CN118398618A

CN118398618A - Shielded gate power device with low leakage and fast recovery capability

Info

Publication number: CN118398618A
Application number: CN202410814070.4A
Authority: CN
Inventors: 安俊杰; 金波; 朱琦; 陈宗琪
Original assignee: Wuxi Xichang Microchip Semiconductor Co ltd
Current assignee: Wuxi Xichang Microchip Semiconductor Co ltd
Priority date: 2024-06-24
Filing date: 2024-06-24
Publication date: 2024-07-26

Abstract

The invention relates to a shielded gate power device, in particular to a shielded gate power device with low electric leakage and quick recovery capability. According to the technical scheme provided by the invention, the shielded gate power device with low electric leakage and quick recovery capability comprises: a semiconductor substrate of a first conductivity type; the active region is distributed in the central region of the semiconductor substrate and comprises a plurality of SGT cells and at least one schottky-like diode, wherein the schottky-like diode is a groove type schottky-like diode, and the schottky-like diode comprises a diode-like groove positioned in the active region; within the active region, the diode-like trench has a greater trench depth than the cell trench depth of any one SGT cell. The invention can effectively reduce the leakage current of the shielded gate power device, enhance the avalanche capacity and improve the stability and reliability of the SGT power device during operation.

Description

Shielded gate power device with low leakage and fast recovery capability

Technical Field

The invention relates to a shielded gate power device, in particular to a shielded gate power device with low electric leakage and quick recovery capability.

Background

The SGT (SHIELD GATE TRENCH, shielded gate trench) power device is a novel power semiconductor device and has the advantages of low conduction loss and low switching loss compared with the traditional power semiconductor device. The SGT power device may include an SGT MOSFET device and an SGT IGBT (Insulated Gate Bipolar Transistor) device, wherein the SGT MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) device is widely used as a switching device and can have excellent power control effect.

The cell of the prior SGT power device generally consists of a shielding gate and a control gate, and when the SGT power device is conducted, drain current flows along the longitudinal side wall of an SGT trench to form an inversion layer channel on the surface of a body region. When the source is forward biased, electrons travel along the inversion layer channel from the source region to the drain region. Electrons pass from the source region through the channel, enter the epitaxial region at the bottom of the trench gate, and then spread across the width of the active region.

In order to improve the reverse recovery efficiency and reverse recovery capability of the SGT power device, schottky-like diodes (Schottky like diode) are currently integrated in the active region, but after the schottky-like diodes are integrated in the active region, electric field concentration can be easily caused, so that leakage is further caused, avalanche capability is low, and reliability of the SGT power device can be reduced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a shielded gate power device with low electric leakage and quick recovery capability, which can effectively reduce the leakage current of the shielded gate power device, enhance the avalanche capability and improve the stability and reliability of the SGT power device during operation.

According to the technical scheme provided by the invention, the shielded gate power device with low electric leakage and quick recovery capability comprises:

a semiconductor substrate of a first conductivity type;

An active region distributed in a central region of the semiconductor substrate and comprising a plurality of SGT cells and at least one Schottky-like diode, wherein,

The schottky-like diode is a trench schottky-like diode, and comprises a diode-like trench located in the active region;

within the active region, the diode-like trench has a greater trench depth than the cell trench depth of any one SGT cell.

For the schottky-like diode, comprising a diode electrode body filled in the diode-like trench, wherein,

The diode electrode body comprises a first electrode body in a groove and a second electrode body in the groove corresponding to the first electrode body in the groove, and the second electrode body in the groove is adjacent to a notch of the diode-like groove;

the first electrode body in the groove comprises a first area of the first electrode body in the groove entering the second electrode body in the groove and a second area of the first electrode body in the groove below the second electrode body in the groove, wherein,

The first region of the first electrode body in the groove is separated from the second electrode body in the groove by an electrode body isolation medium layer, and the second region of the first electrode body in the groove is isolated from the bottom wall and the corresponding side wall of the diode-like groove by using a field oxide layer in the groove;

the second electrode body in the groove is insulated and isolated from the side wall of the diode-like groove by the gate oxide layer in the groove, the thickness of the gate oxide layer in the groove is smaller than that of the field oxide layer in the groove, and the gate oxide layer in the groove is contacted with the field oxide layer in the groove;

The first electrode body in the groove and the second electrode body in the groove are electrically connected with the first electrode metal of the device above the semiconductor substrate, wherein,

The device first electrode metal is also in ohmic contact with the diode first conductivity type source region corresponding to the outside of the diode-like trench and the second conductivity type base region traversing the active region,

The diode first conduction type source region and the second conduction type base region are both in contact with the outer side wall of the diode-like groove.

In the diode-like groove, the width of the second electrode body in the groove is larger than that of the first electrode body in the groove;

The width of the first area of the first electrode body in the groove is smaller than that of the second area of the first electrode body in the groove;

the end face of the first region of the first electrode body in the groove is positioned above the bottom face of the second conductive type base region;

The end face of the second electrode body in the groove, which is adjacent to the bottom of the diode-like groove, is not higher than the bottom face of the second conductive type base region.

A self-isolating unit is arranged in the active region at least at one side of the schottky-like diode, wherein,

The self-isolation unit comprises a self-isolation groove and an isolation unit electrode body filled in the self-isolation groove;

The isolation unit electrode body is isolated from the side wall and the bottom wall of the self-isolation groove through an oxide layer in the isolation groove;

the isolation unit electrode body is electrically connected with the first electrode metal of the device.

In the active region, the depth of the self-isolation trench is consistent with the depth of the diode-like trench;

The height of the isolation unit electrode body is consistent with that of the first electrode body in the groove, and the second end part of the isolation unit electrode body is level with the end part of the first area of the first electrode body in the groove;

The first end of the isolation unit electrode body is adjacent to the bottom of the self-isolation trench.

The self-isolation unit also comprises an isolation unit first conductive type source region positioned outside the self-isolation trench, wherein,

The isolation unit first conductive type source region is positioned in the second conductive type base region outside the self-isolation trench, and the isolation unit first conductive type source region and the second conductive type base region are both in contact with the outer side wall of the self-isolation trench;

the first electrode metal of the device is also electrically connected with the first conductive type source region and the second conductive type base region of the isolation unit.

The self-isolation unit also comprises an isolation unit second conductivity type injection region arranged outside the self-isolation trench and an isolation unit external contact hole corresponding to the isolation unit second conductivity type injection region,

The second conductive type injection region of the isolation unit penetrates through the second conductive type base region outside the isolation groove, the doping concentration of the second conductive type injection region of the isolation unit is larger than that of the second conductive type base region, and the bottom of the second conductive type injection region of the isolation unit is positioned below the bottom surface of the second conductive type base region;

The isolation unit second conductivity type injection region is in contact with the corresponding outer side wall of the self-isolation trench, and the isolation unit second conductivity type injection region is in ohmic contact with the device first electrode metal filled in the isolation unit outer contact hole.

