Power device, electronic equipment and vehicle

Abstract

The utility model discloses a power device, an electronic device and a vehicle, and the power device comprises a substrate of a first conductive type; the drift region of the first conduction type is located on the substrate in the first direction, at least one recess is formed in the side face of the drift region in the second direction, and the first direction is perpendicular to the second direction. By adopting the power device, the risk of short-circuit thermal failure can be reduced, and the reliability of the power device is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a power device, an electronic device and a vehicle. Background Art

[0002] At present, the trench gate SiC MOSFET eliminates the JFET (Junction Field Effect Transistor) region compared to the planar gate structure, reduces the on-resistance of the device, and increases the current density of the device. However, in the short-circuit state, the increase in current density causes the trench gate SiC MOSFET device to be in a state of high current and high voltage at the same time. The excessive current density causes the lattice temperature inside the device to rise rapidly, making the device more susceptible to short-circuit thermal failure. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a power device, which can reduce the risk of short-circuit thermal failure and improve the reliability of the power device.

[0004] The second purpose of the utility model is to provide a method for preparing a power device.

[0005] The third purpose of the present utility model is to provide an electronic device.

[0006] A fourth object of the present invention is to provide a vehicle.

[0007] In order to solve the above problems, an embodiment of the first aspect of the utility model provides a power device, including: a substrate of a first conductive type; a drift region of the first conductive type, wherein in a first direction, the drift region is located on the substrate, and in a second direction, a side surface of the drift region has at least one recess, wherein the first direction is perpendicular to the second direction.

[0008] According to the power device of the embodiment of the utility model, by forming at least one recess on the side of the drift region in the second direction, the current channel at the drift region inside the device can be limited, which is equivalent to increasing the resistance of the current channel and reducing the flowable current. Therefore, in the short-circuit state, the short-circuit current is suppressed because the current channel is limited, thereby weakening the rise of the internal lattice temperature of the power device when short-circuited to a certain extent, reducing the risk of short-circuit thermal failure, and improving the reliability of the power device.

[0009] In some embodiments, the power device further includes: a doped column of a second conductivity type; in a first direction, the drift region and the doped column are both located on the substrate, and the doped column and the drift region are arranged and connected along a second direction; in the second direction, the doped column has at least one protruding widened region on one side of the drift region, and the protruding widened region is matched with the recess.

[0010] In some embodiments, the doped column has a plurality of the protruding widened regions on a side facing the drift region, and the plurality of the protruding widened regions are distributed at intervals along the first direction.

[0011] In some embodiments, the heights of the plurality of protruding widened regions along the first direction are the same.

[0012] In some embodiments, at least two of the plurality of protruding widening regions have different heights along the first direction.

[0013] In some embodiments, the widths of the plurality of protruding widened regions along the second direction are the same.

[0014] In some embodiments, at least two of the plurality of protruding widened regions have different widths along the second direction.

[0015] In some embodiments, starting from the protruding widening region close to the substrate along the second direction, heights of the plurality of protruding widening regions along the first direction gradually decrease.

[0016] In some embodiments, the number of the plurality of protruding widened areas is an even number.

[0017] In some embodiments, the number N of the plurality of protruding widening areas satisfies: 2≤N≤10.

[0018] In some embodiments, the doped column includes: a first doped column and a second doped column, and the first doped column and the second doped column are located at two sides of the drift region along the second direction.

[0019] In some embodiments, a height of the protruding widening region of the first doped column along the first direction is the same as or different from a height of the protruding widening region of the second doped column along the first direction.

[0020] In some embodiments, a width of the protruding widening region of the first doped column along the second direction is the same as or different from a width of the protruding widening region of the second doped column along the second direction.

[0021] In some embodiments, the number of the protruding widening regions of the first doped column is equal to or unequal to the number of the protruding widening regions of the second doped column.

[0022] In some embodiments, a thickness of the drift region along the first direction is equal to a thickness of the doped column along the first direction.

