Silicon controlled rectifier used for electro-static discharge protection of thin epitaxial process and preparation method for silicon controlled rectifier

Abstract

The invention provides a silicon controlled rectifier (SCR) device used for electro-static discharge (ESD) protection of a thin epitaxial process and a preparation method for the SCR device, and belongs to the technical field of electro-static discharge protection of a super-large-scale integrated circuit. The SCR device comprises a P+ silicon substrate and a P- epitaxial layer; an N well region, a P well region and a deep N well layer which are adjacent are formed in the P- epitaxial layer; N+ heavily-doped regions, P+ heavily-doped regions and STI (shallow trench isolation) regions are formed in the two well regions respectively; the deep N well layer is positioned below the N well region and the P well region, and are in effective contact with the N well region and the P well region, so that diffusion of heavily doped ions in the P type silicon substrate to the P well is effectively prevented, and the problem of reduction of P well body resistance is solved; and meanwhile, the reverse breakdown voltage of the deep N well and the P well is far less than that of the N well and the P well, so that the trigger voltage of the SCR device can be effectively lowered, and improvement of the ESD resistance performance of the circuit in the thin epitaxial process is realized.

Description

technical field [0001] The invention belongs to the technical field of VLSI electrostatic discharge (English: Electro-Static discharge, ESD for short) protection, and relates to a silicon controlled rectifier (English: Silicon Controlled Rectifier, short for ESD) which can be applied to ESD protection in thin epitaxy process : SCR) and its preparation method. Background technique [0002] With the continuous development of semiconductor technology, the performance of very large scale integrated circuit (English: Very Large Scale Integrated circuit, VLSI for short) has also been improved by 5 orders of magnitude in the past few decades. The current integrated circuit chip has the ability to integrate hundreds of millions of transistors, but at the same time, the reduction of process size also faces many obstacles, the most important ones are reliability problems, process fluctuations and power consumption. In terms of reliability, electrostatic discharge / electrostatic overst...

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Problems solved by technology

[0007] It can be seen that the turn-on voltage of SCR is related to the reverse breakdown voltage of N well and P well, so the turn-on voltag

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