MOSFET device with suspended gate junction terminal

Abstract

The utility model is applicable to the technical field of semiconductors, and provides an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device with a suspended gate junction terminal, which comprises a substrate, an extension layer disposed over the substrate; an active operation area and a terminal structure area are arranged on the expansion layer; the active operation region comprises a P-type region, an N-type region and a gate structure; the P-type regions and the N-type regions are alternately arranged to jointly form a source electrode structure of the MOSFET; according to the utility model, the electric field regulation and control capability of the device is obviously enhanced, and electric field abrupt change is reduced, so that the breakdown voltage and the stability of the device are greatly improved; moreover, through the multi-layer protection measures of the metal field plate, the passivation layer and the like, and the efficient cooperative work of the polycrystalline silicon gate structure and the metal interconnection layer, the device is prevented from being influenced by the external environment, and meanwhile, the rapid response and accurate regulation and control of a gate signal are realized; and the requirements on rapid switching and accurate adjustment of the current in a complex application scene are met.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of semiconductor technology, especially relate to a MOSFET device with suspended grid junction terminal. BACKGROUND

[0002] In the rapid development of semiconductor technology, MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as the core component of electronic equipment, its performance improvement has been the focus of the industry attention,

[0003] When the traditional MOSFET device works in high-voltage environment, the shortage of breakdown voltage becomes the key factor restricting its performance improvement, when the working voltage exceeds the bearing capacity of the device, the occurrence of breakdown phenomenon will seriously affect the stability and reliability of the device. In addition, the significant existence of edge effect is also a big challenge, it not only leads to uneven electric field distribution, but also may cause current leakage, further reducing the performance of the device;

[0004] At the same time, the traditional MOSFET device also has limitations in electric field regulation ability, with the increase of working frequency, the device needs to regulate the electric field distribution more accurately to realize more efficient current control, however, the deficiency of traditional device in electric field regulation makes it difficult to meet the demand of high-performance application;

[0005] Furthermore, stability and reliability are important indicators to measure the performance of MOSFET device. In complex application scenarios, the device needs to run stably for a long time and can resist external environmental interference, however, the traditional MOSFET device has the problem of poor stability and reliability, which limits its application in high-end electronic systems. UTILITY MODEL CONTENTS

[0006] The utility model provides a kind of MOSFET device with suspended grid junction terminal, to solve the problem that traditional MOSFET device is short of breakdown voltage, edge effect is significant, electric field regulation ability is limited and stability is poor in complex application scenarios such as high voltage, high frequency.

[0007] The utility model discloses a MOSFET device with suspended grid junction terminal, including substrate, the extension layer of being located substrate top, the active operation area and terminal structure area of being provided with on the extension layer, the active operation area includes P type area, N type area and grid structure, P type area and N type area are arranged alternately, and the source structure of MOSFET is formed together, the grid structure is located P type area top, and the grid structure realizes the isolation with P type area through grid oxide layer, the terminal structure area includes suspended grid structure and control board, the suspended grid structure is annular distribution, and is separated with control board through insulating layer, and control board is electrically connected with suspended grid structure through metal interconnection layer, the outer surface of extension layer is sequentially provided with metal field plate and passivation layer.

[0008] Preferably, a transition layer with gradually changing doping is arranged between the extension layer and the substrate, and the doping concentration of the transition layer gradually increases from the substrate to the extension layer.

[0009] Preferably, the insulating layer adopts a multilayer composite insulating structure, and the insulating layer includes a base layer adjacent to the suspended grid structure, and a high-k material layer and a protective layer are arranged on the side of the base layer away from the suspended grid structure.

[0010] Preferably, the doping concentration of the extension layer ranges from about 1e15 / cm 3 -1e18 / cm 3 .

[0011] Preferably, the passivation layer adopts a multilayer composite structure, and includes an anti-reflection layer adjacent to the extension layer, and a stress buffer layer and a chemical corrosion resistant layer are arranged on the side of the anti-reflection layer away from the extension layer.

[0012] Preferably, the grid structure is made of polysilicon material, and the grid structure is electrically connected with an external circuit through a metal interconnection layer.

