DCS Tx filters using AlN resonators with iridium electrodes

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 57; no. 3; pp. 518 - 523
• Main Authors: Clement, M., Iborra, E., Olivares, J., Rimmer, N., Giraud, S., Bila, S., Reinhardt, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-03-2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic wave devices, piezoelectric and piezoresistive devices; Acoustics; Aluminum nitride; Applied sciences; Bandwidth; Bulk acoustic wave devices; Cellular; Circuit simulation; Computational modeling; Computer simulation; Coupling circuits; Design engineering; Digital filters; Distributed control; Electrodes; Electronics; Engineering Sciences; Exact sciences and technology; Fabrication; Fundamental areas of phenomenology (including applications); Iridium; Physics; Resonator filters; Resonators; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transduction; acoustical devices for the generation and reproduction of sound; Acoustic wave device; Input output; Acoustic wave resonator; Aluminium nitride; Bulk wave; Topology; Experimental study; Modeling; Electromechanical coupling; Optimization; Digital system; Piezoelectric device; Manufacturing process; Equivalent circuit; Coupling factor; Frequency response; Frequency filtering; Acoustic wave filter; acoustic resonator filters; iridium; bulk acoustic wave device; electrode; aluminium compounds; band-pass filters; electromechanical effects; metal-semiconductor-metal structures; wide band gap semiconductors; UHF filters; III-V semiconductors
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2010.1442

In this paper we present the design, fabrication technology, and characterization of BAW filters for the Digital Cellular System (DCS) Tx-band at 1.75 GHz. The filters are fabricated with AlN-based solidly mounted resonators (SMR) using iridium electrodes, in an attempt to increase the effective electromechanical coupling factor of the BAW devices and achieve the bandwidth requirements of DCS filters. The design and optimization of the filters is performed with a simulation tool that uses a circuit model to compute the filter frequency response. Tx filters with balanced inputs and outputs and different topologies are designed and fabricated. The experimental filter response is compared with the simulations to determine the suitability of each design. DCS bandwidth requirements are fulfilled by using Ir/AlN/Ir stacks.