Isolation structure and process thereof

Abstract

The invention discloses an isolation structure. The isolation structure is characterized in that a P-type epitaxy is formed on a P-type substrate; in the P-type epitaxy, an annular N-type deep trap and a P trap located at an annular central region are formed; an annular epitaxial layer is spaced between the annular N-type deep trap and the P trap; an N-type buried layer is arranged under the annular N-type deep trap, and a P-type buried layer is arranged under the P trap; the N-type deep strap also includes an annular N trap; a field oxygen layer is arranged on the surface of the P-type epitaxy, and windows are arranged on the field oxide layer for respectively extracting the N trap and the P trap; an N-type injection region is also arranged in the substrate directly under the P-type buried layer; and the P-type buried layer and the N-type injection region do not touch each other. For the isolation structure, the N-type injection region is formed directly under the P-type buried layer;and N-type doping changes potential distribution under the P-type buried layer and widens the width of a depletion region so as to improve the breakdown voltage of the isolation structure. The process of the isolation structure only adjusts injection and does not need adding additional process steps.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to an isolation structure, and also relates to a process method of the isolation structure. Background technique [0002] Conventional isolation structures such as figure 1 shown. The voltage bias during isolation is: the N-type heavily doped region 109 on the left is connected to a positive voltage (grounded), the middle P-type heavily doped region 110 is grounded (grounded), and the right N-type heavily doped region is connected to a positive voltage (connected to a positive voltage). That is to say, both of the above bias modes may exist. [0003] figure 2 It is the distribution of the depletion region when the conventional isolation structure breaks down (the N-type heavily doped region on the left is connected to positive voltage). It can be seen that when breakdown occurs, the middle P-type buried layer 102 and P-type epitaxial layer 104 are only half depleted lateral...

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Problems solved by technology

That is to say, both of the above biasing methods may exist

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