blocking injection layer 14 in the vertical direction can cover the projection of the edge area 122 in the vertical direction, and the projection of the blocking injection layer 14 in the vertical direction coincides with at least part of the projection of the flow-through area 121 of the anode layer 12 in the vertical direction, that is, the projection of the blocking injection layer 14 in the vertical direction can at least partly cover the projection of the flow-through area 121 in the vertical direction.

[0042] In this way, when the blocking injection layer 14 extends from the terminal region 120 to the active region 110, the blocking injection layer 14 can extend to correspond to the edge region 122 of the anode layer 12 in the vertical direction, and further extend to correspond to at least a part of the flow region 121 of the anode layer 12 in the vertical direction. In this way, the position of the blocking injection layer 14 can be optimized, so that the blocking injection layer 14 can not only block the field stop layer 13 from injecting electrons into the drift layer 11 of the terminal region 120, but also block the field stop layer 13 from injecting electrons into the drift layer 11 corresponding to the edge region 122, thereby reducing the current density of the drift layer 11 near the edge region 122 and the current density of the drift layer 11 in the terminal region 120, thereby avoiding the electric field concentration in the edge region 122 of the anode layer 12 during reverse recovery, and avoiding the dynamic avalanche of the diode module 100.

[0043] Combination Figure 1 As shown, the thickness of the blocking injection layer 14 is extended in the vertical direction, and the thickness of the blocking injection layer 14 is D1, and D1 satisfies the relationship: 0.1μm<D1<2μm. Specifically, considering that the blocking injection layer 14 is arranged in the drift layer 11, the thickness of the blocking injection layer 14 will not only affect its own blocking effect on the injection efficiency of the field stop layer 13 into the drift layer 11, but also affect the thickness of the drift layer 11, and affect the withstand voltage performance of the diode module 100.

[0044] When the thickness of the blocking injection layer 14 is not greater than 0.1 μm, the thickness of the blocking injection layer 14 is too small, which will cause the blocking injection layer 14 to have too low an effect of blocking the injection of the field stop layer 13 into the drift layer 11 , resulting in the inability to effectively reduce the current density of the drift layer 11 in the terminal region 120 .

[0045] When the thickness of the blocking injection layer 14 is not less than 2 μm, the thickness of the blocking injection layer 14 is too large, which may cause the thickness of the drift layer 11 to be too small, resulting in reduced withstand voltage performance of the diode module 100 .

[0046] In this way, by setting the thickness of the blocking injection layer 14 to be greater than 0.1μm and setting the thickness of the blocking injection layer 14 to be less than 2μm, the thickness of the blocking injection layer 14 can be set within a reasonable range. Under the premise of ensuring the voltage resistance performance of the diode module 100, the current density of the drift layer 11 in the edge area 122 of the anode layer 12 is reduced, thereby avoiding electric field concentration in the edge area 122 of the anode layer 12 during reverse recovery, avoiding dynamic avalanche of the diode module 100, and improving the dynamic robustness of the diode module 100.

[0047] In some embodiments of the present invention, the blocking injection layer 14 is a buried layer of the second conductivity type. Specifically, the blocking injection layer 14 can be set as a buried layer of the second conductivity type, so that an NPN transistor can be formed between the drift layer 11, the buried layer and the field stop layer 13. When a forward bias voltage is applied to the anode of the diode module 100, the transistor will not be turned on, thereby effectively blocking the injection of the field stop layer 13 into the drift layer 11, reducing the current density of the drift layer 11 in the terminal region 120, and thus avoiding the electric field concentration in the edge region 122 of the anode layer 12 during reverse recovery, avoiding the dynamic avalanche of the diode module 100, and improving the dynamic robustness of the diode module 100.

[0048] In other embodiments of the present invention, the blocking injection layer 14 is a silicon dioxide layer. Specifically, the blocking injection layer 14 can be set as a silicon dioxide layer, and the silicon dioxide layer can be used as an insulating layer, so as to effectively block the injection of the field stop layer 13 into the drift layer 11, reduce the current density of the drift layer 11 in the terminal region 120, and thus avoid the electric field concentration in the edge region 122 of the anode layer 12 during reverse recovery, avoid the dynamic avalanche of the diode module 100, and improve the dynamic robustness of the diode module 100.

