Groove-type MOS Schottky rectifier with deep grooves and T-POLY structure and manufacturing method thereof

Abstract

The invention relates to a groove-type MOS Schottky rectifier with deep grooves and a T-POLY structure and a manufacturing method thereof. The groove-type MOS Schottky rectifier comprises an epitaxial layer, wherein the epitaxial layer is etched at intervals along the transverse direction to form a plurality of longitudinal grooves, the grooves extend downwards from the upper surface of the epitaxial layer, the thickness of the epitaxial layer is D, D is greater than 0, and the depth of the grooves ranges from 1 / 2[D(1-20%)] to 1 / 2[D(1+20%)]; the bottom part and two inner side walls of each groove are provided with an insulating medium, and the insulating medium at the two inner side walls is of a stepped shape; polycrystal is deposited in each groove, the polycrystal is of a T-shaped structure and composed of a horizontal shoulder portion and a longitudinal extending portion, the upper surface of the horizontal shoulder portion is flush with the upper surface of the epitaxial layer, and the lower surface of the horizontal shoulder portion extends to the upper surface of the longitudinal extending portion; and the thickness of the horizontal shoulder portion is one third to half of the depth of the corresponding groove. Under high reverse bias, the groove-type MOS Schottky rectifier provided by the invention increases the potential longitudinal landing space, improves electric field distribution near corners of the bottom part of each groove and inside an oxide, and reduces the electric field intensity near barrier metal.

Description

technical field [0001] The invention relates to the field of electronic components, in particular to a trench type MOS Schottky rectifier with a deep trench and a T-POLY structure and a manufacturing method thereof. Background technique [0002] Trench-type Schottky rectifier TMBS usually adopts a small-scale trench structure (trench width and depth) close to the process limit to make full use of the active area area and current path. First, the trench is etched on the epitaxial layer, followed by thermal growth or deposition of a certain thickness of silicon dioxide on the sidewall and bottom of the trench; after doping polycrystalline filling and etching back to the height of the step at the top of the trench, the remaining The crystal stands between the silicon dioxide in the trench, which is similar to the English letter "I" in appearance; finally, barrier metal deposition or sputtering, annealing, conductive metal deposition, etc. are performed. Typically, three layers...

AI Technical Summary

Problems solved by technology

Due to the constraints of the structure and the resistivity of the epitaxial layer of the traditional trench Schottky rectifier TMBS, the optimization space for the forward voltage drop and reverse withstand voltage, which are two main performance indicators, is relatively limited, which is not conducive to giving full play to this type of rectifier. Device Advantages

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