Semiconductor Recess Structure for Low Contact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor manufacturing methods face challenges in achieving low contact resistance between contact plugs and source/drain regions due to poor interconnection with silicon materials, necessitating improved processes to enhance device performance.
Innovation Solution
A semiconductor device and manufacturing method involving the formation of an epitaxial structure with a recess in the substrate, where the recess has a cross-section that expands gradually from its opening, allowing for increased contact area and reduced resistance through the formation of a silicide layer on the recess's inner surface during the contact opening etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional planar contact structure is used, then the manufacturing process is simple, but the contact resistance between contact plug and source/drain is high
Solution Approach 1:
The patent applies curvature by forming a recess with gradually expanded cross-section (trapezoidal or curved shape) instead of a planar contact interface. This curved/expanded geometry increases the contact area between the contact plug and silicide layer, thereby reducing contact resistance while maintaining manufacturing feasibility through standard etching processes
Solution Approach 2:
The patent transitions from a two-dimensional planar contact interface to a three-dimensional recess structure with vertical depth and expanded cross-section. This dimensional change creates additional contact surface area within the vertical profile, enabling lower contact resistance without increasing lateral footprint
2Reliability
If the contact area between contact plug and source/drain is increased, then contact resistance is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The recess structure is formed preliminarily during the contact hole etching process before contact plug deposition. By pre-forming the expanded cross-section recess, the patent enables subsequent silicide formation and contact plug filling to utilize the increased surface area automatically, without requiring additional complex manufacturing steps
Solution Approach 2:
The patent merges the recess formation step with the existing contact hole etching process. The same etching apparatus and process conditions that create the contact opening also form the recess with gradually expanded cross-section, consolidating two functions into one manufacturing step and avoiding additional process complexity
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 significantly reduces contact resistance between the contact plug and the source/drain, thereby enhancing the overall electric performance of the semiconductor device by increasing the contact area and facilitating better ohmic contact.
Implementation Method 1
the silicide layer may be formed subsequently on the inner surface of the recess to dramatically reduce the resistance between the contact plug and the silicide layer
Implementation Method 2
an epitaxial structure is formed in the first recess
Data Source
AI summary
The present invention relates to a semiconductor device and a manufacturing method thereof. The semiconductor device includes a substrate, an epitaxial structure, and a recess. The epitaxial structure is disposed in the substrate. The recess is formed in the epitaxial structure, where the recess has a cross-section in a direction perpendicular to the substrate, and at least one portion of the recess is gradually expanded from an opening of the recess.