On the section of the shielding grid power device, the outer contact hole of the isolation unit is trapezoid, wherein,

The width of the first end of the outer contact hole of the isolation unit is smaller than that of the second end of the outer contact hole of the isolation unit, wherein the first end of the outer contact hole of the isolation unit is positioned below a notch of the self-isolation groove;

the width of the second end of the isolation unit outer contact hole is greater than the width of the isolation unit second conductivity type injection region, so that the second end of the isolation unit outer contact hole enters the notch region of the self-isolation trench.

For any SGT cell, placing an SGT structure within a cell trench of the SGT cell, wherein,

When the SGT structure adopts an up-down structure, the SGT structure comprises a cell lower electrode body and a cell upper electrode body, wherein the cell upper electrode body is positioned above the cell lower electrode body, and the cell upper electrode body is insulated and isolated from the cell lower electrode body;

the upper electrode body of the cell is insulated and isolated from the side wall of the cell groove through the cell gate oxide layer;

The thickness of the cellular gate oxide layer is larger than that of the gate oxide layer in the groove;

the upper electrode body of the cell is electrically connected with the second electrode metal of the device above the semiconductor substrate, and the lower electrode body of the cell is electrically connected with the first electrode metal of the device.

In the active region, a plurality of source region contact hole units are arranged, wherein,

The source region contact hole units are at least distributed between two adjacent SGT unit cells;

the source region contact hole unit comprises a source region contact hole and a contact Kong Xiadi two conductivity type injection region positioned right below the source region contact hole, wherein,

The doping concentration of the contact Kong Xiadi second conductive type injection region is larger than that of the second conductive type base region, and the contact Kong Xiadi second conductive type injection region is positioned below the second conductive type base region and is in contact with the corresponding second conductive type base region;

The first electrode metal of the device is filled in the contact hole of the source region, and is in ohmic contact with the two conductive type injection regions of the contact Kong Xiadi, the second conductive type base region and the cell first conductive type source regions at two sides of the contact hole of the filled source region;

The first conductivity type source region of the cell is in contact with the outer sidewall of the corresponding cell trench.

The invention has the advantages that: when the fast recovery capability of the shielded gate power device is improved by arranging the schottky-like diode in the active region, the depth of the diode-like groove of the schottky-like diode can be configured, the self-isolation unit and/or the source region contact hole unit can be increased, the occurrence of electric leakage breakdown at the gate oxide layer in the groove of the schottky-like diode can be avoided, the electric leakage of the shielded gate power device can be reduced, the voltage withstanding capability of the shielded gate power device can be improved, and the avalanche capability of the shielded gate power device can be enhanced.

Drawings

Fig. 1 is a structural cross-sectional view of a first embodiment of the present invention.

Fig. 2 is a structural cross-sectional view of a second embodiment of the present invention.

Fig. 3 is a structural cross-sectional view of a third embodiment of the present invention.

Fig. 4 is a structural cross-sectional view of a fourth embodiment of the present invention.

Fig. 5 is a structural cross-sectional view of a fifth embodiment of the present invention.

Reference numerals illustrate: 1-substrate, 2-epitaxial layer, 3-cell trench, 4-diode-like trench, 5-cell field oxide layer, 6-cell bottom electrode body, 7-P-type base region, 8-cell top electrode body, 9-interlayer oxide layer, 10-cell gate oxide layer, 11-notch oxide layer, 12-cell N+ source region, 13-contact P+ injection region, 14-in-trench field oxide layer, 15-in-trench first electrode body, 16-in-trench gate oxide layer, 17-in-trench second electrode body, 18-electrode body isolation dielectric layer, 19-self-isolation trench, 20-isolation trench inner oxide layer, 21-isolation cell electrode body, 22-diode electrode body contact hole, 23-contact hole bottom P+ injection region, 24-isolation cell P+ injection region, 25-isolation cell outer contact hole, 26-isolation cell inner contact hole, 27-source region contact hole, 28-diode N+ source region, 29-isolation cell N+ source region.

Detailed Description

The invention will be further described with reference to the following specific drawings and examples.

In order to effectively reduce leakage current of a shielded gate power device, enhance avalanche capability and improve stability and reliability of the SGT power device during operation, the invention provides a shielded gate power device with low leakage current and fast recovery capability, taking a first conductive type as an N type as an example, specifically, the shielded gate power device comprises:

A semiconductor substrate of N conductivity type;

The schottky-like diode is a groove type schottky-like diode, and comprises a diode-like groove 4 positioned in the active region;

Within the active region, the diode-like trench 4 has a greater trench depth than the cell trench 3 of any SGT cell.

It will be appreciated that the shielded gate power device may be the SGT MOSFET device, SGT IGBT device, or other type of power device mentioned above, and the type of shielded gate power device may be selected as desired, so as to meet the actual application requirements. For the shielded gate power device, the semiconductor substrate is generally included, that is, the power device is generally fabricated on the semiconductor substrate, the conductivity type of the semiconductor substrate is N-type, and fig. 1 to 5 show an embodiment of the semiconductor substrate, in which the semiconductor substrate includes a substrate 1 and an epitaxial layer 2 on the substrate 1, and at this time, the conductivity types of the substrate 1 and the epitaxial layer 2 are both N-type. Generally, the doping concentration of the epitaxial layer 2 is smaller than that of the substrate 1, the thickness of the epitaxial layer 2 is larger than that of the substrate 1, and the conditions of the substrate 1 and the epitaxial layer 2 are consistent with those of the conventional semiconductor substrate, and are not repeated here.

For the shielded gate power device, the shielded gate power device generally comprises an active region and a terminal region located at the outer ring of the active region, the terminal region generally surrounds the active region, the voltage withstand of the active region can be improved by utilizing the terminal region, the distribution of the active region and the terminal region on the semiconductor substrate, and the specific matching working mode are consistent with the prior art, and the detailed description is omitted herein.

The shielding grid power device comprises a plurality of SGT cells in an active area, wherein the SGT cells in the active area are connected in parallel into a whole, and the number of the SGT cells in the active area can be selected according to actual scenes so as to meet actual requirements.

In order to improve the reverse recovery efficiency and the reverse recovery capability of the shielded gate power device, it is known from the above description that at least one schottky-like diode can be disposed in the active region, that is, the disposed schottky-like diode can be utilized to improve the reverse recovery efficiency and the reverse recovery capability of the shielded gate power device. Meanwhile, after the schottky-like diode is arranged in the active region, leakage current of the shielded gate power device is increased, avalanche capacity is reduced, and it can be understood that after the schottky-like diode is arranged, a region where leakage occurs, namely a region where the schottky-like diode is arranged.

