Reverse conducting insulated gate bipolar transistor

Abstract

A reverse conducting insulated gate bipolar transistor (RC-IGBT) is provided. The present invention relates to a power semiconductor device. In view of the problem of an RC-IGBT device in the prior art, the present invention provides a design scheme which can solve the problem in the prior art by optimizing the distribution of the n+ cathode region on the back side of the RC-IGBT device. Comparedwith a conventional RC-IGBT device, the RC-IGBT device of the present invention, by special design of the back structure, can suppress the turn-on voltage jumpback problem of the device whiling maintaining the low forward and reverse on-state loss of the device and not increasing the process cost, and is beneficial to improvement in the reliability of the RC-IGBT in practical application.

Description

technical field [0001] The invention relates to a power semiconductor device, in particular to the structural design of a reverse conduction insulated gate bipolar transistor (RC-IGBT), that is, a reverse conduction insulated gate bipolar transistor. Background technique [0002] Insulated gate bipolar transistors (IGBTs) are key semiconductor components in electronic systems and are widely used in various medium and high voltage power control systems, such as motor drives and power conversion. An IGBT device contains three electrodes: a collector, an emitter, and a gate that controls the switching of the device. Generally, when the gate is turned off, the traditional IGBT is equivalent to a PNP transistor with an open base, so it does not have the capability of reverse current flow. As a result, the traditional IGBT can only be used as a unidirectional conduction device, that is, the current can only flow from collector to emitter. However, most power circuit systems have...

AI Technical Summary

Problems solved by technology

This turn-on voltage foldback phenomenon has a huge negative impact on the reliability of RC-IGBT applications

For example, for multiple parallel-connected RC-IGBTs or RC-IGBTs with a large chip area, due to the deviation of chip processing technology, the The voltage return point of the chip is often not consistent, which leads to the current concentrated flow to a single chip or a certain local area of ​​a single large chip, causing the chip to be burned due to excessive current

[0006] In order to avoid the turn-on voltage foldback phenomenon, it is necessary to make the PN junction between the p-type collector layer (106) and the n-type field stop layer (105) of the RC-IGBT able to be closed under the lowest possible forward voltage drop of the device. Open, several common methods include: (a) increasing n - The doping concentration of the drift region (101) or reduce n - The thickness of the drift region (101) to reduce n - The resistance of the drift region, but this method will reduce the breakdown voltage of the device; (b) reduce the doping concentration or thickness of the n-type field stop layer (105), and improve the n-type field stop layer (105) on the electronic current path resistance to increase p + The potential difference of the PN junction between the collector region (106) and the n-type field stop layer (105) allows the above-mentioned PN junction to be opened at a lower electron current, but this method also reduces the breakdown voltage of the device (c) extend the current path length of electrons in the n-type field stop layer (105), that is, increase the adjacent n + The interval of the cathode region (107) can also improve the resistance of the n-type field stop layer (105) on the electron current path, increasing the p + The potential difference of the PN junction between the collector region (106) and the n-type field stop layer (105), but this method will aggravate the inhomogeneity of the current distribution inside the device and increase the forward conduction loss of the device

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