A power device

Abstract

The application discloses a power device, which comprises an active region and a terminal region, the terminal region is arranged on the outer side of the active region in a circumferential manner; the terminal region comprises a substrate, a drift layer of a first conductive type arranged between the first main surface and the second main surface of the substrate, a field limiting ring of a second conductive type arranged in the drift layer, the side of the field limiting ring facing the first main surface constitutes at least part of the first main surface, a cathode metal arranged on the second main surface, a passivation layer arranged on the first main surface, at least one first field plate arranged in the passivation layer in a linear shape, and at least one second field plate arranged in the passivation layer in an H shape; wherein the first field plate and the second field plate are arranged alternately and spaced apart in the horizontal direction. According to the power device, the reliability is higher in the HTRB experiment.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a power device. Background Technology

[0002] As the most commonly used electronic switching devices, power devices are in increasing demand due to the large-scale development of electronic power systems. Currently, they are mainly used in industrial control inverters, photovoltaics, automotive-grade applications, and other fields, with increasingly wider applications and higher reliability requirements. The reliability of power devices is a crucial indicator of chip performance, with the HTRB (High Temperature Reverse Bias) test being the most important. The HTRB test measures the long-term leakage current of power devices under high-temperature reverse bias conditions to ensure compliance with standards. A decrease in the high-temperature reverse bias withstand voltage of power devices reduces their lifespan and can lead to malfunctions in electronic power systems. Therefore, designing power devices that can operate stably under high-temperature reverse bias conditions is of paramount importance.

[0003] The main reasons for HTRB test failure include a surge in online leakage current leading to test failure, or degradation of breakdown voltage after the test. Among these, there are many common causes of breakdown voltage degradation, the most common being mobile ion failure. The mobile ions that can cause HTRB failure are mainly Na+, which are widely available. Contamination of mobile ions can occur during wafer manufacturing and packaging processes, and a certain amount of mobile ions are also present in the molding compound.

[0004] In existing power devices, during HTRB testing, mobile ions can easily move along the high electric field terminal towards the zero potential active region. In other words, mobile ions can easily pass through the passivation layer of the power device and enter the inside of the power device and the active region, resulting in weak anti-interference ability against ion contamination and causing the HTRB test to fail.

[0005] Therefore, improvements are needed to at least partially address the aforementioned problems. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, the object of this invention is to provide a power device that exhibits higher reliability in HTRB experiments.

[0007] The power device according to a first embodiment of the present invention includes an active region and a terminal region, wherein the terminal region is circumferentially disposed around the outside of the active region;

[0008] The terminal area includes:

[0009] A substrate having a first main surface and a second main surface opposite to the first main surface, wherein the first main surface and the second main surface are spaced apart in the vertical direction;

[0010] A drift layer of a first conductivity type is disposed between the first main surface and the second main surface, wherein the side of the drift layer facing the first main surface constitutes at least a portion of the first main surface, and the side of the drift layer facing the second main surface constitutes at least a portion of the first main surface.

[0011] A field limiting ring of a second conductivity type is disposed in the drift layer, wherein the side of the field limiting ring facing the first main surface constitutes at least a portion of the first main surface;

[0012] Cathode metal, wherein the cathode metal is disposed on the second main surface;

[0013] A passivation layer is disposed on the first main surface;

[0014] The first field plate is in the shape of a line and there is at least one of them. The first field plate is disposed in the passivation layer.

[0015] The second field plate is in the shape of an inverted I-beam and there is at least one of them, and the second field plate is at least partially disposed in the passivation layer;

[0016] The first field plate and the second field plate are arranged alternately in the horizontal direction.

[0017] The above technical solution has the following advantages and beneficial effects: The setting of the first field plate and the second field plate can significantly increase the movement path of mobile ions through the passivation layer into the power device and the active region, thereby effectively enhancing the anti-interference ability of mobile ions and improving the reliability of the power device in the HTRB test.

[0018] In some embodiments, both the first field plate and the second field plate are floating field plates.

[0019] The above technical solution has the following advantages and beneficial effects: due to the charge compensation effect of the field plate, the surface electric field of the power device terminal area can be reduced, making the electric field line distribution more uniform. In addition, charges can be induced in the floating field plate, which can pair with mobile ions to achieve a shielding effect.

[0020] In some embodiments, the second field plate includes a first field plate portion, a second field plate portion, and a third field plate portion, wherein the first field plate portion is parallel to the second field plate portion, the third field plate portion is located between the first field plate portion and the second field plate portion, and the third field plate portion is perpendicular to the first field plate portion and the second field plate portion;

[0021] The first field plate portion is located in the passivation layer, the second field plate portion is located on the side of the passivation layer away from the first main surface, the length of the second field plate portion in the horizontal direction is greater than the length of the first field plate portion in the horizontal direction, and the projection of the second field plate portion in the vertical direction partially overlaps with the first field plate portion adjacent to the second field plate portion.

[0022] The above technical solution has the following advantages and beneficial effects: the first field plate and the second field plate can cover a larger area of ​​the terminal region in the vertical direction, thereby enhancing the anti-interference ability against mobile ions.

[0023] In some embodiments, the first field plate is made of polycrystalline silicon and / or metal;

[0024] The material of the second field plate is polycrystalline silicon and / or metal.