[0013] Preferably, the base layer adopts silicon dioxide, the high-k material layer adopts zirconium dioxide, and the protective layer adopts silicon nitride material.

[0014] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0015] One: the device significantly improves its breakdown voltage and reliability, in the active operation area, the gate structure precisely controls the opening and closing of the channel region, realizes the effective regulation of the current flow between the source and the drain, at the same time, in the terminal structure area, the floating gate structure is distributed in a ring shape, and is separated from the regulation plate through the insulating layer, which optimizes the electric field distribution of the device, significantly reduces the edge effect, and further improves the breakdown voltage of the device, in addition, the transition layer design between the extension layer and the substrate further enhances the electric field regulation ability of the device, and smooths the transition of the electrical properties, reduces the electric field mutation, thereby improving the stability and reliability of the device.

[0016] Secondly, the device optimizes its performance and improves the current regulation efficiency through multiple protection measures and efficient current regulation mechanism, the setting of the metal field plate and the passivation layer not only assists in regulating the electric field distribution and improves the breakdown voltage of the device, but also provides all-round protection for the device from the influence of the external environment, at the same time, the gate structure is made of polysilicon material, which has high stability and good conductivity, and works with the metal interconnection layer to realize the rapid transmission and accurate regulation of the gate signal, so that the MOSFET device can realize the rapid switching and accurate regulation of the current according to the control signal of the external circuit, thereby meeting the needs of various complex application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a three-dimensional structure schematic diagram of the utility model;

[0018] Figure 2 is a three-dimensional structure schematic diagram of the utility model;

[0019] Figure 3 is a top view of the utility model;

[0020] Figure 4 is a front view of the utility model;

[0021] Figure 5 is a front view structure schematic diagram of the utility model;

[0022] In the drawing: 1, substrate; 2, extension layer; 3, active operation area; 4, terminal structure area; 5, P-type area; 6, N-type area; 7, gate structure; 8, gate oxide layer; 9, floating gate structure; 10, regulation plate; 11, insulating layer; 12, metal field plate; 13, passivation layer. DETAILED DESCRIPTION

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] This utility model embodiment provides a MOSFET device with a floating gate junction termination, such as... Figures 1-5 As shown, the device includes a substrate; an extended layer disposed above the substrate; an active operating region and a termination structure region disposed on the extended layer; the active operating region includes a P-type region, an N-type region, and a gate structure; the P-type region and the N-type region are arranged alternately to form the source structure of the MOSFET; the gate structure is located above the P-type region and is isolated from the P-type region by a gate oxide layer; the termination structure region includes a floating gate structure and a control plate; the floating gate structure is distributed in a ring and is separated from the control plate by an insulating layer; the control plate is electrically connected to the floating gate structure by a metal interconnect layer; a metal field plate and a passivation layer are sequentially disposed on the outer surface of the extended layer.

[0026] It should be noted that traditional MOSFET devices face challenges such as insufficient breakdown voltage, significant edge effects, limited electric field control capabilities, and poor stability in complex applications involving high voltage and high frequency. This solution significantly improves the breakdown voltage of the device by precisely controlling the channel opening and closing and optimizing the electric field distribution. It also enhances the electric field control capability and smooths the transition of electrical properties, thereby greatly improving the stability and reliability of the device. Secondly, through multi-layered protection measures and an efficient current control mechanism, not only is comprehensive environmental protection provided for the device, but also rapid transmission and precise control of the gate signal are ensured. This allows the MOSFET device to flexibly respond to control signals from external circuits, achieving rapid switching and precise current regulation, meeting the diverse needs of complex application scenarios.

