Nanosheet Gate Isolation With Dielectric Walls for Lower Parasitic Capacitance
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Solution Overview
Problem
The integration of semiconductor devices with reduced dimensions and increased density poses challenges in adjusting component characteristics, particularly in managing parasitic capacitance among devices with varying metal dimensions, which affects performance and functionality.
Innovation Solution
The implementation of a fork-sheet-like dielectric wall structure and an embedded cut metal gate isolation structure to minimize gate-to-source/drain parasitic capacitance, utilizing a multi-gate device design with nanosheet channels and a dielectric wall structure formed during the metal gate isolation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If device density is increased and dimensions are reduced, then more components can be integrated into a given area, but parasitic capacitance between devices increases and becomes harder to control
Solution Approach 1:
The patent introduces a dielectric wall structure that segments and isolates adjacent transistors with different metal dimensions. This segmentation creates physical barriers that reduce parasitic capacitance coupling between devices, allowing high integration density while controlling harmful electrical interactions.
Solution Approach 2:
The dielectric wall acts as an intermediary structure between transistors with different gate lengths. This intermediate layer mediates the electrical interaction by reducing direct capacitive coupling, enabling closer device spacing without excessive parasitic capacitance.
2Adaptability or versatility
If metal dimensions are varied among devices, then device characteristics can be adjusted for different functions, but parasitic capacitance adjustment becomes difficult
Solution Approach 1:
The dielectric wall structure is strategically positioned between devices with different metal dimensions to provide localized capacitance control. This allows each device to have its optimal metal dimensions for specific functions while the local dielectric barrier prevents excessive parasitic capacitance from affecting neighboring devices.
3Quantity of substance
If device dimensions are reduced, then more components fit in a given area, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses the manufacturing precision challenge by introducing a vertical dimension - the dielectric wall extends in the vertical direction between devices. This three-dimensional structure provides isolation without requiring extremely tight lateral dimensional control, thereby facilitating high integration density while maintaining manufacturability.
Data Source
AI summary
Various embodiments of the disclosure provide a semiconductor device structure. In one embodiment, the semiconductor device structure includes a first dielectric wall disposed over a substrate, and a first metal gate structure portion and a second metal gate structure portion disposed on opposing sides of the first dielectric wall, each comprising a plurality of semiconductor layers vertically stacked and separated from each other; a high-k dielectric layer surrounding at least three surfaces of each semiconductor layer, a gate electrode layer disposed between adjacent semiconductor layers, and a second dielectric wall disposed adjacent to the first metal gate structure portion, the second dielectric wall having a top surface at an elevation lower than a top surface of the first dielectric wall, and a metal layer disposed over the second dielectric wall and in contact with the gate electrode layer of the first and second metal gate structure portions.