ESD Protection Structure With Segmented Emitters for Higher Holding Voltage
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Solution Overview
Problem
Existing electrostatic discharge (ESD) protection structures for integrated circuits face challenges in effectively reducing emitter injection efficiency and enhancing holding voltage to prevent damage from transient ESD power.
Innovation Solution
The proposed electrostatic discharge protection structure incorporates doped regions of different conductivity types connected with doped regions used as emitters of bipolar junction transistors (BJTs) to reduce emitter injection efficiency and enhance holding voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESD protection structures are used, then basic ESD protection is provided, but emitter injection efficiency cannot be effectively reduced and holding voltage cannot be enhanced
Solution Approach 1:
The emitter region is segmented into multiple doped regions (first doped region, second doped region, third doped region, fourth doped region) with different conductivity types arranged in a specific pattern. This segmentation allows independent control of injection efficiency while maintaining protection function, resolving the contradiction between reliability improvement and device complexity by dividing the emitter into functional segments rather than using a uniform structure
Solution Approach 2:
Different doped regions are assigned different conductivity types (n-type and p-type) and doping concentrations to create local variations in electrical properties. The first and third doped regions have one conductivity type while the second and fourth have another, creating localized zones with optimized injection characteristics. This local quality differentiation enables reduced emitter injection efficiency in specific areas while maintaining overall ESD protection reliability
2Object-affected harmful factors
If doped regions of different conductivity types are added to reduce emitter injection efficiency, then holding voltage is enhanced, but device complexity increases
Solution Approach 1:
Multiple doped regions with different conductivity types are merged into a single integrated emitter structure that functions as one bipolar junction transistor emitter. The first, second, third, and fourth doped regions are combined to form a unified emitter configuration that simultaneously achieves reduced injection efficiency and enhanced holding voltage without requiring separate discrete components, thus managing device complexity through functional integration
Solution Approach 2:
The emitter structure uses composite doping configuration combining n-type and p-type doped regions in a specific arrangement. This composite structure of oppositely doped regions creates the desired electrical characteristics (reduced injection efficiency and enhanced holding voltage) while maintaining a single integrated emitter entity, balancing performance improvement with acceptable device complexity
Data Source
AI summary
An electrostatic discharge protection structure includes a semiconductor substrate, a gate structure disposed on the semiconductor substrate, a first well region of a first conductivity type disposed in the semiconductor substrate, a first doped region of the first conductivity type, a second doped region of a second conductivity type, a third doped region of the first conductivity type, and a fourth doped region of the second conductivity type. The first and second doped regions are disposed in the first well region and connected with each other. The second doped region is an emitter of a first bipolar junction transistor. The third and fourth doped regions are disposed in the semiconductor substrate and connected with each other. The third and second doped regions are located at two opposite sides of the gate structure in a first horizontal direction. The third doped region is an emitter of a second bipolar junction transistor.