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Palacios, Tomás Jiao, Yixuan Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science 2025-11-17T19:06:56Z 2025-11-17T19:06:56Z 2025-05 2025-08-14T19:31:56.993Z https://hdl.handle.net/1721.1/163680 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. S.M. Massachusetts Institute of Technology In Copyright - Educational Use Permitted Copyright retained by author(s) https://rightsstatements.org/page/InC-EDU/1.0/ CMOS-Compatible Wafer-Scale Synthesis and Rapid Characterization of Two-Dimensional Transition Metal Dichalcogenides Thesis application/pdf Master Master of Science in Electrical Engineering and Computer Science Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="38b68a73-fb3f-47e1-9322-0d119568c814"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Title>CMOS-Compatible Wafer-Scale Synthesis and Rapid Characterization of Two-Dimensional Transition Metal Dichalcogenides</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2025-05</PublicationDate> <Authors> <Author> <DisplayName>Jiao, Yixuan</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>https://rightsstatements.org/page/InC-EDU/1.0/</License> <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.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>