Substrate, semiconductor device and preparation method thereof

Abstract

The invention provides a substrate, a semiconductor device and a preparation method of the semiconductor device, and the substrate comprises a first cut-off layer, wherein the doping concentration ofthe first cut-off layer is uniformly distributed in the thickness direction; a second cut-off layer which is arranged on one surface of the first cut-off layer, wherein the doping concentration in thesecond cut-off layer is gradually reduced in the direction away from the first cut-off layer; a drift region which is arranged on the surface, away from the first cut-off layer, of the second cut-offlayer, wherein the doping concentration in the drift region is smaller than or equal to that in the second cut-off layer. A device comprising the substrate has a good soft switching characteristic inthe switching process, does not have too high peak current and voltage, and has better consistency and stability.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular, to a substrate, a semiconductor device and a preparation method thereof. Background technique [0002] IGBT is the most ideal switching device in the field of power electronics, but it has a compromise relationship between electrical parameters, especially the compromise relationship between the blocking withstand voltage BV and the conduction voltage drop Vce, as well as the conduction voltage drop Vce and The trade-off relationship between the off-time toff. Therefore, since its inception, IGBT has continued to develop in terms of structural design and manufacturing process, mainly to optimize the compromise relationship and stability between various electrical parameters to improve its overall performance. At present, the mainstream technology of IGBT is field-terminated IGBT. A buffer layer (ie, cut-off layer) with a concentration higher than that of the base ar...

AI Technical Summary

Problems solved by technology

With the continuous upgrading of technology, the chip thickness is getting thinner and thinner, and the device-to-conduction loss and switching loss are getting lower and lower. However, the thinner chip thickness also speeds up the switching speed of the chip, and higher current and voltage spikes occur during switching. , resulting in device failure

[0003] In the related art, the field stop type IGBT (field stop layer structure and doping distribution such as Figure 12 (shown) has good switching softness, and it is not easy to introduce high peaks during the switching process, but its substrate thickness is thin, and the front-side process also requires a thin-film process, while the front-side production process is relatively difficult, and there is a greater risk of debris. The fluctuation of the thinned thickness on the back has a great influence on the front injection efficiency of the device, and the stability and consistency of the device cannot be guaranteed

[0004] Therefore, the current IGBT-related technologies still need to be improved

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