2D Semiconductor Contacts With Hydrogen-Plasma Alloy Interfaces
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Solution Overview
Problem
The electrical resistance at the junction of the source/drain regions and the source/drain electrode contact in 2D semiconductor devices is a performance-limiting factor, hindering their effectiveness.
Innovation Solution
A method involving the use of a hydrogen plasma to replace the chalcogen at the surface of a metal dichalcogenide layer, followed by the application of a reactive metal to form a metal alloy interface, which reduces electrical resistance and provides a seamless contact with the semiconductor material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a metal dichalcogenide layer is used as a 2D semiconductor material, then the device achieves atomic-scale thickness and natural semiconductor properties, but high electrical resistance at the source/drain junction limits performance
Solution Approach 1:
The patent applies local quality by creating a hydrogen-terminated surface layer specifically at the source/drain contact regions of the metal dichalcogenide. This hydrogen termination is applied locally rather than uniformly across the entire device, targeting only the contact interfaces where high resistance occurs. The hydrogenated surface provides improved electrical contact properties at these critical locations while leaving the channel region unchanged, thus resolving the contradiction between maintaining atomic-scale thickness and reducing contact resistance.
Solution Approach 2:
The patent changes the surface chemical state parameter of the metal dichalcogenide by introducing hydrogen termination. This parameter change transforms the surface from a high-resistance state to a low-resistance state at the contact interfaces. By modifying the surface chemistry (adding hydrogen) rather than changing the bulk material properties, the patent achieves reduced electrical resistance while preserving the atomic-scale thickness of the semiconductor layer.
2Ease of manufacture
If conventional contact methods are used with metal dichalcogenides, then the fabrication process remains simple, but van der Waals gaps create high electrical resistance at the interface
Solution Approach 1:
The patent introduces hydrogen as an intermediary substance between the metal contact and the metal dichalcogenide layer. This hydrogen layer acts as a mediator that eliminates the van der Waals gap and creates a seamless interface. The hydrogen termination layer facilitates direct chemical bonding between the metal contact and the semiconductor, replacing the weak van der Waals interaction with strong covalent bonds, thereby improving interface conductivity while adding only a monolayer of hydrogen.
Solution Approach 2:
The patent substitutes the mechanical van der Waals contact with a chemical bond formed through hydrogen termination. Instead of relying on physical contact between metal and semiconductor (which creates gaps), the hydrogen-mediated chemical bonding creates a seamless electrical pathway. This substitution of mechanical contact with chemical bonding resolves the contradiction between simple fabrication and good interface conductivity.
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 significantly lowers the electrical resistance at the junction, enhancing the performance of 2D semiconductor devices by improving conductivity and reducing van der Waals gaps.
Implementation Method 1
The chalcogen is plasma stripped from a surface layer of the exposed portions of the metal dichalcogenide film
Implementation Method 2
The chalcogen in the surface layer of the exposed portions of the metal dichalcogenide film is replaced with hydrogen
Implementation Method 3
The hydrogen in the surface layer of the exposed portions of the metal dichalcogenide film is replaced with a second metal to form a metal alloy interface
Data Source
AI summary
A method of fabricating a semiconductor device includes applying a plasma to a portion of a metal dichalcogenide film. The metal dichalcogenide film includes a first metal and a chalcogen selected from the group consisting of S, Se, Te, and combinations thereof. A metal layer including a second metal is formed over the portion of the metal dichalcogenide film after applying the plasma.