High-voltage-resistant terminal device with NRing field limiting ring and manufacturing method of high-voltage-resistant terminal device
By adding an N-type field limiting ring and a P-type field limiting ring in the field limiting ring region to form a lateral PN junction, the problems of large terminal area and insufficient electric field control capability in the prior art are solved, thereby improving the withstand voltage performance of the device and enhancing the uniformity of electric field distribution.
Patent Information
- Application Number
- CN202511106536.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2025-11-11
AI Technical Summary
In the existing technology, the composite structure of multi-stage field plates and field limiting rings of P-type field limiting rings has problems such as large terminal area, limited field plate length, and insufficient electric field control capability.
A composite structure of a single field limiting ring and a field plate is adopted. By adding an N-type field limiting ring and a P-type field limiting ring in the field limiting ring region to form a transverse PN junction, a charge compensation effect is formed, reducing the number of field limiting rings and increasing the length of the field plate to control the electric field.
This improved the device's withstand voltage performance, reduced the terminal area, enhanced the uniformity of the electric field distribution and the ability to control the electric field, and reduced chip loss.
Smart Images
Figure CN120936079A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power semiconductor technology, specifically to a high-voltage resistant terminating device with an NRing field limiting ring and its manufacturing method. Background Technology
[0002] With the continuous development of the semiconductor industry, the market share of power devices in the international market is constantly expanding, making it particularly important to ensure the voltage withstand capability of IGBT devices. Because the radius of curvature at the edge of the IGBT device's main junction is small, electric field concentration can occur, leading to premature breakdown. Junction Termination Technology (JTT) improves the electric field distribution by expanding the depletion region of the main junction, making the electric field curvature at the main junction edge smoother, thereby reducing electric field concentration and improving the device's voltage withstand performance.
[0003] Common junction termination technologies include: field-limiting ring (FCR) technology, field plate technology, junction termination extension technology, and edge grinding termination. Because FCR and field plate technologies are well-matched with the active region process flow, they are often combined to mitigate the effects of thermal oxidation interface charge present in single FCR technologies and significantly enhance device breakdown voltage. Multi-stage field plate structures with FCRs utilize field plates of varying heights to slow the outward expansion of the depletion region, thereby improving termination efficiency.
[0004] In the existing technology, the composite structure of multi-stage field plate and field limiting ring of P-type field limiting ring has certain problems. This structure requires a large number of field limiting rings and a large terminal area. Moreover, the length of the field plate is limited by the number of field limiting rings, which limits the field plate's ability to control the electric field. Summary of the Invention
[0005] In view of this, this application discloses a high-voltage resistant terminating device with an NRing field limiting ring and a method for manufacturing the same, in order to solve the above problems;
[0006] A high-voltage resistant terminal device with an NRing field limiting ring adopts a composite structure of a single field limiting ring and a field plate. The high-voltage resistant terminal device with an NRing field limiting ring is composed of a composite unit, which includes: a back area, a field limiting ring area, and a multi-field plate area.
[0007] The back surface region includes: heavily doped region 1, field cutoff region 2, and drift region 3; the field confinement ring region includes: N-type field confinement ring 4 and P-type field confinement ring 5; the multiple field plate region includes: field oxygen region 6, phosphorus-doped N-type polysilicon field plate region 7, BPSG (Boro-phospho-silicate Glass) field plate region 8, PSG (Phosphosilicate Glass) field plate region 9, and metal field plate region 10;
[0008] Furthermore, the field cutoff region 2 is positioned above the heavily doped region 1; the drift region 3 is positioned above the field cutoff region 2; the N-type field limiting ring 4 and the P-type field limiting ring 5 are connected in the horizontal direction to form a PN junction and are embedded above the drift region 3; the field oxygen region 6 is positioned above the drift region 3, the N-type field limiting ring 4, and the P-type field limiting ring 5; the phosphorus-doped N-type Poly field plate region 7 is positioned above the field oxygen region 6 and is connected to the drift region 3 and the P-type field limiting ring 5; the BPSG field plate region 8 is positioned above the phosphorus-doped N-type Poly field plate region 7 and the field oxygen region 6, covering the phosphorus-doped N-type Poly field plate region 7 and the field oxygen region 6; the PSG field plate region 9 is positioned on the BPSG field plate region 8; and the metal field plate region 10 is positioned on the BPSG field plate region 8 and is connected to the PSG field plate region 9.
