A fabrication method for multiple epitaxial superjunction devices with improved reverse recovery characteristics

Abstract

The invention belongs to the technical field of manufacturing semiconductor devices, and relates to a manufacturing method for multiple epitaxial superjunction devices with improved reverse recovery characteristics. By growing multiple epitaxial layers on a substrate, each epitaxial layer is alternately injected with the first conductive Type impurity + selective implantation of first conductivity type impurity and general injection of second conductivity type impurity + selective injection of first conductivity type impurity, so repeated and alternate, and then push well at high temperature to form a multiple epitaxial super junction structure; the present invention adopts Deposition epitaxy + N-type ion general implantation + selective implantation of P-type ions + deposition epitaxy + P-type ion general implantation + selective implantation of N-type ions, replacing the existing deposition epitaxy + N-type ion general implantation + selective Injection of P-type ions + high-temperature push well increases the distance between the formed P-type columns, so that the N-type epitaxial layer can store a higher concentration of majority carriers during forward conduction, and the reverse recovery time is longer, increasing the The softness of reverse recovery is increased, and the dynamic parameter characteristics of di / dt and dv / dt are improved.

Description

technical field [0001] The invention relates to a method for manufacturing a superjunction device, in particular to a method for manufacturing a multiple epitaxial superjunction device with improved reverse recovery characteristics, and belongs to the technical field of manufacturing semiconductor devices. Background technique [0002] The on-resistance of traditional power MOSFET devices is mainly determined by the length and doping concentration of the drift region. The smaller the length of the drift region, the smaller the on-resistance, and the higher the doping concentration of the drift region, the smaller the on-resistance. However, changes in these two aspects will lead to a decrease in the breakdown voltage of the device, so the on-resistance and the breakdown voltage are in a contradictory relationship or a compromise relationship, that is, the reduction of the on-resistance is limited by the breakdown voltage. [0003] The emergence of superjunction structures br...

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Problems solved by technology

[0004] At present, a common method for preparing a superjunction structure is multiple epitaxy plus photolithography plus implantation technology, that is, first do an N-type epitaxy on the N+ type substrate material, and then photoetch the P-type column area and perform P-type ionization. Implantation, followed by the second N-type epitaxy, photoetching the P-type column area again and performing P-type ion implantation, and repeating the above process for the third, fourth or even more times according to the breakdown voltage requirements of the device. However, this The area occupied by the terminal area of ​​the structure is relatively large, and the production cost of multiple epitaxy, multiple lithography and multiple implants is relatively high

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