抄録
In this paper, we will report the results of TFBAR with BST film deposited by the spin-on metal organic decomposition method. The acoustic reflectors were fabricated by spin on techniques using multiple layers of silicon dioxide and tantalum dioxide (9 layers) in order to obtain acoustic isolation from high resistivity silicon substrate. After the deposition of each layer of spin on film, they were annealed at a temperature of 800°C for 10 minutes. 100 nm of Platinum with 10 nm of Titanium was used as the bottom electrode, and 100 nm Platinum was used as the top electrode. The thickness of BST layer used for implementing TFBAR is about 150 nm and was annealed at a temperature of 800°C for 30 minutes in an oxygen environment. The bottom electrode, BST film and top electrodes were patterned by the standard photolithography technique and ion-milling. The structural characterization of the BST films is performed by x-ray diffraction. The electrical characterization of the BST films was performed by capacitance-voltage (C-V) technique. The bulk acoustic resonance characteristics of the resonators were determined by one port s-parameter measurements under DC bias. With an increase in the DC bias above 2 V, the devices showed resonance characteristics and the depth of resonance peaks. In addition, their frequency was found to depend on the applied DC bias. The tunability of the resonators was about 1% for an applied voltage of 10V. The ‘Q’ factors of the resonators were depended on an applied DC bias and a maximum Q factor of 97 was observed at a bias voltage of 10 V. [DOI: 10.1380/ejssnt.2012.558]
