Wavy Doping Regions for ESD Protection Diodes
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Solution Overview
Problem
Current diode structures for electrostatic discharge (ESD) protection in high-speed I/O applications face challenges in maintaining robustness as IC dimensions decrease, leading to increased ESD failure current with longer diode lengths and wider doping regions.
Innovation Solution
A diode structure featuring wavy N-doping and P-doping regions on a P-type substrate, with identical widths and alternating arrangements, sandwiched by side doping regions, and incorporating shallow trench isolations to enhance current-handling capability and prevent electric current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of the diode structure is increased to improve ESD protection, then the ESD failure current increases, but the layout area increases
Solution Approach 1:
The patent applies wavy curvature to the doping regions instead of straight lines, increasing the junction perimeter length within the same layout area. This allows the diode to achieve higher ESD protection capability without proportionally increasing the occupied area, effectively resolving the contradiction between ESD robustness and area consumption.
Solution Approach 2:
The invention transitions from one-dimensional straight doping regions to two-dimensional wavy patterns, maximizing the use of layout space. By utilizing the perpendicular dimension through wave patterns, the junction perimeter is extended without linearly increasing the footprint area, thereby improving ESD protection density.
2Reliability
If the width of the doping regions is increased to improve current-handling capability, then the ESD failure current increases, but the junction area increases
Solution Approach 1:
The wavy doping region design increases the junction perimeter length without proportionally increasing the junction area. The curved boundaries provide more surface area for current handling while maintaining compact footprint, effectively decoupling current-handling capability from area consumption.
Solution Approach 2:
The doping regions are segmented into multiple wavy segments rather than single straight regions. This segmentation increases the total junction perimeter through repeated wave patterns, enhancing current-handling capability while keeping the overall structure compact and area-efficient.
3Area of stationary object
If the diode structure is made more compact to reduce layout area, then the ESD protection capability diminishes
Solution Approach 1:
The wavy doping regions pack more junction perimeter into a smaller footprint by utilizing curved geometry. This allows the compact structure to maintain high ESD protection capability that would otherwise require a larger area with straight doping regions, effectively resolving the area-performance tradeoff.
Solution Approach 2:
The invention changes the geometric parameters of the doping regions from linear dimensions to curved dimensions, maximizing the perimeter-to-area ratio. This parameter transformation enables compact layouts to achieve the same ESD performance as larger conventional designs.
Data Source
AI summary
The present disclosure provides a diode structure and an electrostatic discharge (ESD) protection circuit including the same. The diode structure includes a P-type substrate. The diode structure further includes a plurality of wavy N-doping regions formed on the P-type substrate. Each of the wavy N-doping regions extends in a first direction and has an N-doping width in a second direction perpendicular to the first direction. The diode structure further includes a plurality of wavy P-doping regions formed on the P-type substrate. Each of the wavy P-doping regions extends in the first direction and has a P-doping width in the second direction. The N-doping widths are essentially identical at different positions along the first direction, and the P-doping widths are essentially identical at different positions along the first direction.