[0027] Specifically, in the present embodiment, the present scheme mainly comprises a substrate; an extension layer is arranged above the substrate, and the extension layer is divided into an active operation area and a terminal structure area; in the active operation area, a P-type region and an N-type region are arranged in an alternating manner, and they jointly constitute a source structure of a MOSFET; a gate structure is located above the P-type region and is electrically isolated from the P-type region through a gate oxide layer; the main function of the gate structure is to control the opening and closing of the channel region, so as to realize the regulation of the current between the source and the drain;

[0028] When a high enough positive voltage is applied to the gate, the electrons in the P-type region below the gate are attracted to the vicinity of the gate, forming a conductive channel, so that the source and the drain can conduct current; on the contrary, when a low voltage or a negative voltage is applied to the gate, the channel is closed, and the current between the source and the drain is blocked;

[0029] In the terminal structure area, the floating gate structure is distributed in a ring shape and is separated from the regulation plate through an insulating layer; the regulation plate is electrically connected to the floating gate structure through a metal interconnection layer; the design of the floating gate structure aims to optimize the electric field distribution of the device, reduce the edge effect, and thus improve the breakdown voltage and reliability of the device; when the device is working, the voltage on the regulation plate can dynamically adjust the potential of the floating gate structure, thereby regulating the electric field distribution and optimizing the performance of the device;

[0030] In addition, the outer surface of the extension layer is further provided with a metal field plate and a passivation layer in sequence; the metal field plate is usually used to assist in regulating the electric field distribution and improving the breakdown voltage of the device; and the passivation layer plays a role in protecting the device from the influence of the external environment, and improves the reliability and stability of the device.

[0031] As shown in the further preferred embodiment of the present application, Figures 1-5 A transition layer with gradually changing doping is arranged between the extension layer and the substrate, and the doping concentration of the transition layer gradually increases from the substrate to the extension layer.

[0032] In the present embodiment, the doping concentration of the transition layer gradually increases from the substrate to the extension layer, which helps to smoothly transition the electrical properties and reduce the electric field abrupt change at the interface, thereby improving the breakdown voltage and stability of the device; as the transition layer extends to the extension layer, the increase of the doping concentration makes the extension layer have specific electrical properties; the extension layer not only provides an additional current channel for the device, but also further enhances the electric field regulation capability of the device through its structural design.

[0033] As shown in the further preferred embodiment of the present application, Figures 1-5 The insulating layer adopts a multilayer composite insulating structure, the insulating layer comprises a base layer adjacent to the floating gate structure, and a high-k material layer and a protective layer are arranged on the side of the base layer away from the floating gate structure.

[0034] In the embodiment, the base layer ensures electrical isolation between the suspended gate structure and the control plate, prevents direct leakage of current, the use of the high-k material layer helps to reduce the gate leakage current, further improves the reliability of the device, and the protective layer material can effectively block the erosion of the high-k material layer by harmful substances from the outside, and at the same time, the protective layer can also play a role in smoothing the surface and improving the overall quality of the device.

[0035] In further preferred embodiments of the utility model, as shown in Figures 1-5 The doping concentration range of the extension layer is about 1e15 / cm 3 -1e18 / cm 3 .

[0036] In the embodiment, at a lower doping concentration, close to 1e15 / cm 3 , the extension layer exhibits a higher resistivity, which helps to reduce the leakage current in the off state of the device and improve the static power consumption performance of the device. When the doping concentration gradually increases to about 1e18 / cm 3 , the conductivity of the extension layer is enhanced, providing an efficient current channel for the device in the on state.

[0037] During the operation of the device, reasonable doping concentration design can ensure that the channel has sufficient carrier concentration in the on state, thereby realizing fast current response and efficient energy conversion.

[0038] In further preferred embodiments of the utility model, as shown in Figures 1-5 The passivation layer adopts a multilayer composite structure, including an anti-reflection layer adjacent to the extension layer, and a stress buffer layer and a chemical corrosion resistant layer are arranged on the side of the anti-reflection layer away from the extension layer.

[0039] In the embodiment, the main function of the anti-reflection layer is to reduce the reflection of light on the surface of the device and improve the transmittance of light, the main function of the stress buffer layer is to relieve and balance the stress caused by the mismatch of the thermal expansion coefficients between different material layers or the process steps in the device, and the chemical corrosion resistant layer protects the device from the erosion of external chemical substances, thereby providing an effective protective barrier for the device.

[0040] In further preferred embodiments of the utility model, as shown in Figures 1-5 The gate structure is made of polysilicon material, and the gate structure is electrically connected to the external circuit through a metal interconnection layer.

