Semester

Spring

Date of Graduation

2009

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Dimitris Korakakis.

Abstract

Aluminum Nitride (AlN) is a promising material for piezoelectric MicroElectroMechanical Systems (pMEMS) and Surface Acoustic Wave (SAW) devices. AlN is a direct bandgap semiconductor possessing moderate piezoelectric coefficients, a high Curie temperature, and a high acoustic velocity. Potential applications of AlN thin film devices include high temperature pMEMS microvalves for use in Solid Oxide Fuel Cell (SOFC) flow control systems and high frequency/sensitivity SAW platforms for use in biosensors.;Since AlN is a robust material capable of operating at high temperatures and harsh environments, it can be used in settings where other widely used piezoelectrics such as Lead Zirconate Titanate (PZT) and Zinc Oxide (ZnO) fail. Piezoelectric beams are commonly used in MEMS and have many possible applications in smart sensor and actuator systems. In this work, the results of 3-dimensional Finite Element Analysis (FEA) of AlN homogeneous bimorphs (d31 mode) are shown. The coupled-field FEA simulations were performed using the commercially available software tool ANSYSRTM Academic Research, v.11.0. The effect of altering the contact geometry and position on the displacement, electric field, stress, and strain distributions for the static case is reported.;Surface acoustic wave devices have drawn increasing interest for use as highly sensitive sensors. Specifically, SAW platforms are being explored for chemical and biological sensor applications. Because AlN has one of the highest acoustic velocities of all the piezoelectric materials, high frequency (and thus highly sensitive) sensors are feasible. In this work, AlN SAW Rayleigh wave platforms were designed, fabricated, and tested. The insertion loss of the SAW platforms for two InterDigitated Transducers (IDTs) separation distances is also presented.

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