Double-split groove gate charge storage type IGBT and manufacturing method thereof

Abstract

The invention belongs to the technical field of a power semiconductor device and specifically relates to a groove gate charge storage type IGBT (insulated gate bipolar transistor). The bottom and side surfaces of a gate electrode in a groove of the device are provided with a double-split electrode equipotential with an emitter and a dielectric layer between the double-split electrode and the gate electrode, so that under the condition of not influencing threshold voltage and turning on of the IGBT device, grid capacitance is reduced, switching speed of the device is improved, and switching loss of the device is reduced; and meanwhile, the side-surface split electrode and a floating p-type base region at one side of the side-surface split electrode improve short circuit safety operation area of the device and carrier concentration distribution of the whole N drifting region, thereby improving performance and reliability of the device. The double-split groove gate charge storage type IGBT manufacturing method does not need extra processing steps, and is compatible with a conventional CSTB manufacturing 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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