In order to reduce the leakage current of the shielded gate power device and enhance the avalanche capability, in one embodiment of the present invention, the schottky-like diode is selected to be a trench schottky-like diode, and thus the schottky-like diode at least includes a schottky-like diode trench 4 located in the active region, and of course, a corresponding schottky-like diode structure is also required to be prepared in the schottky-like diode trench 4, and the schottky-like diode structure will be described in detail below.

In one embodiment of the present invention, the depth of the diode-like trench 4 is greater than the depth of the cell trench 3 of any SGT cell, and one distribution embodiment of the diode-like trench 4 and the cell trench 3 is shown in fig. 1 to 5, in which the notch of the diode-like trench 4 and the notch of the cell trench 3 are both located on the surface of the epitaxial layer 2, and the bottom of the diode-like trench 4 and the bottom of the cell trench 3 are both located in the epitaxial layer 2. In general, all the cell trenches 3 in the active area may have the same trench depth, and of course, the cell trenches 3 in the active area may also have different trench depths, which may be specifically selected as required, so as to meet the actual requirements. One embodiment in which all cell trenches 3 in the active area have the same trench depth is shown in fig. 1-5.

In specific implementation, the groove depth of all the cell grooves 3 in the active region is smaller than the groove depth of the diode-like groove 4, wherein when the groove depth of the diode-like groove 4 is larger than the groove depth of the cell groove 3, the groove bottom of the diode-like groove 4 is positioned below the groove bottom of the cell groove 3. As is clear from the above description, when the schottky-like diode is disposed in the active region, the region where the leakage current increases occurs in the region where the schottky-like diode is located. When the groove depth of the diode-like groove 4 is larger than that of the cell groove 3, the withstand voltage of the area where the schottky-like diode is located can be increased, so that the breakdown area of the shielded gate power device is as much as possible in the area where the SGT cell is located when the shielded gate power device is turned off in the reverse direction, thereby reducing the leakage current of the shielded gate power device when the shielded gate power device is turned off in the reverse direction and enhancing the avalanche capability.

In one embodiment of the present invention, the schottky-like diode includes a diode electrode body filled in the diode-like trench 4, wherein,

The diode electrode body comprises a first electrode body 15 in a groove and a second electrode body 17 in the groove corresponding to the first electrode body 15 in the groove, and the second electrode body 17 in the groove is adjacent to the notch of the diode-like groove 4;

The in-cell first electrode body 15 includes an in-cell first electrode body first region that enters the in-cell second electrode body 17 and an in-cell first electrode body second region that is located below the in-cell second electrode body 17, wherein,

The first electrode body first area in the groove is separated from the second electrode body 17 in the groove by an electrode body isolation medium layer 18, and the second electrode body second area in the groove is isolated from the bottom wall and the corresponding side wall of the diode-like groove 4 by the field oxide layer 14 in the groove;

the second electrode body 17 in the groove is insulated and isolated from the side wall of the diode-like groove 4 by the gate oxide layer 16 in the groove, the thickness of the gate oxide layer 16 in the groove is smaller than that of the field oxide layer 14 in the groove, and the gate oxide layer 16 in the groove is contacted with the field oxide layer 14 in the groove;

The first electrode body 15 in the groove and the second electrode body 17 in the groove are electrically connected with the first electrode metal of the device above the semiconductor substrate, wherein,

The device first electrode metal is also in ohmic contact with the diode N + source region 28 corresponding to the outside of the diode-like trench 4 and the P-base region 7 traversing the active region,

The diode n+ source region 28 and the P-type base region 7 are both in contact with the outer sidewall of the diode-like trench 4.

Fig. 1 to 5 each show an embodiment of disposing a schottky-like diode, that is, an embodiment of disposing a schottky-like diode structure in the diode-like trench 4, in which the schottky-like diode further includes a diode electrode body filled in the diode-like trench 4, that is, the diode electrode body is located in the diode-like trench 4; in addition, the embodiment of the diode electrode body including the first electrode body 15 in the groove and the second electrode body 17 in the groove is shown in the figure, the first electrode body 15 in the groove and the second electrode body 17 in the groove can be generally selected from the conventional conductive polysilicon, and of course, other common electrode body materials can be adopted, and the materials corresponding to the first electrode body 15 in the groove and the second electrode body 17 in the groove can be selected according to actual needs, so as to meet actual application requirements.

In fig. 1 to 5, in the diode-like trench 4, the second electrode body 17 in the trench is adjacent to the notch of the diode-like trench 4, the length direction of the first electrode body 15 in the trench is consistent with the length direction of the diode-like trench 4, the lower end of the first electrode body 15 in the trench is adjacent to the bottom of the diode-like trench 4, and the upper end of the first electrode body 15 in the trench is correspondingly matched with the second electrode body 17 in the trench. Specifically, the first electrode body 15 in the groove includes a first region of the first electrode body in the groove entering the second electrode body 17 in the groove and a second region of the first electrode body in the groove located below the second electrode body 17 in the groove, and an embodiment in which the first region of the first electrode body in the groove is smaller than the height/thickness of the second electrode body 17 in the groove is shown in fig. 1, 2, 4 and 5, and an embodiment in which the first region of the first electrode body in the groove is the same as the height/thickness of the second electrode body 17 in the groove is shown in fig. 3.

In fig. 1 to 5, a first region of a first electrode body in a groove is separated from a second electrode body 17 in the groove by an electrode body isolation dielectric layer 18, the electrode body isolation dielectric layer 18 may be a silicon dioxide layer, and the electrode body isolation dielectric layer 18 is coated on the first region of the first electrode body in the groove; in fig. 3, the end surface of the first region of the first electrode body in the trench may be covered by another isolating dielectric layer in the diode-like trench 4. In fig. 1,2, 4 and 5, the electrode body isolation dielectric layer 18 may entirely cover the first region of the first electrode body within the trench.

The second region of the first electrode body in the groove is the lower region of the first electrode body 15 in the groove, and the second region of the first electrode body in the groove is insulated and isolated from the bottom wall and the corresponding side wall of the diode-like groove 4 by the field oxide layer 14 in the groove. The second electrode body 17 in the trench is insulated from the side wall of the diode-like trench 4 by the gate oxide layer 16 in the trench, so that the gate oxide layer 16 in the trench is adjacent to the notch of the diode-like trench 4, and the height of the gate oxide layer 16 in the trench is generally smaller than the height of the second electrode body 17 in the trench, wherein the height is the dimension along the length direction of the diode-like trench 4.

