A study of potentiostatic and galvanostatic electrochemical etching of silicon in tetramethylammonium hydroxide (TMAH) has been carried out. In TMAH baths,, we find that biased (100) silicon etch rates increase 21% over OCP etch rates. For TMAH baths seasoned with silicon, biased silicon etch rates increase to 63% over those at OCP. Electrochemical etching eliminates the growth of hillocks on etching surfaces regardless of etchant pH, [TMAH] or silicon loading, resulting in highly smooth etching surfaces. Potentiostatic and galvanic etching yield similar etch rates and surface consistency. / Graduation date: 2003

Graduation date: 1998

Graduation date: 1995

Methylene-butyrolactones are readily accessed by two methodologies based on a particular ene reaction. Both methodologies have been applied to the synthesis of the northern fragment of Polycavernoside. A reverse Julia reaction was used as the key step of a new methodology towards triene frameworks ; a mechanistic study revealed the unexpected role of triflic acid in the field of metal triflates catalysed acylation of alcohols, and a new tandem Brook rearrangement-allylation sequence was developed in the viewpoint of an improved total synthesis of Polycavernoside A.

Biaxial tensile strained Si grown on SiGe virtual substrates will be incorporated into future generations of CMOS technology due to the lack of performance increase with scaling. Compressively strained Ge-rich alloys with high hole mobilities can also be grown on relaxed SiGe. We review progress in strained Si and dual channel heterostructures, and also introduce high hole mobility digital alloy heterostructures. By optimizing growth conditions and understanding the physics of hole and electron transport in these devices, we have fabricated nearly symmetric mobility p- and n-MOSFETs on a common Si₀.₅Ge₀.₅ virtual substrate. / Singapore-MIT Alliance (SMA)

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 64-69). Also available in electronic version.

Thesis (M.Ch.E.)--University of Delaware, 2007. / Principal faculty advisor: Brian G. Willis, Dept. of Chemical Engineering. Includes bibliographical references.

Not available

This thesis describes the fabrication and characterization of integrated hollow Bragg waveguides fabricated by controlled thin film buckling. Hollow waveguides based on two different set of materials were studied. In the first case, thermal tuning of air-core dimensions was studied using waveguides, with chalcogenide glass and polymer claddings. Results showed that the change in air- core height as a function of small temperature variations was in good agreement with theory. Planar, silicon based, hollow core waveguides with Si/SiO2 Bragg reflector claddings are also described. Fabrication was accomplished by incorporating compressive stress in the sputtered Si and SiO2 layers and then heating samples to induce buckling along predefined areas of low adhesion. Several low adhesion layers were studied, but a fluorocarbon layer was deposited by CVD gave the best results. Optical experiments demonstrated optical confinement in the air-core, with loss in the ~5 dB/cm range at the 1550 nm wavelength. / Photonics and Plasmas

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references. Also available in electronic version.