[0025] The power device according to a second embodiment of the present invention includes an active region and a terminal region, wherein the terminal region is circumferentially disposed around the outside of the active region;

[0026] The terminal area includes:

[0027] A substrate having a first main surface and a second main surface opposite to the first main surface, wherein the first main surface and the second main surface are spaced apart in the vertical direction;

[0028] A drift layer of a first conductivity type is disposed between the first main surface and the second main surface, wherein the side of the drift layer facing the first main surface constitutes at least a portion of the first main surface, and the side of the drift layer facing the second main surface constitutes at least a portion of the first main surface.

[0029] A field limiting ring of a second conductivity type is disposed in the drift layer, wherein the side of the field limiting ring facing the first main surface constitutes at least a portion of the first main surface;

[0030] Cathode metal, wherein the cathode metal is disposed on the second main surface;

[0031] A passivation layer is disposed on the first main surface;

[0032] The first field plate is in the shape of a line and there is at least one of them. The first field plate is disposed in the passivation layer.

[0033] The second field plate is in the shape of a line and there is at least one of them. The second field plate is disposed on the side of the passivation layer away from the first main surface.

[0034] When there are multiple first field plates, the multiple first field plates are arranged alternately and at intervals in the horizontal direction;

[0035] When there are multiple second field plates, the multiple second field plates are arranged alternately and at intervals in the horizontal direction.

[0036] The above technical solution has the following advantages and beneficial effects: The setting of the first field plate and the second field plate can significantly increase the movement path of mobile ions through the passivation layer into the power device and the active region, thereby effectively enhancing the anti-interference ability of mobile ions and improving the reliability of the power device in the HTRB test.

[0037] In some embodiments, both the first field plate and the second field plate are floating field plates.

[0038] The above technical solution has the following advantages and beneficial effects: due to the charge compensation effect of the field plate, the surface electric field of the power device terminal area can be reduced, making the electric field line distribution more uniform. In addition, charges can be induced in the floating field plate, which can pair with mobile ions to achieve a shielding effect.

[0039] In some embodiments, the projection of the second field plate in the vertical direction partially overlaps with one or both of the first field plates.

[0040] The above technical solution has the following advantages and beneficial effects: the first field plate and the second field plate can cover a larger area of ​​the terminal region in the vertical direction, thereby enhancing the anti-interference ability against mobile ions.

[0041] The power device according to a third embodiment of the present invention includes an active region and a terminal region, wherein the terminal region is circumferentially disposed around the outside of the active region;

[0042] The terminal area includes:

[0043] A substrate having a first main surface and a second main surface opposite to the first main surface, wherein the first main surface and the second main surface are spaced apart in the vertical direction;

[0044] A drift layer of a first conductivity type is disposed between the first main surface and the second main surface, wherein the side of the drift layer facing the first main surface constitutes at least a portion of the first main surface, and the side of the drift layer facing the second main surface constitutes at least a portion of the first main surface.

[0045] A field limiting ring of a second conductivity type is disposed in the drift layer, wherein the side of the field limiting ring facing the first main surface constitutes at least a portion of the first main surface;

[0046] Cathode metal, wherein the cathode metal is disposed on the second main surface;

[0047] A passivation layer is disposed on the first main surface;

[0048] The first field plate is I-shaped and there is at least one of them, and the first field plate is at least partially disposed in the passivation layer;

[0049] The second field plate is in the shape of an inverted I-beam and there is at least one of them, and the second field plate is at least partially disposed in the passivation layer;

[0050] The first field plate and the second field plate are arranged alternately in the horizontal direction.

[0051] The above technical solution has the following advantages and beneficial effects: The setting of the first field plate and the second field plate can significantly increase the movement path of mobile ions through the passivation layer into the power device and the active region, thereby effectively enhancing the anti-interference ability of mobile ions and improving the reliability of the power device in the HTRB test.

[0052] In some embodiments, both the first field plate and the second field plate are floating field plates.

[0053] The above technical solution has the following advantages and beneficial effects: due to the charge compensation effect of the field plate, the surface electric field of the power device terminal area can be reduced, making the electric field line distribution more uniform. In addition, charges can be induced in the floating field plate, which can pair with mobile ions to achieve a shielding effect.

[0054] In some embodiments, the first field plate includes a first field plate portion, a second field plate portion, and a third field plate portion. The first field plate portion is parallel to the second field plate portion, the third field plate portion is located between the first field plate portion and the second field plate portion, and the third field plate portion is perpendicular to the first field plate portion and the second field plate portion. The first field plate portion is located in the passivation layer, the second field plate portion is located on the side of the passivation layer away from the first main surface, and the length of the first field plate portion in the horizontal direction is greater than the length of the second field plate portion in the horizontal direction.

[0055] The second field plate includes a fourth field plate portion, a fifth field plate portion, and a sixth field plate portion. The fourth field plate portion is parallel to the fifth field plate portion, and the sixth field plate portion is located between the fourth field plate portion and the fifth field plate portion. The sixth field plate portion is perpendicular to the first field plate portion and the second field plate portion. The fourth field plate portion is located in the passivation layer, and the fifth field plate portion is located on the side of the passivation layer away from the first main surface. The length of the fifth field plate portion in the horizontal direction is greater than the length of the fourth field plate portion in the horizontal direction.

[0056] The projection of the fifth field plate portion in the vertical direction partially overlaps with the first field plate portion of the first field plate adjacent to the fifth field plate portion.