[0023] In some embodiments, the power device further includes: a base region of a second conductivity type, the base region being located on a side of the drift region and the doped column away from the substrate, and being in contact with the doped column and the drift region, respectively; an ohmic contact region of a second conductivity type, the ohmic contact region being located on a side of the base region away from the substrate; a source region of a first conductivity type, the source region being located on a side of the base region away from the substrate, and in the second direction, the ohmic contact region being located outside the source region; a trench gate structure, the trench gate structure penetrating the source region and the base region along the first direction and extending to the drift region; a source metal layer, the source metal layer covering the ohmic contact region, the source region and the trench gate structure; a drain metal layer, the drain metal layer being located on a side of the substrate away from the drift region.

[0024] In some embodiments, the trench gate structure includes: a gate trench, the gate trench penetrates the source region and the base region along the first direction and extends to the drift region; a gate oxide layer, the gate oxide layer is located on the inner wall of the gate trench; a gate, the gate is formed on the surface of the gate oxide layer and fills the gate trench; an isolation dielectric, the isolation dielectric is formed between the source metal layer and the gate and between the source metal layer and the gate oxide layer.

[0025] In some embodiments, the trench gate structure further includes: a gate protection zone, wherein the gate protection zone is located in the drift region and wraps the bottom of the gate oxide layer in the gate trench.

[0026] The second object of the utility model is to propose a method for preparing a power device, comprising: providing a substrate of a first conductive type, and preparing a drift region of the first conductive type on the substrate along a first direction; preparing a drift region of the first conductive type on the substrate along the first direction, wherein in a second direction, a side surface of the drift region has at least one recess, wherein the first direction is perpendicular to the second direction.

[0027] According to the preparation method of the embodiment of the utility model, by forming at least one recess on the side of the drift region in the second direction, the current channel at the drift region inside the device can be limited, which is equivalent to increasing the resistance of the current channel and reducing the current that can flow. Therefore, in the short-circuit state, the short-circuit current is suppressed because the current channel is limited, thereby weakening the rise in the internal lattice temperature of the power device when short-circuited to a certain extent, reducing the risk of short-circuit thermal failure, and improving the reliability of the power device.

[0028] In some embodiments, the preparation method further includes: preparing a doped column of a second conductivity on the substrate and along a second direction on the side of the drift region, wherein in the second direction, the doped column has at least one protruding widened region on a side facing the drift region, and the protruding widened region is matched with the recess.

[0029] In some embodiments, the preparation method also includes: along the first direction, respectively preparing a base region of a second conductivity type, an ohmic contact region of a second conductivity type, a source region of a first conductivity type, a trench gate structure and a source metal layer on a side of the drift region and the doped column away from the substrate, wherein the base region is located on a side of the drift region and the doped column away from the substrate, and is in contact with the doped column and the drift region respectively, the ohmic contact region is located on a side of the base region away from the substrate, the source region is located on a side of the base region away from the substrate, and in the second direction, the ohmic contact region is located outside the source region, the trench gate structure penetrates the source region and the base region along the first direction and extends to the drift region, and the source metal layer covers the ohmic contact region, the source region and the trench gate structure; and a drain metal layer is prepared on a side of the substrate away from the drift region.

[0030] In some embodiments, the preparation method further includes: preparing a gate protection zone in the drift region, wherein the gate protection zone wraps the bottom of the gate oxide layer in the gate trench.

[0031] A third aspect of the present invention provides an electronic device, comprising at least one power device as described in the above embodiment.

[0032] According to the electronic equipment of the embodiment of the utility model, the risk of short circuit thermal failure can be reduced and the reliability of the power device can be improved by adopting the power device of the above embodiment.

[0033] A fourth aspect of the present invention provides a vehicle, comprising the electronic device described in the above embodiment.

