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

A charge storage and charge storage layer technology, applied in circuits, electrical components, semiconductor/solid-state device manufacturing, etc., can solve problems such as reducing device breakdown voltage, reducing switching speed, and increasing charge/discharge time to improve overall performance. Effect

Active Publication Date: 2020-06-30
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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  • 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

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0096] This embodiment 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 Figure 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 ;

[0097] The quarter 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, a front trench gate structure, The front shield trench structure, the front N+ emitte...

Embodiment 2

[0101] This embodiment 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 ;

[0102] Compared with Embodiment 1, the difference of this implementation is that: the front P-type layer 10 is introduced at the bottom of the front shield trench structure, and the front P-type layer 10 and the front shield electrode 81 are connected through the front shield electrode dielectric layer 82, so The improvement of ...

Embodiment 3

[0104] This embodiment 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 ;

[0105] Compared with Embodiment 2, the difference of this implementation is that the front side wall gate electrode 71 extends from one end of the device to the other end along the z-axis, that is, the upper half of the front shield trench structure is protected by the front trench gate structure along the z-axis. The directio...

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Abstract

A bidirectional trench gate charge storage type IGBT belongs to the technical field of semiconductor power devices. By widening the traditional trench gate structure and adopting the sidewall gate electrode structure to form a mesa structure under the base region and introducing a shielding trench structure, the present invention realizes the symmetrical forward / reverse conduction and turn-off characteristics of the device At the same time, it increases the carrier injection enhancement effect and improves the forward conduction voltage drop V ceon and turn-off loss E off The compromise between; alleviate the electric field concentration effect at the sharp corner of the bottom of the trench, effectively improve the breakdown voltage of the device; reduce the gate capacitance of the device, thereby improving the switching speed of the device, reducing the switching loss of the device and the Requirements for the capability of the gate drive circuit; avoiding the limitation of the doping concentration and thickness of the N-type charge storage layer on the device withstand voltage; reducing the saturation current density and improving the short-circuit safe working area of ​​the device; and effectively inhibiting the device from being turned on EMI effect. In addition, the manufacturing method provided by the present invention is compatible with the traditional CSTBT manufacturing method.

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 CSTBT). Background technique [0002] The insulated gate bipolar transistor (IGBT) was invented and realized by introducing a PN junction into the back substrate of the power MOSFET structure in the late 1970s and early 1980s based on the research of power MOSFET, BJT and SCR / GTO. mass-produced. The conductance modulation effect introduced by the PN junction on the back of the device when it is turned on makes the IGBT a new type of power electronic device that combines a MOS field effect transistor and a bipolar junction transistor (BJT), and can also be equivalent to a bipolar junction transistor (BJT). drive the MOSFET. IGBT combines the characteristics of both MOSFET and BJT: not only has the advantages of high input impedance, low control power, easy to dri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L29/739H01L29/40H01L21/331
CPCH01L29/407H01L29/66348H01L29/7397
Inventor 张金平赵倩王康刘竞秀李泽宏张波
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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