[0057] The above technical solution has the following advantages and beneficial effects: the first field plate and the second field plate can cover a larger area of ​​the terminal region in the vertical direction, thereby enhancing the anti-interference ability against mobile ions.

[0058] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0059] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions, thereby explaining the apparatus and principles of the invention. In the drawings,

[0060] Figure 1 This is a schematic diagram of the structure of power devices in related technologies;

[0061] Figure 2 This is a schematic diagram of the power device according to the first embodiment of this application;

[0062] Figure 3 This is a schematic diagram of the power device according to the second embodiment of this application;

[0063] Figure 4 This is a schematic diagram of the structure of a power device according to a third embodiment of this application.

[0064] Explanation of reference numerals in the attached figures:

[0065] 100 - Terminal area, 110 - Substrate, 1101 - First main surface, 1102 - Second main surface, 111 - Drift layer, 112 - Field limiting ring, 113 - Cut-off ring, 120 - Cathode metal, 130 - Passivation layer, 140 - Field plate, 150 - Field plate, 160 - First field plate, 170 - Second field plate, 171 - First field plate section, 172 - Second field plate section, 173 - Third field plate section;

[0066] 160' - First round, 170' - Second round;

[0067] 160” - First court board, 161” - First court board section, 162” - Second court board section, 163” - Third court board section, 170” - Second court board, 171” - Fourth court board section, 172” - Fifth court board section, 173” - Sixth court board section;

[0068] 200 - Active region; Detailed Implementation

[0069] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0070] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0071] It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or parts, these elements, components, areas, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or part from another element, component, area, layer, or part. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or part discussed below may be referred to as the second element, component, area, layer, or part.

[0072] Spatial relation terms such as "below," "under," "below," "under," "above," and "above" are used here for convenience to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of devices in use and operation.

[0073] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0074] Embodiments of the invention are described herein with reference to cross-sectional views that serve as schematic diagrams of preferred embodiments (and intermediate structures) of this application. Thus, variations in the shown shape are contemplated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of this application should not be limited to the specific shapes shown herein, but include shape deviations due to, for example, manufacturing processes. Consequently, the figures are substantially schematic, and their shapes are not intended to show the actual shape of the device and are not intended to limit the scope of this application.

[0075] See attached document Figure 1 The structure of a power device in the related art will be described by way of example. This power device can be an IGBT (Insulated Gate Bipolar Transistor) or an RC-IGBT (Reverse Conducting Insulated Gate Bipolar Transistor), but is not limited to these. In the following description, N and P represent the conductivity type of the semiconductor. In this embodiment, the first conductivity type is described as N-type and the second conductivity type as P-type.

[0076] The power device includes an active region 200 and a terminal region 100, with the terminal region 100 circumferentially surrounding the outer side of the active region 200. For example, a transition region may also be provided between the active region 200 and the terminal region 100.

[0077] The terminal region 100 includes a substrate 110, a drift layer 111 of a first conductivity type, a field limiting ring 112 of a second conductivity type, a cathode metal 120, a passivation layer 130, a cutoff ring 113 of a first conductivity type, a field plate 140, and a field plate 150.

[0078] The substrate 110 has a first main surface 1101 and a second main surface 1102 opposite to the first main surface 1101, and the first main surface 1101 and the second main surface 1102 are spaced apart in the vertical direction.

[0079] A drift layer 111 is disposed between the first main surface 1101 and the second main surface 1102. The side of the drift layer 111 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101, and the side of the drift layer 111 facing the second main surface 1102 constitutes at least a portion of the first main surface 1101.

[0080] A field limiting ring 112 is disposed in the drift layer 111, and the side of the field limiting ring 112 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. Multiple field limiting rings 112 are arranged at intervals in the horizontal direction. The arrangement of the field limiting rings 112 can effectively disperse the concentrated electric field, making the electric field distribution more uniform, improving the stability and reliability of the power device under high voltage, and preventing breakdown of the device during operation. For example, the field limiting ring 112 can also be referred to as a withstand voltage ring.

[0081] The cathode metal 120 is disposed on the second main surface 1102.

[0082] A passivation layer 130 is disposed on the first main surface 1101. For example, the passivation layer 130 is a silicon dioxide layer.

[0083] A cutoff ring 113 is disposed in the drift layer 111, and the side of the cutoff ring 113 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. The cutoff ring 113 is located on the side of the field limiting ring 112 furthest from the active region 200, away from the active region 200, and is spaced apart from the field limiting ring 112. The arrangement of the cutoff ring 113 can effectively modulate the electric field distribution, disperse the concentrated electric field, make the electric field distribution more uniform, improve the breakdown voltage of the device, and reduce surface leakage current.

[0084] The passivation layer 130 has a first contact hole corresponding to the portion of the cutoff ring 113. The field plate 140 is at least partially disposed in the first contact hole and in contact with the cutoff ring 113. The field plate 140 can be a polysilicon field plate or a metal field plate. The field plate 140 can work in conjunction with the cutoff ring 113 to change the electric field distribution on the device surface, making the electric field distribution on the device surface more uniform and improving the breakdown voltage of the device.

[0085] The passivation layer 130 has a second contact hole corresponding to a portion of a field limiting ring 112 adjacent to the stop ring 113. The field plate 150 is at least partially disposed in the second contact hole and in contact with the field limiting ring 112. The field plate 150 can effectively adjust the electric field distribution, enhance the withstand voltage performance, and reduce surface charge accumulation, thereby significantly improving the reliability and stability of the device. The field plates 140 and 150 can be floating field plates.