[0049] Combination Figure 2 As shown, the diode module 100 may further include a semiconductor region 15 of the first conductivity type, which is disposed in the anode layer 12 and located at one end of the anode layer 12 adjacent to the terminal region 120 , and the semiconductor region 15 is in contact with the anode metal layer 30 .

[0050] Specifically, the injection efficiency of the anode layer 12 into the drift layer 11 will also affect the carrier storage capacity in the drift layer 11 of the terminal region 120. By providing a semiconductor region 15 of a first conductive type in the anode layer 12 and being located at one end of the anode layer 12 adjacent to the terminal region 120, and making the semiconductor region 15 contact with the anode metal layer 30, an ohmic contact can be formed between the anode metal layer 30 and the semiconductor region 15.

[0051] When the diode module 100 is forward-conducted, since both the semiconductor region 15 and the anode layer 12 are connected to the anode metal and have the same potential, the PN junction formed by the semiconductor region 15 of the first conductivity type and the anode layer 12 of the second conductivity type will not be forward-conducted, and since the semiconductor region 15 occupies a portion of the area of ​​the anode layer 12 adjacent to the terminal region 120, the anode layer 12 emits fewer holes to the terminal region 120, and the holes need to move from the side of the semiconductor region 15 away from the terminal region 120 to the side of the semiconductor region 15 adjacent to the terminal region 120, and the flow path of the holes becomes longer, so the potential of the edge region 122 of the anode layer 12 is reduced, thereby reducing the injection efficiency and the carrier storage capacity of the drift layer 11 of the terminal region 120, thereby avoiding the electric field concentration in the edge region 122 of the anode layer 12 during the reverse recovery process of the diode module 100 and causing dynamic avalanche, thereby damaging the diode module 100.

[0052] Combination Figure 2 As shown, the length of the semiconductor region 15 extends circumferentially in the horizontal direction, and the width of the semiconductor region 15 extends from the active area 110 toward the terminal area 120 in the horizontal direction. The width of the semiconductor region 15 is L2, and L2 satisfies the relationship: L2>50μm.

[0053] Specifically, the width of the semiconductor region 15 affects the flow path of the holes in the forward conduction of the diode module 100, and further affects the potential of the edge region 122 of the anode layer 12. Specifically, the larger the width of the semiconductor region 15, the longer the flow path of the holes, and the lower the potential of the edge region 122 of the anode layer 12. By setting the width of the semiconductor region 15 to be greater than 50 μm, the potential of the edge region 122 of the anode layer 12 can be more effectively and reliably reduced, avoiding electric field concentration in the edge region 122 of the anode layer 12 during reverse recovery, avoiding dynamic avalanche during reverse recovery and causing thermal damage to the diode module 100, thereby improving the dynamic robustness of the diode module 100.

[0054] Furthermore, combined with Figure 2 As shown, the distance between one end of the semiconductor region 15 close to the terminal region 120 and one end of the anode layer 12 close to the terminal region 120 is L3, and L3 satisfies the relationship: L3>2μm.

[0055] Specifically, when the distance between one end of the semiconductor region 15 close to the terminal region 120 and one end of the anode layer 12 close to the terminal region 120 is less than 2 μm, the depletion region will be concave, thereby reducing the withstand voltage performance of the diode module 100. By setting one end of the semiconductor region 15 close to the terminal region 120 and one end of the anode layer 12 close to the terminal region 120 at a distance, and setting the distance between one end of the semiconductor region 15 close to the terminal region 120 and one end of the anode layer 12 close to the terminal region 120 to be greater than 2 μm, the setting position of the semiconductor region 15 can be optimized, and the withstand voltage performance of the diode module 100 can be guaranteed.

