Shield grid groove type MOSFET terminal structure
By setting equal spacing between the target terminal voltage divider ring trench and the active region trench in the shielded gate trench MOSFET termination structure, the problems of unstable withstand voltage and excessive leakage current of the shielded gate MOSFET device are solved, and the stable withstand voltage and reduced leakage current of the device are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 捷捷微电(南通)科技有限公司
- Filing Date
- 2025-05-19
- Publication Date
- 2026-05-08
AI Technical Summary
Existing shielded gate MOSFET devices suffer from unstable withstand voltage and excessive leakage current.
A shielded gate trench MOSFET termination structure is adopted, including a substrate, an active region trench, a termination voltage divider ring trench, and a termination cutoff ring trench. By setting the spacing between the target termination voltage divider ring trench and the active region trench to be equal, the charge is ensured to be depleted evenly, the device withstand voltage is stabilized, and leakage current is reduced.
This achieves stable withstand voltage and reduced leakage current, thereby reducing the risk of device failure during withstand voltage testing.
Smart Images
Figure CN224218742U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and more specifically, to a shielded gate trench MOSFET termination structure. Background Technology
[0002] Semiconductor power devices, specifically switching transistors, are the core of modern power converters. Commonly used power devices are fabricated from metal, oxide, and semiconductor materials. Conventional shielded-gate trench power metal-oxide-semiconductor transistors (MOS transistors) control the switching of the device by controlling the external bias applied to the polysilicon gate. When a forward bias is applied to the gate, the gate electric field forms an inversion layer conductive channel on the oxide and semiconductor surfaces, turning the device on. Conversely, when the gate is connected to zero or a negative potential, the device is off.
[0003] A shielded-gate MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) increases avalanche breakdown voltage by introducing a vertical polysilicon field plate into the bulk, transforming the triangular electric field distribution required for directional breakdown into a rectangular one. This utilizes the two-dimensional charge depletion effect: firstly, the P-type bulk region and drift region deplete each other; secondly, the shielded gate structure and drift region deplete each other. Therefore, while increasing the doping concentration in the drift region to reduce on-resistance, the device's breakdown voltage can be maintained. Furthermore, because the shielded gate is located between the control gate and the drain, it shields part of the feedback capacitance, resulting in lower switching failure rates for the shielded-gate MOSFET.
[0004] Shielded-gate MOSFETs are two-dimensional charge-depletion devices. The charge depletion state of the termination structure determines the stability of the avalanche breakdown voltage and the repetitive avalanche withstand capability of the shielded-gate MOSFET device. When the charge in the termination region of a conventional structure cannot be perfectly depleted, the device termination is prone to unstable withstand voltage, and the termination region can easily become a weak point. Furthermore, the termination region is more complex than two-dimensional depletion due to the presence of charge depletion in multiple directions, resulting in a smaller process window. Process fluctuations can lead to larger leakage currents during the withstand voltage process, failing to meet application requirements.
[0005] In summary, existing technologies suffer from problems such as unstable withstand voltage and excessive leakage current in shielded gate MOSFET devices. Utility Model Content
[0006] The purpose of this application is to provide a shielded gate trench MOSFET termination structure to solve the problems of unstable withstand voltage and excessive leakage current in existing shielded gate MOSFET devices.
[0007] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:
[0008] This application provides a shielded gate trench MOSFET termination structure, the shielded gate trench MOSFET termination structure comprising:
[0009] Substrate;
[0010] The substrate surface includes multiple active region trenches, at least one terminal voltage divider ring trench, and at least one terminal cutoff ring trench; the terminal voltage divider ring trench is located outside the active region trenches and surrounds them, and the terminal cutoff ring trench is located outside the terminal voltage divider ring trench; wherein,
[0011] The at least one terminal voltage divider ring groove includes a target terminal voltage divider ring groove that is closest to the active area groove. The distance between the target terminal voltage divider ring groove and the active area groove, and the distance between two adjacent active area grooves are equal.
[0012] Optionally, the target terminal pressure dividing ring groove includes an integrally connected first transverse groove and a first longitudinal groove. The first longitudinal groove is arranged parallel to the active area groove, and the first transverse groove is arranged perpendicular to the active area groove. Furthermore, any point at the end of each active area groove is equal to the shortest distance between the first transverse groove and the first transverse groove.
[0013] Optionally, the end of each active area trench is configured as a first arc shape, and the first transverse trench is configured as multiple segments of a second arc shape connected in sequence. Each segment of the second arc shape is located outside a first arc shape, and the center of each segment of the second arc shape and the center of the corresponding first arc shape are located at the same point.
[0014] Optionally, when the number of terminal pressure dividing ring grooves is at least two, the at least two terminal pressure dividing ring grooves are arranged in parallel.