[0034] According to the vehicle of the embodiment of the utility model, the risk of short circuit thermal failure can be reduced and the reliability of power devices can be improved by adopting the electronic equipment of the above embodiment.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0037] Figure 1 It is a schematic diagram of the structure of a power device according to a specific embodiment of the utility model;

[0038] Figure 2 It is a structural schematic diagram of a drift region according to a specific embodiment of the utility model;

[0039] Figure 3 It is a structural schematic diagram of another power device according to a specific embodiment of the utility model;

[0040] Figure 4 It is a structural schematic diagram of another power device according to a specific embodiment of the utility model;

[0041] Figure 5 It is a structural schematic diagram of another power device according to a specific embodiment of the utility model;

[0042] Figure 6 It is a flow chart of a method for preparing a power device according to a specific embodiment of the utility model;

[0043] Figure 7 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0044] Figure 8 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0045] Fig. 9 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0046] Fig.10 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0047] Fig.11 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0048] Fig.12It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0049] Fig.13 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0050] Fig.14 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0051] Fig.15 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0052] Fig.16 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0053] Fig.17 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0054] Fig.18 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0055] Fig.19 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0056] Fig. 20 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model;

[0057] Fig.21 It is a schematic diagram of one process of a method for preparing a power device according to a specific embodiment of the utility model.

[0058] Reference numerals:

[0059] Power device 100;

[0060] A substrate 10 of a first conductivity type; a drift region 20 of a first conductivity type; a doped column 30 of a second conductivity type; a protruding widening region 31; a base region 40 of a second conductivity type; an ohmic contact region 50 of a second conductivity type; a source region 60 of a first conductivity type; a trench gate structure 70; a source metal layer 80; a drain metal layer 90; a gate trench 71; a gate oxide layer 72; a gate 73; an isolation dielectric 74; and a gate protection region 75. DETAILED DESCRIPTION

[0061] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0062] In order to solve the above problems, a first embodiment of the utility model provides a power device, which can reduce the risk of short-circuit thermal failure and improve the reliability of the power device.

[0063] Reference below Figure 1 and Figure 2 The power device of the embodiment of the utility model is described as follows: Figure 1 and Figure 2 As shown, the power device 100 includes a substrate 10 of a first conductivity type and a drift region 20 of a first conductivity type.

[0064] In the first direction, the drift region 20 is located on the substrate 10, and in the second direction, the side surface of the drift region 20 has at least one recess 21. The first direction is perpendicular to the second direction.

[0065] Specifically, under normal working conditions, the current can flow normally in the drift region 20, thereby ensuring the current conduction characteristics of the power device 100; under short-circuit conditions, Figure 1 and Figure 2 As shown, based on the structure that the side of the drift region 20 has at least one recess 21 in the second direction, compared with the structure that the side of the drift region is not provided with a recess, the at least one recess 21 formed on the side of the drift region in the present application can effectively limit the current channel at the drift region 20 inside the device, which is equivalent to increasing the resistance of the current channel, thereby effectively suppressing the short-circuit current, thereby weakening the rise of the internal lattice temperature of the power device when short-circuited to a certain extent, reducing the risk of short-circuit thermal failure, and improving the reliability of the power device 100. Therefore, the power device 100 of the present application can achieve the effect of taking into account both the current conduction characteristics and the short-circuit reliability, improve the comprehensive performance of the power device 100, and improve the product's competitive advantage.

[0066] According to the power device 100 of the embodiment of the utility model, at least one recess is formed on the side of the drift region 20 in the second direction, thereby limiting the current channel at the drift region 20 inside the device, which is equivalent to increasing the resistance of the current channel and reducing the current that can flow. Therefore, in the short-circuit state, the short-circuit current is suppressed because the current channel is limited, thereby weakening the rise in the internal lattice temperature of the power device 100 when short-circuited to a certain extent, reducing the risk of short-circuit thermal failure, and improving the reliability of the power device.

[0067] In some embodiments, reference Figure 1 As shown, the power device 100 further includes a doped column 30 of the second conductivity type.