[0086] For the aforementioned power devices, on the one hand, during the HTRB test, mobile ions can easily enter the interior of the power device through the passivation layer 130 and move along the terminal region 100 of the high electric field to the active region 200 of zero potential. The power device has a weak anti-interference ability against ion contamination, which leads to the failure of the HTRB test. On the other hand, there are usually many field limiting rings 112, and the spacing between the field limiting rings 112 is difficult to adjust. The field strength between the rings is easily unevenly distributed, which causes the potential lines to concentrate on some field rings. This makes it easy for avalanche breakdown to occur at these points under high electric field strength, making them weak points.

[0087] See attached document Figure 2 The power device according to the first embodiment of this application will be described by way of example.

[0088] The power device can be an IGBT (Insulated Gate Bipolar Transistor) or an RC-IGBT (Reverse Conducting Insulated Gate Bipolar Transistor), but is not limited to these. In the following description, N and P represent the conductivity type of the semiconductor. In this embodiment, the first conductivity type is defined as N-type and the second conductivity type as P-type.

[0089] The power device includes an active region 200 and a terminal region 100, with the terminal region 100 circumferentially surrounding the outer side of the active region 200. For example, a transition region may also be provided between the active region 200 and the terminal region 100.

[0090] The terminal region 100 includes a substrate 110, a drift layer 111 of a first conductivity type, a field confinement ring 112 of a second conductivity type, a cathode metal 120, a passivation layer 130, a first field plate 160, and a second field plate 170.

[0091] The substrate 110 has a first main surface 1101 and a second main surface 1102 opposite to the first main surface 1101, and the first main surface 1101 and the second main surface 1102 are spaced apart in the vertical direction.

[0092] A drift layer 111 is disposed between the first main surface 1101 and the second main surface 1102. The side of the drift layer 111 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101, and the side of the drift layer 111 facing the second main surface 1102 constitutes at least a portion of the first main surface 1101.

[0093] A field limiting ring 112 is disposed in the drift layer 111, and the side of the field limiting ring 112 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. Multiple field limiting rings 112 are arranged at intervals in the horizontal direction. The arrangement of the field limiting rings 112 can effectively disperse the concentrated electric field, making the electric field distribution more uniform, improving the stability and reliability of the power device under high voltage, and preventing breakdown of the device during operation. For example, the field limiting ring 112 can also be referred to as a withstand voltage ring.

[0094] The cathode metal 120 is disposed on the second main surface 1102.

[0095] A passivation layer 130 is disposed on the first main surface 1101. For example, the passivation layer 130 is a silicon dioxide layer.

[0096] At least one first field plate 160 is in a straight line shape and is disposed in the passivation layer 130. In this embodiment, there are multiple first field plates 160, which are arranged at intervals in the horizontal direction. For example, the multiple first field plates 160 are located at the same height in the vertical direction.

[0097] The second field plate 170 is in the shape of an inverted I-beam and there is at least one. The second field plate 170 is at least partially disposed in the passivation layer 130. Specifically, the second field plate 170 includes a first field plate portion 171, a second field plate portion 172, and a third field plate portion 173. The first field plate portion 171 is parallel to the second field plate portion 172, and the third field plate portion 173 is located between the first field plate portion 171 and the second field plate portion 172, and is perpendicular to the first field plate portion 171 and the second field plate portion 172. The first field plate portion 171 is located in the passivation layer 130, and the second field plate portion 172 is located on the side of the passivation layer 130 away from the first main surface 1101. The horizontal length of the second field plate portion 172 is greater than the horizontal length of the first field plate portion 171. In this embodiment, there are multiple second field plates 170, and the multiple second field plates 170 are arranged at intervals in the horizontal direction. For example, multiple second field plates 170 are located at the same height in the vertical direction, that is, the first field plate portion 171 of the multiple second field plates 170 is located at the same height in the vertical direction, and the second field plate portion 172 of the multiple second field plates 170 is located at the same height in the vertical direction.

[0098] The first field plate 160 and the second field plate 170 are arranged alternately in the horizontal direction. For example, the first field plate portion 171 of the first field plate 160 and the second field plate 170 are located at the same height in the vertical direction and are arranged alternately in the horizontal direction.

[0099] The arrangement of the first field plate 160 and the second field plate 170 can significantly increase the movement path of mobile ions through the passivation layer 130 into the power device and the active region 200. In particular, the tortuous shape of the second field plate 170 can greatly increase the movement path of mobile ions into the power device, thereby effectively enhancing the device's anti-interference ability against mobile ions and improving the reliability of the power device in the HTRB test.

[0100] In this embodiment, both the first field plate 160 and the second field plate 170 are floating field plates, or non-contact field plates. The first field plate 160 and the second field plate 170 are not connected to any fixed potential and are in a "floating" state. Their potential is determined by their own induced charges and their interaction with the internal electric field of the device. When the power device is powered on, an electric field is generated inside the device. Because the floating field plate is close to the active region 200 or junction region of the device, it generates induced charges through electric field coupling. These induced charges generate their own electric field around the floating field plate, which in turn superimposes with the electric field inside the device. This superposition effect changes the electric field distribution in the device terminal region 100, dispersing the originally concentrated electric field and making the electric field distribution more uniform. Due to the charge compensation effect of the floating field plate, the surface electric field of the power device terminal region 100 can be effectively reduced, making the electric field line distribution more uniform. Furthermore, charges can be induced in the floating field plates, which pair with mobile ions to achieve a shielding effect. Specifically, in the HTRB test, negative charges can be induced in the first field plate 160 and the second field plate 170, which pair with the positively charged main mobile ions Na+ that cause HTRB failure, restricting their further movement into the semiconductor device, thereby achieving a shielding effect, enhancing the device's anti-interference capability against mobile ions, and improving the reliability of power devices in the HTRB test.

