CN210723036U

CN210723036U - Power device with super-junction structure

Info

Publication number: CN210723036U
Application number: CN201921484238.0U
Authority: CN
Inventors: 曾爱平
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2020-06-09
Anticipated expiration: 2029-09-05

Abstract

The utility model belongs to the technical field of microelectronics, a power device of super junction structure is disclosed, in the longitudinal direction of power device, the semiconductor substrate includes first drift layer, second drift layer, third drift layer, substrate from top to bottom in proper order; the second drift layer comprises a plurality of pairs of first semiconductor columns of the second conductivity type and second semiconductor columns of the first conductivity type, the plurality of pairs of first semiconductor columns and the plurality of pairs of second semiconductor columns are arranged in the second drift layer in a staggered mode, and the first semiconductor columns extend in the direction close to the substrate in the second drift layer; arranging a grid of the second conductivity type in a third drift layer below the first semiconductor column in a transverse direction of the power device; the super junction structure comprises a plurality of first semiconductor columns, a plurality of second semiconductor columns, a second drift layer, a third drift layer and a grid; the breakdown voltage is improved, and meanwhile, the on-resistance is reduced, so that the switching speed of the power device is improved; the performance of the power device and the system applying the power device is improved.

Description

Power device with super-junction structure

Technical Field

The utility model belongs to the technical field of the microelectronics, especially, relate to super junction structure's power device.

Background

The power device with the super junction structure in the traditional market comprises a cell area located in the central area of a semiconductor substrate and a terminal protection area arranged outside the cell area in a surrounding mode, wherein the cell area comprises a plurality of cells regularly distributed in a first drift layer of a first conduction type; in the longitudinal direction of the power device, the semiconductor substrate comprises a first drift layer, a second drift layer of the first conduction type, a third drift layer of the first conduction type and a substrate of the first conduction type, wherein the second drift layer is located below the first drift layer, the third drift layer of the first conduction type is located below the second drift layer, the substrate of the first conduction type is located below the third drift layer of the first conduction type, the second drift layer comprises a plurality of pairs of first semiconductor columns of the second conduction type and second semiconductor columns of the first conduction type, the first semiconductor columns and the second semiconductor columns are arranged in the second drift layer of the first conduction type in a staggered mode, and the first semiconductor columns extend towards the direction close to the substrate in the second drift layer. Since the super junction structure is formed by only a plurality of pairs of the first semiconductor columns of the second conductivity type and the second semiconductor columns of the first conductivity type, the breakdown voltage cannot be increased while the on-resistance cannot be reduced, and thus the power device of the super junction structure and the system to which the power device is applied have poor reliability.

The conventional power device with the super junction structure has the defect that the reliability of the power device with the super junction structure and an applied system thereof is poor because the super junction structure is formed by only a plurality of pairs of first semiconductor columns with the second conductivity type and second semiconductor columns with the first conductivity type, and the on-resistance cannot be reduced while the breakdown voltage is improved.

SUMMERY OF THE UTILITY MODEL

The utility model provides a super junction structure's power device aims at solving only many second semiconductor columns to the first semiconductor column of second conductivity type and first conductivity type that exist in the power device of traditional technique super junction structure and forms super junction structure, can't reduce on-resistance when improving breakdown voltage to lead to super junction structure's power device and the problem that applied system reliability is poor.

The utility model discloses a realize like this, including the cell district that is located the central zone of semiconductor substrate and enclose and establish the terminal protection zone that is located the cell district outside, the cell district includes a plurality of rules and arranges the cell in first drift layer of first conductivity type; in a longitudinal direction of the power device, the semiconductor substrate includes the first drift layer, a second drift layer of the first conductivity type located below the first drift layer, a third drift layer of the first conductivity type located below the second drift layer, and a substrate of the first conductivity type located below the third drift layer of the first conductivity type, the second drift layer includes a plurality of pairs of first semiconductor pillars of the second conductivity type and second semiconductor pillars of the first conductivity type, the pairs of first semiconductor pillars and second semiconductor pillars are arranged alternately in the second drift layer of the first conductivity type, and the first semiconductor pillars extend in the second drift layer to a direction close to the substrate; providing a grid of a second conductivity type in the third drift layer below the first semiconductor pillar in a lateral direction of the power device;

the super junction structure includes a plurality of the first semiconductor pillars, a plurality of the second semiconductor pillars, the second drift layer, the third drift layer, and the grid.

