Reverse blocking type IGBT and manufacturing method therefor

Abstract

The invention discloses a reverse blocking type IGBT and a manufacturing method therefor, and belongs to the technical field of a power semiconductor device. By introducing a floating P type body region on one side of a trench gate and introducing a trench collector structure in a collector region and a field stop layer, the positive breakdown voltage of a device is improved without influencing the threshold voltage and switch-on of an IGBT device; the gate-collector capacitance is lowered, and adverse influence caused by a Miller effect can be relieved; the overall gate capacitance is lowered, the switching speed of the device is improved, the switching loss of the device is lowered, and the compromising relation between forward switch-on voltage drop and switch-off loss of the conventional CSTBT device is improved; the problems of current, voltage oscillation and EMI in the device starting dynamic process can be avoided, and device reliability is improved; the current carrier enhancement effect at the emitter end of the device is improved, the current carrier concentration distribution in a drift region can be improved, and compromising between forward switch-on voltage drop andswitch-off loss can be further improved; and the reverse breakdown voltage of the device is improved, and high forward characteristic of the device is ensured while excellent reverse blocking performance is obtained.

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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