[0015] Optionally, when the number of terminal voltage divider ring grooves is at least two, the spacing between two adjacent terminal voltage divider ring grooves is equal to the spacing between two adjacent active area grooves.
[0016] Optionally, the terminal pressure dividing ring groove includes a first transverse groove and a first longitudinal groove integrally connected; the terminal stop ring groove includes a second transverse groove and a second longitudinal groove integrally connected, the connection between the first transverse groove and the first longitudinal groove is set to be arc-shaped, the connection between the second transverse groove and the second longitudinal groove is also set to be arc-shaped, and the arc of the connection between the first transverse groove and the first longitudinal groove and the arc of the connection between the second transverse groove and the second longitudinal groove are equal.
[0017] Optionally, each of the active region trenches is provided with a gate contact hole, and the gate contact holes on multiple active region trenches are connected in a straight line, and the gate contact holes are connected to the gate metal.
[0018] Optionally, each of the active region trenches is provided with a first source contact hole, the target terminal voltage divider ring trench is provided with a second source contact hole between the active region trench and the two adjacent active region trenches, and the terminal voltage divider ring trench is provided with a third source contact hole. The first source contact hole, the second source contact hole and the third source contact hole are all connected to the source metal.
[0019] Optionally, a portion of the second source contact hole is connected to the first source contact hole in a straight line, and another portion of the second source contact hole is connected to the third source contact hole in a straight line.
[0020] Optionally, a first drain contact hole is provided on the terminal stop ring trench, and a second drain contact hole is provided on the substrate near the terminal stop ring trench. Both the first drain contact hole and the second drain contact hole are connected to the drain metal.
[0021] Compared with the prior art, this application has the following advantages:
[0022] This application provides a shielded gate trench MOSFET termination structure, comprising: a substrate; multiple active region trenches, at least one termination voltage divider ring trench, and at least one termination cutoff ring trench located on the substrate surface; the termination voltage divider ring trench is located outside the active region trenches and surrounds them, and the termination cutoff ring trench is located outside the termination voltage divider ring trench; wherein, at least one termination voltage divider ring trench includes a target termination voltage divider ring trench closest to the active region trench, and the spacing between the target termination voltage divider ring trench and the active region trench, and the spacing between two adjacent active region trenches are equal. Because this application sets the spacing between the target termination voltage divider ring trench and the active region trench, and the spacing between two adjacent active region trenches, equal spacing allows the charge between adjacent active region trenches and the charge between the end of the active region trench and the termination voltage divider ring trench to be uniformly depleted, thereby achieving stable device withstand voltage and reducing leakage current during the withstand voltage process.
[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a plan view of the shielded gate trench MOSFET termination structure provided in an embodiment of this application.
[0026] Figure 2 This is another planar schematic diagram of the shielded gate trench MOSFET termination structure provided in the embodiments of this application.
[0027] Figure 3 This is a planar schematic diagram of the shielded gate trench MOSFET termination structure provided in the embodiments of this application after removing the gate metal, source metal, and drain metal.
[0028] In the picture:
[0029] 101-Substrate; 102-Active region; 103-Termination region; 104-Active region trench; 105-Termination voltage divider ring trench; 106-Termination cutoff ring trench; 107-Gate contact hole; 108-First source contact hole; 109-Second source contact hole; 110-Third source contact hole; 111-First drain contact hole; 112-Second drain contact hole; 113-Gate metal; 114-Source metal; 115-Drain metal. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0031] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0032] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0033] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.
[0034] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0035] As described in the background section, existing shielded gate MOSFET devices suffer from unstable withstand voltage and excessive leakage current. Therefore, this application provides a shielded gate trench MOSFET termination structure to address these issues.
[0036] The shielded gate trench MOSFET termination structure provided in this application is illustrated below:
[0037] As an optional implementation, please refer to Figures 1-3 The shielded gate trench MOSFET termination structure includes: a substrate 101; a plurality of active region trenches 104, at least one termination voltage divider ring trench 105, and at least one termination cutoff ring trench 106 located on the surface of the substrate 101; the termination voltage divider ring trench 105 is located outside the active region trenches 104 and surrounds the active region trenches 104, and the termination cutoff ring trench 106 is located outside the termination voltage divider ring trench 105; wherein, at least one termination voltage divider ring trench 105 includes a target termination voltage divider ring trench that is closest to the active region trenches 104, and the spacing between the target termination voltage divider ring trench and the active region trenches 104, and the spacing between two adjacent active region trenches 104 are equal.
[0038] Understandably, the substrate 101 described in this application is a wafer epitaxial substrate. The substrate 101 is divided into an active region 102 and a termination region 103. The termination region 103 is disposed around the active region 102 and surrounds it. An active region trench 104 is disposed within the active region 102, and a termination voltage divider ring trench 105 and a termination stop ring trench 106 are disposed within the termination region 103.
