FinFET Source Drain Epitaxy Oxide Removal
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Solution Overview
Problem
In FinFET devices, a thick oxide layer remaining on trench sidewalls after epitaxial layer formation limits the growth of epitaxial layers, impacting device performance by restricting volume and increasing resistance.
Innovation Solution
A method involving the etching of the thin oxide layer on trench sidewalls to expand the volume of epitaxial layer trenches, comprising steps such as forming fin structures, depositing gate structures, removing sidewalls, forming trenches, and anisotropically etching the oxide layer to increase epitaxial layer volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick oxide layer is kept on trench sidewalls to protect structures during fabrication, then device structure integrity is maintained, but the volume of the epitaxial layer is limited
Solution Approach 1:
The oxide layer is selectively removed from trench sidewalls at a specific stage in the fabrication process, before epitaxial layer deposition, to maximize the available volume for epitaxial growth while maintaining structural integrity during subsequent processing steps
Solution Approach 2:
The oxide layer is differentially treated: removed from trench sidewalls where epitaxial growth is desired, but potentially retained in other areas where structural protection is needed, creating localized variations in oxide presence to optimize both volume and integrity
2Reliability
If the volume of epitaxial layer is increased to enhance stress and reduce resistance, then device performance is improved, but the fabrication process becomes more complex
Solution Approach 1:
The oxide removal step is integrated into the existing fabrication sequence, combining the volume enhancement objective with standard process steps rather than adding completely separate complex processing equipment or methods
Solution Approach 2:
The fabrication process parameters are adjusted to control oxide layer thickness and removal characteristics, allowing optimization of epitaxial layer volume through parameter tuning rather than fundamental process redesign
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 method enhances epitaxial layer volume, increasing stress and reducing source and drain resistance, thereby improving FinFET device performance without damaging other components and reducing production costs.
Implementation Method 1
etching the oxide layer in step 5 is anisotropic etching
Implementation Method 2
forming an epitaxial layer structure at the trenches
Data Source
AI summary
A method making a fin device structure includes: forming a plurality of fin structures arranged spaced out from each other in a longitudinal direction and covered with a thin oxide layer; forming a plurality of gate structures in a transverse direction; depositing sidewalls covering the thin oxide layer of the gate structures and the fin structures; removing the sidewalls on the gate structures and the sidewalls of the fin structures; removing the thin oxide layer on the sidewalls of the trenches to expand the volume of each trench; forming an epitaxial layer structure at the trenches; the method further includes removing the oxides on the sidewalls to increase the volume of the subsequently grown epitaxial layer, such that it is conducive to increasing the stress and reducing the source and drain resistance, thus improving the performance of the device.