Dielectric Wall Isolation in Nanosheet Transistors to Prevent Gate Bridging
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Solution Overview
Problem
The integration of multi-gate devices in semiconductor manufacturing is challenging due to increased complexity and the need for advanced manufacturing processes to achieve improved gate control, reduced OFF-state current, and reduced short-channel effects in smaller, faster electronic devices.
Innovation Solution
The formation of semiconductor structures with nanostructures, such as nanosheet or nanowire transistors, using a dielectric wall structure with a cap layer to isolate gate structures and prevent bridging between source/drain structures, which is achieved through a series of patterning and etching processes involving sacrificial layers, spacers, and dielectric shell layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate devices are integrated to improve gate control and reduce short-channel effects, then device performance is improved, but manufacturing complexity increases
Solution Approach 1:
The semiconductor structure is divided into multiple segments including channel structures, source/drain structures, gate structures, and dielectric wall structures. Each segment is formed through separate patterning and etching processes, allowing independent optimization and control of each component while managing overall manufacturing complexity.
Solution Approach 2:
The patent implements a nested structure where dielectric wall structures are positioned between gate structures and between source/drain structures, creating a hierarchical arrangement. The dielectric wall structure includes a bottom portion, sidewall portion, and extending portion that nest around the channel structures, providing isolation and control in a compact configuration.
2Volume of moving object
If device dimensions are scaled down to produce smaller electronic devices, then device size is reduced, but manufacturing process complexity increases
Solution Approach 1:
The patent transitions from planar device architecture to three-dimensional structures with channel structures extending in multiple dimensions. The dielectric wall structure wraps around channel structures in a multi-dimensional configuration, enabling compact integration while maintaining control through vertical and lateral positioning rather than relying solely on lateral scaling.
Solution Approach 2:
Different regions of the semiconductor structure are assigned different properties and functions. The dielectric wall structure has varying compositions and geometries in different locations - with bottom portions, sidewall portions, and extending portions - each optimized for local requirements such as isolation, mechanical support, and electrical control.
3Reliability
If dielectric wall structure with cap layer is used to isolate gate structures and prevent bridging, then device reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The dielectric wall structure serves as an intermediary element positioned between gate structures and between source/drain structures. This intermediate component provides electrical isolation and mechanical separation without requiring direct modification of the gate or source/drain structures themselves, simplifying the overall isolation strategy.
Solution Approach 2:
The dielectric wall structure is formed prior to the formation of gate structures and source/drain structures. By establishing the isolation framework in advance, subsequent patterning and deposition processes can proceed without concern for bridging or contamination between adjacent structures.
Data Source
AI summary
Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes channel structures vertically stacked over a substrate and a source/drain structure laterally attached to the channel structures in the first direction. The semiconductor structure also includes a dielectric wall structure laterally attached to the channel structures in the second direction. The second direction is different from the first direction. In addition, the dielectric wall structure includes a bottom portion and a cap layer formed over the bottom portion. The semiconductor structure also includes an isolation feature vertically overlapping the cap layer of the dielectric wall structure and a gate structure formed around the channel structures and covering a sidewall of the isolation feature.