Bidirectional trench gate charge storage IGBT and manufacturing method therefor

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 problems such as poor device reliability, increased gate capacitance, and reduced device breakdown voltage

Active Publication Date: 2018-08-28
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] 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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  • Bidirectional trench gate charge storage IGBT and manufacturing method therefor
  • Bidirectional trench gate charge storage IGBT and manufacturing method therefor
  • Bidirectional trench gate charge storage IGBT and manufacturing method therefor

Examples

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Effect test

Embodiment 1

[0104] The invention provides a bidirectional trench gate charge storage type IGBT, one quarter of the cell is as Figure 4 As shown, the section along AB line and A'B' line is as follows Image 6 and Figure 7 As shown, a three-dimensional coordinate system is established with any inflection point of the quarter cell as the origin, and the bottom surface of the 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 ;

[0105] The quarter cell includes a MOS structure symmetrically 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, a front trench gate structure, The front shield trench structure, the front N+ emitter...

Embodiment 2

[0111] The invention provides a bidirectional trench gate charge storage type IGBT, one quarter of the cell is as Figure 8 As shown, the section along AB line and A'B' line is as follows Figure 10 and Figure 11 As shown, a three-dimensional coordinate system is established with any inflection point of the quarter cell as the origin, and the bottom surface of the 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 8 ;

[0112] Compared with Example 1, the difference of this implementation is that the first P-type layer 10 is introduced at the bottom of the front shield trench structure, the first P-type layer 10 is connected to the gate electrode 81 through the gate dielectric layer 82, and the back shield The trench structure is the same as the ...

Embodiment 3

[0115] The invention provides a bidirectional trench gate charge storage type IGBT, one quarter of the cell is as Figure 12 As shown, the section along AB line and A'B' line is as follows Figure 14 and Figure 15 As shown, a three-dimensional coordinate system is established with any inflection point of the quarter cell as the origin, and the bottom surface of the 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 12 ;

[0116] Compared with Embodiment 2, the difference of this implementation is that in the front MOS structure, the front shielding electrode 71 extends from one end of the device to the other along the x-axis, and the front gate electrode 81 extends from one end of the device to the front shielding electrode along the z-axis. The ...

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Abstract

The invention discloses a bidirectional trench gate charge storage IGBT, and belongs to the technical field of semiconductor power devices. A shielding trench structure having the same potential as anemitter metal is introduced on the basis of a conventional bidirectional CSTBT device structure, and the trench depth is enabled to be greater than the thickness of a charge storage layer, so as to shield the electric field of the charge storage layer. The introduction of the shielding trench structure achieves the effective charge compensation for the charge storage layer, thereby reducing the constraint, caused by the doping concentration and thickness of the charge storage layer, on the withstand voltage of a device, and improving the breakdown voltage of the device. The improvement of thecompromise relation between a forward voltage drop Vceon of the device and the turn-off loss Eoff is facilitated, and a wider short-circuit safety work region is obtained, thereby facilitating the reduction of the saturation current intensity of the device, and further improving the short-circuit safety work region of the device. In addition, the IGBT remarkably reduces the gate capacitance of the device, especially the gate-collector capacitance, thereby improving the switching speed of the device, and reducing the turn-off loss of the device and the requirements for the capability of a gatedrive circuit.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, in particular to a bidirectional trench gate charge storage type insulated gate bipolar transistor (Bi-directional trench IGBT). Background technique [0002] Insulated gate bipolar transistor (IGBT) is a new type of power electronic device developed based on the research 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 mainstream power device widely used in medium and high voltage fields ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L29/40H01L29/423H01L29/739H01L21/331H01L21/28
CPCH01L29/407H01L29/4236H01L29/66348H01L29/7397H01L29/7398
Inventor 张金平赵倩罗君轶刘竞秀李泽宏张波
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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