[0056] Combination Figure 3 As shown, the diode module 100 may further include a high barrier metal layer 50, and a avoidance hole 31 is provided on the side of the anode metal layer 30 facing the first main surface 101, and the avoidance hole 31 is located at one end of the anode metal layer 30 adjacent to the terminal area 120, and the high barrier metal layer 50 is arranged in the avoidance hole 31 and in contact with the flow-through area 121 of the anode layer 12, and the barrier height of the high barrier metal layer 50 is higher than the barrier height of the anode metal layer 30.

[0057] Specifically, the injection efficiency of the anode layer 12 into the drift layer 11 will also affect the carrier storage capacity in the drift layer 11 of the terminal region 120. By arranging the high-barrier metal layer 50 in the avoidance hole 31 and in contact with the flow area 121 of the anode layer 12, the contact barrier between the high-barrier metal layer 50 and the anode layer 12 can be made higher than the contact barrier between the anode metal layer 30 and the anode layer 12, thereby reducing the tunneling effect and increasing the contact resistance, thereby reducing the emission efficiency of the edge area 122 of the anode layer 12, reducing the carrier accumulation in the drift layer 11 of the terminal region 120, avoiding electric field concentration in the edge area 122 of the anode layer 12 during reverse recovery, and avoiding dynamic avalanche during reverse recovery to cause thermal damage to the diode module 100.

[0058] Further, the high barrier metal layer 50 is at least one of a titanium metal layer and a platinum metal layer. Specifically, the chemical properties of metal titanium and metal platinum are both stable, and the work functions are both small. By setting the high barrier metal layer 50 to at least one of a titanium metal layer and a platinum metal layer, it is possible to ensure that the contact barrier between the high barrier metal layer 50 and the anode layer 12 is high, thereby more effectively and reliably reducing the tunneling effect, increasing the contact resistance between the high barrier metal layer 50 and the anode layer 12, and reducing the emission efficiency of the anode layer 12, thereby reducing the accumulation of carriers in the drift layer 11 of the terminal region 120, avoiding the electric field concentration in the edge region 122 of the anode layer 12 during reverse recovery, and avoiding the occurrence of dynamic avalanche during reverse recovery to cause thermal damage to the diode module 100.

[0059] Combination Figure 3As shown, the thickness of the high barrier metal layer 50 in the vertical direction is D2, and D2 satisfies the relationship: 0.015μm≤D2≤0.025μm. Specifically, a contact barrier is formed between the high barrier metal layer 50 and the anode layer 12, and the thickness of the high barrier metal layer 50 in the vertical direction not only affects the contact resistance between the high barrier metal layer 50 and the anode layer 12, but also affects the thermal stability. Specifically, the greater the thickness of the high barrier metal layer 50, the greater the contact resistance, but the lower the thermal stability.

[0060] By setting the thickness of the high barrier metal layer 50 in the vertical direction to be no less than 0.015 μm and setting the thickness of the high barrier metal layer 50 in the vertical direction to be no more than 0.025 μm, the thickness of the high barrier metal layer 50 in the vertical direction can be set within a reasonable range. This can not only increase the contact resistance, reduce the accumulation of carriers in the drift layer 11 in the terminal region 120, and avoid dynamic avalanche during reverse recovery to cause thermal damage to the diode module 100, but also ensure the thermal stability of the high barrier metal layer 50 and even the diode module 100, thereby improving the dynamic robustness of the diode module 100 and improving the reliability of the diode module 100.

