Source/Drain Contact Structure With Barrier Extension for Low Resistance
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Solution Overview
Problem
As the degree of integration in semiconductor devices increases, insufficient interconnection areas lead to increased contact resistance due to the need for smaller line widths and pitches, which affects the reliability and performance of high-speed, multifunctional semiconductor devices.
Innovation Solution
The semiconductor device incorporates a contact structure with a conductive barrier layer and insulating liner, featuring a barrier extension portion that extends downwardly from the liner to increase the contact area with the source/drain region, thereby enhancing the electrical connection and reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the degree of integration is increased by decreasing line width and pitch, then device integration is improved, but contact area becomes insufficient leading to increased contact resistance
Solution Approach 1:
The contact structure extends in the vertical dimension by adding a barrier extension portion that protrudes downward from the interlayer insulating layer. This vertical extension compensates for the reduced horizontal contact area caused by decreased line width and pitch, thereby maintaining adequate contact area and low contact resistance while enabling higher device integration.
Solution Approach 2:
The barrier extension portion is formed in advance during the contact structure fabrication process, before final interconnection formation. This preliminary extension ensures adequate contact area is established early, preventing contact resistance issues that would otherwise arise from subsequent miniaturization of line width and pitch.
2Area of stationary object
If line width and pitch are decreased to increase integration, then device density is improved, but interconnection area becomes insufficient
Solution Approach 1:
The contact structure transitions from a purely horizontal footprint to a three-dimensional structure with vertical extension. The barrier extension portion adds vertical height to compensate for reduced horizontal area, maintaining adequate interconnection area despite decreased line width and pitch required for higher device density.
3Reliability
If contact area is increased by extending barrier downward, then contact resistance is reduced, but device complexity increases
Solution Approach 1:
The barrier extension portion is integrated with the existing contact plug and insulating liner structure rather than being a separate component. This merging approach reduces overall device complexity while achieving the benefit of extended contact area and reduced contact resistance through the vertical barrier extension.
Data Source
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AI summary
A semiconductor device includes: an active pattern extending in a first direction, parallel to an upper surface of a substrate, on the substrate; a gate structure extending in a second direction, intersecting the first direction, on the active pattern; a source/drain region disposed in a region, adjacent to the gate structure, on the active pattern; an interlayer insulating layer covering the gate structure and the source/drain region; and a contact structure penetrating through the interlayer insulating layer and contacting the source/drain region. The contact structure may include a contact plug, an insulating liner surrounding a sidewall of the contact plug, and a conductive barrier layer disposed between the insulating liner and the contact plug and on a bottom surface of the contact plug. The conductive barrier layer may have a barrier extension portion extending downwardly from a lower end of the insulating liner.