Thin film ZnO-based resonators for integrated wireless applications.

摘要

The purpose of this research is to investigate the manufacturability of miniature on-chip RF front-end bandpass filters needed for next-generation wireless applications. The filters are required to be low-loss, very small, and highly compatible with existing IC processing. At the frequency of interest, thin-film bulk acoustic wave resonators are the best choice for the development of the on-chip filter. An equivalent circuit model of the thin-film resonator was implemented on HP Eesof; an industry-standard circuit analysis tool. Sensitivity analysis of the filter was performed to determine the effects of physical parameters on the performance of the filter. This analysis is useful in developing processes for high volume manufacturing. The possibility of depositing filter-quality zinc oxide thin-film in the Microelectronics Research Center cleanroom was investigated. Analysis of deposited films was performed to aid in developing filter fabrication processing steps. Sample resonator devices were fabricated on zinc oxide grown by Motorola, Kobe Steel, and the author. Experimental responses from fabricated devices were then used to validate theoretical models. Q-factors of fabricated devices were reported and the piezoelectric coupling coefficient of sputtered zinc oxide films were extracted from measured responses and reported.