Role of Am Piezoelectric Crystal Orientation in Solidly Mounted Film Bulk Acoustic Wave Resonators |
Si-Hyung Lee, Sang-Chul Kang, Sang-Chul Han1, Byung-Kwon Ju2, Ki-Hyun Yoon, Jeon-Kook Lee |
Thin Film Materials Research Center, KIST 1Microsystem Research Center. KIST 2Department of Ceramic Engineering, Yonsei University |
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ABSTRACT |
To investigate the effect of AIN c-axis orientation on the resonance performance of film bulk acoustic wave resonators, solidly mounted resonators with crybtallographically different AIN piezoelectric films were prepared by changing only the bottom electrode surface conditions. As increasing the degree of c-axis texturing, the effective electromechanical coupling coefficient ($kappa$$_$eff/)$^2$ in resonators increased gradually. The least 4 degree of full width at half maximum in an AIN(002) rocking curve, which corresponds to $kappa$$^2$$_$eff/ of above 5%, was measured to be necessary for band pass filter applications in wireless communication system. The longitudinal acoustic wave velocity of AIN films varied with the degree of c-axis texturing. The velocity of highly c-axis textured AIN film was extracted to be about 10200 n/s by mathematical analysis using Matlab. |
Key words:
AIN, Solidly mounted resonator, Effective coupling coefficient, Rocking curve, Acoustic wave velocity |
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