A kind of reverse resistance type igbt and its manufacturing method

Abstract

A reverse resistance type IGBT and a manufacturing method thereof belong to the technical field of power semiconductor devices. The present invention introduces a floating P-type body region on one side of the trench gate and introduces a trench collector structure into the collector region and the field stop layer, without affecting the threshold voltage and turn-on of the IGBT device, and improves the The forward breakdown voltage of the device; reduce the gate-collector capacitance, improve the adverse effects of the Miller effect; reduce the overall gate capacitance, increase the switching speed of the device, reduce the switching loss of the device, and improve the traditional CSTBT device positive The trade-off relationship between conduction voltage drop and turn-off loss; avoid current, voltage oscillation and EMI problems in the dynamic process of device turn-on, improve device reliability; improve the carrier enhancement effect of the emitter terminal of the device, and improve the carrier in the drift region The carrier concentration distribution further improves the compromise between forward conduction voltage drop and turn-off loss; improves the reverse breakdown voltage of the device, and obtains excellent reverse blocking performance while ensuring good forward characteristics of the device.

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 reverse resistance IGBT and a manufacturing method thereof. Background technique [0002] An insulated gate bipolar transistor (IGBT) is a power semiconductor device composed of a MOS 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 easy driving of MOSFET, low input impedance and fast switching speed, but also has the advantages of high on-state current density, low conduction voltage, low loss and stability of power transistor. The advantages of good performance make it significantly improve the performance of power electronic systems in applications. At present, IGBT has beco...

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Problems solved by technology

[0008] On the one hand, the implementation of method (2) will increase the gate capacitance of the device, resulting in a decrease in the switching speed of the device and an increase in switching loss, which will affect the compromise between the conduction voltage drop and switching loss of the device. On the other hand, the large channel Density will also increase the saturation current density of the device, deteriorating the short-circuit safe operating area of ​​the device

[0009] In addition, the gate oxide layer in the trench gate structure of the IGBT device is formed in the trench by one-time 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 capacitance of the MOS and the oxide layer The thickness is inversely proportional to the thickness, which makes the thin gate oxide layer thickness in traditional IGBT devices will also significantly increase the gate capacitance of the device; at the same time, the electric field concentration effect at the bottom of the trench will cause the breakdown voltage of the device to decrease, resulting in poor reliability of the device ; Moreover, IGBT still has the disadvantage of poor reverse blocking ability of FS-IGBT structure, so it is difficult to be directly applied to applications that require IGBT to have reverse blocking ability

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