[0068] In the first direction, the drift region 20 and the doping column 30 are both located on the substrate 10, and the doping column 30 and the drift region 20 are arranged and connected along the second direction; in the second direction, the doping column 30 has at least one protruding widening region 31 on the side facing the drift region 20, and the protruding widening region 31 is matched with the recess 21. That is to say, along the second direction, the doping column 30 is widened correspondingly at each recess 21 on the side of the drift region 20 to form a protruding widening region 31, so that the side of the drift region 20 is completely matched and connected with the side of the doping column 30, so as to ensure the current conduction characteristics of the power device under normal working conditions on the one hand, and on the other hand, limit the current channel at the drift region 20 to suppress the short-circuit large current under the short-circuit state, so as to achieve the purpose of enhancing the short-circuit reliability.

[0069] In some embodiments, reference Figure 1 As shown, the doping column 30 has a plurality of protruding widened regions 31 on one side facing the drift region 20 , and the plurality of protruding widened regions 31 are distributed at intervals along the first direction.

[0070] In some embodiments, reference Figure 1 As shown, the heights of the plurality of protruding widened areas 31 along the first direction are the same. This design facilitates simplifying the steps in the manufacturing process of the power device and improves the manufacturing efficiency.

[0071] In some embodiments, reference Figure 3 As shown, at least two of the plurality of protruding widened regions 31 have different heights along the first direction. Thus, by changing the heights of different protruding widened regions 31 in the first direction, it is beneficial to further improve the balance between the current conduction capability and the short-circuit reliability of the power device 100, optimize the comprehensive performance of the power device 100, and improve the reliability of the power device 100.

[0072] In some embodiments, reference Figure 1 As shown, the widths of the plurality of protruding widened regions 31 along the second direction are the same. This design facilitates simplifying the steps in the manufacturing process of the power device and improves the manufacturing efficiency.

[0073] In some embodiments, reference Figure 3 As shown, at least two of the plurality of protruding widened regions have different widths along the second direction. Thus, by changing the widths of different protruding widened regions 31 in the second direction, it is beneficial to further improve the balance between the current conduction capability and the short-circuit reliability of the power device 100, optimize the comprehensive performance of the power device 100, and improve the reliability of the power device 100.

[0074] In some embodiments, reference Figure 3As shown, starting from the protruding widening area 31 close to the substrate 10 along the second direction, the heights of the multiple protruding widening areas 31 along the first direction gradually decrease. Therefore, the protruding widening area 31 close to the trench gate structure is set to have a relatively narrow overall structure, and the depletion area of ​​the protruding widening area 31 in the drift region 20 is small, so that the current capacity of the device under normal working conditions can be better guaranteed. At the same time, the protruding widening areas 31 gradually approaching the substrate 10 are gradually widened in sequence, thereby gradually limiting the current channel in the drift region 20, so that the short-circuit current of the device can be better suppressed in a short-circuit state, and the short-circuit reliability can be enhanced.

[0075] In some embodiments, reference Figure 1 As shown, the number of the plurality of protruding widened areas 31 is an even number. For example, the number of the protruding widened areas 31 can be 2, 4 or 6, etc., which is not limited.

[0076] In some embodiments, the number N of the plurality of protruding widening regions satisfies: 2≤N≤10. For example, N may be 2, 3, 6 or 10, without limitation.

[0077] In some embodiments, reference Figure 4 As shown, the doped column 30 includes a first doped column 32 and a second doped column 33 , and the first doped column 32 and the second doped column 33 are located at two sides of the drift region 20 along the second direction.

[0078] In some embodiments, a height of the protruding widened region of the first doped column 32 along the first direction is the same as or different from a height of the protruding widened region of the second doped column 33 along the first direction.

[0079] In some embodiments, the width of the protruding widened region of the first doped column 32 along the second direction is the same as or different from the width of the protruding widened region of the second doped column 33 along the second direction.

[0080] In some embodiments, the number of the protruding widening regions of the first doped pillar 32 is equal to or unequal to the number of the protruding widening regions of the second doped pillar 33 .

