Semiconductor Contact Structure With Tapered Base for Stable Integration
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Solution Overview
Problem
The increasing demand for high-performance, high-speed, and multifunctional semiconductor devices necessitates finer patterns and three-dimensional channel structures to overcome limitations in planar metal oxide semiconductor field-effect transistors (MOSFET) due to reduced size, requiring improved integration and reliability.
Innovation Solution
A semiconductor device design featuring a substrate with active regions, gate structures, source/drain regions, and contact structures, where the contact structure's width increases towards the substrate, and insulating structures are inclined to enhance integration and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact structure has a constant width, then the manufacturing process is simple, but the electrical connection stability is insufficient
Solution Approach 1:
The contact structure employs an asymmetric trapezoidal cross-section with different widths at the top and bottom. The wider bottom portion (first width) provides enhanced electrical connection stability with the source/drain region, while the narrower top portion (second width) facilitates proper integration with upper interlayer structures. This asymmetric geometry resolves the contradiction by optimizing both connection reliability and manufacturability.
Solution Approach 2:
The contact structure's width parameter varies along its height, transitioning from a first width at the bottom to a second width at the top. This parameter change creates a trapezoidal profile that simultaneously achieves stable electrical connection at the broader base and compatibility with overlying structures at the narrower top, thereby improving reliability without excessive complexity.
2Reliability
If the contact structure width increases toward the substrate, then the electrical connection stability improves, but the integration with upper structures becomes more difficult
Solution Approach 1:
The asymmetric trapezoidal geometry with wider base and narrower top simultaneously achieves stable electrical connection at the substrate interface and proper integration with upper insulating structures. The insulating structures are configured with corresponding asymmetric profiles that complement the contact structure, making the integration process feasible despite the non-uniform width.
Solution Approach 2:
Different portions of the contact structure serve different functions: the wider bottom portion locally optimizes for electrical connection stability with the source/drain region, while the narrower top portion locally optimizes for integration with insulating structures and upper interlayer elements. This local quality differentiation resolves the contradiction between connection stability and ease of integration.
3Productivity
If finer patterns are implemented to increase integration density, then the degree of integration improves, but the manufacturing precision requirements increase
Solution Approach 1:
The asymmetric contact structure geometry is established early in the fabrication process through selective etching and deposition steps. By pre-forming the trapezoidal profile before subsequent patterning operations, the design accommodates finer integration patterns while managing manufacturing precision requirements through staged process implementation.
Solution Approach 2:
The contact structure's width parameter varies along its height, transitioning from a first width at the bottom to a second width at the top. This parameter change creates a trapezoidal profile that simultaneously achieves stable electrical connection at the broader base and compatibility with overlying structures at the narrower top, thereby improving reliability without excessive complexity.
Data Source
AI summary
A semiconductor device includes: a substrate comprising an active region extending in a first direction; a gate structure extending in a second direction on the substrate, intersecting the first direction and the active region; a source/drain region on a side of the gate structure, on the active region; a contact structure electrically connected to the source/drain region and on the source/drain region; and an insulating structure in contact, in the second direction, with a first contact side surface of the contact structure, wherein at least a portion of the first contact side surface of the contact structure in contact with the insulating structure is inclined such that a width of the contact structure increases toward the substrate.