[0009] A method for manufacturing a high-voltage resistant terminating device with an NRing field limiting ring, comprising:
[0010] Step 1: Select N-type single crystal silicon as the main body of drift region 3;
[0011] Step 2: Inject N-type impurities into the drift region 3 and heat-anneal to form an N-type field limiting ring 4; Inject P-type impurities next to the N-type field limiting ring 4 and anneal to obtain a P-type field limiting ring 5; The junction depth of the N-type field limiting ring 4 is 1 / 3 of the junction depth of the P-type field limiting ring.
[0012] Step 3: Thermally grow field oxygen on drift region 3, N-type field confinement ring 4 and P-type field confinement ring 5, and etch out field oxygen region 6;
[0013] Step 4: Deposit polysilicon on the field oxygen region 6 and etch out the phosphorus-doped N-type poly field plate region 7;
[0014] Step 5: Deposit BPSG on the oxygen field region 6 and the phosphorus-doped N-type Poly field plate region 7 to form BPSG field plate region 8; deposit PSG on BPSG field plate region 8 and etch out PSG field plate region 9.
[0015] Step 6: Deposit metal on BPSG field plate region 8 and PSG field plate region 9, and etch out metal field plate region 10;
[0016] Step 7: Perform thinning, hydrogen implantation, and rapid thermal annealing operations sequentially below the drift region 3 to form the field cutoff region 2. Perform boron implantation and rapid thermal annealing operations sequentially on the field cutoff region 2 to form the heavily doped region 1.
[0017] Step 8: Deposit and etch metal in the heavily doped region 1 to form the back electrode, and obtain a high-voltage resistant terminal device with NRing field limiting ring.
[0018] The beneficial effects of this invention include:
[0019] By adding an N-type field limiting ring in the field limiting ring region, forming a lateral PN junction with the P-type field limiting ring, the interaction between their depletion regions creates a charge compensation effect, reducing the lateral diffusion range of the depletion region. This charge compensation effect makes the lateral electric field distribution more uniform, reduces the spacing between adjacent field limiting rings, and shrinks the device size. Adding the N-type field limiting ring allows each pair of rings to share more voltage, thus reducing the overall number of field limiting rings. Due to the reduced number of field limiting rings, the field plate length can be set longer for a given terminal area, thereby increasing the field plate's ability to control the electric field. Furthermore, reducing the overall thickness lowers chip losses. This provides a new design approach for power semiconductor devices. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the composite unit in the embodiments of this application;
[0021] Figure 2 This is a schematic diagram of the high-voltage resistant terminal device with NRing field limiting ring in the embodiments of this application;
[0022] Figure 3 This is a schematic diagram of step 1 in an embodiment of this application;
[0023] Figure 4 This is a schematic diagram of step 2 in an embodiment of this application;
[0024] Figure 5 This is a schematic diagram of step 3 in an embodiment of this application;
[0025] Figure 6 This is a schematic diagram of step 4 in an embodiment of this application;
[0026] Figure 7 This is a schematic diagram of step 5 in an embodiment of this application;
[0027] Figure 8 This is a schematic diagram of step 6 in an embodiment of this application;
[0028] Figure 9 This is a schematic diagram of a high-voltage resistant terminal device with an NRing field limiting ring obtained in the embodiments of this application;
[0029] Figure 10 This is a schematic diagram of the electric field distribution of a high-voltage resistant terminal device with an NRing field limiting ring in an embodiment of this application;
[0030] The numbers in the figure are: 1-Heavily doped region, 2-Field cutoff region, 3-Drift region, 4-N-type field confinement ring, 5-P-type field confinement ring, 6-Field oxygen region, 7-Phosphorus-doped N-type Poly field plate region, 8-BPSG field plate region, 9-PSG field plate region, 10-Metal field plate region. Detailed Implementation
[0031] To make the objectives, technical solutions, features, and advantages of this application clearer and to enable those skilled in the art to better understand the technical solutions of this application, the following detailed description of this application is provided in conjunction with the accompanying drawings and embodiments.
