Dissimilar Square Waffle Gate Patterns for Transistor RDSon Reduction
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Solution Overview
Problem
Transistors with high resistance (RDSon) when activated limit their ability to handle higher voltages and result in power loss and signal degradation, making them unsuitable for high-voltage applications due to asymmetrical source and drain regions and parallel transistor layouts that are not performance-matched.
Innovation Solution
A gate pattern for adjacent parallel transistors with unequal source and drain areas, featuring a first frame around the source region and a second frame around the drain region, forming a dissimilar square waffle gate pattern, which allows for source/drain asymmetry and performance matching across transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If standard gate parallel transistors are used, then power capacity is increased, but RDSon remains high causing power loss and signal degradation
Solution Approach 1:
The patent applies asymmetry by creating dissimilar square waffle gate patterns where the gate structure is intentionally made asymmetric with respect to source and drain regions. The gate extends different distances from the source and drain, creating unequal channel lengths that optimize carrier flow and reduce RDSon while maintaining high power capacity through parallel transistor configuration.
Solution Approach 2:
The patent implements local quality by varying the gate pattern characteristics in different regions. The waffle gate structure has different mesh densities, gate widths, and spacing in specific areas to locally optimize electrical properties. This allows different portions of the transistor to have tailored characteristics that collectively reduce overall RDSon while maintaining high power handling capability.
2Reliability
If source/drain asymmetry is introduced to decrease RDSon, then transistor performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the gate into multiple discrete segments or fingers that form the waffle pattern. This segmentation allows the asymmetric gate structure to be fabricated using standard photolithography techniques with defined pattern rules, making the complex asymmetric design manufacturable through repeated modular units rather than requiring custom complex patterning processes.
Solution Approach 2:
The patent transitions from conventional planar gate structures to a three-dimensional waffle-like gate pattern with vertical components. This dimensional change allows the asymmetric source/drain configuration to be achieved through layer stacking and vertical interconnects, enabling complex electrical characteristics to be realized through geometric arrangement rather than complex lateral patterning, thus improving manufacturability.
3Power
If parallel transistor layouts are used to increase power capacity, then voltage handling is improved, but all transistors are limited by the lowest performing transistor
Solution Approach 1:
The patent applies parameter changes by systematically varying gate dimensions, spacing, and pattern density across different transistor regions within the parallel layout. By adjusting these geometric parameters, each transistor can be optimized to have matched performance characteristics, ensuring that all transistors in the parallel configuration operate at similar efficiency levels rather than being limited by the weakest unit.
Data Source
AI summary
The present disclosure is directed to a plurality of waffle gate parallel transistors having a shared gate on a surface of a semiconductor substrate. The shared gate has connected channels that form a plurality of squares, lines of each of the squares over the perimeter of a respective source or drain region of the plurality of waffle gate parallel transistors. The shared gate includes squares of a first size and shape and a second size and shape. The squares having the first size and shape are each over a respective source region and the squares having the second size and shape are each over a respective drain region. Each of the squares having a first size and shape share at least one side with one of the squares having the second size and shape.