[0101] For example, the first field plate 160 and the second field plate 170 can be made of polycrystalline silicon or metal, or a combination of both, which can be flexibly selected by those skilled in the art according to actual process requirements. That is, the first field plate 160 is made of polycrystalline silicon and / or metal, and the second field plate 170 is made of polycrystalline silicon and / or metal.

[0102] In this embodiment, the vertical projection of the second field plate 170 partially overlaps with the first field plate 160 adjacent to the second field plate 172. Specifically, the first field plate 160 adjacent to the second field plate 172 refers to the first field plate 160 adjacent to the second field plate 170 including the second field plate 172, that is, the first field plate 160 on one or both sides of the second field plate 170 in the horizontal direction. The vertical projection of the second field plate 172 partially overlaps with the first field plate 160, meaning that the projection of the second field plate 172 at the height of the first field plate 160 in the vertical direction partially overlaps with the first field plate 160. With this arrangement, the first field plate 160 and the second field plate 170 can cover a larger area of ​​the terminal region 100 in the vertical direction, thereby enhancing the anti-interference capability against mobile ions.

[0103] In this embodiment, the terminal region 100 further includes a cutoff ring 113 of a first conductivity type, a field plate 140, and a field plate 150.

[0104] A cutoff ring 113 is disposed in the drift layer 111, and the side of the cutoff ring 113 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. The cutoff ring 113 is located on the side of the field limiting ring 112 furthest from the active region 200, away from the active region 200, and is spaced apart from the field limiting ring 112. The arrangement of the cutoff ring 113 can effectively modulate the electric field distribution, disperse the concentrated electric field, make the electric field distribution more uniform, improve the breakdown voltage of the device, and reduce surface leakage current.

[0105] The passivation layer 130 has a first contact hole corresponding to the portion of the cutoff ring 113. The field plate 140 is at least partially disposed in the first contact hole and in contact with the cutoff ring 113. The field plate 140 can be a polysilicon field plate or a metal field plate. The field plate 140 can work in conjunction with the cutoff ring 113 to change the electric field distribution on the device surface, making the electric field distribution on the device surface more uniform and improving the breakdown voltage of the device.

[0106] The passivation layer 130 has a second contact hole corresponding to a portion of a field limiting ring 112 adjacent to the stop ring 113. The field plate 150 is at least partially disposed in the second contact hole and in contact with the field limiting ring 112. The field plate 150 can effectively adjust the electric field distribution, enhance the withstand voltage performance, and reduce surface charge accumulation, thereby significantly improving the reliability and stability of the device. The field plates 140 and 150 can be floating field plates.

[0107] See attached document Figure 3 The power device according to the second embodiment of this application will be described by way of example.

[0108] The power device can be an IGBT (Insulated Gate Bipolar Transistor) or an RC-IGBT (Reverse Conducting Insulated Gate Bipolar Transistor), but is not limited to these. In the following description, N and P represent the conductivity type of the semiconductor. In this embodiment, the first conductivity type is defined as N-type and the second conductivity type as P-type.

[0109] The power device includes an active region 200 and a terminal region 100, with the terminal region 100 circumferentially surrounding the outer side of the active region 200. For example, a transition region may also be provided between the active region 200 and the terminal region 100.

[0110] The terminal region 100 includes a substrate 110, a drift layer 111 of a first conductivity type, a field confinement ring 112 of a second conductivity type, a cathode metal 120, a passivation layer 130, a first field plate 160', and a second field plate 170'.

[0111] The substrate 110 has a first main surface 1101 and a second main surface 1102 opposite to the first main surface 1101, and the first main surface 1101 and the second main surface 1102 are spaced apart in the vertical direction.

[0112] A drift layer 111 is disposed between the first main surface 1101 and the second main surface 1102. The side of the drift layer 111 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101, and the side of the drift layer 111 facing the second main surface 1102 constitutes at least a portion of the first main surface 1101.

[0113] A field limiting ring 112 is disposed in the drift layer 111, and the side of the field limiting ring 112 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. Multiple field limiting rings 112 are arranged at intervals in the horizontal direction. The arrangement of the field limiting rings 112 can effectively disperse the concentrated electric field, making the electric field distribution more uniform, improving the stability and reliability of the power device under high voltage, and preventing breakdown of the device during operation. For example, the field limiting ring 112 can also be referred to as a withstand voltage ring.

[0114] The cathode metal 120 is disposed on the second main surface 1102.

[0115] A passivation layer 130 is disposed on the first main surface 1101. For example, the passivation layer 130 is a silicon dioxide layer.

[0116] At least one first field plate 160' is in a straight line shape and is disposed in the passivation layer 130. In this embodiment, there are multiple first field plates 160', which are arranged at intervals in the horizontal direction. For example, the multiple first field plates 160' are located at the same height in the vertical direction.

