Source/Drain Contact Structure With Dipole Layer for Lower 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 FETs, which affects device performance due to high Schottky barrier heights between materials.
Innovation Solution
The formation of dipole layers and ternary compound layers at interfaces between source/drain regions and silicide layers, achieved by doping the silicide layers with metals of lower electronegativity, reduces the Schottky barrier heights and contact resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicide layers are used at source/drain contacts, then manufacturing is simpler, but contact resistance is high due to Schottky barrier heights
Solution Approach 1:
The patent applies composite materials by forming a dipole layer at the interface between the source/drain region and the silicide layer. This dipole layer, composed of materials with different electronegativities, creates an electric dipole that reduces the Schottky barrier height at the contact interface, thereby decreasing contact resistance while maintaining the overall contact structure
Solution Approach 2:
The patent changes the electrical parameters at the contact interface by introducing the dipole layer, which modifies the work function and Schottky barrier height. By selecting materials with specific electronegativity differences, the dipole layer alters the energy band alignment, reducing the Schottky barrier and improving charge carrier injection efficiency
2Reliability
If dipole layers are formed to reduce Schottky barrier heights, then contact resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The dipole layer is formed preliminarily at the contact interface before subsequent processing steps. By establishing the dipole layer early in the fabrication sequence, the patent ensures that the Schottky barrier reduction is achieved before any thermal or chemical processes that might otherwise degrade the contact properties, thereby simplifying the overall manufacturing flow
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 decreases contact resistances by 50% to 70%, thereby enhancing the performance of FETs by reducing the Schottky barrier heights and improving electrical conductivity.
Implementation Method 1
The formation of dipole layers and ternary compound layers at interfaces between source/drain regions and silicide layers, achieved by doping the silicide layers with metals of lower electronegativity, reduces the Schottky barrier heights and contact resistances
Implementation Method 2
The formation of dipole layers and ternary compound layers at interfaces between source/drain regions and silicide layers, achieved by doping the silicide layers with metals of lower electronegativity, reduces the Schottky barrier heights and contact resistances
Data Source
AI summary
A semiconductor device with different configurations of contact structures and a method of fabricating the same are disclosed. The semiconductor device includes a substrate, a fin structure disposed on the substrate, a gate structure disposed on the fin structure, a source/drain (S/D) region disposed adjacent to the gate structure, a contact structure disposed on the S/D region, and a dipole layer disposed at an interface between the ternary compound layer and the S/D region. The contact structure includes a ternary compound layer disposed on the S/D region, a work function metal (WFM) silicide layer disposed on the ternary compound layer, and a contact plug disposed on the WFM silicide layer.