In one embodiment, the grid includes a plurality of bars disposed below and corresponding to the plurality of first semiconductor pillars one to one, and a frame surrounding the plurality of bars.

In one embodiment, distances between the plurality of first semiconductor columns are equal, distances between the plurality of semiconductor turns of the terminal protection region are equal, and distances between the plurality of first semiconductor columns are greater than distances between the plurality of semiconductor turns of the terminal protection region.

The embodiment of the utility model provides a through in the horizontal direction of power device, set up the grid of second conductivity type in the third drift layer below the first semiconductor post; the super junction structure comprises a plurality of first semiconductor columns, a plurality of second semiconductor columns, a second drift layer, a third drift layer and grids, the breakdown voltage of the terminal protection region is greater than that of the cell region, and the cell region has smaller on-resistance, so that the on-resistance is reduced while the breakdown voltage is improved; the power device with the super junction structure and the system performance applied by the power device are effectively improved. The power device only comprises three drift layers, so that the manufacturing process is simplified while the breakdown voltage is ensured.

Drawings

In order to more clearly illustrate the technical utility model in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a top plan view of a super junction structure power device provided in an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a longitudinal cross section of a super junction structure power device provided in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a cross section of a super junction structure power device provided in an embodiment of the present invention;

the designations in the above figures have the following meanings:

01-cellular region; 02-terminal protection area; 101-a first drift layer of a first conductivity type; 102-a cell; 103-a second drift layer of the first conductivity type; 104-a third drift layer of the first conductivity type; 105-a substrate of a first conductivity type; 106-a first semiconductor pillar of a second conductivity type; 107-a second semiconductor pillar of the first conductivity type; 108-a grid of a second conductivity type; 109-a semiconductor ring of a second conductivity type; 110-grid bars; 111-frame.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

Fig. 1 shows a module structure of a power device with a super junction structure provided by an embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:

as shown in fig. 1, the power device with the super junction structure includes a cell region 01 located in a central region of a semiconductor substrate and a terminal protection region 02 defined outside the cell region 01, where the cell region 01 includes a plurality of cells 102 regularly arranged in a first drift layer 101 of a first conductivity type; in the longitudinal direction of the power device, as shown in fig. 2, the semiconductor substrate includes a first drift layer 101, a second drift layer 103 of the first conductivity type located below the first drift layer 101, a third drift layer 104 of the first conductivity type located below the second drift layer 103, and a substrate 105 of the first conductivity type located below the third drift layer 104, the second drift layer 103 includes a plurality of pairs of first semiconductor pillars 106 of the second conductivity type and second semiconductor pillars 107 of the first conductivity type, the plurality of pairs of first semiconductor pillars 106 and second semiconductor pillars 107 are alternately arranged in the second drift layer 103, and the first semiconductor pillars 106 extend in the second drift layer 103 in a direction close to the substrate 105; in the lateral direction of the power device, as shown in fig. 3, a grid 108 of the second conductivity type is provided within the third drift layer 104 below the first semiconductor pillar 106; the super junction structure includes a plurality of first semiconductor pillars 106, a plurality of second semiconductor pillars 107, a second drift layer 103, a third drift layer 104, and a grid 108.

By arranging the grid 108 of the second conductivity type in the third drift layer 104 below the first semiconductor pillars 106 and applying a reverse bias voltage to the drift layer, a lateral electric field is generated by the plurality of first semiconductor pillars 106 of the second conductivity type and the plurality of second semiconductor pillars 107 of the first conductivity type, so that the pn junction is depleted, and the on-resistance is greatly reduced. And, through the depth of the longitudinal stretching electric field, prevent the surface from exchanging the electric charge, has kept the stability of the breakdown voltage.

