Canted Body Contact Layouts for Low On-State Resistance
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Solution Overview
Problem
Conventional body contacts in semiconductor structures, such as MOSFETs, reduce the source region width significantly, leading to increased on-state resistance, which is not optimal for performance, especially in low-voltage applications where source opening is a substantial portion of the pitch.
Innovation Solution
The use of 'canted' body contacts with polygon or modified polygon shapes, where each side is oriented at an angular deviation from the gate, maintains a wider source region width adjacent to the gates while minimizing the distance between gates, thereby reducing on-state resistance without sacrificing pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional body contacts are used in semiconductor structures, then the layout is simple and manufacturing is easier, but the source region width is significantly reduced leading to increased on-state resistance
Solution Approach 1:
The body contact is designed with an asymmetric shape where one side is parallel to the gate and the other side is offset, creating an asymmetric source region. This asymmetric configuration maintains a wider effective source region width compared to conventional symmetric body contacts, thereby reducing on-state resistance while still providing proper body contact function.
Solution Approach 2:
The invention transitions from conventional square or rectangular body contact shapes to a more complex two-dimensional shape with parallel and offset sides. This dimensional optimization allows the body contact to maintain better spacing relationships with the gate in multiple directions, preserving source region width and reducing resistance.
2Productivity
If body contacts are placed closer to gates to minimize pitch, then device density increases, but source region width is reduced increasing on-state resistance
Solution Approach 1:
The body contact design implements local quality optimization by having one side parallel to the gate (maintaining minimal spacing for density) and the other side offset (maintaining source region width for low resistance). This localized differentiation allows the structure to simultaneously achieve high device density and low on-state resistance.
Solution Approach 2:
The body contact shape is segmented into distinct sides with different orientations - one side parallel to the gate and another side offset. This segmentation allows each side to serve a different function: the parallel side minimizes pitch for high density while the offset side preserves source region width for low resistance.
3Reliability
If source region width is increased to reduce on-state resistance, then pitch between gates must be increased, reducing device density
Solution Approach 1:
The asymmetric body contact configuration allows the source region to maintain greater width in directions perpendicular to the gate while keeping the pitch (distance between gates) minimal. The parallel side of the body contact maintains tight spacing for small pitch, while the offset side preserves source region width for low resistance.
Solution Approach 2:
The invention optimizes the two-dimensional layout of the body contact to achieve better spacing in multiple directions simultaneously. By configuring the body contact with parallel and offset sides, the design maintains small gate pitch in one dimension while preserving adequate source region width in the perpendicular dimension.
Data Source
AI summary
Body contact layouts for semiconductor structures are disclosed. In at least one exemplary embodiment, a semiconductor structure comprises: a plurality of gates disposed on a semiconductor layer, each gate extending parallel to a y-axis in a coordinate space; a source region disposed between two of the plurality of gates; a plurality of body contacts disposed in each source region; and wherein a portion of each source region, adjacent to the gate, has a width extending parallel to the y-axis that is greater than the width of the source region parallel to the y-axis at a distance on an x-axis from the gate.