Trench type super junction and manufacturing method thereof

Abstract

The invention discloses a groove-type super junction which comprises a plurality of grooves. Each groove is filled with a first epitaxial layer of the second conductivity type. The smallest grooves in size tend to be full filled with the first epitaxial layer, the grooves which are not fully filled with the first epitaxial layer are also filled with a second epitaxial layer, the second epitaxial layer which is stacked on the surface of the first epitaxial layer fully fills each groove. The second epitaxial layer has no doping or doping of the second conductivity type with a lower doping concentration relative to the first epitaxial layer. The difference of doping between the second epitaxial layer and the first epitaxial layer makes the total doping amount of the thin layer of the second conductivity type determined by the first epitaxial layer. Thus, the impact on the breakdown voltage of the super junction by the size differences of the grooves is reduced, so that the uniformity in surface of the breakdown voltage of the super junction is improved. The invention further discloses a manufacturing method of the grooved super junction. The groove-type super junction and the manufacturing method thereof are capable of improving the uniformity in surface of the breakdown voltage of the super junction with a simple technology, which has an important significance in the quantity production of the platform of the super junction technology.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a trench super junction; the invention also relates to a method for manufacturing the trench super junction. Background technique [0002] The super junction is composed of alternately arranged P-type thin layers (also called P-type pillars) and N-type thin layers (also called N-type pillars) formed in a semiconductor substrate, and the matching is completed by using P-type thin layers and N-type thin layers The formed depletion layer supports the reverse withstand voltage while maintaining a small on-resistance. [0003] The pillar structure of the PN interval of the super junction is the biggest feature of the super junction. Currently, there are mainly two methods for manufacturing the pillar structure of the PN spacer, one is obtained by multiple epitaxy and ion implantation, and the other is made by deep trench etching and epitaxy (EPI) filling....

AI Technical Summary

Problems solved by technology

In the etching of trenches, the morphology of trenches in different regions of the same semiconductor substrate is not exactly the same, and the reverse breakdown voltage of super junction devices is greatly affected by the morphology of trenches, making the same crystal The uniformity of the reverse breakdown voltage of the super junction device on the circle is poor

Images