[0041] In this embodiment, polysilicon is a semiconductor material with high stability and good conductivity, and the metal interconnection layer is usually made of copper, aluminum or other high-conductivity metals, which plays a role in transmitting gate signals to external circuits; when the external circuit applies a voltage to the gate structure, the voltage is transmitted to the gate structure through the metal interconnection layer, and the voltage change on the gate changes the electric field distribution below the gate, thereby controlling the opening and closing of the conductive channel, so that the MOSFET device can realize the switching and regulating functions of the current according to the control signal of the external circuit.

[0042] As shown in the further preferred embodiment of the utility model, Figures 1-5 The base layer is made of silicon dioxide, the high-k material layer is made of zirconium dioxide, and the protective layer is made of silicon nitride material.

[0043] In this embodiment, silicon dioxide has good thermal stability and chemical stability, can effectively isolate the suspended gate structure from the semiconductor substrate below, prevent direct leakage of current, zirconium dioxide can store more charges under the same electric field, thereby increasing the effective capacitance of the gate, and silicon nitride has excellent chemical stability and mechanical strength, which can effectively block the erosion of harmful substances such as moisture and pollutants in the external environment to the internal insulating layer.

[0044] Working principle: the device is based on a substrate, which is provided with an expansion layer; the expansion layer is subdivided into an active operation area and a terminal structure area; in the active operation area, the P-type area and the N-type area are arranged in an alternating manner, which together constitute the source structure of the MOSFET; the gate structure is located above the P-type area and is electrically isolated from the P-type area by a gate oxide layer; the main function of the gate structure is to control the opening and closing of the channel region, thereby regulating the current flow between the source and the drain;

[0045] When a high enough positive voltage is applied to the gate, the electrons in the P-type area below the gate will be attracted to the vicinity of the gate, forming a conductive channel, so that the source and the drain can conduct current; on the contrary, when a low voltage or negative voltage is applied to the gate, the channel is closed, and the current between the source and the drain is blocked;

[0046] In the terminal structure area, the suspended gate structure is distributed in a ring shape and is separated from the control plate by an insulating layer; the control plate is electrically connected to the suspended gate structure through a metal interconnection layer; the design of the suspended gate structure aims to optimize the electric field distribution of the device and reduce the edge effect, thereby improving the breakdown voltage and reliability of the device; during the operation of the device, the voltage on the control plate can dynamically adjust the potential of the suspended gate structure, thereby regulating the electric field distribution and optimizing the performance of the device;

[0047] In addition, the outer surface of the extension layer is sequentially provided with a metal field plate and a passivation layer; the metal field plate is used to assist in regulating the electric field distribution and improving the breakdown voltage of the device; the passivation layer protects the device from the external environment and improves the reliability and stability of the device;

[0048] A transition layer is provided between the extension layer and the substrate, and the doping concentration gradually increases from the substrate to the extension layer; this design helps to smoothly transition the electrical properties and reduce the electric field at the interface, thereby improving the breakdown voltage and stability of the device; as the transition layer extends to the extension layer, the increase in doping concentration enables the extension layer to have specific electrical properties, not only providing additional current channels for the device, but also further enhancing the electric field regulation capability of the device through its structural design;

[0049] The insulating layer, as a key isolation layer between the suspended gate structure and the control plate, is composed of multiple layers; the base layer ensures electrical isolation between the suspended gate structure and the control plate, preventing direct current leakage; the use of high-k material layer helps to reduce gate leakage current, further improving the reliability of the device; the protective layer can effectively block harmful substances from the outside from eroding the high-k material layer, while also smoothing the surface and improving the overall quality of the device;

[0050] The doping concentration design of the extension layer is also critical; at a lower doping concentration (close to 1e15 / cm 3 ), the extension layer exhibits high resistivity, which helps to reduce leakage current and improve the static power consumption performance of the device in the off state; when the doping concentration gradually increases to around 1e18 / cm 3 , the conductivity of the extension layer is enhanced, providing an efficient current channel for the device in the on state;