[0117] The second field plate 170' is in the shape of a line and there is at least one. The second field plate 170' is disposed on the side of the passivation layer 130 away from the first main surface 1101. In this embodiment, there are multiple second field plates 170', which are arranged at intervals in the horizontal direction. For example, the multiple second field plates 170' are located at the same height in the vertical direction.

[0118] The arrangement of the first field plate 160' and the second field plate 170' can significantly increase the movement path of mobile ions through the passivation layer 130 into the power device and the active region 200, thereby effectively enhancing the device's anti-interference capability against mobile ions and improving the reliability of the power device in the HTRB test.

[0119] In this embodiment, both the first field plate 160' and the second field plate 170' are floating field plates, or non-contact field plates. The first field plate 160' and the second field plate 170' are not connected to any fixed potential and are in a "floating" state. Their potential is determined by their own induced charges and their interaction with the internal electric field of the device. When the power device is powered on, an electric field is generated inside the device. Because the floating field plate is close to the active region 200 or junction region of the device, it generates induced charges through electric field coupling. These induced charges generate their own electric field around the floating field plate, which in turn superimposes with the electric field inside the device. This superposition effect changes the electric field distribution in the device terminal region 100, dispersing the originally concentrated electric field and making the electric field distribution more uniform. Due to the charge compensation effect of the floating field plate, the surface electric field of the power device terminal region 100 can be effectively reduced, making the electric field line distribution more uniform. Furthermore, charges can be induced in the floating field plates, which pair with mobile ions to achieve a shielding effect. Specifically, in the HTRB test, negative charges can be induced in the first field plate 160' and the second field plate 170', which pair with the positively charged main mobile ions Na+ that cause HTRB failure, restricting their further movement into the semiconductor device, thereby achieving a shielding effect, enhancing the device's anti-interference capability against mobile ions, and improving the reliability of power devices in the HTRB test.

[0120] For example, the first field plate 160' and the second field plate 170' can be made of polycrystalline silicon or metal, or a combination of both, which can be flexibly selected by those skilled in the art according to actual process requirements. That is, the first field plate 160' is made of polycrystalline silicon and / or metal, and the second field plate 170' is made of polycrystalline silicon and / or metal.

[0121] In this embodiment, the projection of the second field plate 170' in the vertical direction partially overlaps with one or two first field plates 160'. Specifically, the projection of a portion of the second field plate 170' in the vertical direction may partially overlap with two adjacent first field plates 160'. It should be noted that the partial overlap of the projection of the second field plate 170' in the vertical direction with two adjacent first field plates 160' means that the projection of the second field plate 170' at the height of the first field plates 160' in the vertical direction simultaneously partially overlaps with two adjacent first field plates 160'. The projection of a portion of the second field plate 170' in the vertical direction may partially overlap with only one first field plate 160'. With this arrangement, the first field plates 160' and the second field plates 170' can cover a larger area of ​​the terminal region 100 in the vertical direction, thereby enhancing the anti-interference capability against mobile ions.

[0122] In this embodiment, the terminal region 100 further includes a cutoff ring 113 of a first conductivity type, a field plate 140, and a field plate 150.

[0123] A cutoff ring 113 is disposed in the drift layer 111, and the side of the cutoff ring 113 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. The cutoff ring 113 is located on the side of the field limiting ring 112 furthest from the active region 200, away from the active region 200, and is spaced apart from the field limiting ring 112. The arrangement of the cutoff ring 113 can effectively modulate the electric field distribution, disperse the concentrated electric field, make the electric field distribution more uniform, improve the breakdown voltage of the device, and reduce surface leakage current.

[0124] The passivation layer 130 has a first contact hole corresponding to the portion of the cutoff ring 113. The field plate 140 is at least partially disposed in the first contact hole and in contact with the cutoff ring 113. The field plate 140 can be a polysilicon field plate or a metal field plate. The field plate 140 can work in conjunction with the cutoff ring 113 to change the electric field distribution on the device surface, making the electric field distribution on the device surface more uniform and improving the breakdown voltage of the device.

[0125] The passivation layer 130 has a second contact hole corresponding to a portion of a field limiting ring 112 adjacent to the stop ring 113. The field plate 150 is at least partially disposed in the second contact hole and in contact with the field limiting ring 112. The field plate 150 can effectively adjust the electric field distribution, enhance the withstand voltage performance, and reduce surface charge accumulation, thereby significantly improving the reliability and stability of the device. The field plates 140 and 150 can be floating field plates.

[0126] See attached document Figure 4 The power device according to the third embodiment of this application will be described by way of example.

[0127] The power device can be an IGBT (Insulated Gate Bipolar Transistor) or an RC-IGBT (Reverse Conducting Insulated Gate Bipolar Transistor), but is not limited to these. In the following description, N and P represent the conductivity type of the semiconductor. In this embodiment, the first conductivity type is defined as N-type and the second conductivity type as P-type.

[0128] The power device includes an active region 200 and a terminal region 100, with the terminal region 100 circumferentially surrounding the outer side of the active region 200. For example, a transition region may also be provided between the active region 200 and the terminal region 100.

[0129] The terminal region 100 includes a substrate 110, a drift layer 111 of a first conductivity type, a field confinement ring 112 of a second conductivity type, a cathode metal 120, a passivation layer 130, a first field plate 160”, and a second field plate 170”.

