Carrier storage layer IGBT device with shielding gates

Abstract

The invention provides a carrier storage layer IGBT (insulated gate bipolar transistor) device with shielding gates. According to the invention, under the condition that the cell width of the device is kept at a certain value, the distance between trench gates is reduced by adding a floating shielding gate on the two sides of an original trench gate. Meanwhile, the grid-emitter capacitance and thegrid-collector capacitance of the device are also reduced, and the switching speed of the device is increased. The switching loss is reduced. Meanwhile, the saturation current density of the device is reduced, so that the short-circuit working area is improved. The voltage-withstanding performance of the device is improved. By reasonably adjusting the concentration thickness of the carrier storage area and the distance between shielding gates, the grid-emitter capacitance and the grid-collector capacitance of the device are reduced under the condition that the breakdown voltage is the same asthat of a conventional carrier storage trench bipolar transistor. As a result, the effect of improving the switching speed is achieved.

Description

technical field [0001] The invention belongs to the technical field of power devices, and relates to an insulated gate bipolar transistor (IGBT), in particular to a trench gate carrier storage type insulated gate bipolar transistor (CSTBT). Background technique [0002] In recent years, with the rapid development of microelectronics technology, society has continuously increased the requirements for the most advantageous power devices in electronic power, and the advantages of insulated gate bipolar transistors, one of the representatives of power devices, have attracted widespread attention. 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 pow...

AI Technical Summary

Problems solved by technology

However, for CSTBT devices, the newly added N-type carrier storage layer with high concentration and certain thickness makes the breakdown voltage of the device significantly lower

Therefore, in order to effectively shield the negative impact of the N-type carrier storage layer on the device withstand voltage, two methods are generally adopted: 1. Increase the depth of the trench, which means that the depth of the trench gate is greater than that of the N-type carrier storage layer. Deep; 2. Reduce the width of the cell, so that the distance between the trench gates is as small as possible; however, these two methods will make the gate-emitter capacitance (Cge) and gate-collector capacitance (Cgc) of the device significantly increase

On the one hand, a large capacitance reduces the switching speed of the device, increases the switching loss of the device, and affects the compromise between the forward conduction voltage drop and switching loss of the device. On the other hand, it increases the saturation current density of the device, making the device The breaking characteristics of the circuit become worse

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