IGBT device and layout structure thereof
By designing a tortuous floating field ring in the IGBT layout, the leakage breakdown problem in the transition zone is solved and the voltage resistance of the IGBT is enhanced.
Patent Information
- Application Number
- CN202422471907.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-10-12
AI Technical Summary
In the existing IGBT layout design, the floating field ring in the transition zone cannot be effectively covered, resulting in leakage breakdown problems and affecting device performance.
The layout structure of the IGBT is designed so that part of the sides of the first floating field ring is tortuous and extends towards the cell region to shorten the spacing with the cell region, and a diffusion region is formed by diffusion of the thermal junction to fully cover the transition region.
It effectively avoids leakage breakdown problems in the transition zone and enhances the voltage withstand performance of the transition zone and the device as a whole.
Smart Images
Figure CN223207454U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor manufacturing, in particular to an IGBT device and a layout structure thereof. Background Art
[0002] An insulated gate bipolar transistor (IGBT) is a fully controlled, voltage-driven, composite power semiconductor device composed of a bipolar junction transistor (BJT) and a metal-oxide-semiconductor field-effect transistor (MOSFET). The IGBT combines the advantages of both MOS and BJTs: high input impedance, low control power, simple drive circuits, fast switching speeds, and low switching losses of MOS, with the high current density, low saturation voltage drop, and strong current handling capability of the BJT.
[0003] However, in order to cater to the application requirements of products in different fields, IGBT designs have shown diverse characteristics, making it difficult to form a set of reference standards in product design. Figure 1 and Figure 2 As shown in the figure, some IGBT layout designs focus on the voltage-resistant structure design of the cell region 10 and the terminal region 12, but neglect the consideration of the transition region 11. That is, due to the certain curvature of the chip corner, the distance D between the floating field ring (P-Ring) 121 in the terminal region 12 and the gate structure 101 in the cell region 10 is relatively large at the chip corner, and the minimum distance D can reach about 8μm to 10μm. Figure 2 As shown in FIG. 1 , this arc-shaped corner layout design will result in the floating field ring 121 in the terminal region 12, after the thermal push junction diffusion, forming a diffusion region 122 that cannot effectively cover the transition region 11, resulting in a partially uncovered region 111. The uncovered region 111 will cause the PN junction of the transition region 11 to be weakened or even missing, which can easily cause leakage breakdown and seriously affect device performance. And, as Figure 3 As shown, the floating field ring 121 distributed at the gate pad position P of the IGBT also has an arc-shaped corner morphology relative to the cell area 10. Due to the curvature of the arc-shaped corner, the distance D between the floating field ring 121 and the corresponding gate structure 101 will also be too large, resulting in the existence of an uncovered area 111, which can easily cause device leakage breakdown problems.
[0004] Therefore, a new IGBT layout design is urgently needed to solve the above technical problems. Utility Model Content
[0005] The purpose of the present utility model is to provide an IGBT device and its layout structure to solve at least one of the problems of alleviating leakage breakdown in the transition region of the IGBT and improving the withstand voltage of the IGBT.
[0006] In order to solve the above technical problems, the present invention provides an IGBT layout structure, comprising: a cell region, a transition region and a terminal region; the terminal region is located at the periphery of the cell region, and the transition region is located between the terminal region and the cell region;
[0007] A first floating field ring is distributed in the terminal region. The first floating field ring is arranged around the periphery of the cell region and close to the transition region. Part of the side of the first floating field ring is zigzag to extend toward the cell region.
[0008] Optionally, in the layout structure of the IGBT, the first floating field ring has a plurality of corners, and at least part of the corners are zigzag toward a side of the transition region.
[0009] Optionally, in the layout structure of the IGBT, the first floating field ring is rectangular and has four corners; and each corner is zigzag on a side facing the transition region.
[0010] Optionally, in the layout structure of the IGBT, the first floating field ring has a protrusion, which extends toward the cell region to serve as a gate pad distribution region; wherein part of the side edges of the protrusion are zigzag.
[0011] Optionally, in the layout structure of the IGBT, the protrusion has a plurality of corners, and at least some of the corners are zigzag toward a side of the transition region.
[0012] Optionally, in the layout structure of the IGBT, the zigzag shape includes a stepped shape, a wavy shape or a sawtooth shape.
[0013] Optionally, in the layout structure of the IGBT, a plurality of gate structures are distributed in the cell region, and a zigzag side portion of the first floating field ring extends toward an adjacent gate structure.
[0014] Optionally, in the layout structure of the IGBT, a distance D between the side of the first floating field ring facing the transition region and the adjacent gate structure is in the range of:
[0015] 2μm≤D≤5μm.
