A terminal layout structure of a shielded gate trench power device

Abstract

The present invention discloses a terminal layout structure of a shielded gate trench power device, which mainly includes a strip-shaped trench plate for etching trenches, the terminal area is surrounded by three trench plates, the area covered by the source polysilicon etching plate and the trench sidewall oxide layer etching plate is the active area of ​​the device, the source metal is connected to the contact hole above the trench plate, and serves as the source polysilicon lead-out area; the gate metal is connected to the contact hole above the trench plate, and serves as the gate polysilicon lead-out area. The ends of the trench plates are connected by spaced arcs, and the ends of the enclosed trench plates are chamfered to ensure that the trench plates are always evenly spaced from each other. On the basis of being fully compatible with existing processes, the charge balance effect of the terminal area is optimized, the electric field current concentration can be avoided, and the consistency and reliability of the power device are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor power devices, and in particular relates to a terminal layout structure of a shielded gate trench power device. Background Art

[0002] In the field of semiconductor power device technology, shielded gate trench power devices (ShieldGate Trench Power Device) have become the leader in many application fields such as power switches, battery management systems, and electrode drivers due to their unique trench structure and efficient charge balance mechanism. With the rapid development of electronic technology, the performance requirements for power devices are becoming increasingly stringent. High power density, low loss, and high reliability have become the core trends in the development of power devices.

[0003] The reason why shielded gate trench power devices stand out among many power devices is mainly due to the design of their trench structure. This design not only optimizes the electric field distribution of the device, but also effectively improves the breakdown voltage and heat resistance of the device through the charge balance mechanism. However, in the process of pursuing higher performance, layout design has gradually become a key factor restricting the improvement of device performance.

[0004] In the traditional shielded gate trench power device layout, there are two major problems that need to be solved: electric field current concentration and charge balance. First, due to the curvature effect of electric field concentration, the breakdown voltage of the fan-shaped terminal area is generally lower than that of the cell area. This means that during device operation, the leakage current tends to concentrate in the fan-shaped area first, resulting in a local temperature increase. When the temperature exceeds the limit temperature of silicon, the device will break down, seriously damaging its reliability and service life.

[0005] Secondly, the T-shaped region at the end of the trench is another important source of electric field and current concentration. Since this region cannot be completely depleted, the electric field and current will concentrate here, further reducing the performance of the device. These problems not only affect the electrical characteristics of the device, but also limit its application under extreme conditions such as high voltage and high frequency.

[0006] In order to meet these challenges, the industry has been actively exploring effective solutions. On the one hand, by optimizing the materials and structures of the devices, such as using higher quality semiconductor materials, improving the shape and size of the grooves, etc., the breakdown voltage and heat resistance of the devices can be improved. On the other hand, new layout design methods are also being explored to improve the electric field distribution and achieve charge balance. However, these solutions are often accompanied by disadvantages such as complex processes, high costs or limited effects, and it is difficult to meet the market's urgent demand for high-performance, low-cost power devices.

[0007] Especially in the field of medium and low voltage power devices, shielded gate trench power devices effectively reduce the on-resistance by virtue of the lateral depletion effect produced by the polysilicon and epitaxial layer connected to the source electrode in the trench. At the same time, the introduction of source polysilicon also reduces the overlapping area between the gate electrode and the drain electrode, thereby greatly reducing the gate-drain capacitance and gate charge. These characteristics make shielded gate trench power devices perform well in conduction loss and switching loss, further broadening their application range.

[0008] Nevertheless, the importance of layout design in power device design cannot be ignored. Figure 1 As shown in the overall layout diagram of the traditional shielded gate trench power device, each corner has a quarter-sector terminal area S. Due to the curvature effect of the electric field concentration, the breakdown voltage of the fan-shaped terminal area is often lower than that of the cell area, resulting in leakage current concentration and increased risk of device breakdown. At the same time, the T-shaped area at the end of the trench is also an important area for electric field current concentration, which has an adverse effect on device performance.

[0009] Therefore, in view of the problems existing in the layout of traditional shielded gate trench power devices, a new layout design method is urgently needed to effectively improve the electric field distribution, achieve charge balance, and enhance the performance and reliability of the device. This is not only the key to meeting the market demand for high-performance power devices, but also an important direction to promote the sustainable development of semiconductor power device technology. Summary of the invention

[0010] In order to overcome the problem of electric field and current concentration in corner areas of power devices in existing designs, the present invention proposes a terminal layout structure of a shielded gate trench power device.

[0011] The specific technical solutions of the present invention are as follows: A terminal layout structure of a shielded gate trench power device, comprising: A groove plate for etching grooves, wherein the terminal periphery is surrounded by three groove plates to form a specific terminal structure; A P-type body region is provided between the groove plates, and the P-type body region is connected to the source metal through the contact hole plate to achieve electrical connection; The area covered by the source polysilicon etching plate and the trench sidewall oxide layer etching plate is defined as the active area of ​​the device; The source metal is connected through the contact hole above the groove plate, serving as the lead-out area of ​​the source polysilicon; The gate metal is connected through a contact hole above the groove plate and serves as a lead-out region for the gate polysilicon.