[0081] In some embodiments, the thickness of the drift region 20 along the first direction is equal to the thickness of the doped pillar 30 along the first direction.

[0082] In some embodiments, Figure 1 As shown, the power device 100 further includes a base region 40 of the second conductivity type, an ohmic contact region 50 of the second conductivity type, a source region 60 of the first conductivity type, a trench gate structure 70 , a source metal layer 80 and a drain metal layer 90 .

[0083] Among them, the base region 40 is located on the side of the drift region 20 and the doped column 30 away from the substrate 10, and is in contact with the doped column 30 and the drift region 20 respectively; the ohmic contact region 50 is located on the side of the base region 40 away from the substrate 10; the source region 60 is located on the side of the base region 40 away from the substrate 10, and in the second direction, the ohmic contact region 50 is located on the outside of the source region 60; the trench gate structure 70 penetrates the source region 60 and the base region 40 along the first direction and extends to the drift region 20; the source metal layer 80 covers the ohmic contact region 50, the source region 60 and the trench gate structure 70; the drain metal layer 80 is located on the side of the substrate 10 away from the drift region 20.

[0084] In some embodiments, Figure 5 As shown, the trench gate structure 70 includes a gate trench 71 (not shown), a gate oxide layer 72 , a gate 73 and an isolation dielectric 74 .

[0085] Among them, the gate trench 71 penetrates the source region 60 and the base region 40 along the first direction and extends to the drift region 20; the gate oxide layer 72 is located on the inner wall of the gate trench 71; the gate 73 is formed on the surface of the gate oxide layer 72 and fills the gate trench 71; the isolation dielectric 74 is formed between the source metal layer 80 and the gate 73 and between the source metal layer 80 and the gate oxide layer 72.

[0086] In some embodiments, Figure 5 As shown, the trench gate structure 70 further includes a gate protection area 75 . The gate protection area 75 is located in the drift region 20 and wraps the bottom of the gate oxide layer 72 in the gate trench 71 .

[0087] The second embodiment of the utility model provides a method for preparing a power device, such as Figure 6 As shown, the preparation method at least includes step S1-step S2.

[0088] Step S1, reference Figure 7 As shown, a substrate 10 of a first conductivity type is provided.

[0089] Step S2, preparing a drift region of the first conductivity type on the substrate along a first direction, wherein a side surface of the drift region has at least one recess in a second direction, wherein the first direction is perpendicular to the second direction.

[0090] In some embodiments, the first conductive type substrate 10 may be an N-type heavily doped substrate, such as an N-type conductive type SiC material substrate, and the doping impurities are n-type conductive impurities, preferably nitrogen ions, and the doping concentration may be 1×10 19 -2×10 19 cm -3 .

[0091] Furthermore, the drift region 20 may be an N-type lightly doped region, which is an N column in the superjunction. The doping impurities may be n-type conductive impurities, preferably nitrogen ions. The thickness of the drift region 20 is determined by the withstand voltage level. For example, for a 1200V device, the thickness of the N-type drift region is preferably 10 μm-12 μm, and the doping concentration is preferably 1×10 16 -2×10 16 cm -3 As for the preparation method of the drift region 20, it is preferably formed by epitaxial preparation using a chemical vapor deposition method.

[0092] In some embodiments, the preparation method further includes: preparing a doped column 30 of a second conductivity on the substrate 10 and on the side of the drift region 20 along the second direction, wherein in the second direction, the doped column 30 has at least one protruding widening region on the side facing the drift region, such as Figures 8 to 11 shown.

[0093] In some embodiments, the doped column 30 may be a P-type lightly doped region, which is a P column in a superjunction. The doped impurities may be p-type conductive impurities, preferably aluminum ions. The thickness of the doped column 30 is the same as that of the drift region 20 and is determined by the withstand voltage level. For example, for a 1200V device, the thickness of the doped column 30 is preferably 10 μm-12 μm, and the doping concentration is the same as that of the drift region 20 to form a charge balance. The doping concentration is preferably 1×10 16 -2×10 16 cm -3 The doping column 30 may be prepared by performing ion implantation on the drift region 20 .

