CMOS-Compatible Wafer-Scale Synthesis and Rapid Characterization of Two-Dimensional Transition Metal Dichalcogenides
Name
jiao-yjiao917-sm-eecs-2025-thesis.pdf
Description
Thesis PDF
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17.4 MB
Format
Adobe PDF
Checksum (MD5)
c3889804da7b87ef9a710af2fa56e4c0
Author(s)
Jiao, Yixuan
Advisor(s)
Palacios, Tomás
Date Issued
May 2025
Publisher
Massachusetts Institute of Technology
Abstract
Two-dimensional transition metal dichalcogenides (TMDs) such as monolayer MoS₂ offer great promise for next generation nanoelectronics due to their atomic thickness, tunable bandgaps, and excellent electrostatic control. However, industrial semiconductor manufacturing demands CMOS-compatible, wafer-scale growth and conventional CVD methods often exceed thermal budgets and introduce contaminants, while achieving uniform, defect-free monolayers remain difficult. This thesis presents in-depth discussion on low-temperature MOCVD system design and optimization methodology for uniform monolayer TMD synthesis. We investigate the effect of alkali halide promoters (e.g. NaCl) and novel alkali-free promoters (e.g. NH4Cl and crystal violet) on synthesis of monolayer MoS₂. By optimizing the NaCl-promoted route, we achieve coalesced monolayer MoS₂ films with enlarged grain domains and demonstrate field-effect transistors with improved mobility. In parallel, we develop a CMOS-compatible crystal violet seeding method that avoids alkali metal contaminants and yields uniform monolayer coverage. To support process development, a rapid characterization pipeline was introduced: optical/SEM imaging combined with machine learning to quickly map thickness, grain size, and infer electronic quality across the wafer. These contributions collectively advance the integration of 2D TMD materials into CMOS fabrication, enabling monolithic 3D integration in future electronics.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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