The in-trench gate oxide 16 is in contact with the in-trench field oxide 14 so that the inner walls and bottom walls of the diode-like trench 4 are covered with oxide. Optionally, the thickness of the electrode body isolation dielectric layer 18 corresponds to the thickness of the in-trench gate oxide layer 16; of course, the thickness of the electrode body isolation dielectric layer 18 may be different from the thickness of the in-trench gate oxide layer 16, and may be specifically selected as needed. When the thickness of the electrode body isolation dielectric layer 18 is the same as that of the gate oxide layer 16 in the groove, and both are silicon dioxide layers, the electrode body isolation dielectric layer 18 and the gate oxide layer 16 in the groove can be formed by the same thermal oxidation process.

In specific implementation, the first electrode body 15 in the groove and the second electrode body 17 in the groove are electrically connected with the first electrode metal of the device above the semiconductor substrate, wherein the first electrode metal of the device is not shown in fig. 1-5, and it can be understood that the first electrode metal of the device can form the first electrode of the shielded gate power device, and the first electrode is the source electrode when the shielded gate power device is an SGT MOSFET device; when the shielded gate power device is an SGT IGBT device, the first electrode is an emitter, and when the shielded gate power device is of another type, the type of first electrode formed based on the device first electrode metal may be determined, and will not be illustrated here.

It will be appreciated that the in-cell first electrode body 15 and the in-cell second electrode body 17 may be led out in a manner commonly known in the art to provide an electrical connection with the device first electrode after the lead-out. When the first electrode body 15 in the groove and the second electrode body 17 in the groove adopt conductive polysilicon, the first electrode body 15 in the groove and the second electrode body 17 in the groove are electrically connected with the first electrode metal of the device, specifically form ohmic contact with the first electrode metal of the device; when the first electrode body 15 in the groove and the second electrode body 17 in the groove are made of other materials, specific states of the metal-to-metal electrical connection with the first electrode of the device can be obtained, and will not be illustrated here.

It should be noted that, a P-type base region 7 is further disposed in the active region, where the P-type base region 7 generally traverses the active region, that is, the P-type base region 7 is distributed throughout the active region, and the bottom of the cell trench 3 and the corresponding bottom of the diode-like trench 4 are located below the P-type base region 7. In order to form a conductive channel on the sidewall of the diode-like trench 4, a diode n+ source region 28 needs to be disposed outside the diode-like trench 4, the diode n+ source region 28 is generally located in a region contacting the P-type base region 7 with the diode-like trench 4, and as shown in fig. 1 to 5, the diode n+ source region 28 contacts the corresponding sidewall of the diode-like trench 4, and the junction depth of the diode n+ source region 28 is smaller than the junction depth of the P-type base region 7.

In specific implementation, the first electrode metal of the device is also electrically connected to the diode n+ source region 28 and the P-type base region 7 outside the diode-like trench 4, where the first electrode metal of the device is generally in ohmic contact with the diode n+ source region 28, and the first electrode metal of the device may be electrically connected to the P-type base region 7 where the diode n+ source region 28 is located in ohmic contact or other manners, that is, the manner of electrically connecting the first electrode metal of the device and the P-type base region 7 where the diode n+ source region 28 is located may be selected. When the first electrode body 15 in the groove and the second electrode body 17 in the groove are arranged in the diode-like groove 4, the first electrode body 15 in the groove and the second electrode body 17 in the groove are separated by the electrode body isolation dielectric layer 18, and the first electrode body 15 in the groove and the second electrode body 17 in the groove are electrically connected with the first electrode metal of the device, the gate-drain capacitance Cgd of the shielded gate power device can be reduced, and the switching loss of the shielded gate power device can be further reduced.

In one embodiment of the present invention, the width of the in-groove second electrode body 17 is larger than the width of the in-groove first electrode body 15 in the diode-like trench 4;

the end face of the first region of the first electrode body in the groove is positioned above the bottom face of the P-type base region 7;

the end face of the second electrode body 17 in the groove, which is adjacent to the bottom of the diode-like groove 4, is not higher than the bottom face of the P-type base region 7.

Fig. 1 to 5 show an embodiment in which the width of the in-groove second electrode body 17 is larger than the width of the in-groove first electrode body 15, in which the in-groove second electrode body 17 is in direct contact with the in-groove gate oxide layer 16, and the in-groove first electrode body second region of the in-groove first electrode body 15 is in contact with the in-groove field oxide layer 14; the width of the first region of the first electrode body in the groove is smaller than that of the second region of the first electrode body in the groove.

In order to further disperse the electric field and reduce the leakage current generated through the gate oxide layer 16 in the trench, the end surface of the first region of the first electrode body in the trench is located above the bottom surface of the P-type base region 7, wherein the bottom surface of the P-type base region 7 specifically refers to the surface of the P-type base region 7 adjacent to the bottom of the diode-like trench 4. In addition, the end face of the second electrode body 17 in the groove, which is adjacent to the bottom of the diode-like groove 4, is not higher than the bottom face of the P-type base region 7. In fig. 1 to 5, an end face of the second electrode body 17 adjacent to the bottom of the diode-like trench 4 in the trench is located below the bottom of the P-type base region 7, that is, the end face is located between the P-type base region 7 and the bottom of the diode-like trench 4. In addition, fig. 1 to 5 also show an embodiment in which the end face of the second electrode body 17 in the groove adjacent to the bottom of the diode-like trench 4 is inclined, and it can be understood that when the end face of the second electrode body 17 in the groove adjacent to the bottom of the diode-like trench 4 is located below the bottom of the P-type base region 7 and the end face of the second electrode body 17 in the groove adjacent to the bottom of the diode-like trench 4 is inclined, the gate-drain capacitance Cgd of the shielded gate power device can be further reduced.

As can be seen from the above description, the first electrode metal of the device is electrically connected to the diode n+ source region 28 and the corresponding P-type base region 7, and an ohmic contact embodiment is shown in fig. 1 to 3, where in fig. 1 to 3, a contact p+ injection region 13 is further disposed in the P-type base region 7, the doping concentration of the contact p+ injection region 13 is greater than that of the P-type base region 7, the contact p+ injection region 13 is in contact with the diode n+ source region 28, and at this time, the first electrode metal of the device may be directly in ohmic contact with the diode n+ source region 28, and at the same time, the first electrode metal of the device is electrically connected to the corresponding P-type base region 7 through the contact p+ injection region 13. In addition, the in-groove first electrode body 15 and the in-groove second electrode body 17 may be electrically connected to the device first electrode metal by an extraction method commonly used in the art, and the specific extraction method is not shown in the drawing.