[0016] Optionally, in the layout structure of the IGBT, a diffusion region is distributed on the periphery of the first floating field ring; and part of the diffusion region extends to the transition region and is connected to the adjacent gate structure.
[0017] Based on the same concept, the present invention also provides an IGBT device, including a semiconductor structure prepared by adopting the layout structure design of the IGBT.
[0018] In summary, the present invention provides an IGBT device and its layout structure. Compared to the prior art, the layout structure of the IGBT provided by the present invention designs part of the side of the first floating field ring to be zigzag and extend toward the cell region, thereby shortening the distance between the side of the first floating field ring and the cell region. This allows the diffusion region formed by the first floating field ring after thermal junction diffusion to fully cover the transition region, effectively avoiding leakage breakdown in the transition region and enhancing the voltage resistance of the transition region and the device as a whole. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.
[0020] Figure 1 It is a schematic diagram of the layout structure of IGBT in the prior art.
[0021] Figure 2 It is a cross-sectional view taken along line AA′ in which an uncovered area is formed in the transition region of the IGBT in the prior art.
[0022] Figure 3 This is a schematic diagram of a structure in which a floating field ring at a gate pad position of an IGBT in the prior art has a large distance relative to a cell region.
[0023] Figure 4 It is a schematic diagram of the layout structure of the IGBT in the embodiment of the present utility model.
[0024] Figure 5 This is a BB' cross-sectional view of an embodiment of the present invention in which the diffusion region fully covers the transition region.
[0025] Figure 6 This is a schematic structural diagram of an embodiment of the present invention in which a corner of the first floating field ring is stepped relative to the gate structure.
[0026] Figure 7 This is a schematic structural diagram of a first floating field ring in an embodiment of the present invention, in which a corner of the first floating field ring is wavy on one side relative to the gate structure.
[0027] Figure 8This is a schematic structural diagram of a first floating field ring in an embodiment of the present invention, in which the corner of the first floating field ring is zigzag-shaped relative to the gate structure.
[0028] Figure 9 1 is a schematic structural diagram of an embodiment of the present invention in which the protrusion relative to the gate structure is stepped.
[0029] And, in the accompanying drawings:
[0030] 10-cell region; 101-gate structure; 11-transition region; 111-uncovered region; 12-terminal region; 121-floating field ring; 122-diffusion region;
[0031] 20 - cell region; 201 - gate structure; 202 - P body region; 203 - carrier storage layer; 204 - N drift region; 21 - transition region; 22 - terminal region; 221 - first floating field ring; 221' - diffusion region; 222 - second floating field ring;
[0032] P-gate pad location; M-corner; N-protrusion; D-distance between the side of the floating field ring facing the transition region and the adjacent gate structure. DETAILED DESCRIPTION
[0033] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis required to be shown in each drawing is different, and sometimes different proportions are used. It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third" and the like in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, and are not used to represent the logical relationship or sequential relationship between the various components, elements, steps, etc. In addition, the X-axis direction, Y-axis direction and Z-axis direction referred to in the specification of this application are three directions perpendicular to each other in three-dimensional space.
[0034] See also Figure 4 This embodiment provides a layout structure of an IGBT, including: a cell region 20, a transition region 21 and a terminal region 22; the terminal region 22 is located at the periphery of the cell region 20, and the transition region 21 is located between the terminal region 22 and the cell region 20; a first floating field ring 221 is distributed in the terminal region 22, and the first floating field ring 221 is arranged around the periphery of the cell region 20 and close to the transition region 21; wherein, part of the side edge of the first floating field ring 221 is zigzag to extend toward the cell region 20.
[0035] Based on this, the layout structure of the IGBT provided in this embodiment designs part of the side of the first floating field ring 221 to be zigzag and extend toward the cell area 20 to shorten the distance between the side of the first floating field ring 221 and the cell area 20, so that the diffusion area 221' formed by the first floating field ring 221 after thermal junction diffusion can fully cover the transition area 21, effectively avoiding the leakage breakdown problem in the transition area 21, and enhancing the voltage resistance performance of the transition area 21 and the device as a whole.
[0036] The following is combined with Figures 4 to 9 , specifically describing the layout structure of the IGBT provided in this embodiment.
[0037] See also Figure 4 and Figure 5 The layout structure of the IGBT includes: a cell region 20, a transition region 21 and a terminal region 22. The cell region 20 is the key device region of the IGBT and is generally provided with a gate structure 201, a P body region 202, a carrier storage layer (CS layer) 203, an N drift region 204 and other well regions. Exemplarily, the gate structure 201 is a trench gate. In other embodiments, the gate structure 201 of the IGBT can also be a planar gate. The transition region 21 is located between the terminal region 22 and the cell region 20, and is used to optimize the combination of the cell region 20 and the terminal region 22, thereby improving the performance of the IGBT device. The terminal region 22 is located at the periphery of the cell region 20 and can be arranged around the periphery of the cell region 20. The terminal region 22 is generally provided with a field plate and a floating field ring, etc., which are used to improve and adjust the electric field distribution and improve the withstand voltage performance of the IGBT device.
