Semiconductor Contact Layer Concave Opening for Low Resistance
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Solution Overview
Problem
Existing semiconductor fabrication methods face challenges in reducing contact resistance between a metal silicide layer and a conductive structure, which affects the performance of semiconductor devices.
Innovation Solution
The method involves forming an additional opening in the contact layer to increase the contact area between the conductive structure and the contact layer, using a concave surface structure to enhance the contact interface, and employing titanium-based materials and atomic layer deposition for the barrier layer to maintain the concave surface and increase the contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area between metal contact layer and conductive structure is increased, then contact resistance is reduced, but device complexity increases
Solution Approach 1:
The contact layer is segmented into multiple portions (first contact layer portion and second contact layer portion) with different structures. The first portion has a first contact area with the conductive structure, while the second portion has a second contact area with the doped region. This segmentation allows each portion to be optimized independently for its specific function, reducing overall contact resistance without requiring a uniformly complex structure throughout.
Solution Approach 2:
Different regions of the contact layer are given different local qualities and structures. The first contact layer portion is designed with specific properties for contacting the conductive structure, while the second contact layer portion is designed with different properties for contacting the doped region. This local differentiation allows optimal contact resistance reduction at each interface without unnecessarily complicating the entire contact layer structure.
2Productivity
If critical dimensions of semiconductor devices are reduced, then more transistors can be placed on one chip, but contact resistance becomes more significant
Solution Approach 1:
The contact layer structure extends into the vertical dimension with multiple portions at different depths and positions. The first contact layer portion contacts the conductive structure at one level, while the second contact layer portion contacts the doped region at another level. This dimensional approach allows contact resistance to be reduced by providing multiple contact pathways without increasing the lateral footprint, thus maintaining high transistor density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces contact resistance by increasing the contact area in the direction of the electrical path, resulting in lower total resistance and improved semiconductor device performance.
Implementation Method 1
performing an annealing process on the initial contact layer to form the contact layer and the third opening in the contact layer
Implementation Method 2
performing a sputtering process on the initial contact layer to form an initial third opening in the initial contact layer
Data Source
AI summary
A method for forming a semiconductor structure includes providing an initial semiconductor structure formed in a substrate; forming a dielectric layer on the substrate; forming a first opening in the dielectric layer to expose a portion of the initial semiconductor structure; etching the portion of the initial semiconductor structure exposed at a bottom of the first opening to form a second opening in the initial semiconductor structure; and forming a contact layer in the second opening and a third opening in the contact layer. The contact layer has a concave top surface, and the third opening is located above the concave top surface of the contact layer and under the first opening. The method further includes forming a conductive structure in the first opening and the third opening.