In the embodiment of fig. 4 to 5, the first electrode metal of the device may be in direct ohmic contact with the n+ source region 28 of the diode, and in addition, by providing the diode-like trench 4 with the diode-like electrode body contact hole 22 in the notch region, the diode-like electrode body contact hole 22 penetrates the second electrode body 17 in the trench and corresponds to the first electrode body first region in the trench, so that after the first electrode metal of the device is filled in the diode-like electrode body contact hole 22, the first electrode metal of the device is electrically connected to the first electrode body 15 in the trench and the second electrode body 17 in the trench. In fig. 4 to 5, the first electrode metal of the device filled in the isolation unit outer contact hole 25 is in contact with the isolation unit p+ injection region 24, and the isolation unit p+ injection region 24 is in contact with the corresponding P-type base region 7, so that a conductive channel can be formed on the side wall of the diode-like trench 4 adjacent to the isolation unit outer contact hole 25, that is, normal operation of the schottky-like diode is not affected.

In one embodiment of the invention, a self-isolating unit is provided in the active region, at least on one side of the schottky-like diode, wherein,

The self-isolation unit comprises a self-isolation trench 19 and an isolation unit electrode body 21 filled in the self-isolation trench 19;

The isolation unit electrode body 21 is insulated and isolated from the side wall and the bottom wall of the self-isolation groove 19 by an oxide layer 20 in the isolation groove;

the isolation unit electrode body 21 is electrically connected with the device first electrode metal.

In order to further reduce the leakage current of the shielded gate power device during reverse recovery, in an embodiment of the present invention, at least one self-isolation unit may be further disposed in the active region, where the self-isolation unit may be generally distributed on one side of the schottky-like diode, or one self-isolation unit may be disposed on both sides of the schottky-like diode, fig. 2 to 4 illustrate an embodiment in which one self-isolation unit is disposed on the left side of the schottky-like diode, and fig. 5 illustrates an embodiment in which one self-isolation unit is disposed on both sides of the schottky-like diode, where the distribution of the self-isolation units in the active region may be selected according to practical needs. At this time, by utilizing the isolation effect of the self-isolation unit, the electric field accumulated on the side wall of the diode-like trench 4 can be dispersed, so that the leakage current at the schottky-like diode can be further reduced.

An embodiment of a self-isolation unit is shown in fig. 2 to 5, in which the self-isolation unit includes a self-isolation trench 19 and an isolation unit electrode body 21 filled in the self-isolation trench 19, a notch of the self-isolation trench 19 is located on a surface of the epitaxial layer 2, and a bottom of the self-isolation trench 19 is located in the epitaxial layer 2. The isolation unit electrode body 21 may be conductive polysilicon or other conductive materials, and the specific material type may be selected according to need.

An isolation trench internal oxide layer 20 is provided in the self-isolation trench 19, the isolation trench internal oxide layer 20 is typically a silicon dioxide layer, and isolation between the isolation cell electrode body 21 and the side walls and bottom walls of the self-isolation trench 19 can be achieved by using the isolation trench internal oxide layer 20. In general, the thickness of the isolation trench oxide layer 20 may be consistent with the thickness of the in-trench field oxide layer 14.

In specific implementation, the isolation unit electrode body 21 is electrically connected with the first electrode metal of the device, wherein the isolation unit electrode body 21 can be electrically connected with the first electrode metal of the device by adopting a common technical means in the technology, and the connection mode of leading out the isolation unit electrode body 21 and connecting with the first electrode metal of the device is not shown in fig. 1-3; fig. 4 to 5 show an embodiment of leading out and connecting the isolation unit electrode body 21, in which an isolation unit inner contact hole 26 is provided in the notch of the self-isolation trench 19, the isolation unit inner contact hole 26 is opened from the notch of the self-isolation trench 19 vertically to the bottom direction of the self-isolation trench 19, the isolation unit electrode body 21 can be exposed through the isolation unit inner contact hole 26, and thereafter, the device first electrode metal can be filled in the isolation unit inner contact hole 26, that is, the contact between the device first electrode metal and the isolation unit electrode body 21 and the electrical connection after the contact can be realized.

It should be noted that, after the self-isolation unit is disposed on one side of the schottky-like diode, since the isolation unit electrode body 21 in the self-isolation unit is also electrically connected with the first electrode metal of the device, when the shielded gate power device is in a reverse recovery state, the electric field can be dispersed, so as to realize protection of the schottky-like diode, so that the region where the electric leakage breakdown occurs is moved from the schottky-like diode to the region where the self-isolation unit is located, even to the region outside the self-isolation unit, thereby avoiding aggregation of the electric field in the region of the side wall corresponding to the trench and the gate oxide layer 16 in the trench, and further reducing the electric leakage and enhancing the avalanche capability of the shielded gate power device under the condition of maintaining the fast recovery capability of the shielded gate power device.

In fig. 2 to 4, a self-isolation unit is disposed on the left side of the schottky-like diode, and at this time, the region where the leakage breakdown occurs may be moved to at least the region where the self-isolation unit is located; in fig. 5, after a self-isolation unit is disposed on two sides of the schottky-like diode, the area where the leakage breakdown occurs can be at least moved to the area where the self-isolation unit is located, so as to reduce the leakage and enhance the avalanche capability of the shielded gate power device.

In one embodiment of the present invention, the trench depth of the self-isolation trench 19 coincides with the trench depth of the diode-like trench 4 within the active region;

the height of the isolation unit electrode body 21 is consistent with the height of the first electrode body 15 in the groove, and the second end part of the isolation unit electrode body 21 is flush with the end part of the first area of the first electrode body in the groove;

the first end of the isolation unit electrode body 21 is adjacent to the bottom of the self-isolation trench 19.

As can be seen from fig. 2 to 5 and the above description, the notch of the self-isolation trench 19 corresponds to the surface of the epitaxial layer 2, and when the trench depth of the self-isolation trench 19 is consistent with the trench depth of the diode-like trench 4, the trench bottoms of the self-isolation trench 19 and the diode-like trench 4 are aligned in the epitaxial layer 2, and at this time, the self-isolation trench 19 and the diode-like trench 4 can be formed based on the same trench process. When the groove depth of the self-isolation groove 19 is consistent with the groove depth of the diode-like groove, the groove depth of the self-isolation groove 19 is larger, at the moment, the pressure resistance of the self-isolation unit can be further increased by utilizing the groove depth of the self-isolation groove 19, at the moment, the avalanche breakdown point of the schottky-like diode can be turned to an SGT cell area with relatively low pressure resistance, the electric field of the schottky-like diode can be effectively reduced, the electric leakage of the schottky-like diode is reduced, and the breakdown capacity of the snow shielding gate power device is improved.

