Shared-Diffusion Standard Cell Architecture for Mobility and Leakage Control
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Solution Overview
Problem
Conventional standard cell architectures experience performance degradation due to reduced Silicon Germanium deposition at diffusion edges, leading to inactive devices at cell edges, which limits the placement of active devices and results in reduced mobility and increased current leakage.
Innovation Solution
The proposed standard cell architecture extends diffusion areas beyond cell boundaries, incorporating polyline gates and dummy devices at the edges, which are deactivated using conductive lines to prevent current leakage, thereby improving device mobility and switching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If diffusion areas are contained within cell boundaries, then device fabrication is simplified, but device performance degrades due to reduced Silicon Germanium deposition at edges
Solution Approach 1:
The diffusion area is segmented into two parts: a first portion within the cell boundary and a second portion extending beyond the cell boundary. This segmentation allows the diffusion area to benefit from extended Silicon Germanium deposition while maintaining the simplified fabrication process associated with contained diffusion areas.
Solution Approach 2:
The diffusion area extends in the lateral dimension beyond the cell boundary, transitioning from a two-dimensional containment to a three-dimensional spatial arrangement. This dimensional extension enables improved device performance through enhanced Silicon Germanium deposition at the extended edges.
2Loss of energy
If dummy gates are placed at cell edges, then current leakage is prevented, but active device placement is restricted
Solution Approach 1:
The harmful function of dummy gates (blocking active device placement) is extracted and replaced by extending the functional diffusion area beyond the cell boundary. The extended diffusion area naturally prevents current leakage without requiring separate dummy gate structures that restrict device placement flexibility.
Solution Approach 2:
The extended diffusion area serves multiple functions simultaneously: it improves device performance through enhanced Silicon Germanium deposition, prevents current leakage at cell edges, and maintains placement flexibility for active devices. This multi-functionality eliminates the need for dedicated dummy gates.
3Speed
If diffusion areas extend beyond cell boundaries, then device mobility improves, but current leakage increases
Solution Approach 1:
The diffusion area exhibits different spatial characteristics: within the cell boundary, it supports active device formation with high mobility; beyond the cell boundary, it extends to prevent current leakage. This local quality differentiation allows simultaneous achievement of improved mobility and reduced leakage.
Solution Approach 2:
The potential harm of extended diffusion areas (current leakage) is converted into a benefit by strategically positioning the extended portion beyond the cell boundary where it can be deactivated or controlled, thereby preventing leakage while maintaining the mobility benefits within the active region.
Data Source
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AI summary
A semiconductor standard cell (200) includes an N-type diffusion area and a P-type diffusion area (202), both extending across the cell and also outside of the cell. The cell also includes a conductive gate (206) above each diffusion area to create a semiconductive device. A pair of dummy gates (208, 218) are also above the N-type diffusion area and the P-type diffusion area creating a pair of dummy devices. The pair of dummy gates are disposed at opposite edges of the cell. The cell further includes a first conductive line (214) configured to couple the dummy devices to power or ground for disabling the dummy devices.