Center-Fed Transistor Gate Layout for Lower Gate Resistance
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Solution Overview
Problem
High power transistors with longer unit gate widths face reduced large-signal gain due to increased gate resistance, leading to less area-efficient and thermally inferior semiconductor dies with lower assembly yield.
Innovation Solution
A center-fed gate structure with a novel gate attachment pad, such as a wire bond pad or solder bump, is implemented to lower parasitic gate resistance, coupled at a center feed point of the transistor gate width, allowing for a more efficient layout and reduced eddy current losses by positioning the gate pad over inactive regions and partitioning the drain contact to minimize capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the unit gate width of a transistor is increased to achieve higher power density, then the power output is improved, but the large-signal gain is reduced due to increased gate resistance
Solution Approach 1:
The gate is divided into multiple segments (first gate portion and second gate portion) separated by a gate recess, with each segment independently connected to the gate electrode. This segmentation reduces the effective gate resistance by providing multiple parallel conduction paths while maintaining the overall gate width for high power density
Solution Approach 2:
The gate structure transitions from a planar two-dimensional configuration to a three-dimensional structure with a gate recess. This vertical dimensionality change allows the gate to be fed from the center through the recess, reducing the current path length and gate resistance while maintaining a compact footprint
2Power
If the unit gate width is increased to improve power density, then the power output increases, but the aspect ratio of the semiconductor die increases reducing area efficiency
Solution Approach 1:
The gate is segmented into multiple portions with a recess between them, allowing the gate width to be effectively utilized without requiring a single long continuous structure. This enables better packing of multiple transistor fingers in parallel, improving die area efficiency while maintaining high power density
Solution Approach 2:
By introducing the gate recess in the vertical dimension, the layout can be optimized to reduce the aspect ratio. The center-fed configuration through the recess allows for more compact and square-like die geometries, improving area efficiency
3Power
If the unit gate width is increased to improve power density, then the power output increases, but the thermal performance of the die deteriorates
Solution Approach 1:
The segmented gate structure with recess creates natural thermal pathways and reduces heat concentration in any single region. The multiple gate portions can be independently managed for heat dissipation, improving overall thermal performance while maintaining high power density
Solution Approach 2:
The gate recess provides an additional vertical pathway for heat dissipation and allows for better thermal management architecture. This three-dimensional structure enables improved heat flow paths from the active regions, enhancing thermal performance
4Power
If the unit gate width is increased to improve power density, then the power output increases, but the assembly yield is reduced due to inferior die pick and package attachment processes
Solution Approach 1:
The segmented gate structure creates distinct attachment regions and improves die geometry for mechanical handling. The segmentation allows for better alignment and attachment during packaging processes, improving assembly yield
Solution Approach 2:
The gate recess and three-dimensional structure provide additional mechanical features that improve die handling and attachment. The modified geometry facilitates better grip and alignment during pick-and-place and package attachment processes, enhancing assembly yield
Data Source
AI summary
A transistor includes a source contact connected to a Through-Silicon Via (TSV). A drain contact is connected to a first pad. A gate structure is interposed between the source contact and the drain contact. A second pad is connected to the gate structure, the second pad comprising a first side diametrically opposed to a second side, and a third side interposed therebetween, the source contact proximal to the third side, a first portion of the first side and a second portion of the second side.