A superjunction IGBT with a shielded gate and a manufacturing method thereof

Abstract

The invention discloses a superjunction IGBT with a shield gate and a manufacturing method thereof. The superjunction IGBT comprises a semiconductor substrate, a cell region and a terminal protectionarea. The semiconductor substrate comprises a second conductivity type collector region, a first conductivity type field termination layer and at least one first conductivity type epitaxial layer. Thecell region comprises a plurality of cells connected in parallel with each other, which includes a plurality of cell trenches and a gate conductive polysilicon and a shield gate filled in the cell trenches, A seventh oxide layer is arranged on both sides and sidewalls of the notch of the cell trench opposite to the gate conductive polysilicon, a fifth oxide layer is arranged between the gate conductive polysilicon and the shield gate, and a fourth oxide layer is arranged on the bottom and sidewalls of the cell trench opposite to the shield gate. A P-pillar is also provided in the first conductivity type epitaxial layer, one end of the P-pillar is connected to the second conductivity type well layer, and the other end extends toward the first conductivity type field termination layer. Theinvention adopts the shielding gate structure, reduces the Miller capacitance, thereby reducing the switching loss.

Description

technical field [0001] The invention relates to the technical field of power semiconductor devices, in particular to a super-junction IGBT with a shielded gate and a manufacturing method thereof. Background technique [0002] Insulated Gate Bipolar Transistor (IGBT) is a mainstream product in high-voltage and high-power power electronic devices. With the continuous upgrading of its structure, its application range is becoming wider and wider. The key parameters of IGBT include conduction voltage drop Vce, switching loss Eoff and short circuit withstand time Tsc. In practical applications, our goal is to obtain the lowest possible turn-on voltage drop Vce and switching loss Eoff, and a longer short-circuit withstand time Tsc. [0003] The introduction of super-junction technology in power devices has broken the contradiction between reducing the conduction voltage drop and improving the withstand voltage in traditional silicon devices. In super-junction IGBTs, the N-type bas...

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Problems solved by technology

[0004] However, although super-junction IGBTs have been greatly improved in terms of conduction voltage drop, etc., as the application requirements become higher and higher, the requirements for reducing the conduction voltage drop Vce and switching loss Eoff are getting higher and higher. At the same time, the requirements for the short-circuit safe working area are getting higher and higher, and the existing IGBT devices are also facing more and more challenges. Therefore, how to further reduce the conduction voltage drop and switching loss of the IGBT device, and at the same time further improve the short-circuit withstand time Tsc has become an important issue. Important research directions for technicians in the technical field

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