[0032] Example 1:
[0033] This embodiment provides a high-voltage resistant terminal device with an NRing field limiting ring, which adopts a composite structure of a single field limiting ring and a field plate. The high-voltage resistant terminal device with an NRing field limiting ring is characterized by being composed of a composite unit, which includes: a back area, a field limiting ring area, and a multi-field plate area.
[0034] The back surface region includes: heavily doped region 1, field cutoff region 2, and drift region 3; the field confinement ring region includes: N-type field confinement ring 4 and P-type field confinement ring 5; the multiple field plate region includes: field oxygen region 6, phosphorus-doped N-type Poly field plate region 7, BPSG field plate region 8, PSG field plate region 9, and metal field plate region 10.
[0035] Among them, the field limiting ring region and the multiple field plate region form a single field limiting ring and field plate composite structure.
[0036] Furthermore, the field cutoff region 2 is positioned above the heavily doped region 1; the drift region 3 is positioned above the field cutoff region 2; the N-type field limiting ring 4 and the P-type field limiting ring 5 are connected in the horizontal direction to form a PN junction and are embedded above the drift region 3; the field oxygen region 6 is positioned above the drift region 3, the N-type field limiting ring 4, and the P-type field limiting ring 5; the phosphorus-doped N-type Poly field plate region 7 is positioned above the field oxygen region 6 and is connected to the drift region 3 and the P-type field limiting ring 5; the BPSG field plate region 8 is positioned above the phosphorus-doped N-type Poly field plate region 7 and the field oxygen region 6, covering the phosphorus-doped N-type Poly field plate region 7 and the field oxygen region 6; the PSG field plate region 9 is positioned on the BPSG field plate region 8; and the metal field plate region 10 is positioned on the BPSG field plate region 8 and is connected to the PSG field plate region 9.
[0037] The N-type field limiting ring 4 and P-type field limiting ring 5 designed in this application form a lateral PN junction. On the one hand, the depletion regions of the two interact, forming a charge compensation effect, which reduces the lateral diffusion range of the depletion region. This charge compensation effect makes the lateral electric field distribution more uniform, reduces the spacing between adjacent field limiting rings, and shrinks the terminal area. On the other hand, in the traditional terminal structure with a single P-type field limiting ring, the voltage shared by each ring is relatively small. By adding the N-type field limiting ring 4, the local PN junction formed in this invention will form a lateral depletion region when a reverse voltage is applied, making the electric field distribution more uniform. Each pair of rings can share more voltage, reducing the number of field limiting rings required and thus shrinking the terminal area. After adding the N-type field limiting ring, due to the reduction in the number of field limiting rings, the length of the field plate can be set to be longer if the terminal area is fixed, increasing the field plate's ability to control the electric field.
[0038] Furthermore, the embedding depth of the N-type field confinement ring 4 is 1 / 3 of the embedding depth of the P-type field confinement ring 5. The field oxygen region 6 covers the N-type field confinement ring 4. The phosphorus-doped N-type Poly field plate region (7) adopts a sloping stepped field plate and a floating potential design. In the floating potential design, the high part of the stepped field plate is supported by the field oxygen region 6, and there is an oxide layer between the low part of the stepped field plate and the drift region 3 and the P-type field confinement ring 5. The high and low parts are connected by a sloping surface.
[0039] Furthermore, such as Figure 2 As shown, the connected composite units constitute a high-voltage resistant terminating device with an NRing field limiting ring, and form the following regions in the connection direction: cell region, transition region, termination region, and cutoff region. The cell region is the active region of the high-voltage device, which is a collection of units that realize the basic functions of the device such as current conduction and switching control. The termination region is a withstand voltage protection zone, used to optimize the edge electric field distribution of the device and improve the withstand voltage capability of the device. The transition region is a buffer region between the cell region and the termination region. In this embodiment, the electric field change is made smoother by increasing the radius of curvature of the electric field at the edge of the main junction. The cutoff region is an auxiliary region used to ensure the withstand voltage capability of the device. By extending the length of the field plate region to reduce the curvature of the electric field, and setting a separate P-type cutoff ring on the drift region 3, the electric field can be further prevented from penetrating to the cutting edge of the device, thereby enhancing the stability of the device.
