Fin Shape Contacts for Semiconductor Devices
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Solution Overview
Problem
Current fin contacts in semiconductor devices face high trench silicide contact resistance and limitations in fin height, which hinder the performance of FinFET devices as contact areas shrink and fins increase in height.
Innovation Solution
A method involving forming fins on a wafer, creating sacrificial contacts and gates, etching to recess the fins, growing epitaxial material, and forming fin contacts through a replacement metal gate process, including deposition of interlayer dielectric layers and metal contact materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If currently available fin contacts are used, then the device structure is simple, but the contact resistance is high which limits FinFET device performance
Solution Approach 1:
The contact structure is divided into multiple segments: a lower contact portion extending into the fin and an upper contact portion extending to the surface, with different materials and functions. This segmentation allows each portion to be optimized for its specific function, reducing overall contact resistance while managing structural complexity.
Solution Approach 2:
The contact structure employs a nested configuration where the lower contact portion is positioned within the fin structure, and the upper contact portion is positioned above it, creating a nested arrangement that reduces contact resistance through multiple contact points while maintaining a manageable overall structure.
2Reliability
If fin height is increased to improve device performance, then device performance improves, but contact area decreases which creates high resistance
Solution Approach 1:
The contact structure transitions from a two-dimensional surface contact to a three-dimensional structure that extends vertically into the fin. The lower contact portion extends down into the fin while the upper contact portion extends to the surface, utilizing the vertical dimension to maintain contact area even as fin height increases.
Solution Approach 2:
The contact is segmented into vertical portions at different heights, allowing the lower portion to maintain contact area within the fin structure while the upper portion provides surface access. This segmentation enables the contact area to be preserved independent of fin height increases.
3Productivity
If contact area is decreased to shrink device size, then device size decreases, but contact resistance increases which limits performance
Solution Approach 1:
The contact structure utilizes the vertical dimension by extending portions at different heights, allowing the device footprint to be reduced while maintaining adequate contact area through the vertical extension into the fin structure.
Solution Approach 2:
The nested arrangement of contact portions at different vertical levels allows compact device sizing while preserving contact area through the multi-level configuration, where the lower portion provides additional contact area within the fin volume.
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 reduces contact resistance and enhances FinFET device performance by allowing for more flexible fin heights and improved contact structures, thereby increasing device yield and efficiency.
Implementation Method 1
growing an epitaxial material over the at least one fin
Data Source
AI summary
Semiconductor devices and methods for forming the devices with fin contacts. One method includes, for instance: obtaining a wafer with at least one isolation region; forming at least one fin on the wafer; forming at least one sacrificial contact; forming at least one sacrificial gate; etching to recess the at least one fin; growing an epitaxial material over the at least one fin; performing replacement metal gate to the at least one sacrificial gate; depositing an interlayer dielectric layer; and forming at least one fin contact. An intermediate semiconductor device is also disclosed.