Materials Science and Engineering Commons^™

Dc, Rf, And Thermal Characterization Of High Electric Field Induced Degradation Mechanisms In Gan-On-Si High Electron Mobility Transistors, Matthew Anthony Bloom

Master's Theses

Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are becoming increasingly popular in power amplifier systems as an alternative to bulkier vacuum tube technologies. GaN offers advantages over other III-V semiconductor heterostructures such as a large bandgap energy, a low dielectric constant, and a high critical breakdown field. The aforementioned qualities make GaN a prime candidate for high-power and radiation-hardened applications using a smaller form-factor. Several different types of semiconductor substrates have been considered for their thermal properties and cost-effectiveness, and Silicon (Si) has been of increasing interest due to a balance between both factors.

In this thesis, the DC, …

Material Characterization And The Effects Of Moisture And Drying On Injection Molded Torlon 5030, Michael R. Di Re

Master's Theses

The effects of water absorption and drying were studied on injection molded Torlon 5030, a high performance thermoplastic fabricated by Solvay Specialty Polymers. Torlon 5030 contains 30% by weight glass fibers in a polyamide-imide base resin. The objective behind this work was to test and better define relevant properties for industrial applications using this material. While the material design guide offers information on many mechanical properties including tensile, fatigue, and creep data; there is little to no publicly published data on the effects of water absorption and any subsequent drying of Torlon 5030. Blistering was also studied. With exposure to …

Deposition, Characterization, And Fabrication Of A Zinc Oxide Piezoelectric Thin Film Microspeaker Using Dc Reactive Sputtering, Adam Olzick

Master's Theses

A piezoelectric microspeaker device that could be used in a variety of acoustic applications was designed and fabricated using a thin film ZnO layer that was reactively DC sputtered onto a single crystalline n-type silicon substrate. When tested the microspeaker did not produce sound due to complications in the etching process, the thickness of the diaphragms, and clamping effects. Instead, a characterization approach was taken and the structural, optical, electrical, and piezoelectric properties of the ZnO were investigated. Scanning electron microscopy, x-ray diffraction, and atomic force microscopy were utilized to discover the ZnO’s structural properties. Using the XRD and SEM, …

Characterization And Implementation Of Low Intensity Pulsed Ultrasound As A Tool To Apply Physical Load To Scaffolds And Bone Cells For Fracture Repair, Scott Frazee

Master's Theses

One current challenge in treating bone fractures is the effective treatment of non-unions and delayed unions. Low Intensity Pulsed Ultrasound (LIPUS) has been approved by the FDA to treat fresh fractures since 1994 and non-unions since 2000 and is an attractive treatment option because it is non-invasive. The mechanism by which it works, however, is not well understood; what is known is largely confined to the resultant changes in chemical output of cells. In this thesis several concepts and techniques were brought together to investigate the following hypothesis: LIPUS produces a measurable physical load that results in measurable deformation and …