In fig. 1 to 5, the length direction of the isolation unit electrode body 21 is consistent with the length direction of the self-isolation trench 19, the isolation unit electrode body 21 has a first end and a second end corresponding to the first end, wherein the first end of the isolation unit electrode body 21 is adjacent to the bottom of the self-isolation trench 19, and at this time, there is: the second end of the isolation unit electrode body 21 is adjacent to the notch of the self-isolation trench 19. In one embodiment of the present invention, the height of the isolation unit electrode body 21 is identical to the height of the first electrode body 15 in the trench, that is, the dimension along the length direction of the self-isolation trench 19 and the diode-like trench 4.

In addition, the second end of the isolation unit electrode body 21 is flush with the end of the first region of the first electrode body in the groove, and at this time, the second end of the isolation unit electrode body 21 is located above the bottom surface of the P-type base region 7, as is clear from the above description. When the second end of the isolation unit electrode body 21 is arranged above the bottom surface of the P-type base region 7, the field plate effect of the first electrode of the shielded gate power device can be further enhanced, the voltage resistance is improved, and the electric leakage is reduced.

In the implementation, a trench p+ injection region can be further arranged at the bottom of the self-isolation trench 19 and/or the diode-like trench 4, the self-isolation trench 19 and the diode-like trench 4 are covered by the trench p+ injection region, the electric field can be further prevented from being gathered at the bottoms of the diode-like trench 4 and the self-isolation trench 19 by the trench p+ injection region, the withstand voltage of the schottky-like diode and the self-isolation unit is further improved, and therefore the withstand voltage of the shielded gate device can be further improved, and the avalanche capability of the shielded gate power device is enhanced.

In one embodiment of the present invention, the self-isolation cell further comprises an isolation cell N + source region 29 located outside the self-isolation trench 19, wherein,

The isolation unit N+ source region 29 is positioned in the P-type base region 7 outside the self-isolation trench 19, and the isolation unit N+ source region 29 and the P-type base region 7 are both in contact with the outer side wall of the self-isolation trench 19;

The device first electrode metal is also electrically connected to the isolation element n+ source region 29 and the P-type base region 7.

In fig. 2-3, an embodiment is shown in which isolation unit n+ source regions 29 are disposed outside the self-isolation trenches 19, the isolation unit n+ source regions 29 being located in the P-type base region 7 in contact with the self-isolation trenches 19, the isolation unit n+ source regions 29 being in contact with the outer sidewalls of the self-isolation trenches 19. When the first electrode metal of the device is electrically connected with the n+ source region 29 of the isolation unit and the P-type base region 7, a conductive channel can be formed on the outer side wall of the self-isolation trench 19 during operation of the shielded gate power device, and at this time, the on-resistance of the shielded gate power device can be reduced.

In one embodiment of the present invention, the self-isolation unit further comprises an isolation unit p+ injection region 24 disposed outside the self-isolation trench 19 and an isolation unit external contact hole 25 corresponding to the isolation unit p+ injection region 24, wherein,

The isolation unit P+ injection region 24 penetrates through the P-type base region 7 outside the isolation trench 19, the doping concentration of the isolation unit P+ injection region 24 is greater than that of the P-type base region 7, and the bottom of the isolation unit P+ injection region 24 is located below the bottom surface of the P-type base region 7;

The isolation unit p+ implantation region 24 is in contact with the corresponding outer sidewall of the self-isolation trench 19, and the isolation unit p+ implantation region 24 is in ohmic contact with the device first electrode metal filled in the isolation unit outer contact hole 25.

As can be seen from fig. 2 to 3 and the above description, when the isolation cell n+ source region 29 is provided outside the self-isolation trench 19, a conductive channel can be formed outside the self-isolation trench 19. In order to reduce the influence of the conductive channel and further improve the withstand voltage of the shielded gate power device, in fig. 4 to 5, an isolation unit p+ injection region 24 and an isolation unit external contact hole 25 corresponding to the isolation unit p+ injection region 24 are disposed outside the self-isolation trench 19, that is, the isolation unit external contact hole 25 corresponds to the isolation unit p+ injection region 24 one by one. Specifically, the isolation unit p+ injection region 24 penetrates through the P-type base region 7, the junction depth of the isolation unit p+ injection region 24 is greater than that of the P-type base region 7, that is, the bottom of the isolation unit p+ injection region 24 is located below the P-type base region 7, and the isolation unit p+ injection region 24 is in contact with the P-type base region 7.

In fig. 4 to 5, the isolation unit p+ implantation region 24 contacts the corresponding outer sidewall of the self-isolation trench 19, and the isolation unit outer contact holes 25 are distributed at least along the outer sidewall of the self-isolation trench 19, and after the isolation unit outer contact holes 25 are formed on the outer sidewall of the self-isolation trench 19, the isolation unit n+ source region 29 is not formed on the outer sidewall of the self-isolation trench 19, that is, a conductive channel cannot be formed on the outer wall of the self-isolation trench 19.

Specifically, the isolation unit p+ injection region 24 can effectively reduce the electric field of the contacted P-type base region 7, and the isolation unit p+ injection region 24 is adjacent to the schottky diode, so that the electric field concentration at the gate oxide layer 16 in the trench of the schottky diode can be further relieved, and the electric leakage is reduced. In addition, the isolation unit p+ injection region 24 can also form an extraction channel of hot carriers, so that the avalanche capability of the shielded gate power device is further enhanced.

The depth of the isolation cell outer contact hole 25 is smaller than the depth of the isolation cell p+ implant region 24. In specific implementation, the device first electrode metal may be filled in the isolation unit outer contact hole 25, and at this time, the device first electrode metal is in ohmic contact with the isolation unit p+ injection region 24, and may be electrically connected to the P-type base region 7 through the isolation unit p+ injection region 24.

In one embodiment of the present invention, the isolation cell outer contact hole 25 has a trapezoid shape in a cross section of the shielded gate power device, wherein,

The width of the first end of the isolation unit outer contact hole 25 is smaller than the width of the second end of the isolation unit outer contact hole 25, wherein the first end of the isolation unit outer contact hole 25 is positioned below the notch of the self-isolation groove 19;

The width of the second end of the isolation unit external contact hole 25 is greater than the width of the isolation unit p+ implant region 24 such that the second end of the isolation unit external contact hole 25 enters the notch region of the self-isolation trench 19.

In fig. 4 to 5, the isolation unit outer contact hole 25 may have a trapezoid shape, the isolation unit outer contact hole 25 has a first end and a second end corresponding to the first end, wherein the first end of the isolation unit outer contact hole 25 is located below the notch of the self-isolation trench 19, and the first end of the isolation unit outer contact hole 25 is adjacent to the bottom of the self-isolation trench 19, and at this time, the second end of the isolation unit outer contact hole 25 corresponds to the notch of the self-isolation trench 19.

