Source/Drain Structure With Necked Double-Diamond Contact Geometry
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Solution Overview
Problem
The challenge in the semiconductor industry is to form reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, which affects the formation of reliable source/drain structures in advanced transistor designs.
Innovation Solution
The solution involves forming a semiconductor device structure with a double-diamond-like source/drain structure, where a sloped spacer layer constrains the maximum width of the source/drain structure, preventing short circuits and increasing the surface area by forming a neck portion between the upper and lower portions, thereby enhancing the contact area with silicide and contact structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then production efficiency is improved and costs are lowered, but fabrication process complexity increases and reliability decreases
Solution Approach 1:
The source/drain structure is segmented into multiple regions with different cross-sectional shapes along its length. The first portion has a first cross-sectional shape while the second portion has a second cross-sectional shape, allowing each segment to be optimized for specific functions such as contact area, stress control, and integration with surrounding structures, thereby maintaining reliability at smaller scales
Solution Approach 2:
Different portions of the source/drain structure are given different local geometries and material properties. The first portion may have a wider cross-section for enhanced contact area, while the second portion may have a narrower cross-section for better integration, creating local quality variations that optimize overall device performance at reduced feature sizes
2Area of stationary object
If feature sizes are decreased to increase functional density, then chip area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The source/drain structure is formed with pre-defined multi-region geometries during the fabrication process. By establishing the different cross-sectional shapes in advance through controlled deposition and etching steps, the structure achieves compact dimensions while maintaining manufacturing feasibility through predetermined geometric configurations
3Productivity
If source/drain structure width is reduced to decrease device size, then functional density increases, but contact area decreases leading to increased resistance
Solution Approach 1:
The source/drain structure utilizes vertical dimension variations through different cross-sectional shapes at different portions. By varying the cross-sectional area along the length of the structure rather than uniformly reducing width, the invention increases functional density in the planar direction while maintaining or enhancing contact area through optimized vertical profiles at critical regions
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate having a base and a fin over the base. The semiconductor device structure includes a gate structure wrapping around a top portion of the fin. The semiconductor device structure includes a first nanostructure over the fin and passing through the gate structure. The semiconductor device structure includes a source/drain structure over the fin. The source/drain structure is over a side of the gate structure and connected to the first nanostructure, the source/drain structure has an upper portion, a lower portion, and a neck portion between the upper portion and the lower portion, the upper portion has a first diamond-like shape, and the lower portion is wider than the neck portion.