[0040] Example 2:
[0041] This embodiment provides a method for manufacturing a high-voltage terminating device with an NRing field limiting ring. In this embodiment, the high-voltage terminating device with an NRing field limiting ring is composed of two connected composite units. The manufacturing method includes:
[0042] Step 1: Select N-type single crystal silicon as the main body of drift region 3.
[0043] Specifically, the crystal orientation is selected as <100> The resistivity of the N-type monocrystalline silicon is selected based on the actual voltage withstand requirements and process conditions; the resulting device is as follows: Figure 3 As shown.
[0044] Step 2: Inject N-type impurities into the drift region 3 and heat-anneal to form an N-type field limiting ring 4; Inject P-type impurities next to the N-type field limiting ring 4 and anneal to obtain a P-type field limiting ring 5; The junction depth of the N-type field limiting ring 4 is 1 / 3 of the junction depth of the P-type field limiting ring 5.
[0045] Specifically, P-type impurities are implanted around the N-type field-limiting ring 4 using ion implantation, with phosphorus ions as the impurities, resulting in a device as shown in the image. Figure 4 As shown.
[0046] Step 3: Thermally grow field oxygen on drift region 3, N-type field confinement ring 4 and P-type field confinement ring 5, and etch field oxygen region 6.
[0047] Thermally grown field oxygen includes: growing a silicon dioxide layer on a substrate through a thermal oxidation process to achieve device isolation, resulting in a device such as... Figure 5 As shown.
[0048] Step 4: Deposit polysilicon on the field oxygen region 6, and etch out the phosphorus-doped N-type poly field plate region 7; to obtain the device as shown. Figure 6 As shown.
[0049] Step 5: Deposit BPSG on the oxygen field region 6 and the phosphorus-doped N-type Poly field plate region 7 to form the BPSG field plate region 8; deposit PSG on the BPSG field plate region 8 and etch out the PSG field plate region 9; obtain the device as shown. Figure 7 As shown.
[0050] Step 6: Deposit metal on BPSG field plate region 8 and PSG field plate region 9, and etch out metal field plate region 10; obtain the device as shown. Figure 8 As shown.
[0051] Step 7: Perform thinning, hydrogen implantation, and rapid thermal annealing operations sequentially below the drift region 3 to form the field stop region 2. Perform boron implantation and rapid thermal annealing operations sequentially on the field stop region 2 to form the heavily doped region 1. Reduce chip loss by thinning the overall thickness.
[0052] Step 8: Deposit and etch metal in heavily doped region 1 to form the back electrode, obtaining a high-voltage resistant termination device with NRing field limiting ring, such as... Figure 9 As shown.
[0053] Furthermore, in the manufacturing method of the high-voltage terminating device with NRing field limiting ring, photolithography is used for etching, and aluminum is selected for metal deposition. The electric field distribution of the high-voltage terminating device with NRing field limiting ring in this embodiment was tested, and the test results are as follows: Figure 10 As shown.
[0054] Finally, it should be noted that the above description only depicts some embodiments of this application. For those skilled in the art, various changes, modifications, substitutions, and variations can be conceived of these embodiments without departing from the principles and spirit of this application. The scope of protection of this application is defined by the appended claims and their equivalents, and all the above-mentioned behaviors should be covered within the scope of protection of this application.
