Already proven in a wide array of industrial applications, surface acoustic wave devices (SAWs) also have been demonstrated to hold substantial potential in the biosensor arena. Currently, SAW resonators coated with a biolayer can distinguish specific biomolecules in both liquid and vapor phases. By incorporating periodic perturbations in the design of a SAW delay line, we are able to introduce a phononic band gap in the propagation of surface waves. With the coating of a specific biolayer on these band gap structures, we looked at how the phononic crystal affected the detection of molecules. Finally, we will discuss our results and compare them with current acoustic wave biosensors.

Photochemical Metal Organic Deposition, or PMOD, combines the ease of spin coating and direct photopatterning to overcome limitations encountered with other high-k dielectric patterning methods. The process can be performed at low temperatures (<400° C) making it ideal for use in temperature sensitive applications. Deposition of titanium oxide by this methodology results in an amorphous, nanoporous thin film. The general objective of this project is to identify the effects that thermal annealing, hydrothermal annealing and plasma annealing have on the porosity, thickness, k-value, breakdown voltage and leakage current of this dielectric material. One focus of this project is to find a processing scheme that maximizes breakdown voltage of the titanium oxide film while retaining a k-value greater than 15. We have used thermal annealing and O2 plasma annealing to achieve these specifications. Titanium oxide films having breakdown voltage of 13.7 V and k-value of 22 have been fabricated by the above method.

Nanostructures metallic materials’ optical and catalytic properties depend on their sizes and shapes. This is of great interest because of their application in biology, optoelectronics, and magnetic devices. This research focused on gold nanopartical fabrication using UV irradiation to form interesting shapes. Xenon lamp irradiation with a filter to select light with 250 nm to 350 nm wavelengths was used to excite gold precursor, hydrogen tetrachloroaurate (III) trihydrate (HAuCl₄). The light-excited gold ion precursor is then reduced to gold metal atoms by reaction with the solvent, ethylene glycol. Polymer Polyvinylpyrrolidone (PVP) was used as the surfactant to control growth rate and stabilize the particles formed. In these studies, both optical spectroscopy and transmission electron microscopy were used. The effects of photo-sensitizer’s addition, HAuCl₄ concentration, PVP concentration, PVP/HAuCl₄ concentration ratio, irradiation density and solution stirring were investigated. While each factor played a role, PVP/HAuCl₄ ratio, HAuCl₄ concentration, and solution stirring mainly controlled particle shapes, sizes, and uniformity, respectively. Controlled particle sizes ranged from 30 nm (± 10nm) to 1000 nm (±100nm) with triangular, pentagonal, and hexagonal shapes were fabricated. It was demonstrated that this convenient method is versatile to fabricate gold nanoparticles with controlled size and shape.

This paper summarizes the experimental phase of implementing a nano-nozzle with a triangular orifice diameter in a few hundred nanometer range through high temperature (1100° C) wet oxidization. The initial orifice of the nozzle was designed with a diameter in a few micron range. The orifice diameter was reduced by growing an oxide layer covering the inside of the silicon nano-nozzle. Cross-sections of the nozzle at various distances from the orifice were examined with a scanning electron microscope (SEM). The data from the SEM were analyzed to characterize the oxide growth layer inside the nozzle, which appeared not to follow the standard Deal-Grove model.

The goal of this project is to determine the ultimate nanometer patter resolution in ZEP-520A electron beam resist. E-beam lithography is done using a JEOL JBX 9300FS system. Thickness measurements of a ZEP-520A are taken using a Woollam Ellipsometer, Tencor KLA Profilometer, and a Veeco Atomic Force Microscope (AFM). Line edge and surface roughness will be compared across a range of E-beam doses using the AFM. E-beam dose is compared to the depth and clarity of trenches of varying dimensions draw in AutoCAD and written in ZEP-520A. Exposed resist is developed using ZED-N50. Trenches of 18 nm have been demonstrated previously. Resolving 10 nm trenches is the specific goal in achieving the maximum resolution of ZEP-520A.

A direct-write waveguide may be patterned by selective decomposition of photodefinable sacrificial polymers templated in a spin-on-glass matrix (SOG). Porosity is formed in the irradiated areas where the sacrificial polymer is decomposed leading to a drop in the refractive index, whereas the unexposed parts of the wafer retained a higher refractive index. To avoid thermal activation of the photoacid generators (PAGs), which are unstable at the glass transition temperature of the SOG, photobase generators were used to initiate base-catalyzed hydrolysis of the silane bonds in the SOG. The silane bonds in the SOG structure are converted into highly reactive silanol groups, which condense via a sol-gel mechanism to form a rigid network consisting of siloxane bonds between SOG cage units. After cross-linking the SOG, 248 nm UV radiation is used to activate the PAG to form photoacid, decomposing the sacrificial polymer only in the irradiated regions of the wafer thus allowing selective decomposition to form patterns of porosity. In the irradiated areas, the refractive index dropped to 1.3579, whereas the unexposed parts of the wafer retained a higher refractive index of 1.4162.