[0051] The passivation layer includes an anti-reflective layer, a stress buffer layer, and a chemical corrosion-resistant layer; the main function of the anti-reflective layer is to reduce light reflection on the device surface and improve light transmittance; the stress buffer layer is used to relieve and balance the stress caused by the mismatch of thermal expansion coefficients between different material layers or process steps within the device; the chemical corrosion-resistant layer protects the device from external chemical erosion, providing an effective protective barrier for the device;

[0052] Finally, the gate structure is made of polysilicon material, which has high stability and good conductivity; the metal interconnection layer is usually made of copper, aluminum, or other high-conductivity metals, which serves to transmit gate signals to external circuits; when the external circuit applies voltage to the gate structure, the voltage is transmitted to the gate structure through the metal interconnection layer, and the voltage change on the gate changes the electric field distribution below the gate, thereby controlling the opening and closing of the conductive channel; in this way, the MOSFET device can realize the switching and regulation of current according to the control signal of the external circuit.

[0053] It should be noted that for the foregoing embodiments, the purpose of simple description is to express them as a series of action combinations, but those skilled in the art should know that the present application is not limited by the order of the described actions, because according to the present application, some steps can be performed in other order or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily necessary for the present application.

[0054] In several embodiments provided in the present application, it should be understood that the disclosed device can be implemented by other ways. For example, the device embodiments described above are only illustrative, for example, the division of the above units, actual implementation can have another division way, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the coupling or communication connection between the displayed or discussed each other can be through some interface, indirect coupling or communication connection between devices or units, which can be electrical or other forms.

[0055] The units described above as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0056] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the protection scope of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add or delete or make other adjustments to the features of the embodiments of the present application according to the circumstances without creative labor, so as to obtain different other technical solutions which do not deviate from the concept of the present application in essence. These technical solutions also belong to the scope of the present application.

Claims

1. A MOSFET device with a floating gate junction termination, characterized by, The application relates to a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) structure, which comprises the following parts: a substrate (1); an extension layer (2) arranged above the substrate (1); an active operation area (3) and a terminal structure area (4) arranged on the extension layer (2); the active operation area (3) comprises a P-type area (5), an N-type area (6) and a gate structure (7); the P-type area (5) and the N-type area (6) are arranged alternately and jointly form a source structure of the MOSFET; the gate structure (7) is arranged above the P-type area (5) and is isolated from the P-type area (5) through a gate oxide layer (8); the terminal structure area (4) comprises a floating gate structure (9) and a control plate (10); the floating gate structure (9) is distributed in a ring shape and is separated from the control plate (10) through an insulating layer (11), and the control plate (10) is electrically connected with the floating gate structure (9) through a metal interconnection layer; an outer surface of the extension layer (2) is sequentially provided with a metal field plate (12) and a passivation layer (13).

2. A MOSFET device with a floating junction termination as defined in claim 1, wherein, a gradually-doped transition layer is arranged between the extension layer (2) and the substrate (1), and the doping concentration of the transition layer gradually increases from the substrate (1) to the extension layer (2).

3. A MOSFET device with a floating junction termination as defined in claim 1, wherein, the insulating layer (11) adopts a multilayer composite insulating structure, the insulating layer (11) comprises a base layer adjacent to the floating gate structure (9), and a high-k material layer and a protective layer are arranged on a side of the base layer away from the floating gate structure (9).

4. A MOSFET device with a floating junction termination as defined in claim 2, wherein, The doping concentration of the extended layer (2) ranges approximately between 1e15 / cm 3 -1e18 / cm 3 .

5. A MOSFET device with a floating junction termination as defined in claim 1, wherein, the passivation layer (13) adopts a multilayer composite structure, and comprises an anti-reflection layer adjacent to the extension layer (2), and a stress buffer layer and a chemical corrosion resistant layer are arranged on a side of the anti-reflection layer away from the extension layer (2).

6. A MOSFET device with a floating junction termination as defined in claim 1, wherein, the gate structure (7) is made of polysilicon material, and the gate structure (7) is electrically connected with an external circuit through a metal interconnection layer.

7. A MOSFET device with a floating junction termination as defined in claim 3, wherein, the base layer is made of silicon dioxide, the high-k material layer is made of zirconium dioxide, and the protective layer is made of silicon nitride.

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