In one embodiment of the present invention, the width of the first end of the isolation unit outer contact hole 25 is smaller than the width of the second end of the isolation unit outer contact hole 25, and the width of the second end of the isolation unit outer contact hole 25 is larger than the width of the isolation unit p+ injection region 24, so that the second end of the isolation unit outer contact hole 25 enters the notch region of the self-isolation trench 19, as shown in fig. 4 to 5, at this time, when the isolation unit outer contact hole 25 is formed by etching, the oxide layer 20 in the isolation trench from the notch of the isolation trench 19 is partially etched, and the width of the isolation unit outer contact hole 25 can be increased.

After the width of the isolation unit outer contact hole 25 is increased, the implantation depth of the isolation unit p+ implantation region 24 can be further increased, and as can be seen from the above description, the protection of the in-groove gate oxide layer 16 can be further increased by utilizing the isolation unit p+ implantation region 24 after the implantation depth of the isolation unit p+ implantation region 24 is increased, that is, the electric field concentration at the in-groove gate oxide layer 16 of the schottky diode can be further relieved, and the electric leakage occurring at the in-groove gate oxide layer 16 of the schottky diode can be reduced. In the implementation, the isolation unit outer contact hole 25 may be etched from the outside of the isolation trench 19, and after the isolation unit outer contact hole 25 is obtained, P-type impurity ion implantation is performed to form the isolation unit p+ implantation region 24.

In one embodiment of the present invention, for any one SGT cell, an SGT structure is provided within cell groove 3 of said SGT cell, wherein,

When the SGT structure adopts an up-down structure, the SGT structure comprises a cell lower electrode body 6 and a cell upper electrode body 8, wherein the cell upper electrode body 8 is positioned above the cell lower electrode body 6, and the cell upper electrode body 8 is insulated and isolated from the cell lower electrode body 6;

The upper cell electrode body 8 is insulated and isolated from the side wall of the cell groove 3 through the cell gate oxide layer 10;

The thickness of the cellular gate oxide layer 10 is greater than the thickness of the gate oxide layer 16 in the groove;

The upper electrode body 8 of the cell is electrically connected with the second electrode metal of the device above the semiconductor substrate, and the lower electrode body 6 of the cell is electrically connected with the first electrode metal of the device.

In fig. 1-5, an embodiment is shown in which an SGT structure is disposed in the cell trench 3, and the SGT structure includes a lower cell electrode body 6 and an upper cell electrode body 8, and it is understood from the foregoing description that the lower cell electrode body 6 and the upper cell electrode body 8 may generally be conductive polysilicon, or other conductive materials may be used, and the specific type of material may be selected according to requirements. In fig. 1-5, the upper cell electrode 8 is located above the lower cell electrode 6, and in this case, in the cell groove 3, the upper cell electrode 8 is adjacent to the notch of the cell groove 3, and the lower cell electrode 6 is further adjacent to the bottom of the cell groove 3.

As can be seen from the SGT cell principle, in the cell trench 3, the upper cell electrode 8 and the lower cell electrode 6 need to be isolated and isolated, and the upper cell electrode 8 is electrically connected to the second electrode metal of the device, and the lower cell electrode 6 is electrically connected to the first electrode metal of the device, where the first electrode metal of the device can form the first electrode of the shielded gate power device; at this time, the second electrode of the shielded gate power device may be formed by using the second electrode metal of the device, and when the shielded gate power device is an SGT MOSFET device, the second electrode is a gate electrode of the SGT MOSFET device, and when the shielded gate power device is an SGT IGBT device, the second electrode is a gate electrode of the SGT IGBT device, and when the shielded gate power device is another type of power device, a type of forming the second electrode based on the second electrode metal of the device may be obtained, which is not described herein again.

In order to realize the insulation and isolation between the upper electrode body 8 and the lower electrode body 6, an interlayer oxide layer 9 is arranged in the cell groove 3, and the insulation and isolation between the upper electrode body 8 and the lower electrode body 6 can be realized by utilizing the interlayer oxide layer 9. In addition, a cell field oxide layer 5 is disposed in the cell trench 3, where the cell field oxide layer 5 corresponds to the cell bottom electrode body 6, and the cell field oxide layer 5 covers the sidewall and the bottom wall of the cell trench 3, so that the cell bottom electrode body 6 can be insulated from the sidewall and the bottom wall of the cell trench 3 by using the cell field oxide layer 5, and of course, the interlayer oxide layer 9 is in contact connection with the cell field oxide layer 5.

The upper cell electrode body 8 is correspondingly contacted with the cell gate oxide layer 10 in the cell groove 3, and the cell gate oxide layer 10 covers the corresponding side wall of the cell groove 3. It should be noted that, the cell gate oxide layer 10, the cell field oxide layer 5 and the interlayer oxide layer 9 are all silicon dioxide layers, and may be formed by a thermal oxidation process; the thickness of the cell gate oxide 10 is smaller than the thickness of the cell field oxide 5, and the thickness of the cell gate oxide 10 is smaller than the thickness of the gate oxide 16 in the trench, so that the turn-on voltage of the schottky-like diode is smaller than the turn-on voltage of the SGT cell.

When the thickness of the cell gate oxide layer 10 is smaller than the thickness of the cell field oxide layer 5, the width of the cell upper electrode body 8 should be larger than the width of the cell lower electrode body 6; in addition, in fig. 1 to 5, a notch oxide layer 11 is further disposed in the cell trench 3, and the notch oxide layer 11 can be used to cover the upper electrode body 8 of the cell, so as to realize insulation and isolation between the upper electrode body 8 of the cell and the first electrode of the device. Further, an end surface of the cell upper electrode body 8 adjacent to the bottom of the cell groove 3 is located below the bottom surface of the P-type base region 7.

In order to form a conductive channel of the SGT cell, a cell N+ source region 12 is arranged on the outer side wall of the cell groove 3, the cell N+ source region 12 is positioned in a P-type base region 7 contacted with the cell groove 3, the cell N+ source region 12 is contacted with the outer side wall of the corresponding cell groove 3, and meanwhile, the cell N+ source region 12 and the P-type base region 7 are in metal ohmic contact with a first electrode of the device. In order to realize ohmic contact with the first electrode metal of the device, in fig. 1 to 3, a contact p+ injection region 13 is disposed in the P-type base region 7, the doping concentration of the contact p+ injection region 13 is greater than that of the P-type base region 7, the contact p+ injection region 13 is in contact with the n+ source region 12 of the cell, and at this time, the first electrode metal of the device can be in ohmic contact with the n+ source region 12 of the cell, and electrical connection with the corresponding P-type base region 7 is realized through the contact p+ injection region 13.

Note that, the contact p+ implantation region 13 may be formed by ion implantation in the P-type base region 7, and fig. 1 to 3 show embodiments in which ion implantation is directly performed in the P-type base region 7, and the contact p+ implantation region 13 is formed.

