Record Details
Growth and characterization of zinc ferrite thin films for high frequency applications
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Growth and characterization of zinc ferrite thin films for high frequency applications |
| Names |
Hu, Jiqing
(creator) Chang, Chih-Hung (Alex) (advisor) Lu, Shih-Lien L. (advisor) Settaluri, Raghu K. (advisor) |
| Date Issued | 2005-10-18T16:41:23Z (iso8601) |
| Internet Media Type | application/pdf |
| Note | Graduation date: 2006 |
| Abstract | Ferrites have been used for various high frequency applications as bulk materials. These applications, however, are limited to large dimension devices. In this thesis, thin film ferrites were deposited from a low temperature solution-based deposition process that is suitable for micro-scale high frequency applications. The low temperature nature of this deposition technique makes it an excellent back end process. In this work, a high rate deposition process for zinc ferrite thin films was established. A deposition rate of 0.2 μm/min was determined by the surface profiler. The deposited films have a plate-like morphology with fibrous texture. Zinc was uniformly incorporated into the ferrite film confirmed by the local chemical analysis by Energy Dispersive X-ray spectroscopy. The deposited films are polycrystalline with a typical cubic ferrite structure. The overall composition of the films was determined by Auger electron spectroscopy as Zn[subscript x]Fe[subscript y]O[subscript 4], x ranges from 0.25 to 0.55, and y ranges from 2.2 to 2.7. A model consisting of resistors, capacitors and inductors was constructed and used for the analysis of impedance spectroscopy. The dielectric properties of zinc ferrite thin films were obtained by fitting the data to the model. The results show that the dielectric constants are around 15 regardless of Zn/Fe ratio. This value is consistent with most of the reported values for bulk ferrite materials. The resistivity changes from 0.6 x 10[superscript 6] ohm.meter to 1.3 x 10[superscript 6] ohm.meter when Zn/Fe ratio varies from 0.06 to 0.14. A grounded coplanar waveguide structure was developed for microwave characterization of the thin film material to obtain the complex relative permittivity and the complex relative permeability. The method is based on conformal mapping and determination of filling factors for the coplanar waveguide configuration and is applicable to a wide range of dielectric as well as magnetic materials. The proposed approach was validated by determining the scattering parameters of a number of test structures using the 3D full-wave electromagnetic simulation. In all examples, the extracted parameters from the proposed technique resulted in values that are within 2% error. |
| Genre | Thesis |
| Topic | zinc ferrits |
| Identifier | http://hdl.handle.net/1957/513 |
