Super-junction structure and manufacturing method thereof

Abstract

The invention discloses a super-junction structure. The super-junction structure is formed by superposing two layers of super-junction substructures, and each of the two layers of P-type sub-columns consists of a P-type sub-epitaxial layer filled in the corresponding sub-groove; each sub-groove is of a structure with the side face inclined and the top width larger than the bottom width. The position corresponding to the change range of the optimal charge balance plus + / -5% of the first super-junction sub-structure at the bottom layer is arranged at the longitudinal center position, and the position of the maximum electric field intensity of the first super-junction sub-structure tends to the longitudinal center position and has a first value; the maximum electric field intensity value in the second super-junction substructure is a second value, and the first value is greater than the second value, so the breakdown position of the whole super-junction unit structure tends to the longitudinal center position of the first super-junction substructure. The invention further discloses a manufacturing method of the super-junction structure. According to the invention, the consistency of device performances such as breakdown voltage and avalanche tolerance can be improved.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a super junction (super junction) structure; the invention also relates to a manufacturing method of the super junction structure. Background technique [0002] The super junction structure is a structure of alternately arranged N-type pillars and P-type pillars. If the superjunction structure is used to replace the N-type drift region in the vertical double-diffused MOS transistor (Vertical Double-diffused Metal-Oxide-Semiconductor, VDMOS) device, a conduction path is provided in the conduction state. For N-type devices, only N The P-type column provides a path, but the P-type column does not provide it; in the off state, it bears the reverse bias voltage. At this time, the P-type column and the N-type column deplete each other laterally and bear together, forming a super junction metal-oxide semiconductor field effect transistor. (Metal-Oxide-Semic...

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Problems solved by technology

However, in order to speed up the filling of the epitaxy in the trench, the trench will be made into a certain inclination angle. At this time, at different horizontal positions of the PN column, the ratio of the width of the P column to the width of the N column will change. Therefore, if it is assumed that N If the concentration of the P-type epitaxial layer is the same, the doping concentration of the P-type column required to fully realize the charge balance at different positions in the vertical direction is different. At this time, the relevant content of the selection of the P-type column concentration has not yet been disclosed.

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