Back-Side Gate Isolation Structure for Dense MOSFET Layouts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of metal-oxide-semiconductor field-effect transistors (MOS-FETs) in semiconductor devices compromises operational characteristics, necessitating improved electrical performance and increased integration density.
Innovation Solution
A semiconductor device design incorporating first and second transistors on a substrate with an isolation transistor between them, a lower power line in the substrate, and back-side gate contacts connected to dummy gate electrodes, enhancing electrical characteristics and integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MOS-FETs are scaled down to increase integration density, then the number of transistors per unit area increases, but operational characteristics deteriorate
Solution Approach 1:
The patent introduces a back-side gate contact that penetrates through the substrate, adding a vertical dimension (third dimension) to the transistor gate structure. This allows the gate to be positioned at the back side of the substrate rather than only at the top, enabling independent control of isolation transistors without increasing planar area, thus maintaining integration density while improving operational characteristics through enhanced isolation.
Solution Approach 2:
The patent segments the gate control into two independent parts: a front-side gate electrode and a back-side gate contact. This segmentation allows independent biasing of the isolation transistor's gate, enabling precise control of the isolation transistor's on/off state without affecting other transistors, thereby improving operational characteristics while maintaining scaled-down dimensions.
2Reliability
If isolation transistors are added between adjacent transistors to improve electrical isolation, then operational characteristics improve, but device complexity and area increase
Solution Approach 1:
The back-side gate contact structure serves multiple functions: it provides gate control for isolation transistors, enables electrical isolation between adjacent transistor regions, and can be integrated into the existing substrate structure without requiring separate isolation components. This multi-functionality improves electrical isolation without proportionally increasing device complexity.
Solution Approach 2:
The patent merges the isolation transistor gate structure with the back-side substrate structure. The back-side gate contact is formed as an integrated part of the substrate architecture, combining the substrate's mechanical support function with the electrical isolation control function, thereby reducing overall device complexity while achieving effective isolation.
3Reliability
If dummy gate electrodes are connected to power lines through back-side contacts to control isolation transistors, then electrical characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The back-side gate contact structure is formed during the early stages of fabrication, before the final transistor assembly is completed. The substrate is prepared with pre-formed contact holes and conductive layers that will later connect to the dummy gate electrodes, allowing the isolation control infrastructure to be established in advance and reducing the complexity of subsequent assembly steps.
Data Source
AI summary
A semiconductor device including: first and second transistors on a substrate; an isolation transistor provided between the first and second transistors; a lower power line in a lower portion of the substrate; and a back-side gate contact penetrating the substrate and connected to the lower power line and a dummy gate electrode of the isolation transistor.