[0094] According to the preparation method of the embodiment of the utility model, by forming at least one recess on the side of the drift region in the second direction, the current channel at the drift region inside the device can be limited, which is equivalent to increasing the resistance of the current channel and reducing the current that can flow. Therefore, in the short-circuit state, the short-circuit current is suppressed because the current channel is limited, thereby weakening the rise in the internal lattice temperature of the power device when short-circuited to a certain extent, reducing the risk of short-circuit thermal failure, and improving the reliability of the power device.

[0095] In some embodiments, the preparation method further includes the following steps S3-S4.

[0096] Step S3, reference Figures 12 to 20As shown, along the first direction, a base region 40 of a second conductivity type, an ohmic contact region 50 of a second conductivity type, a source region 60 of a first conductivity type, a trench gate structure 70 and a source metal layer 80 are respectively prepared on the side of the drift region 20 and the doped column 30 away from the substrate 10, wherein the base region is located on the side of the drift region and the doped column away from the substrate, and contacts the doped column and the drift region respectively, the ohmic contact region is located on the side of the base region away from the substrate, the source region is located on the side of the base region away from the substrate, and in the second direction, the ohmic contact region is located outside the source region, the trench gate structure penetrates the source region and the base region along the first direction and extends to the drift region, and the source metal layer covers the ohmic contact region, the source region and the trench gate structure.

[0097] Step S4, reference Fig.21 As shown, a drain metal layer is prepared on a side of the substrate away from the drift region.

[0098] The doping impurities of the base region 40 may be p-type conductive impurities, preferably aluminum ions, and the thickness thereof is preferably 0.6 μm-1 μm, and the doping concentration is preferably 1.5×10 17 -2.5×10 17 cm -3 The base region 40 is prepared by epitaxial preparation using a chemical vapor deposition method.

[0099] The ohmic contact region 50 is prepared by ion implantation on the base region 40. The doping impurities may be p-type conductive impurities, preferably aluminum ions, and the doping concentration is preferably 1×10 19 -2×10 19 cm -3 , the thickness is preferably 0.2 μm-0.5 μm.

[0100] The source region 60 is prepared by ion implantation on the base region 40. The doping impurities may be n-type conductive impurities, preferably nitrogen ions, and the doping concentration is preferably 1×10 19 -2×10 19 cm -3 .

[0101] The gate oxide layer is made of silicon dioxide SiO 2 Considering that the thickness of the gate oxide layer affects the threshold voltage, gate control capability and gate oxide reliability of the device, the thickness of the gate oxide layer is preferably 50nm. The gate oxide layer is preferably prepared by dry oxygen oxidation, which can form an oxide layer with good compactness.

[0102] The gate material is polysilicon poly Si, preferably N-type heavily doped polysilicon, and the polysilicon gate is prepared by depositing and filling the entire trench.

[0103] The isolation medium is formed by deposition, and its material can be SiO 2, SiN or BPSG (boron phospho-silicate glass), the isolation medium is used to isolate the polysilicon gate and source metal layers.

[0104] The source metal layer is a metal or alloy that can form an ohmic contact with the source region, and is prepared by sputtering and alloying. It is preferably an aluminum-copper alloy AlCu, NiAlCu, or TiNAlCu. The thickness of the source metal layer is preferably 4 μm to 5 μm.

[0105] The drain metal layer may be a metal or alloy that forms an ohmic contact with the source region, and is prepared by sputtering and alloying. It is preferably an aluminum-copper alloy AlCu or NiAlCu. The thickness of the drain metal layer is preferably 1 μm to 2 μm.

[0106] In some embodiments, reference Figures 16 to 20 As shown, the preparation method further includes: preparing a gate protection area in the drift region, the gate protection area wrapping the bottom of the gate oxide layer in the gate trench.

