Dual-Side Source/Drain Contact Structure for Lower Schottky Resistance
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing contact resistance between source/drain regions and contact structures in semiconductor devices, which hinders performance improvements due to increased complexity in manufacturing processes as devices scale down.
Innovation Solution
The implementation of dual side contact structures with epitaxial source/drain regions and gate structures on fin structures, using n-type and p-type work function metal silicide layers to reduce Schottky barrier heights, thereby forming arrays of NFET and PFET with reduced contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional contact structures are used in scaled-down semiconductor devices, then device dimensions are reduced, but contact resistance increases and manufacturing complexity increases
Solution Approach 1:
The contact structure is divided into multiple segments: a first contact structure formed on a first surface of the source/drain region, and a second contact structure formed on a second surface (side surface) of the source/drain region. This segmentation allows each contact structure to serve specific functions and reduces overall contact resistance by providing multiple conduction paths.
Solution Approach 2:
The invention transitions from conventional single-surface contact structures to dual-surface contact structures by utilizing the side surface (second surface) of the source/drain region in addition to the top surface (first surface). This dimensional expansion creates additional contact areas and conduction paths, effectively reducing contact resistance in scaled-down devices.
2Productivity
If device dimensions are scaled down to increase storage capacity and processing speed, then higher performance is achieved, but manufacturing process complexity increases
Solution Approach 1:
The first contact structure is formed on the first surface of the source/drain region before the gate structure is formed. This preliminary action simplifies the overall manufacturing process by establishing contact structures early in the fabrication sequence, avoiding the need for complex subsequent steps to create contacts through or around the gate structure.
Solution Approach 2:
Different contact structures are formed on different surfaces of the source/drain region with potentially different materials and properties optimized for their specific locations and functions. The first contact structure on the top surface and the second contact structure on the side surface can be tailored to their respective electrical and mechanical requirements.
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 by 50% to 70%, enhancing the performance of semiconductor devices by improving electrical conduction between source/drain regions and contact structures.
Implementation Method 1
using n-type and p-type work function metal silicide layers to reduce Schottky barrier heights, thereby forming arrays of NFET and PFET with reduced contact resistance
Data Source
AI summary
A semiconductor device with dual side source/drain (S/D) contact structures and a method of fabricating the same are disclosed. The method includes forming a fin structure on a substrate, forming a superlattice structure on the fin structure, forming first and second S/D regions within the superlattice structure, forming a gate structure between the first and second S/D regions, forming first and second contact structures on first surfaces of the first and second S/D regions, and forming a third contact structure, on a second surface of the first S/D region, with a work function metal (WFM) silicide layer and a dual metal liner. The second surface is opposite to the first surface of the first S/D region and the WFM silicide layer has a work function value closer to a conduction band energy than a valence band energy of a material of the first S/D region.