[0039] The active region trenches 104 are arranged in parallel, and the length and width of the active region trenches 104 are the same, and the ends of the active regions 102 are flush. In addition, the spacing between two adjacent active region trenches 104 is equal.
[0040] The number of terminating voltage divider ring trenches 105 is not limited; it can be one, two, or even more. Generally, the number of terminating voltage divider ring trenches 105 can be adjusted according to the rated voltage requirements of the device. When the rated voltage is high, the number of terminating voltage divider ring trenches 105 can be increased accordingly. Furthermore, when there is only one terminating voltage divider ring trench 105, that trench is designated as the target terminating voltage divider ring trench. When there is more than one terminating voltage divider ring trench 105, the terminating voltage divider ring trench 105 closest to the active region trench 104 is designated as the target terminating voltage divider ring trench. The spacing between the target terminating voltage divider ring trench and the active region trench 104, and the spacing between two adjacent active region trenches 104, are set to be equal.
[0041] Since the distance between the end of the active region trench 104 and the terminal voltage divider ring trench 105 is equal to the distance between two adjacent active region trenches 104, the charge between two adjacent active region trenches 104 and the charge between the end of the active region trench 104 and the terminal voltage divider ring trench 105 can be uniformly depleted, thereby stabilizing the device withstand voltage, reducing leakage current of the device during the withstand voltage process, and thus reducing the risk of device failure.
[0042] As one implementation, the target terminal voltage divider ring groove includes an integrally connected first transverse groove and a first longitudinal groove. The first longitudinal groove is arranged parallel to the active area groove 104, and the first transverse groove is arranged perpendicular to the active area groove 104. Furthermore, any point at the end of each active area groove 104 is equal to the shortest distance between the first transverse groove and the first transverse groove.
[0043] Generally, the end of each active area trench 104 is configured as a first arc. In order to achieve the effect that any point at the end of each active area trench 104 is equal to the shortest distance of the first transverse trench, the first transverse trench is configured as multiple segments of second arc connected in sequence. Each segment of the second arc is located outside a first arc, and the center of each segment of the second arc and the center of the corresponding first arc are located at the same point.
[0044] In this application, the first transverse groove is wavy, the first longitudinal groove is straight, and the circles corresponding to the first and second arcs are concentric circles. By setting the first transverse groove in the terminal voltage divider ring groove 105 to a curved shape, it can be ensured that the distance between the end of each active area groove 104 and the first transverse groove is equal, and for any point on the end of each active area groove 104, the shortest distance between it and the first transverse groove is equal, and the distance between it and two adjacent active area grooves 104 is equal. Therefore, it can be ensured that the charge is uniformly depleted within the area surrounded by the target terminal voltage divider ring groove, thereby stabilizing the device withstand voltage and reducing leakage current during the withstand voltage process.
[0045] It should be noted that when the number of terminal voltage divider ring grooves 105 is at least two, the at least two terminal voltage divider ring grooves 105 are arranged in parallel. Furthermore, the spacing between two adjacent terminal voltage divider ring grooves 105 is equal to the spacing between two adjacent active region grooves 104. This implementation method can better achieve the effect of uniformly depleting the charge.
[0046] Furthermore, the terminal pressure dividing ring groove 105 includes a first transverse groove and a first longitudinal groove integrally connected. The first transverse groove is straight, and the first longitudinal groove is curved. The terminal stop ring groove 106 includes a second transverse groove and a second longitudinal groove integrally connected, both of which are straight. The connection between the first transverse groove and the first longitudinal groove is arc-shaped, and the connection between the second transverse groove and the second longitudinal groove is also arc-shaped. The arc of the connection between the first transverse groove and the first longitudinal groove and the arc of the connection between the second transverse groove and the second longitudinal groove are equal.
[0047] This configuration ensures a reasonable spacing between the terminal voltage divider ring groove 105 and the terminal stop ring groove 106, and minimizes the area occupied by the entire terminal area 103, which is beneficial for miniaturizing the device.
[0048] As one implementation, each active region trench 104 is provided with a gate contact hole 107, and the gate contact holes 107 on multiple active region trenches 104 are connected in a straight line, and the gate contact hole 107 is connected to the gate metal 113.
[0049] Furthermore, each of the active region trenches 104 is provided with a first source contact hole 108, and each of the target terminal voltage divider ring trenches and the active region trenches 104, as well as between two adjacent active region trenches 104, is provided with a second source contact hole 109. A third source contact hole 110 is provided on the terminal voltage divider ring trench 105. The first source contact hole 108, the second source contact hole 109, and the third source contact hole 110 are all connected to the source metal 114. Simultaneously, some of the second source contact holes 109 are aligned with the first source contact holes 108 in a straight line, and another portion of the second source contact holes 109 are aligned with the third source contact holes 110 in a straight line. In one implementation, the gate contact hole 107 is located in the middle of the active region trench 104, and the first source contact hole 108, the second source contact hole 109 and the third source contact hole 110 are distributed on both sides of the gate contact hole 107, so that the entire source metal 114 can be provided with a "U" shaped structure.