[0130] The substrate 110 has a first main surface 1101 and a second main surface 1102 opposite to the first main surface 1101, and the first main surface 1101 and the second main surface 1102 are spaced apart in the vertical direction.

[0131] A drift layer 111 is disposed between the first main surface 1101 and the second main surface 1102. The side of the drift layer 111 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101, and the side of the drift layer 111 facing the second main surface 1102 constitutes at least a portion of the first main surface 1101.

[0132] A field limiting ring 112 is disposed in the drift layer 111, and the side of the field limiting ring 112 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. Multiple field limiting rings 112 are arranged at intervals in the horizontal direction. The arrangement of the field limiting rings 112 can effectively disperse the concentrated electric field, making the electric field distribution more uniform, improving the stability and reliability of the power device under high voltage, and preventing breakdown of the device during operation. For example, the field limiting ring 112 can also be referred to as a withstand voltage ring.

[0133] The cathode metal 120 is disposed on the second main surface 1102.

[0134] A passivation layer 130 is disposed on the first main surface 1101. For example, the passivation layer 130 is a silicon dioxide layer.

[0135] The first field plate 160” is I-shaped and there is at least one. The first field plate 160” is at least partially disposed in the passivation layer 130. Specifically, the first field plate 160” includes a first field plate portion 161”, a second field plate portion 162” and a third field plate portion 173”. The first field plate portion 161” is parallel to the second field plate portion 162”. The third field plate portion 173” is located between the first field plate portion 161” and the second field plate portion 162” and is perpendicular to the first field plate portion 161” and the second field plate portion 162”. The first field plate portion 161” is located in the passivation layer 130. The second field plate portion 162” is located on the side of the passivation layer 130 away from the first main surface 1101. The length of the first field plate portion 161” in the horizontal direction is greater than the length of the second field plate portion 162” in the horizontal direction. In this embodiment, there is only one first field plate 160". In some other embodiments, there may be multiple first field plates 160", which are arranged at intervals in the horizontal direction. For example, the multiple first field plates 160" are located at the same height in the vertical direction, that is, the first field plate portion 161" of the multiple first field plates 160" is located at the same height in the vertical direction, and the second field plate portion 162" of the multiple first field plates 160" is located at the same height in the vertical direction.

[0136] The second field plate 170” is in the shape of an inverted I and has at least one portion. The second field plate 170” is at least partially disposed in the passivation layer 130. Specifically, the second field plate 170” includes a fourth field plate portion 171”, a fifth field plate portion 172”, and a sixth field plate portion 173”. The fourth field plate portion 171” is parallel to the fifth field plate portion 172”. The sixth field plate portion 173” is located between the fourth field plate portion 171” and the fifth field plate portion 172” and is perpendicular to the fourth field plate portion 171” and the fifth field plate portion 172”. The fourth field plate portion 171” is located in the passivation layer 130. The fifth field plate portion 172” is located on the side of the passivation layer 130 away from the first main surface 1101. The horizontal length of the fifth field plate portion 172” is greater than the horizontal length of the fourth field plate portion 171”. In this embodiment, there is only one second field plate 170". In some other embodiments, there may be multiple second field plates 170", which are arranged at intervals in the horizontal direction. For example, the multiple second field plates 170" are located at the same height in the vertical direction, that is, the fourth field plate portion 171" of the multiple second field plates 170" is located at the same height in the vertical direction, and the fifth field plate portion 172" of the multiple second field plates 170" is located at the same height in the vertical direction.

[0137] The first field plate 160” and the second field plate 170” are arranged alternately in the horizontal direction. For example, the first field plate portion 161” in the first field plate 160” and the fourth field plate portion 171” in the second field plate 170” are located at the same height in the vertical direction and are arranged alternately in the horizontal direction; the second field plate portion 162” in the first field plate 160” and the fifth field plate portion 172” in the second field plate 170” are located at the same height in the vertical direction and are arranged alternately in the horizontal direction.

[0138] The arrangement of the first field plate 160” and the second field plate 170” can significantly increase the movement path of mobile ions through the passivation layer 130 into the power device and the active region 200. In particular, the tortuous shape of the first field plate 160” and the second field plate 170” can greatly increase the movement path of mobile ions into the power device, thereby effectively enhancing the device's anti-interference capability against mobile ions and improving the reliability of the power device in HTRB tests.

[0139] In this embodiment, both the first field plate 160” and the second field plate 170” are floating field plates, also known as non-contact field plates. The first field plate 160” and the second field plate 170” are not connected to any fixed potential and are in a “floating” state. Their potential is determined by their own induced charges and their interaction with the internal electric field of the device. When the power device is powered on, an electric field is generated inside the device. Because the floating field plate is close to the active region 200 or junction region of the device, it generates induced charges through electric field coupling. These induced charges generate their own electric field around the floating field plate, which in turn superimposes with the electric field inside the device. This superposition effect changes the electric field distribution in the device terminal region 100, dispersing the originally concentrated electric field and making the electric field distribution more uniform. Due to the charge compensation effect of the floating field plate, the surface electric field of the power device terminal region 100 can be effectively reduced, making the electric field line distribution more uniform. In addition, charges can be induced in the floating field plates, which pair with mobile ions to achieve a shielding effect. Specifically, in the HTRB test, negative charges can be induced in the first field plate 160” and the second field plate 170”, which pair with the positively charged main mobile ions Na+ that cause HTRB failure, restricting their further movement into the semiconductor device, thereby achieving a shielding effect, enhancing the device's anti-interference capability against mobile ions, and improving the reliability of power devices in the HTRB test.