[0038] It should be noted that as a high-voltage power device, one of the important parameters of IGBT is breakdown voltage. The breakdown voltage of IGBT depends on the lowest breakdown voltage among the three regions. -The J2 junction formed by the drift region is the primary voltage-withstanding structure, capable of withstanding a high forward voltage drop. The terminal region 22, through its floating field ring plus field plate structure, can improve the device's lateral voltage withstand. In contrast, the transition region 21 lacks an effective voltage-withstanding structure, making the IGBT susceptible to leakage problems in this area during operation. In particular, the corners of the floating field ring have a certain curvature, resulting in a large distance between them and the gate structure 201 of the cell region 20. This can easily result in some areas not being covered by the ion diffusion region, leading to J2 junction failure and leakage breakdown. Therefore, the IGBT layout structure provided in this embodiment includes a first floating field ring 221 distributed within the terminal region 22. Part of the side edges of the first floating field ring 221 are zigzag and extend toward the cell region 20. This ensures that the diffusion region 221' formed by the first floating field ring 221 after thermal junction diffusion can fully cover the transition region 21, thereby enhancing the voltage withstand capability of the transition region 21 and effectively preventing leakage breakdown.
[0039] For details, please refer to Figure 4 and Figure 6 The first floating field ring 221 in the termination region 22 surrounds the periphery of the cell region 20 and is adjacent to the transition region 21. It should be noted that multiple second floating field rings 222 are also distributed within the termination region 22. Both the second floating field rings 222 and the first floating field ring 221 are P-type doped regions, and the first floating field ring 221 and the multiple second floating field rings 222 are sequentially arranged around the periphery of the cell region 20. However, the first floating field ring 221 is located at the edge of the termination region 22 and directly connects to the transition region 21. In other words, the first floating field ring 221 is the innermost floating field ring in the termination region 22. Since the cell region 20 is generally rectangular or square, the first floating field ring 221 surrounding the exterior of the cell region 20 also approximates a rectangle or square. Consequently, the first floating field ring 221 has multiple corners M.
[0040] In order to avoid the influence of the curvature at the corner M causing the distance between the first floating field ring 221 and the cell region 20 to be too large, thereby affecting the coverage of the diffusion region 221' of the first floating field ring 221, at least part of the corner M of the first floating field ring 221 provided in this embodiment is zigzag-shaped toward the side of the transition region 21. Optionally, the zigzag shape includes but is not limited to Figure 6 The stepped shape shown, Figure 7 The wavy or Figure 8 As shown in the sawtooth shape. Exemplarily, the corner M is stepped toward the side of the transition zone 21. Figure 5 and Figure 6As shown, the distance D between the stepped corner M and the cell region 20 is smaller than that between the curved corner M and the cell region 20, which is conducive to the diffusion region 221' formed after the first floating field ring 221 undergoes thermal push junction diffusion to fully cover the transition region 21, thereby enhancing the pressure resistance of the transition region 21 and effectively avoiding leakage breakdown problems. Based on this, preferably, all the corners A of the first floating field ring 221 are zigzag on the side facing the transition region 21, so as to effectively alleviate the leakage breakdown problem of the transition region 21 and improve the pressure resistance of the transition region 21. For example, as Figure 4 As shown, the first floating field ring 221 is rectangular and has four corners M, and the four corners M are all stepped on the side facing the transition area 21 .
[0041] For further information, please refer to Figure 4 According to the layout design of the IGBT, it is necessary to form a gate pad in the transition region 21 to achieve electrical connection to all gate structures 201 in the cell region 20. In addition, a floating field ring is generally provided under the gate pad to ensure that the gate signal can be effectively transmitted to the internal structure of the IGBT, thereby achieving precise control of its working state. Based on this, the first floating field ring 221 has a protrusion N, and the protrusion N extends toward the cell region 20 to serve as a gate pad distribution area. Part of the gate structure 201 will extend into the protrusion N. However, since the protrusion N also has several corners M, in order to avoid the distance D between the gate structure 201 and the protrusion N being too large, it is preferred that at least some of the corners M in the protrusion N are zigzag toward one side of the transition region 21. And the zigzag shape can be stepped, wavy or sawtooth, etc. For example, as Figure 4 and Figure 9 As shown, since one side of the protrusion N is connected to the main body of the first floating field ring 221, and the other side of the protrusion N has two corners M, preferably, the two corners M of the protrusion N are both zigzag-shaped toward the side of the transition region 21. It should be noted that, in other examples, the protrusion N is located at one of the corners M of the main body of the first floating field ring 221, and the protrusion N has only one corner M. In this way, the corner M is zigzag-shaped toward the side of the transition region 21 to reduce the distance between the protrusion N and the adjacent gate structure 201, which is conducive to the formed diffusion region 221' fully covering the transition region 21, thereby avoiding the problem of leakage breakdown in the transition region 21.
