SCR Floating Guard Ring for ESD Triggering Voltage
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Solution Overview
Problem
Silicon-controlled rectifiers face limitations in electro-static discharge (ESD) protection due to high triggering voltage and low holding voltage, which restrict their application in higher voltage peripheral interface circuits.
Innovation Solution
A silicon-controlled rectifier structure with a floating guard ring and a gated diode is introduced, where the guard ring is spaced from the heavily-doped regions by shallow trench isolations, and an active area is used between the guard ring and the P-type heavily-doped region connected to the anode, reducing the current gain of parasitic bipolar transistors and increasing the holding voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If shallow trench isolation is used to space the heavily-doped regions, then device isolation is achieved, but the active area between the guard ring and P-type heavily-doped region is reduced
Solution Approach 1:
The shallow trench isolation is applied locally only where needed to provide electrical isolation between adjacent devices, while leaving the active area between the floating guard ring and the P-type heavily-doped region uninterrupted. This localized application maintains device isolation functionality while preserving maximum active area for current flow
Data Source
AI summary
The present disclosure provides a silicon-controlled rectifier structure and a manufacturing method therefor. The silicon-controlled rectifier structure comprises a substrate; and an N-Well and a P-Well in the substrate, wherein an N-type heavily-doped region 410 and a P-type heavily-doped region 422 which are connected to an anode are provided in the N-Well, and a floating guard ring 416 is further provided in the N-Well between the N-type heavily-doped region 410 and the P-type heavily-doped region 422, the guard ring being spaced from the N-type heavily-doped region 410 by a shallow trench isolation, and an active area having a predetermined width exists between the guard ring and the P-type heavily-doped region 422; and an N-type heavily-doped region 414 and a P-type heavily-doped region 424 which are connected to a cathode are provided in the P-Well.