[0055] Furthermore, in the above description of the embodiments, unless otherwise explicitly specified and limited, the use of terms such as "upper," "lower," "horizontal," and "inner" to indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the invention is in use, is merely for the convenience of describing this application and simplifying the description, and does not limit or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The use of the term "horizontal" does not mean that the component is required to be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" merely means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. The use of terms such as "set," "install," "connect," and "link" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
Claims
1. A high-voltage resistant terminating device with an NRing field limiting ring, employing a composite structure of a single field limiting ring and a field plate, characterized in that, The high-voltage terminating device with NRing field limiting ring is composed of a composite unit, which includes: a back area, a field limiting ring area, and a multi-field plate area; The back surface region includes: a heavily doped region (1), a field cutoff region (2), and a drift region (3); the field limiting ring region includes: an N-type field limiting ring (4) and a P-type field limiting ring (5); the multiple field plate region includes: a field oxygen region (6), a phosphorus-doped N-type Poly field plate region (7), a BPSG field plate region (8), a PSG field plate region (9), and a metal field plate region (10); The field cutoff region (2) is located above the heavily doped region (1); the drift region (3) is located above the field cutoff region (2); the N-type field limiting ring (4) and the P-type field limiting ring (5) are connected to form a horizontal PN junction and are embedded above the drift region (3); the field oxygen region (6) is located above the drift region (3), the N-type field limiting ring (4) and the P-type field limiting ring (5); the phosphorus-doped N-type Poly field plate region (7) is located above the field oxygen region (6) and is connected to the drift region (3) and the P-type field limiting ring (5); the BPSG field plate region (8) is located above the phosphorus-doped N-type Poly field plate region (7) and the field oxygen region (6) and covers the phosphorus-doped N-type Poly field plate region (7) and the field oxygen region (6); the PSG field plate region (9) is located on the BPSG field plate region (8); the metal field plate region (10) is located on the BPSG field plate region (8) and is connected to the PSG field plate region (9).
2. The high-voltage resistant terminating device with NRing field limiting ring according to claim 1, characterized in that, The embedding depth of the N-type field confinement ring (4) is 1 / 3 of the embedding depth of the P-type field confinement ring (5).
3. The high-voltage resistant terminating device with NRing field limiting ring according to claim 1, characterized in that, The phosphorus-doped N-type Poly field plate region (7) adopts a sloping stepped field plate and a floating potential design.
4. A method for manufacturing a high-voltage resistant terminating device with an NRing field limiting ring, characterized in that, For manufacturing a high-voltage resistant terminating device with an NRing field limiting ring as described in any one of claims 1 to 3, comprising: Step 1: Select N-type single crystal silicon as the main body of the drift region (3); Step 2: Inject N-type impurities into the drift region (3) and heat anneal to form an N-type field limiting ring (4); Inject P-type impurities next to the N-type field limiting ring (4) and anneal to obtain a P-type field limiting ring (5); The junction depth of the N-type field limiting ring (4) is 1 / 3 of the junction depth of the P-type field limiting ring (5); Step 3: Thermally grow field oxygen on the drift region (3), N-type field confinement ring (4) and P-type field confinement ring (5), and etch the field oxygen region (6); Step 4: Deposit polysilicon on the field oxygen region (6) and etch out the phosphorus-doped N-type Poly field plate region (7); Step 5: Deposit BPSG on the oxygen field region (6) and the phosphorus-doped N-type Poly field plate region (7) to form the BPSG field plate region (8); deposit PSG on the BPSG field plate region (8) and etch out the PSG field plate region (9); Step 6: Deposit metal on the BPSG field plate region (8) and the PSG field plate region (9), and etch out the metal field plate region (10); Step 7: Thinning, hydrogen implantation and rapid thermal annealing are performed sequentially below the drift region (3) to form the field cutoff region (2). Boron implantation and rapid thermal annealing are performed sequentially on the field cutoff region (2) to form the heavily doped region (1). Step 8: Deposit and etch metal in the heavily doped region (1) to form a back electrode and obtain a high-voltage terminal device with NRing field limiting ring.
5. The method for manufacturing a high-voltage resistant terminating device with an NRing field limiting ring according to claim 4, characterized in that, The substrate is selected with the following crystal orientation: <100> N-type monocrystalline silicon.
6. The method for manufacturing a high-voltage resistant terminating device with an NRing field limiting ring according to claim 4, characterized in that, N-type impurities are implanted into the drift region (3) by ion implantation, and the impurities are phosphorus ions.
7. The method for manufacturing a high-voltage resistant terminating device with an NRing field limiting ring according to claim 4, characterized in that, Aluminum is selected as the deposited metal.