[0107] The gate protection area is formed by ion implantation and high temperature driving. The final area needs to completely wrap the bottom and corners of the trench gate oxide to protect the gate oxide. The gate protection area can be doped with p-type conductive impurities, preferably aluminum Al ions, with a thickness of 0.3μm-0.4μm and a doping concentration of 7×10 17 -8×10 17 cm -3 .

[0108] The following is an example of the method for preparing the power device of the present application. Specifically, a SiC material substrate of N-type conductivity with suitable parameters is provided. The substrate has a 1×10 19 cm -3 The doping concentration is 1×10 16 cm -3 The pattern of the prepared photomask is transferred to the photoresist and hard mask layers by etching technology, and Al ions are implanted by ion implantation technology to form the designed doped columns with lightly doped P-type conductivity, with a doping concentration of 1×10 16 cm -3 The mask size was adjusted, and epitaxy and ion implantation were repeated many times, finally forming a superjunction structure with a depth of 10 μm and multiple partially widened P columns; CVD epitaxial growth of a lightly doped P-type conductivity epitaxial layer was performed on the obtained structure, with a doping concentration of 2×10 17 cm -3, with a thickness of 1 μm; the pattern of the prepared photomask was transferred to the photoresist and hard mask layers by etching technology, and Al ions were implanted by ion implantation technology to form the designed heavily doped P-type conductive type ohmic contact region with a doping concentration of 1×10 19 cm -3 , with a depth of 0.2 μm; the pattern of the prepared photomask was transferred to the photoresist and hard mask layers by etching technology, and N ions were implanted by ion implantation technology to form the designed heavily doped N-type conductive source region with a doping concentration of 1×10 19 cm -3 , with a depth of 0.2 μm; the pattern of the prepared photomask was transferred to the photoresist and hard mask layers by etching technology, and the designed groove part, namely the groove gate structure, was prepared by reactive ion etching technology and chemical etching, and the obtained groove depth was 2 μm; Al ions were injected by ion implantation technology, and annealing was performed to push the well, and the designed P-type doped groove gate protection area, namely the gate protection area, was obtained, with a doping concentration of 8×10 17 cm -3 , with a thickness of 0.3 μm; a gate oxide layer with a thickness of 50 nm is grown around the inner wall of the trench by dry oxygen oxidation technology; polysilicon is deposited by chemical vapor deposition and the trench is filled with photolithography to prepare a polysilicon gate; BPSG is deposited to form an interlayer isolation dielectric to isolate the gate from the source metal layer; Ni and AlCu alloy are sputtered on the front side as the source metal layer, and the source metal layer forms an ohmic contact with the source region and the ohmic contact region 50; Ni and AlCu alloy are sputtered on the back side as the drain metal layer, and the drain metal layer forms an ohmic contact with the N-type heavily doped substrate drain region.

[0109] It should be noted that by changing the process of preparing the super junction structure of the power device, by changing the P-type doped column ion implantation window and the ion implantation process, it is possible to form convex widening areas of different sizes, numbers and thicknesses, so as to adjust the device performance according to the needs and make a compromise between the conduction current capability and the short-circuit reliability. Figure 3 The process flow shown can be prepared according to the above method. The difference is that when performing layer-by-layer epitaxy and ion implantation, the window size and ion implantation process are adjusted, and finally a partially widened, protruding and widened area is obtained which widens from top to bottom. The rest of the process flow is exactly the same.

[0110] A third aspect of the present invention provides an electronic device, comprising at least one power device according to the above embodiment.

[0111] According to the electronic equipment of the embodiment of the utility model, the risk of short circuit thermal failure can be reduced and the reliability of the power device can be improved by adopting the power device of the above embodiment.

[0112] A fourth aspect of the present invention provides a vehicle, comprising the electronic device of the above embodiment.

[0113] According to the vehicle of the embodiment of the utility model, the risk of short circuit thermal failure can be reduced and the reliability of power devices can be improved by adopting the electronic equipment of the above embodiment.