[0050] Of course, a first drain contact hole 111 is provided on the terminal stop ring trench 106, and a second drain contact hole 112 is provided on the substrate 101 near the terminal stop ring trench 106. Both the first drain contact hole 111 and the second drain contact hole 112 are connected to the drain metal 115.
[0051] In summary, this application provides a shielded gate trench MOSFET termination structure, which includes: a substrate; multiple active region trenches, at least one termination voltage divider ring trench, and at least one termination cutoff ring trench located on the substrate surface; the termination voltage divider ring trench is located outside the active region trench and surrounds it, and the termination cutoff ring trench is located outside the termination voltage divider ring trench; wherein, at least one termination voltage divider ring trench includes a target termination voltage divider ring trench closest to the active region trench, and the spacing between the target termination voltage divider ring trench and the active region trench, as well as the spacing between two adjacent active region trenches, are equal. Because this application sets the spacing between the target termination voltage divider ring trench and the active region trench, as well as the spacing between two adjacent active region trenches, to be equal, the charge between adjacent active region trenches and the charge between the end of the active region trench and the termination voltage divider ring trench can be uniformly depleted, thereby achieving the effect of stabilizing the device's withstand voltage and reducing leakage current during the withstand voltage process.
[0052] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
[0053] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.
Claims
1. A shielded gate trench MOSFET termination structure, characterized in that, The shielded gate trench MOSFET termination structure includes: Substrate; The substrate surface includes multiple active region trenches, at least one terminal voltage divider ring trench, and at least one terminal cutoff ring trench; the terminal voltage divider ring trench is located outside the active region trenches and surrounds them, and the terminal cutoff ring trench is located outside the terminal voltage divider ring trench; wherein, The at least one terminal voltage divider ring groove includes a target terminal voltage divider ring groove that is closest to the active area groove. The distance between the target terminal voltage divider ring groove and the active area groove, and the distance between two adjacent active area grooves are equal.
2. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, The target terminal pressure dividing ring groove includes an integrally connected first transverse groove and a first longitudinal groove. The first longitudinal groove is arranged parallel to the active area groove, and the first transverse groove is arranged perpendicular to the active area groove. Furthermore, any point at the end of each active area groove is equal to the shortest distance between the first transverse groove and the first transverse groove.
3. The shielded gate trench MOSFET termination structure as described in claim 2, characterized in that, The end of each active area trench is configured as a first arc shape, and the first transverse trench is configured as multiple segments of a second arc shape connected in sequence. Each segment of the second arc shape is located outside a first arc shape, and the center of each segment of the second arc shape and the center of the corresponding first arc shape are located at the same point.
4. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, When the number of terminal pressure dividing ring grooves is at least two, the at least two terminal pressure dividing ring grooves are arranged in parallel.
5. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, When the number of terminal voltage divider ring grooves is at least two, the spacing between two adjacent terminal voltage divider ring grooves is equal to the spacing between two adjacent active area grooves.
6. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, The terminal pressure dividing ring groove includes a first transverse groove and a first longitudinal groove integrally connected; the terminal stop ring groove includes a second transverse groove and a second longitudinal groove integrally connected. The connection between the first transverse groove and the first longitudinal groove is set to be arc-shaped, and the connection between the second transverse groove and the second longitudinal groove is also set to be arc-shaped. The arc of the connection between the first transverse groove and the first longitudinal groove and the arc of the connection between the second transverse groove and the second longitudinal groove are equal.
7. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, Each of the active region trenches is provided with a gate contact hole, and the gate contact holes on multiple active region trenches are connected in a straight line, and the gate contact holes are connected to the gate metal.
8. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, Each of the active area trenches is provided with a first source electrode contact hole. The target terminal voltage divider ring trench and the active area trench, as well as the two adjacent active area trenches, are provided with a second source electrode contact hole. The terminal voltage divider ring trench is provided with a third source electrode contact hole. The first source electrode contact hole, the second source electrode contact hole, and the third source electrode contact hole are all connected to the source electrode metal.
9. The shielded gate trench MOSFET termination structure as described in claim 8, characterized in that, A portion of the second source contact hole is connected to the first source contact hole in a straight line, and another portion of the second source contact hole is connected to the third source contact hole in a straight line.
10. The shielded gate trench MOSFET termination structure as described in claim 1, characterized in that, A first drain contact hole is provided on the terminal cutoff ring trench, and a second drain contact hole is provided on the substrate near the terminal cutoff ring trench. Both the first drain contact hole and the second drain contact hole are connected to the drain metal.