[0012] The groove plate is distributed in the shape of long strips, and the distance extending inward from the fan-shaped corner area of ​​the layout is 100um to 10000um, and the width is between 1um and 3um, so as to ensure the uniformity of the electric field and charge distribution.

[0013] The ends of the groove plates are connected by arcs at intervals, and the ends of the enclosed groove plates are chamfered to ensure that the groove plates are always distributed at equal intervals, thereby further optimizing the electric field distribution.

[0014] The trench plate in the terminal area is surrounded by three trench plates, among which the trench plate closest to the inner side is connected to the source metal through a contact hole to achieve electrical connection and balanced charge distribution.

[0015] The gate lead-out region is located in the active region, and the source lead-out region is located at the end of the groove plate, so as to realize independent lead-out and connection of the gate and the source.

[0016] The source lead-out region connects the upwardly protruding source polysilicon to the source metal through the contact hole above the groove plate; The gate polysilicon in the gate lead-out region is located above the source polysilicon; There is a transition region between the source lead-out region and the gate lead-out region to ensure smooth transition of the electric field and stable operation of the device.

[0017] The novel terminal layout design of a shielded gate trench power device proposed in the present invention has significant beneficial effects compared with the prior art.

[0018] First, the present invention connects the ends of the trench plates in the terminal area of ​​the shielded gate trench power device with arc intervals and performs chamfering to ensure that the trench plates are always evenly spaced. This design effectively solves the problem of charge imbalance in the T-shaped area at the end of the trench in the traditional layout, avoids the concentration of electric field current in this area, and thus improves the breakdown voltage and reliability of the device.

[0019] Secondly, the layout design of the present invention is optimized on the basis of being fully compatible with existing processes, without introducing additional complex processes or high costs. This not only reduces production costs, but also facilitates the rapid promotion and application of new technologies.

[0020] In addition, the terminal layout design of the present invention optimizes the charge balance effect of the terminal area, so that the overall performance of the device is significantly improved. This includes reducing the on-resistance, reducing the gate-drain capacitance and gate charge, and improving the consistency and reliability of the device. These improvements make the application of shielded gate trench power devices in the fields of power switches, battery management systems, electrode drives, etc. more extensive and stable.

[0021] In summary, the new terminal layout design of the shielded gate trench power device proposed in the present invention not only solves the problems existing in the prior art, but also significantly improves the performance and reliability of the device while ensuring process compatibility. It has broad market application prospects and important technical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall layout of an existing traditional shielded gate trench power device.

[0023] Figure 2 The present invention is a schematic diagram of a terminal layout of a shielded gate trench power device provided by the prior art.

[0024] Figure 3 It is a schematic diagram of the terminal layout of a shielded gate trench power device provided by the present invention. DETAILED DESCRIPTION

[0025] The technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. The embodiments described in the drawings here can usually be combined and designed by different position layouts. Therefore, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] like Figure 2 As shown, a schematic diagram of the terminal layout of a shielded gate trench power device provided by the prior art specifically includes the following key components: Grooved plate 11: A strip-shaped structure used for etching grooves, the terminal periphery of which is surrounded by three grooved plates 11. These grooved plates play the role of forming grooves and guiding current in the device.

[0027] P-type body region: a region disposed between the groove plates 11, formed by P-type doping. This region is connected to the source metal 31 by the contact hole plate 21 to achieve electrical connection.

[0028] Active area: The area covered by the source polysilicon etching plate 41 and the trench sidewall oxide layer etching plate 51. This is the main area where electrical conversion and current conduction occur in the device.

[0029] Source metal 31 and gate metal 32: connected to source polysilicon and gate polysilicon through contact holes 22 and 23 above the trench plate, respectively, serving as lead-out regions for the source and gate.

[0030] Contact holes: including contact holes 22 and 23, which are used for leading out the source and gate electrodes respectively. These contact holes enable the metal layer to be electrically connected to the polysilicon layer.

[0031] In the prior art, the groove plates 11 are usually connected at the corners with rounded corners, but they can also be connected at right angles or bevel angles. The number of groove plates at the periphery of the terminal can be two or more, and the groove plate closest to the inner side needs to be connected to the source metal 31 through the contact hole 22.

[0032] Figure 3 A schematic diagram of a terminal layout of a shielded gate trench power device provided in an embodiment of the present invention.

[0033] A terminal layout structure of a shielded gate trench power device mainly includes a strip-shaped trench plate 11 for etching the trench. The terminal periphery is surrounded by three trench plates 11. Such a design can form a specific terminal structure to optimize electric field distribution and charge balance.

[0034] P-type doping (P-type body region) is provided between the groove plates 11, and the P-type body region is connected to the source metal 31 through the contact hole plate 21 to achieve electrical connection. This design helps to form an effective charge transfer path between the P-type body region and the source metal when the device is working.

[0035] The area covered by the source polysilicon etching plate 41 and the trench sidewall oxide layer etching plate 51 is defined as the active area of ​​the device. In this area, the source polysilicon and the gate polysilicon are formed through specific process steps respectively and play their respective functions.

