Uniform TitleModification of silicon by self-assembled monolayers for
application in nano-electronics and biology
NameLi, Meng (author), Chabal, Yves (chair), Garfunkel, Eric (internal member), Zamick, Larry (internal member), Kojima, Haruo (internal member), Kim, Sobin (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectPhysics and Astronomy,
DescriptionFourier Transform Infrared Spectroscopy (FTIR) is employed to investigate surface and interface properties of several self-assembled monolayers (SAMs) systems on silicon and applications in optimizing attachment of biomolecules and Atomic Layer Deposition (ALD) of high-k metal oxides are explored. The SAM systems include silane-based SAMs on SiO2 and alkene-based SAMs (with different terminal groups) on H-terminated Si (111).
Modification of SiO2 by silane-based SAMs is presented first with emphasis on SAM/SiO2 interfacial characteristics. Spectral changes in the longitudinal-optical (LO) phonon mode of the SiO2 substrate after modification with silane-based SAMs suggest the formation of a dense cross-linked SAM chemically attached to the SiO2 substrate through Sisubstrate-O-Si bonds. A novel method is developed to prepare -NH2 terminated surface for optimized biomolecules surface attachment using (3-Aminopropyl) triethoxysilane (APTES) and hydrogen-terminated Si (111). It is demonstrated that APTES can form more stable siloxane layers on hydrogen-terminated Si (111) without extra pre-hydration or pre-oxidization of surface required by conventional silane-based methods.
The formation, structure and stability of alkene-based SAMs thermally grafted on H- terminated silicon (111) via Si-C bond (Si-C SAMs) has been investigated by infrared spectroscopy. The SAM with reactive terminal group (-COOH) shows higher thermal stability than SAM with -CH3 termination. The decomposition of alkyl chains at high temperature is through β-hydride elimination with cleavage of Si-C bond. The alkene-based SAMs are further used as model systems to study reaction and nucleation processes in ALD. The ALD of aluminum oxide on SAM-functionalized silicon with various terminal groups (-CH3, - NH2, -COOH and -OH) was systematically investigated using in situ FTIR. The results show that all Si-C bound SAMs with different terminal groups efficiently eliminate the formation of unwanted interfacial silicon oxide during ALD growth. The results also show that aluminum oxide can grow on all terminations of SAM surfaces but in a type-dependent manner, forming more homogeneous films on the -NH2, -COOH surfaces and very non-homogeneous films on -CH3-terminated surfaces due to a lack of reactive nucleation sites at the starting CH3-terminated surface.
NoteIncludes bibliographical references.
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.