Trench gate charge storage-type IGBT device with clamp structure and manufacturing method thereof

Abstract

The invention discloses a trench gate charge storage-type IGBT device with a clamp structure and a manufacturing method thereof, which belong to the field of semiconductor power devices. A clamp electrode connected with emitter metal through a series diode structure is introduced below a gate electrode in the device trench, and a connected P-type layer is arranged below the clamp electrode. Negative influences on the voltage withstanding performance of the device by improvement of the doping concentration of an N-type charge storage layer can be effectively shielded, and the contradiction between forward conduction and voltage withstanding of the traditional CSTBT structure is overcome; the saturation current density of the device is reduced, and the device short circuit safe working areais improved; the device switching speed is improved, and the device switching loss is reduced; negative differential capacitance effects are not formed during an opening dynamic process, current and voltage oscillation and an EMI problem during the opening dynamic process can be effectively avoided, and the device reliability is improved; and the electric field concentration effects at the bottomof the trench are improved, and the breakdown voltage of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor power devices, in particular to an insulated gate bipolar transistor (IGBT), in particular to a trench gate charge storage type insulated gate bipolar transistor (CSTBT) with a clamping structure and its manufacture method. Background technique [0002] Insulated gate bipolar transistor (IGBT), as one of the core electronic components in modern power electronic circuits, is widely used in various fields such as transportation, communication, household appliances, and aerospace. Insulated gate bipolar transistor (IGBT) is a new type of power electronic device composed of an insulated field effect transistor (MOSFET) and a bipolar junction transistor (BJT), which can be equivalent to a MOSFET driven by a bipolar junction transistor. . IGBT combines the working mechanism of MOSFET structure and bipolar junction transistor. It not only has the advantages of MOSFET easy to drive, low input impe...

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Problems solved by technology

[0005] The implementation of method (1) will increase the gate-emitter capacitance and gate-collector capacitance at the same time, and the switching process of the IGBT is essentially the process of charging / discharging the gate capacitance, so the increase in the gate capacitance will Makes the charging / discharging time longer, which in turn causes the switching speed to decrease

Therefore, the deep trench gate depth will reduce the switching speed of the device, increase the switching loss of the device, and affect the compromise characteristics of the device's conduction voltage drop and switching loss; and the implementation of method (2) will increase the device's switching loss The gate capacitance will reduce the switching speed of the device and increase the switching loss, which will affect the compromise between the conduction voltage drop and switching loss of the device. On the other hand, it will also increase the saturation current density of the device and make the short-circuit safe working area of ​​the device worse.

In addition, the gate oxide layer in the trench gate structure is formed in the trench by one thermal oxidation. In order to ensure a certain threshold voltage, the thickness of the entire gate oxide layer is required to be small. However, the MOS capacitance and the thickness of the oxide layer Inversely proportional, which makes the thin gate oxide thickness in traditional CSTBT devices will significantly increase the gate capacitance of the device, and the electric field concentration effect at the bottom of the trench will reduce the breakdown voltage of the device, resulting in poor reliability of the device

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