[0036] The source metal 31 is connected through the contact hole 22 above the groove plate 11, serving as the lead-out region of the source polysilicon. In this way, the source metal can effectively form an electrical connection with the source polysilicon, thereby realizing the source function of the device.

[0037] The gate metal 32 is also connected through the contact hole 23 above the groove plate 11, serving as the lead-out region of the gate polysilicon. The electrical connection between the gate metal and the gate polysilicon enables the device to realize the control function of the gate.

[0038] In the present invention, the groove plate 11 is distributed in a long strip shape, and the distance extending inward from the fan-shaped corner area of ​​the layout is 100um to 10000um, and the width is between 1um and 3um. Such design parameters help to ensure the uniformity of the electric field and charge distribution, thereby improving the performance and reliability of the device.

[0039] The ends of the groove plates 11 are connected by arcs, and the ends of the enclosed groove plates are chamfered. Such a design can ensure that the groove plates are always evenly spaced, further optimize the electric field distribution, and reduce the electric field concentration effect, thereby improving the breakdown voltage and reliability of the device.

[0040] The trench plate in the terminal region is surrounded by three trench plates, of which the trench plate closest to the inner side is connected to the source metal 31 through the contact hole 22. Such a design can achieve electrical connection and balanced distribution of charges, thereby enhancing the performance stability of the device.

[0041] In addition, the gate lead-out region is located in the active region, while the source lead-out region is located at the end of the groove plate 11. Such a layout enables the gate and source to be independently led out and connected, which is beneficial to the circuit design and optimization of the device.

[0042] Furthermore, the source lead-out region connects the upwardly protruding source polysilicon to the source metal 31 through the contact hole 22 above the groove plate 11. This design enables the source metal to effectively contact the source polysilicon and form a good electrical connection. At the same time, the gate polysilicon of the gate lead-out region is located above the source polysilicon, and there is a transition region between the source lead-out region and the gate lead-out region. Such a design ensures a smooth transition of the electric field and stable operation of the device.

[0043] In addition, in the present invention, only source polysilicon is contained in the grooves in the area covered by the polysilicon etching plate, and the source polysilicon is connected to the source metal through the contact hole above the groove plate. Such a design simplifies the process steps and reduces the production cost. At the same time, the area not covered by the active area etching plate is provided with N-type heavy doping, which belongs to the conductive area of ​​the device. Such a design makes the conductive performance of the device more excellent.

[0044] Compared with the prior art, the embodiment of the present application connects the grooved plate in the terminal area with arc intervals through layout design, optimizes the charge balance effect in the terminal area on the basis of full compatibility with the existing process, avoids the concentration of electric field current, and effectively improves the consistency and reliability of the device.

[0045] The above embodiments have been described in detail to explain the present invention in detail, but these do not constitute a limitation of the present invention. Without departing from the principle of the present invention, those skilled in the art may make many variations and improvements, which should also be considered as the protection scope of the present invention.

Claims

1. A terminal layout structure of a shielded gate trench power device, characterized in that: include: A groove plate (11) for etching grooves, wherein the terminal periphery is surrounded by three groove plates (11) to form a terminal structure; A P-type body region is provided between the groove plates (11), and the P-type body region is connected to the source metal (31) via the contact hole plate (21) to achieve electrical connection; The area covered by the source polysilicon etching plate (41) and the trench sidewall oxide layer etching plate (51) is defined as the active area of ​​the device; The source metal (31) is connected via a contact hole (22) above the groove plate, serving as a lead-out region for the source polysilicon; The gate metal (32) is connected via a contact hole (23) above the groove plate and serves as a lead-out region for the gate polysilicon.

2. The terminal layout structure of the shielded gate trench power device according to claim 1, characterized in that: The groove plate (11) is distributed in the shape of long strips, and the distance extending inward from the fan-shaped corner area of ​​the plate is 100 um to 10000 um, and the width is between 1 um and 3 um.

3. The terminal layout structure of the shielded gate trench power device according to claim 2, characterized in that: The ends of the grooved plates (11) are connected by arcs at intervals, and the ends of the enclosed grooved plates are chamfered, so that the grooved plates are always distributed at equal intervals.

4. The terminal layout structure of the shielded gate trench power device according to claim 1, characterized in that: The groove plate in the terminal area is surrounded by three groove plates (11), wherein the groove plate closest to the inner side is connected to the source metal (31) through a contact hole (22).

5. The terminal layout structure of the shielded gate trench power device according to claim 1, characterized in that: The gate lead-out region is located in the active region, while the source lead-out region is located at the end of the groove plate, for realizing independent lead-out and connection of the gate and the source.

6. The terminal layout structure of the shielded gate trench power device according to claim 5, characterized in that: The source lead-out region connects the upwardly protruding source polysilicon to the source metal (31) through a contact hole above the groove plate; The gate polysilicon in the gate lead-out region is located above the source polysilicon; There is a transition region between the source lead-out region and the gate lead-out region.

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