Latch-up prevention IGBT with mixed crystal emission area with variable components

Abstract

The invention discloses a latch-up prevention IGBT with a mixed crystal emission area with variable components and belongs to the technical field of power semiconductor devices. The latch-up prevention IGBT is based on a conventional IGBT structure, pure silicon materials in the emission area are changed into a mixed crystal with the variable components, and therefore a emission area energy band structure with an energy gap changed gradually is formed. The energy band structure forms an accelerating field of an emission area carrier in the emission area under the precondition that built-in potential of a PN junction formed by the emission area and a base area is not reduced, therefore, carrier diffusion current density in the emission area is increased, and injection on the emission area by the base area is enhanced; on the other hand, injection on the base area by the emission area remains unchanged. Therefore, injection efficiency of an emitter junction of a parasitic transistor formed by the emission area, the base area and a drifting area is reduced, current amplification factors are lowered, the parasitic transistor in the IGBT can not achieve the latch-up condition, consequently, critical latch-up current of the IGBT is improved, safe work areas of the IGBT are increased, and reliability of the IGBT is improved.

Description

technical field [0001] The invention belongs to the technical field of power semiconductors and relates to an IGBT device with good anti-latch performance. Background technique [0002] IGBT is a representative type of power semiconductor device, because it has the advantages of high withstand voltage, low on-resistance, easy driving, fast switching speed, etc. There are important applications in the field. Latch-up problem is one of the important reasons that threaten the reliability of IGBT. [0003] The basic IGBT structure and its equivalent circuit such as Figure 1.1 with Figure 1.2 shown by Figure 1.1 It can be seen that the IGBT structure includes an N-P-N-P four-layer three-junction thyristor structure 14 composed of an N+ emitter region 3 , a P-type base region 6 , an N-drift region 10 and a P+ collector region 12 . Depend on Figure 1.2 The equivalent circuit of the IGBT is used to explain the mechanism of IGBT latch-up: when the IGBT works normally, the par...

AI Technical Summary

Problems solved by technology

However, these two methods will reduce the forward conduction voltage drop of the NPN emitter junction PN junction, the PN junction is easy to be forward biased, and the parasitic NPN transistor is easy to open, which is not good for improving the anti-latch-up ability of the IGBT

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