A bidirectional trench gate charge storage type igbt and its manufacturing method

A technology of charge storage and charge storage layer, which is applied in the manufacture of circuits, electrical components, semiconductor/solid-state devices, etc., and can solve the problems of increasing charging/discharging time, reducing device breakdown voltage, and increasing gate capacitance, etc.

Active Publication Date: 2020-08-28
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, there are still obvious defects in the implementation of the above means: the implementation of the method (1) will increase the gate-emitter capacitance and the gate-collector capacitance, and the switching process of the IGBT is essentially charging / discharging the gate capacitance Therefore, the increase of gate capacitance will increase the charging / discharging time, which in turn will cause the switching speed to decrease
However, the size of the MOS capacitance in the device is inversely proportional to the thickness of the gate oxide layer, which will lead to a significant increase in the gate capacitance in the traditional CSTBT device. In addition, the electric field concentration effect at the bottom of the trench will also reduce the breakdown voltage of the device, resulting in The reliability of the device is poor

Method used

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  • A bidirectional trench gate charge storage type igbt and its manufacturing method
  • A bidirectional trench gate charge storage type igbt and its manufacturing method
  • A bidirectional trench gate charge storage type igbt and its manufacturing method

Examples

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Effect test

Embodiment 1

[0084] A bidirectional trench gate charge storage type IGBT, one half of its cells are as Figure 4 As shown, its section along AB line and CD line is as follows Image 6 with Figure 7 As shown, a three-dimensional coordinate system is established with any inflection point of one-half cell as the origin, and the bottom surface of one-quarter cell intersects with the two sides of the inflection point as the x-axis and z-axis respectively, passing through the inflection point and A straight line perpendicular to the bottom surface is used as the y-axis, and the directions of the x, y, and z-axes refer to Figure 4 ;

[0085] The half cell includes MOS structures respectively arranged on the front and back of the N-type drift region 9; it is characterized in that: the front MOS structure includes a front emitter metal 1, a front isolation dielectric layer 2, and a front split trench gate structure , the front first conductivity type semiconductor emitter region 3, the front sid...

Embodiment 2

[0089] A bidirectional trench gate charge storage type IGBT, one half of its cells are as Figure 8 As shown, its section along AB line, CD line, EF line and GH line is as follows Figures 10 to 13 As shown, the establishment method of the coordinate system is as in the embodiment, see for details Figure 8 ;

[0090] The difference between this embodiment and Embodiment 1 is that the extension depth of the front gate electrode 71 in the top layer of the N-type drift region 9 in this embodiment is equal to the extension depth of the front split electrode 81, and the extension width of the front gate electrode 71 in the top layer of the device It is less than the extension width of the front split electrode 81, and at the same time, a part of the front split electrode dielectric layer 82 and a part of the front split electrode 81 structure are retained on the top layer of the device; the thickness of the front split electrode dielectric layer 82 is greater than the thickness o...

Embodiment 3

[0093] A bidirectional trench gate charge storage type IGBT, one half of its cells are as Figure 14 As shown, its section along AB line, CD line, EF line and GH line is as follows Figures 16 to 19 As shown, the establishment method of the coordinate system is as in the embodiment, see for details Figure 14 ;

[0094] The difference between this embodiment and Embodiment 2 is that in this embodiment, the front split electrode 81 and the split electrode dielectric layer 82 are not provided on the top layer of the device front MOS structure, and the front split electrode 81 and the front split electrode dielectric layer 82 are located on the front gate electrode. 71 bottom, the front N+ emitter region 3 and the front P+ body contact region 4 have the same depth along the z-axis direction and are less than the depth of the front P-type base region 5 along the z-axis direction, and at the same time pass the front gate dielectric layer 72 with the front N+ emitter region 3 The ...

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Abstract

A bidirectional trench gate charge storage type IGBT and a manufacturing method thereof belong to the technical field of power semiconductor devices. By reducing the depth of the emitter region extending along the top layer of the base region in the traditional bidirectional trench gate charge storage type IGBT structure, and introducing a split trench gate structure, the split trench gate structure includes the gate electrode and its surrounding gate dielectric layer and The split electrode located at the bottom of the gate electrode and connected with the gate dielectric layer and its surrounding split electrode dielectric layer, the split electrode is equipotential to the emitter metal. The device structure proposed by the present invention improves the overall performance of the device while realizing symmetrical forward / reverse conduction and turn-off characteristics, and can avoid the limitation of the doping concentration and thickness of the charge storage layer on the device withstand voltage, while improving the performance of the device. The short-circuit safe working area of ​​the device, temperature characteristics, the trade-off relationship between the device's forward conduction voltage drop Vceon and the turn-off loss Eoff, avoids the current, voltage oscillation and EMI problems in the dynamic process of device opening, and improves the reliability of the device sex.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, and relates to an insulated gate bipolar transistor (IGBT), in particular to a bidirectional trench gate charge storage type insulated gate bipolar transistor (Bi-directional CSTBT). Background technique [0002] Insulated gate bipolar transistor (IGBT) is a new type of power electronic device developed on the basis of the development of power MOSFET and power bipolar junction transistor (BJT), which is equivalent to a MOSFET driven by bipolar junction transistor (BJT). IGBT has the advantages of both power MOSFET structure and bipolar junction transistor (BJT) structure: it has the advantages of easy driving of power MOSFET, low input impedance and fast switching speed, and has the on-state current density of bipolar junction transistor (BJT) Large, low conduction voltage, low loss, and good stability. Based on these excellent device characteristics, IGBT has become a mainst...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L29/739H01L21/331H01L29/06
CPCH01L29/0611H01L29/0684H01L29/66325H01L29/7393
Inventor 张金平赵倩赵阳刘竞秀李泽宏张波
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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