FinFET Source/Drain Epitaxy Using Isolation Recess Volume
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in increasing the volume of epitaxial source/drain regions in FinFETs without inducing short-channel effects or merging adjacent devices, as existing methods struggle to optimize the depth and width of source/drain recesses for efficient carrier provision and strain generation.
Innovation Solution
The method involves patterning source/drain recesses in fins and isolation regions, followed by epitaxial growth of source/drain regions, where the recesses in isolation regions provide additional volume and allow for reduced fin loss, enabling greater epitaxial growth without merging adjacent devices by controlling the depth and height of the epitaxial source/drain structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the volume of epitaxial source/drain regions is increased to improve carrier provision and strain generation, then device performance is improved, but short-channel effects are induced and adjacent devices may merge
Solution Approach 1:
The patent extends source/drain recesses horizontally into isolation regions beneath the top surface, creating a three-dimensional structure that increases epitaxial growth volume without increasing vertical height. This dimensional transition allows greater carrier provision and strain generation while maintaining control over channel length effects.
Solution Approach 2:
The source/drain structure is divided into multiple segments: recesses in the fin, recesses in the isolation region, and selective epitaxial growth in each zone. This segmentation allows independent optimization of each region's depth and volume to maximize performance while preventing device merging.
2Quantity of substance
If the depth and width of source/drain recesses are increased to improve epitaxial growth volume, then carrier provision is enhanced, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The isolation region serves as an intermediary space that accommodates extended source/drain recesses. By providing this intermediate zone, the patent enables greater recess depth and width without directly impacting the fin structure or adjacent devices, thereby maintaining manufacturing precision while increasing carrier provision.
3Quantity of substance
If epitaxial growth is extended deeper into fins to increase source/drain volume, then strain generation is improved, but fin loss increases
Solution Approach 1:
The patent merges the source/drain structure with the isolation region, creating a continuous epitaxial growth zone that extends from the fin into the isolation region. This merging allows strain generation to be maintained through increased total volume while reducing fin loss by distributing the source/drain material into the isolation region rather than deepening recesses in the fin itself.
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 allows for increased volume and reduced contact resistance of epitaxial source/drain regions, enhancing carrier provision and strain generation in FinFETs while minimizing fin loss and avoiding short-channel effects.
Implementation Method 1
epitaxial source/drain regions are grown in source/drain recesses
Data Source
AI summary
An embodiment device includes: an isolation region on a substrate; a first fin extending above a top surface of the isolation region; a gate structure on the first fin; and an epitaxial source/drain region adjacent the gate structure, the epitaxial source/drain region having a first main portion and a first projecting portion, the first main portion disposed in the first fin, the first projecting portion disposed on a first sidewall of the first fin and beneath the top surface of the isolation region.