The power device only comprises three drift layers, so that the manufacturing process is simplified while the breakdown voltage is ensured.

In a specific implementation, the first conductivity type is N-type, and the second conductivity type is P-type. In a second case, the first conductivity type is P-type and the second conductivity type is N-type.

In an implementation, the grid 108 includes a plurality of bars 110 disposed below the plurality of first semiconductor pillars 106 and corresponding to the plurality of first semiconductor pillars 106 one to one, and a frame 111 surrounding the plurality of bars 110.

The pass grid 108 includes a plurality of bars 110 disposed below the plurality of first semiconductor pillars 106 and corresponding to the plurality of first semiconductor pillars 106 one to one, and a frame surrounding the plurality of bars 110, so that PN junctions formed by the plurality of first semiconductor pillars 106 of the second conductivity type, the plurality of second semiconductor pillars 107 of the first conductivity type, the second drift layer 103 of the first conductivity type, the third drift layer 104 of the first conductivity type, and the grid layer 108 of the second conductivity type are uniformly distributed, and thus the super junction structure formed is more stable.

In a specific implementation, the distances between the plurality of first semiconductor pillars 106 are equal, the distances between the plurality of semiconductor turns 109 of the termination protection region are equal, and the distances between the plurality of first semiconductor pillars 106 are greater than the distances between the plurality of semiconductor turns 109 of the termination protection region.

The distance between the plurality of first semiconductor columns of the second conduction type is larger than the distance between the plurality of semiconductor rings of the second conduction type of the terminal protection area, so that the breakdown voltage of the terminal protection area is larger than the breakdown voltage of the cell area, the on-resistance is reduced, and the breakdown voltage is improved.

The embodiment of the utility model provides a through in the horizontal direction of power device, set up the grid of second conductivity type in the third drift layer of first conductivity type below the first semiconductor post of second conductivity type; the super junction structure includes a plurality of first semiconductor pillars of a second conductivity type, a plurality of second semiconductor pillars of a first conductivity type, a second drift layer of the first conductivity type, a third drift layer of the first conductivity type, and a grid layer of the second conductivity type; the breakdown voltage of the terminal protection area is greater than that of the cell area, and the cell area has smaller on-resistance, so that the on-resistance is reduced while the breakdown voltage is improved, and the reliability of the power device with the super-junction structure and the system applying the power device are effectively improved. The power device only comprises three drift layers, so that the manufacturing process is simplified while the breakdown voltage is ensured.

The above description is only for the preferred embodiment of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A power device with a super junction structure comprises a cell area located in the central area of a semiconductor substrate and a terminal protection area arranged outside the cell area in a surrounding mode, wherein the cell area comprises a plurality of cells regularly arranged in a first drift layer of a first conduction type; in a longitudinal direction of the power device, the semiconductor substrate includes the first drift layer, a second drift layer of the first conductivity type located below the first drift layer, a third drift layer of the first conductivity type located below the second drift layer, and a substrate of the first conductivity type located below the third drift layer of the first conductivity type, the second drift layer includes a plurality of pairs of first semiconductor pillars of the second conductivity type and second semiconductor pillars of the first conductivity type, the pairs of first semiconductor pillars and second semiconductor pillars are arranged alternately in the second drift layer of the first conductivity type, and the first semiconductor pillars extend in the second drift layer to a direction close to the substrate; wherein a grid of a second conductivity type is provided in the third drift layer below the first semiconductor pillar in a lateral direction of the power device;

2. The power device of the super junction structure of claim 1, wherein the grid comprises a plurality of bars disposed below and in one-to-one correspondence with the plurality of first semiconductor pillars and a frame surrounding the plurality of bars.

3. The power device of the super junction structure according to claim 1, wherein distances between the plurality of first semiconductor columns are equal, distances between the plurality of semiconductor turns of the termination protection region are equal, and distances between the plurality of first semiconductor columns are greater than distances between the plurality of semiconductor turns of the termination protection region.