[0061] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0063] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A diode module, characterized in that: include: A substrate (10), the substrate (10) comprising a first main surface (101) and a second main surface (102) on the opposite side of the first main surface (101), the first main surface (101) and the second main surface (102) being arranged at an interval in the vertical direction; A drift layer (11) of a first conductivity type, wherein the drift layer (11) is provided between the first main surface (101) and the second main surface (102); an anode layer (12) of a second conductivity type, the diode module (100) comprising an active region (110) and a terminal region (120), the terminal region (120) being arranged circumferentially outside the active region (110), the anode layer (12) being arranged on a side of the drift layer (11) facing the first main surface (101) and being located in the active region (110), the side of the anode layer (12) facing away from the drift layer (11) constituting at least a portion of the first main surface (101), the anode layer (12) comprising a flow-through region (121) and an edge region (122), the edge region (122) being arranged circumferentially at an outer edge of the flow-through region (121); An insulating layer (20), the insulating layer (20) being arranged on the first main surface (101), and a contact hole (21) being arranged in a portion of the insulating layer (20) corresponding to the flow-through region (121) of the anode layer (12); an anode metal layer (30), the anode metal layer (30) being at least partially disposed in the contact hole (21) and in contact with the flow-through region (121) of the anode layer (12); a field stop layer (13) of a first conductivity type, the field stop layer (13) being arranged on a side of the drift layer (11) facing the second main surface (102), and a side of the field stop layer (13) facing away from the drift layer (11) constituting at least a portion of the second main surface (102); a cathode metal layer (40), the cathode metal layer (40) being arranged on the second main surface (102); a blocking injection layer (14), the blocking injection layer (14) being arranged on a side of the drift layer (11) facing the second main surface (102) and between the field stop layer (13) and the drift layer (11), the blocking injection layer (14) extending from the terminal region (120) towards the active region (110); The projection of the blocking injection layer (14) in the vertical direction and the projection of the anode layer (12) in the vertical direction at least partially overlap with each other to form an overlapping portion (141), and the width of the overlapping portion (141) extends from the terminal area (120) to the active area (110) in the horizontal direction, and the width of the overlapping portion (141) is L1, and L1 satisfies the relationship: 10μm<L1<50μm; A semiconductor region (15) of a first conductivity type is provided in the anode layer (12) and is located at one end of the anode layer (12) adjacent to the terminal region (120), the semiconductor region (15) is in contact with the anode metal layer (30), the length of the semiconductor region (15) is circumferentially extended in a horizontal direction, the width of the semiconductor region (15) is extended in a horizontal direction from the active region (110) toward the terminal region (120), the width of the semiconductor region (15) is L2, and L2 satisfies the relationship: L2>50μm.

2. The diode module according to claim 1, characterized in that: The projection of the blocking injection layer (14) in the vertical direction coincides with the projection of the edge region (122) of the anode layer (12) in the vertical direction, and the projection of the blocking injection layer (14) in the vertical direction coincides with at least part of the projection of the flow region (121) of the anode layer (12) in the vertical direction.

3. The diode module according to claim 1, characterized in that: The thickness of the blocking injection layer (14) is extended in the vertical direction, and the thickness of the blocking injection layer (14) is D1, and D1 satisfies the relationship: 0.1 μm<D1<2 μm.

4. The diode module according to claim 1, characterized in that: The blocking injection layer (14) is a buried layer of the second conductivity type; and / or the blocking injection layer (14) is a silicon dioxide layer.

5. The diode module according to claim 1, characterized in that: The distance between one end of the semiconductor region (15) close to the terminal region (120) and one end of the anode layer (12) close to the terminal region (120) is L3, and L3 satisfies the relationship: L3>2μm.

6. The diode module according to claim 1, characterized in that: It also includes a high barrier metal layer (50), a side of the anode metal layer (30) facing the first main surface (101) is provided with an avoidance hole (31), the avoidance hole (31) is located at one end of the anode metal layer (30) adjacent to the terminal area (120), the high barrier metal layer (50) is arranged in the avoidance hole (31) and is in contact with the flow-through area (121) of the anode layer (12), and the barrier height of the high barrier metal layer (50) is higher than the barrier height of the anode metal layer (30).

7. The diode module according to claim 6, characterized in that: The high barrier metal layer (50) is at least one of a titanium metal layer and a platinum metal layer.

8. The diode module according to claim 6, characterized in that: The thickness of the high barrier metal layer (50) in the vertical direction is D2, and D2 satisfies the relationship: 0.015 μm≤D2≤0.025 μm.

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