TMD Transistor Structure With Monolayer Channel and Doped Multilayer S/D
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor fabrication lies in forming defect-free monolayer transition metal dichalcogenides (TMDs) across large areas and creating adequately conductive source and drain contacts for TMD-based semiconductor devices, as monolayer TMDs have superior electrical properties but are difficult to dope and connect effectively.
Innovation Solution
The approach involves forming transistors with a monolayer TMD channel and multilayer TMD source and drain regions, where the upper layers of the multilayer TMD are doped and the monolayer channel is created by selectively removing layers using atomic layer etching or exfoliation, allowing for fewer defects and improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monolayer TMD is used for the entire device including source and drain, then superior electrical properties are achieved, but conductivity of source and drain contacts is insufficient
Solution Approach 1:
The patent applies different layer configurations to different regions of the TMD device: monolayer TMD is used specifically for the channel region to maintain superior electrical properties, while multilayer TMD is used for the source and drain regions to provide adequate conductivity. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirement.
2Area of stationary object
If monolayer TMD is formed across large wafer area, then device scalability is improved, but defect formation increases
Solution Approach 1:
The patent segments the TMD structure into monolayer and multilayer regions, where the multilayer TMD serves as a more defect-tolerant foundation and contact region, while the monolayer channel is formed in controlled areas. This segmentation allows large-area fabrication while maintaining high precision in the critical channel region.
3Reliability
If monolayer TMD is used for channel, then electrical properties are superior, but difficulty in doping and connecting increases
Solution Approach 1:
The patent uses multilayer TMD for source and drain regions where doping and connection are required, while maintaining monolayer TMD for the channel where superior electrical properties are needed. The multilayer structure provides easier doping and better mechanical properties for contact formation, resolving the manufacturing difficulty without compromising channel performance.
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 enables the production of TMD-based transistors with reduced defects and enhanced conductivity, overcoming the limitations of monolayer TMDs by utilizing multilayer TMDs for source and drain regions and maintaining the superior electrical properties of monolayer channels.
Implementation Method 1
the monolayer channel is created by selectively removing layers using atomic layer etching or exfoliation
Implementation Method 2
where the upper layers of the multilayer TMD are doped
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Described herein are transistors with monolayer transition metal dichalcogenides (TMD) semiconductor material. TMD materials include combination of a transition metal (e.g., molybdenum or tungsten) and a chalcogen (e.g., sulfur or selenium) in a monolayer having a hexagonal crystal structure. A transistor has a single layer of TMD forming a channel region, and multiple layers of the TMD material at the source and drain regions. Upper portions of the multilayer TMD source and drain regions are doped, and conductive contacts are formed over the doped portions.