In practice, the cell trench 3, the diode-like trench 4 and the self-isolation trench 19 are elongated, and the cell trench 3, the diode-like trench 4 and the self-isolation trench 19 are parallel to each other.

The following describes the recovery capability of the shielded gate power device by disposing a schottky-like diode in the active region, specifically:

When reverse recovery current flows through the metal of the first electrode of the shielding grid power device, voltage drop is generated when the current flows through the schottky-like diode, and then the schottky-like diode is positive voltage. Because the thickness of the gate oxide layer 16 in the trench is smaller than that of the gate oxide layer 10 Yu Yuanbao, before the forward bias voltage of the PN junction between the P-type base region 7 and the epitaxial layer 2 is increased to 0.7v, the channel at the gate oxide layer 16 in the trench can be conducted earlier than the channel at the gate oxide layer 10 in the cell, so that the forward bias voltage of the PN junction between the P-type base region 7 and the epitaxial layer 2 is smaller than 0.7v. That is, before the PN junction is conducted, the channel at the schottky-like diode is conducted, so that the loss and consumption of mobile charges in the PN junction are caused, the mobile charges in the PN junction cannot be accumulated, the voltage of the PN junction cannot rise to 0.7v, the variation generated by the influence of the voltage on the depletion region of the PN junction is reduced, the PN junction can be recovered more rapidly, the reverse recovery charge Qrr and the reverse recovery time Trr of the shielded gate power device are reduced, and the reverse recovery characteristic of the shielded gate power device is improved.

In one embodiment of the invention, a plurality of source contact hole units are arranged in the active region, wherein,

the source contact hole unit includes a source contact hole 27 and a contact hole lower P + implant region 23 located directly under the source contact hole 27, wherein,

The doping concentration of the p+ injection region 23 under the contact hole is larger than that of the P-type base region 7, and the p+ injection region 23 under the contact hole is positioned below the P-type base region 7 and is in contact with the corresponding P-type base region 7;

The first electrode metal of the device is filled in the source region contact hole 27 and is in ohmic contact with the p+ injection region 23, the P-type base region 7 and the cellular N+ source region 12 at two sides of the filled source region contact hole;

the cell n+ source region 12 is in contact with the outer sidewall of the corresponding cell trench 3.

In order to further protect the schottky-like diode, a source contact hole unit may be further disposed in the active region, where the source contact hole unit is at least distributed between two adjacent SGT cells, as shown in fig. 4, and of course, the source contact hole unit may also be distributed between the schottky-like diode and the SGT cells, as shown in fig. 4 and 5, and the source contact hole unit may be specifically related to the distribution position of the schottky-like diode when the source contact hole unit is distributed between the schottky-like diode and the SGT cells; specifically, the source region contact hole unit corresponds to the contact p+ injection region 13, that is, the position where the contact p+ injection region 13 is located is improved, so that the withstand voltage of the shielded gate power device can be further improved, and the purpose of protecting the schottky-like diode is achieved.

Fig. 4 and 5 show an embodiment of a source contact hole unit, where the source contact hole unit includes a source contact hole 27 and a p+ injection region 23 under the contact hole located right below the source contact hole 27, and it is known from the above description that the position of the source contact hole 27 may be different from the position of the contact p+ injection region 13, where the width of the source contact hole 27 is larger than the width of the contact p+ injection region 13, and it is understood that when the contact p+ injection region 13 shown in fig. 1 to 3 is provided, the step of opening the contact hole may be omitted in the case of meeting the connection of the first electrode metal of the device. When the source contact hole 27 is disposed in the active region, the source contact hole 27 must be disposed outside the cell trench 3 and/or outside the diode-like trench 4, and the source contact hole 27 may be formed by a contact hole process commonly used in the art.

In one embodiment of the present invention, the depth of the source contact hole 27 is at least consistent with the thickness of the P-type base region 7, where the hole opening of the source contact hole 27 is located on the surface of the epitaxial layer 2, the hole bottom of the source contact hole 27 is flush with the bottom surface of the P-type base region 7, or the hole bottom of the source contact hole 27 is located below the P-type base region 7, where the source contact hole 27 is in contact with the cellular n+ source regions 12 on both sides. In a specific implementation, after the source region contact hole 27 is formed, an ion implantation process is used to form a p+ implantation region 23 under the source region contact hole 27, where the doping concentration of the p+ implantation region 23 under the contact hole is greater than that of the P-type base region 7, and the p+ implantation region 23 under the contact hole contacts the corresponding P-type base region 7, as shown in fig. 4 and 5.

After the first electrode metal of the device is filled in the source region contact hole 27, the first electrode metal of the device is in ohmic contact with the cellular N+ source region 12, the P-type base region 7 and the p+ injection region 23 below the contact hole at two sides of the source region contact hole 27; at this time, the p+ injection region 23 under the contact hole can be used to realize the dispersion of the electric field, so that the aggregation of the electric field in the gate oxide layer 16 in the schottky diode-like trench can be further reduced, and the possibility of electric leakage at the gate oxide layer 16 in the schottky diode-like trench can be reduced.

Claims

1. A shielded gate power device with low leakage and fast recovery capability, the shielded gate power device comprising:

a semiconductor substrate of a first conductivity type;

in the active region, the groove depth of the diode-like groove is larger than the groove depth of a cell groove of any SGT cell;

2. The shielded gate power device with low leakage and fast recovery capability of claim 1, wherein a width of the second electrode body in the trench is greater than a width of the first electrode body in the trench in the diode-like trench;

3. The shielded gate power device with low leakage and fast recovery capability according to claim 1, wherein a self-isolation cell is provided in the active region at least on one side of the schottky-like diode, wherein,

4. A shielded gate power device with low leakage and fast recovery capability according to claim 3, wherein the self-isolation trench has a trench depth in the active region that corresponds to the trench depth of the diode-like trench;

5. The shielded gate power device with low leakage and fast recovery capability according to claim 3, further comprising an isolation cell source region of a first conductivity type outside the self-isolation trench for the self-isolation cell, wherein,

6. The device of claim 3, further comprising an isolation cell second conductivity type injection region disposed outside the self-isolation trench and an isolation cell external contact hole corresponding to the isolation cell second conductivity type injection region for the self-isolation cell,

7. The shielded gate power device with low leakage and fast recovery capability according to claim 6, wherein the isolation cell outer contact hole has a trapezoid shape in a cross section of the shielded gate power device, wherein,

8. The shielded gate power device with low leakage and fast recovery capability according to any one of claims 1 to 7, wherein for any one SGT cell, an SGT structure is provided in a cell trench of said SGT cell, wherein,

9. The shielded gate power device with low leakage and fast recovery capability according to claim 8, wherein a plurality of source contact hole cells are disposed in the active region, wherein,