Super-junction device and manufacturing method thereof

Abstract

The invention discloses a super-junction device. All P-type thin layers in a current flow region do not contact with an N+ silicon substrate. The distances from the bottoms of all the P-type thin layers in the current flow region to the surface of the N+ silicon substrate are larger than the thickness of a transition region between an N-type silicon epitaxial layer and the N+ silicon substrate. The invention further discloses a manufacturing method of the super-junction device. Consistence between reverse breakdown voltage and overshoot current resistance of the super-junction device can be improved, and accordingly the reverse breakdown voltage and overshoot current resistance of the super-junction device can be improved.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a super junction device; the invention also relates to a manufacturing method of the super junction device. Background technique [0002] The super junction MOSFET adopts a new voltage-resistant layer structure, and uses a series of alternately arranged P-type semiconductor thin layers and N-type semiconductor thin layers to combine the P-type semiconductor thin layers and N-type semiconductor thin layers at a lower voltage in the off state. The thin layer of semiconductor is depleted to achieve mutual compensation of charges, so that the thin layer of P-type semiconductor and thin layer of N-type semiconductor can achieve high breakdown voltage under high doping concentration, so as to obtain low on-resistance and high breakdown at the same time voltage, breaking the theoretical limit of traditional power MOSFETs. In U.S. Patent US5216275, the above...

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Problems solved by technology

The other is to etch the trench after growing one type of epitaxy with the required thickness at a time, and then fill the trench with silicon of the opposite type; the process cost and process cycle of this method are short; but if the thin layer There is a certain thickness between the groove and the substrate. Due to certain process changes in the etching of the groove, the depth of the groove is easy to change, so the reverse breakdown voltage of the device varies widely.

Especially when the distance between the bottom of the trench and the N+ substrate is less than a certain value, not only the breakdown voltage of the device tends to change greatly with the change of the process, but also the anti-current impact capability of the device such as the single pulse avalanche breakdown energy (FAS) also undergoes large changes, which greatly affects the consistency of the device

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