Study On Nano Thin Film Solidly Mounted Bulk Acoustic Resonator

Recently film bulk acoustic resonator have attracted much atttention for the terminal devices getting smaller,complexer and handling higher power.At the same time,due to high mechanical strength,great reliabilirty and excellent compatible with integrated circuit,solidly mounted type?SMR-FBAR?has attracted strong interest and been considered as ideal future radio frequency communication technique.This paper mainly focus on SMR-FBAR shows as follows:1.A conclusion is presented from this paper that magnesium doped zinc oxide(Mg_xZn_1-x-x O)is a novel piezoelectric material when a certain content of magnesium?Mg?atoms were doped into pure zinc oxide?ZnO?as piezoelectric layer of FBAR.Compared with pure zinc oxide?ZnO?,it has been proved that Mg_xZn_1-xO still remains hexagonal wurtzite which is suitable and desired for piezoelectric property.And the electrical resistivity and acoustic velocity are a little higher than pure ZnO from the experimental results.Its excellent radio frequency characterastics show the potential application on Monolithic Microwave Integrated Circuit.2.Excellent nano c-axis orientation Mg_xZn_1-xO films were fabricated by magnetron sputtering technique.The best sputtering process parameters suited Mg_xZn_1-xO films growth was obtained through comparing the influence of four parameters on c-axis growing and surface roughness respectively.Then the piezoelectric films deposited on different thickness bottom electrodes were fabricated to choose the suited electrode thickness of devices.3.SMR devices which central frequency was at 2.4GHz had been fabricated through sputtering process and micro-manufacturing technique,and effective electro-mechanical coupling coefficient was calculated at4.081%,serial resonant quality factor and parallel resonant quality factor were 604 and 638 respectively.4.X band SMR-FBAR device were processed based on piezoelectric Mg_xZn_1-xO films with a thickness of 342.7nm.The return loss was calculated at-4.4dB and the type of ultra-high frequency SMRs were discussed in this paper as well.With the increasement of the spectrum congestion of wireless communication,surface acostic wave?SAW?filters have a poor characteristic with FBAR filters above 2GHz frequency,so that FBAR technique may be the best choice for radio frequency front-end filter,however,for the finiteness of sputtering process and much more layers of deposition films,SMR-FBAR will be confronted with opportunites,chanllenge and developing.