[0042] For further information, please refer to Figure 5, since the corner M of the first floating field ring 221 is zigzag on the side facing the transition region 21, the spacing D between the first floating field ring 221 and the adjacent gate structure 201 on the side facing the transition region 21 can be reduced to 2μm to 5μm; that is, 2μm≤D≤5μm. For example, the spacing D is 2μm, 3μm or 5μm. Therefore, after performing thermal push junction diffusion on the first floating field ring 221, a diffusion region 221' is formed on the periphery of the first floating field ring 221. Part of the diffusion region 221' extends to the transition region 21 and connects to the adjacent gate structure 201, thereby achieving full coverage of the transition region 21, effectively avoiding leakage breakdown problems in the transition region 21, and enhancing the voltage resistance of the transition region 21.
[0043] It should be noted that the IGBT layout structure provided in this embodiment is a layout designed for the distribution of doped regions within a chip substrate. Based on this layout structure, device structures such as metal interconnect layers will be further formed in subsequent processes. Furthermore, based on the same concept, this embodiment also provides an IGBT device. This IGBT device includes a semiconductor structure fabricated using the aforementioned IGBT layout structure design.
[0044] To sum up, the IGBT device and its layout structure provided in this embodiment are designed to design the corner M of the first floating field ring 221 to be zigzag toward the side of the transition region 21, and extend this part of the side toward the adjacent gate structure 201 in the cell region 20, so as to shorten the distance between the side of the first floating field ring 221 and the adjacent gate structure 201, so that the diffusion region 221' formed after the first floating field ring 221 is thermally pushed and diffused can fully cover the transition region 21, effectively avoiding the leakage breakdown problem of the transition region 21, and enhancing the voltage resistance performance of the transition region 21 and the IGBT device as a whole.
[0045] Furthermore, it should be recognized that although the present invention has been disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. Any person skilled in the art will be able to utilize the above-disclosed technical content to make numerous possible variations and modifications to the present invention, or to modify the present invention into equivalent embodiments with equivalent variations, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.
Claims
1. An IGBT layout structure, characterized in that: include: A cellular region, a transition region and a terminal region; the terminal region is located at the periphery of the cellular region, and the transition region is located between the terminal region and the cellular region; A first floating field ring is distributed in the terminal region. The first floating field ring is arranged around the periphery of the cell region and close to the transition region. Part of the side of the first floating field ring is zigzag to extend toward the cell region.
2. The IGBT layout structure according to claim 1, characterized in that: The first floating field ring has a plurality of corners, and at least part of the corners are zigzag toward a side of the transition zone.
3. The layout structure of the IGBT according to claim 2, characterized in that: The first floating field ring is rectangular and has four corners; and each corner is zigzag on a side facing the transition zone.
4. The IGBT layout structure according to claim 1, characterized in that: The first floating field ring has a protruding portion, which extends toward the cell region to serve as a gate pad distribution region; wherein part of the side edges of the protruding portion are zigzag.
5. The IGBT layout structure according to claim 4, characterized in that: The protrusion has a plurality of corners, and at least part of the corners are zigzag toward a side of the transition zone.
6. The IGBT layout structure according to any one of claims 1 to 5, characterized in that: The zigzag shape includes a stepped shape, a wavy shape or a sawtooth shape.
7. The IGBT layout structure according to claim 1, characterized in that: A plurality of gate structures are distributed in the cell region, and a zigzag side portion of the first floating field ring extends toward the adjacent gate structure.
8. The IGBT layout structure according to claim 7, characterized in that: The distance D between the side of the first floating field ring facing the transition region and the adjacent gate structure is: 2μm≤D≤5μm.
9. The IGBT layout structure according to claim 7 or 8, characterized in that: A diffusion region is distributed on the periphery of the first floating field ring; and a portion of the diffusion region extends to the transition region and is connected to the adjacent gate structure.
10. An IGBT device, characterized in that: The invention comprises a semiconductor structure prepared by adopting the layout structure design of the IGBT according to any one of claims 1 to 9.