[0114] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0115] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A power device, characterized in that: include: a substrate of a first conductivity type; A drift region of a first conductivity type is located on the substrate in a first direction, and a side surface of the drift region has at least one recess in a second direction, wherein the first direction is perpendicular to the second direction.

2. The power device according to claim 1, characterized in that: The power device further comprises: a doped column of a second conductivity type; In the first direction, the drift region and the doped column are both located on the substrate, and the doped column and the drift region are arranged and connected along the second direction; In the second direction, the doped column has at least one protruding widening region on a side facing the drift region.

3. The power device according to claim 2, characterized in that: The convex widened area is matched with the concave area.

4. The power device according to claim 2 or 3, characterized in that: A side of the doped column facing the drift region has a plurality of the protruding widened regions, and the plurality of the protruding widened regions are distributed at intervals along the first direction.

5. The power device according to claim 4, characterized in that: The heights of the plurality of protruding widened areas along the first direction are the same.

6. The power device according to claim 4, characterized in that: At least two of the plurality of protruding widening regions have different heights along the first direction.

7. The power device according to claim 4, characterized in that: The widths of the plurality of protruding widened areas along the second direction are the same.

8. The power device according to claim 4, characterized in that: At least two of the plurality of protruding widened regions have different widths along the second direction.

9. The power device according to claim 4, characterized in that: Starting from the protruding widening region close to the substrate along the second direction, heights of the plurality of protruding widening regions along the first direction gradually decrease.

10. The power device according to claim 4, characterized in that: The number of the plurality of protruding widened areas is an even number.

11. The power device according to claim 8, characterized in that: The number N of the plurality of protruding widened areas satisfies: 2≤N≤10.

12. The power device according to claim 2, characterized in that: The doped column comprises: A first doped column and a second doped column, wherein the first doped column and the second doped column are located at two sides of the drift region along the second direction.

13. The power device according to claim 12, characterized in that: A height of the protruding widening region of the first doped column along the first direction is the same as or different from a height of the protruding widening region of the second doped column along the first direction.

14. The power device according to claim 12, characterized in that: A width of the protruding widening region of the first doped column along the second direction is the same as or different from a width of the protruding widening region of the second doped column along the second direction.

15. The power device according to claim 12, characterized in that: The number of the protruding widening regions of the first doped column is equal to or unequal to the number of the protruding widening regions of the second doped column.

16. The power device according to claim 2, characterized in that: A thickness of the drift region along the first direction is equal to a thickness of the doped column along the first direction.

17. The power device according to claim 1, characterized in that: The power device further comprises: a base region of a second conductivity type, the base region being located at a side of the drift region and the doped column away from the substrate and contacting the doped column and the drift region respectively; An ohmic contact region of a second conductivity type, the ohmic contact region being located on a side of the base region away from the substrate; a source region of a first conductivity type, the source region being located at a side of the base region away from the substrate, and the ohmic contact region being located outside the source region in the second direction; a trench gate structure, wherein the trench gate structure penetrates the source region and the base region along the first direction and extends to the drift region; A source metal layer, wherein the source metal layer covers the ohmic contact region, the source region and the trench gate structure; A drain metal layer is located on a side of the substrate away from the drift region.

18. The power device according to claim 17, characterized in that: The trench gate structure comprises: a gate trench, wherein the gate trench penetrates the source region and the base region along the first direction and extends to the drift region; A gate oxide layer, wherein the gate oxide layer is located on an inner wall of the gate trench; A gate, the gate being formed on the surface of the gate oxide layer and filling the gate trench; An isolation dielectric is formed between the source metal layer and the gate and between the source metal layer and the gate oxide layer.

19. The power device according to claim 18, characterized in that: The trench gate structure further includes: A gate protection zone is located in the drift region and wraps the bottom of the gate oxide layer in the gate trench.

20. An electronic device, characterized in that: Comprising at least one power device according to any one of claims 1 to 19.

21. A vehicle, characterized in that: An electronic device comprising the electronic device described in claim 20.

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