Homogeneous Silicidation of FinFET End Faces
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Solution Overview
Problem
Advanced integrated circuits face variability in device characteristics due to non-uniform silicidation processes and selective epitaxial growth techniques, leading to inconsistent drive current and operational stability in multiple gate transistors like FinFETs.
Innovation Solution
The approach involves exposing the end faces of Fins in multiple gate transistors to form homogeneous contact regions through silicidation, eliminating the need for selective epitaxial growth and enhancing contact resistance uniformity by embedding Fins in dielectric material and creating openings for metal silicide formation, thereby establishing a consistent and efficient electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If selective epitaxial growth techniques are used to form contact regions, then device characteristics can be improved, but manufacturing complexity and process variability increase
Solution Approach 1:
The patent removes the selective epitaxial growth step from the process flow entirely. Instead of using complex epitaxial techniques to form contact regions, the invention directly forms metal silicide contacts on the Fin end portions after simple dielectric removal, extracting the problematic step while maintaining device performance.
Solution Approach 2:
Rather than building up contact regions through epitaxial growth (adding material), the patent inverts the approach by removing dielectric material to expose Fin end portions and directly forming contacts. This inversion simplifies the process while achieving homogeneous contact regions.
2Productivity
If non-uniform silicidation processes are used, then manufacturing speed can be maintained, but contact resistance uniformity deteriorates
Solution Approach 1:
The patent applies silicidation locally and uniformly to all exposed Fin end portions simultaneously. By exposing all Fin ends through dielectric removal and applying a uniform metal layer followed by silicidation, each contact region receives identical treatment, ensuring homogeneous contact resistance across all devices without requiring complex process control.
Solution Approach 2:
The patent performs preliminary exposure of Fin end portions by removing dielectric material before the silicidation step. This preliminary action ensures that all contact regions are prepared in advance with identical geometry and surface conditions, so that subsequent silicidation proceeds uniformly across all regions, guaranteeing contact resistance uniformity.
3Ease of manufacture
If variable contact resistance is present, then device fabrication can be simplified, but operational stability deteriorates
Solution Approach 1:
The patent merges the contact formation process with the Fin structure fabrication by directly forming metal silicide contacts on the Fin end portions within the same process sequence. This integration ensures that contact regions are formed under identical process conditions as the Fin structures themselves, guaranteeing homogeneous electrical characteristics and operational stability while maintaining fabrication simplicity.
Solution Approach 2:
The patent achieves homogeneous contact regions by exposing all Fin end portions identically through dielectric removal and applying uniform metal silicide formation. All contact regions have identical geometry, material composition, and electrical characteristics, ensuring consistent drive current and operational stability across all devices.
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 reduces variability in contact resistance and enhances operational stability by ensuring uniform silicidation across all channel regions, improving the overall performance and reliability of multiple gate transistors.
Implementation Method 1
forming a contact region in a cross-sectional area of each of the end portions that is exposed in the opening... forming a contact element in the opening, wherein the contact element connects to each of the contact regions
Data Source
AI summary
In a multiple gate transistor, the plurality of Fins of the drain or source of the transistor are electrically connected to each other by means of a common contact element, wherein enhanced uniformity of the corresponding contact regions may be accomplished by an enhanced silicidation process sequence. For this purpose, the Fins may be embedded into a dielectric material in which an appropriate contact opening may be formed to expose end faces of the Fins, which may then act as silicidation surface areas.