Fabrication of high-aspect-ratio metallic micro-structures by reverse exposure method

Master'sMASTER OF ENGINEERIN

Rectangular Symmetry Morphologies in a Topographically Templated Block Copolymer

Using an array of majority-block-functionalized posts makes it possible to locally control the self-assembly of a block copolymer and achieve several morphologies on a single substrate. A template consisting of a square symmetry array of posts produces a square-symmetry lattice of microdomains, which doubles the areal density of features.Semiconductor Research CorporationFENA CenterSemiconductor Research Corporation. Nanoscale Research InitiativeSingapore-MIT AllianceNational Science Foundation (U.S.)Taiwan Semiconductor Manufacturing CompanyTokyo Electron LimitedNational University of Singapor

Serially connected monolayer MoS FETs with channel patterned by a 7.5 nm resolution directed self-assembly lithography

We demonstrate sub-10 nm transistor channel lengths by directed self-assembly patterning of monolayer MoS[subscript 2] in a periodic chain of homojunction semiconducting-(2H) and metallic-phase (1T') MoS[subscript 2] regions with half-pitch of 7.5 nm. The MoS[subscript 2] composite transistor possesses an off-state current of 100 pA/μm and an I[subscript on]/I[subscript off] ratio in excess of 10[subscript 5]. Modeling of the resulting current-voltage characteristics reveals that the 2H/1T' MoS[subscript 2] homojunction has a resistance of 75 Ω.μm while the 2H-MoS[subscript 2] exhibits low-field mobility of ~8 cm[superscript 2]/V.s and carrier injection velocity of ~10[superscript 6] cm/s.United States. Office of Naval Research. Presidential Early Career Award for Scientists and EngineersNational Science Foundation (U.S.). Nano-Engineered Electronic Device Simulatio

An Investigation on High-resolution Nanopatterning Techniques

Ph.DDOCTOR OF PHILOSOPH

Multilayer block copolymer meshes by orthogonal self-assembly

Continued scaling-down of lithographic-pattern feature sizes has brought templated self-assembly of block copolymers (BCPs) into the forefront of nanofabrication research. Technologies now exist that facilitate significant control over otherwise unorganized assembly of BCP microdomains to form both long-range and locally complex monolayer patterns. In contrast, the extension of this control into multilayers or 3D structures of BCP microdomains remains limited, despite the possible technological applications in next-generation devices. Here, we develop and analyse an orthogonal self-assembly method in which multiple layers of distinct-molecular-weight BCPs naturally produce nanomesh structures of cylindrical microdomains without requiring layer-by-layer alignment or high-resolution lithographic templating. The mechanisms for orthogonal self-assembly are investigated with both experiment and simulation, and we determine that the control over height and chemical preference of templates are critical process parameters. The method is employed to produce nanomeshes with the shapes of circles and Y-intersections, and is extended to produce three layers of orthogonally oriented cylinders.National Science Foundation (U.S.) (CMMI-1246740)Semiconductor Research CorporationTaiwan Semiconductor Manufacturing Compan

Templating Three-Dimensional Self-Assembled Structures in Bilayer Block Copolymer Films

The registration and alignment of a monolayer of microdomains in a self-assembled block copolymer thin film can be controlled by chemical or physical templating methods. Although planar patterns are useful for nanoscale device fabrication, three-dimensional multilevel structures are required for some applications. We found that a bilayer film of a cylindrical-morphology block copolymer, templated by an array of posts functionalized with a brush attractive to the majority block, can form a rich variety of three-dimensional structures consisting of cylinder arrays with controllable angles, bends, and junctions whose geometry is controlled by the template periodicity and arrangement. This technique allows control of microdomain patterns and the ability to route and connect microdomains in specific directions.Semiconductor Research CorporationUniversity of California, Los Angeles. Center on Functional Engineered Nano ArchitectonicsNanoelectronics Research InitiativeSingapore-MIT Allianc