A double split trench gate charge storage type igbt and its manufacturing method

Abstract

The invention belongs to the technical field of power semiconductor devices, and in particular relates to a trench gate charge storage type insulated gate bipolar transistor. In the present invention, by introducing a double split electrode with equal potential to the emitter and a dielectric layer between the double split electrode and the gate electrode at the bottom and side of the gate electrode in the device trench, without affecting the threshold voltage and turn-on of the IGBT device, The gate capacitance is reduced, thereby increasing the switching speed of the device and reducing the switching loss of the device; at the same time, the wide bottom split electrode and floating p-type base region further improve the carrier concentration distribution of the entire N-type drift region, and The short-circuit safe working area and breakdown characteristics of the device are improved, and the performance and reliability of the device are improved. The method for fabricating the double-split trench gate charge storage IGBT proposed by the present invention does not require additional process steps, and is compatible with the conventional CSTBT fabrication method.

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 trench gate charge storage type insulated gate bipolar transistor (CSTBT). Background technique [0002] Insulated Gate Bipolar Transistor (IGBT) is a new type of power electronic device combining MOS field effect and bipolar transistor. It not only has the advantages of easy driving and simple control of MOSFET, but also has the advantages of low conduction voltage of power transistor, large on-state current and small loss. It has become one of the core electronic components in modern power electronic circuits and is widely used in Various fields of the national economy such as communications, energy, transportation, industry, medicine, household appliances and aerospace. The application of IGBT plays an extremely important role in improving the performance of power electronic systems. [0003] S...

AI Technical Summary

Problems solved by technology

However, for the CSTBT device structure, due to the existence of a higher doping concentration and a certain thickness of the N-type charge storage layer, the breakdown voltage of the device is significantly reduced. In order to effectively shield the adverse effects of the N-type charge storage layer to obtain a certain device withstand voltage , it is necessary to adopt: 1) deep trench gate depth, so that the depth of the trench gate is greater than the junction depth of the N-type charge storage layer, but the deep trench gate depth not only increases the gate-emitter capacitance, but also increases Therefore, the switching speed of the device is reduced, the switching loss of the device is increased, and the compromise characteristics of the conduction voltage drop and switching loss of the device are affected; 2) the small cell width makes the channel The distance between the trench gates should be reduced as much as possible. However, the high-density trench MOS structure not only increases the gate capacitance of the device, but also reduces the switching speed of the device, increases the switching loss of the device, and affects the conduction of the device. The trade-off characteristics of on-voltage drop and switching loss, and increase the saturation current density of the device, making the short-circuit safe working area of ​​the device worse

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