Segmented SCR Layout for Uniform ESD Triggering
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Solution Overview
Problem
Silicon controlled rectifiers (SCRs) are insufficient in protecting against Electrostatic Discharge (ESD) due to increasing susceptibility in miniaturized electronic devices, leading to potential damage during production and operation, particularly in automotive systems where unwanted voltage pulses can occur.
Innovation Solution
The design of a silicon controlled rectifier with specific surface contact areas and conductivity types, including well regions and trigger regions, to enhance ESD protection by adjusting base resistance and improving uniformity of triggering, thereby preventing current filamentation and early failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SCR design is used, then device structure is simple, but ESD protection capability is insufficient
Solution Approach 1:
The SCR structure is segmented into multiple functional regions including a first conductivity type region, a second conductivity type region, a third conductivity type region, and a fourth conductivity type region. Each region serves specific functions in controlling current flow and providing ESD protection, allowing the device to handle complex protection requirements while maintaining a systematic structure.
Solution Approach 2:
Different regions of the SCR are doped with different conductivity types and concentrations to create localized functional zones. The first and third regions have higher doping concentrations for low resistance contacts, while the second and fourth regions have lower doping concentrations for voltage blocking, enabling the device to provide comprehensive ESD protection through spatially differentiated properties.
2Area of stationary object
If miniaturization is pursued, then chip area is reduced, but susceptibility to ESD increases
Solution Approach 1:
The SCR structure utilizes vertical stacking of multiple conductivity type regions to provide ESD protection functionality. By transitioning from a planar to a three-dimensional structure with stacked p-n-p-n regions, the device achieves comprehensive protection capability without requiring proportional increases in chip area, thus resolving the contradiction between miniaturization and ESD susceptibility.
Data Source
AI summary
A silicon-controlled rectifier includes a semiconductor body including a first main surface, an active device region, a first, a second, a third and a fourth surface contact area at the first main surface and arranged directly one after another along a first lateral direction, wherein the semiconductor body is electrically contacted at each of the first to fourth surface contact areas, and a first, a second, a third and a fourth SCR region, wherein the first and third SCR regions are of a first conductivity type and directly adjoin the first and third surface contact areas, respectively, and wherein the second and fourth SCR regions are of a second conductivity type and directly adjoin the second and fourth surface contact areas, respectively, wherein the first SCR region is electrically connected to the fourth SCR region, and the second SCR region is electrically connected to the third SCR region.