[0140] For example, the first field plate 160” and the second field plate 170” can be made of polycrystalline silicon or metal, or a combination of both, which can be flexibly selected by those skilled in the art according to actual process requirements. That is, the material of the first field plate 160” is polycrystalline silicon and / or metal, and the material of the second field plate 170” is polycrystalline silicon and / or metal.

[0141] In this embodiment, the vertical projection of the fifth field plate portion 172” partially overlaps with the first field plate portion 161” of the first field plate 160” adjacent to the fifth field plate portion 172”. Specifically, the first field plate 160” adjacent to the fifth field plate portion 172” refers to the first field plate 160” adjacent to the second field plate 170” including the fifth field plate portion 172”, that is, the first field plate 160 on one or both sides of the second field plate 170” in the horizontal direction. The vertical projection of the fifth field plate portion 172” partially overlaps with the first field plate portion 161” means that the vertical projection of the fifth field plate portion 172” at the height of the first field plate portion 161” partially overlaps with the first field plate portion 161”. With this arrangement, the first field plate 160” and the second field plate 170” can cover a larger area of ​​the terminal region 100 in the vertical direction, thereby enhancing the anti-interference capability against mobile ions.

[0142] In this embodiment, the terminal region 100 further includes a cutoff ring 113 of a first conductivity type, a field plate 140, and a field plate 150.

[0143] A cutoff ring 113 is disposed in the drift layer 111, and the side of the cutoff ring 113 facing the first main surface 1101 constitutes at least a portion of the first main surface 1101. The cutoff ring 113 is located on the side of the field limiting ring 112 furthest from the active region 200, away from the active region 200, and is spaced apart from the field limiting ring 112. The arrangement of the cutoff ring 113 can effectively modulate the electric field distribution, disperse the concentrated electric field, make the electric field distribution more uniform, improve the breakdown voltage of the device, and reduce surface leakage current.

[0144] The passivation layer 130 has a first contact hole corresponding to the portion of the cutoff ring 113. The field plate 140 is at least partially disposed in the first contact hole and in contact with the cutoff ring 113. The field plate 140 can be a polysilicon field plate or a metal field plate. The field plate 140 can work in conjunction with the cutoff ring 113 to change the electric field distribution on the device surface, making the electric field distribution on the device surface more uniform and improving the breakdown voltage of the device.

[0145] The passivation layer 130 has a second contact hole corresponding to a portion of a field limiting ring 112 adjacent to the stop ring 113. The field plate 150 is at least partially disposed in the second contact hole and in contact with the field limiting ring 112. The field plate 150 can effectively adjust the electric field distribution, enhance the withstand voltage performance, and reduce surface charge accumulation, thereby significantly improving the reliability and stability of the device. The field plates 140 and 150 can be floating field plates.

[0146] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0147] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0148] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0149] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0150] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0151] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose.

[0152] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0153] It should be noted that the above embodiments are illustrative of this application and not restrictive of this application, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims.

Claims

1. A power device, characterized in that, The power device includes an active region and a terminal region, with the terminal region circumferentially surrounding the outside of the active region; The terminal area includes: A substrate having a first main surface and a second main surface opposite to the first main surface, wherein the first main surface and the second main surface are spaced apart in the vertical direction; A drift layer of a first conductivity type is disposed between the first main surface and the second main surface, wherein the side of the drift layer facing the first main surface constitutes at least a portion of the first main surface, and the side of the drift layer facing the second main surface constitutes at least a portion of the second main surface. A field limiting ring of a second conductivity type is disposed in the drift layer, wherein the side of the field limiting ring facing the first main surface constitutes at least a portion of the first main surface; Cathode metal, wherein the cathode metal is disposed on the second main surface; A passivation layer is disposed on the first main surface; The first field plate is I-shaped and there is at least one of them, and the first field plate is at least partially disposed in the passivation layer; The second field plate is in the shape of an inverted I-beam and there is at least one of them, and the second field plate is at least partially disposed in the passivation layer; The first field plate and the second field plate are arranged alternately in the horizontal direction; Both the first field plate and the second field plate are floating field plates; The first field plate includes a first field plate portion, a second field plate portion, and a third field plate portion. The first field plate portion is parallel to the second field plate portion, and the third field plate portion is located between the first field plate portion and the second field plate portion. The third field plate portion is perpendicular to the first field plate portion and the second field plate portion. The first field plate portion is located in the passivation layer, and the second field plate portion is located on the side of the passivation layer away from the first main surface. The length of the first field plate portion in the horizontal direction is greater than the length of the second field plate portion in the horizontal direction. The second field plate includes a fourth field plate portion, a fifth field plate portion, and a sixth field plate portion. The fourth field plate portion is parallel to the fifth field plate portion, and the sixth field plate portion is located between the fourth field plate portion and the fifth field plate portion. The sixth field plate portion is perpendicular to the first field plate portion and the second field plate portion. The fourth field plate portion is located in the passivation layer, and the fifth field plate portion is located on the side of the passivation layer away from the first main surface. The length of the fifth field plate portion in the horizontal direction is greater than the length of the fourth field plate portion in the horizontal direction. The projection of the fifth field plate portion in the vertical direction partially overlaps with the first field plate portion of the first field plate adjacent to the fifth field plate portion.

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