Integrated aluminum nitride piezoelectric microelectromechanical system for radio front ends

Abstract

This article summarizes the most recent technological developments in the realization of integrated aluminum nitride (AlN) piezoelectric microelectromechanical system (MEMS) for radio frequency (rf) front ends to be employed in next generation wireless communication devices. The AlN-based resonator and switch technologies are presented, their principle of operation explained, and some key experimental achievements showing device operations between 20MHz and 10GHz are introduced. Fundamental material, device, and fabrication aspects that needed to be taken into account for the demonstration of the first integrated rf MEMS solution based on the combination of AlN MEMS resonators and switches are highlighted. Given the ability to operate over a broad range of frequencies on a single silicon chip, the AlN MEMS technology is extremely attractive for the demonstration of reconfigurable and multiband rf transceivers. Next generation rf architectures that take advantage of large scale integration of AlN MEMS resonators and switches are briefly presented.

On/Off micro-electromechanical switching of AlN piezoelectric resonators

“…MEMS capacitive switches [8,9] and contour-mode AlN resonators [6] have been topics of research over the past decade, but to our knowledge, there have been no reports of integrating these two technologies to realize switching of piezoelectric resonances. Other relevant prior work includes capacitive switches using AlN dielectrics [10], MEMS resonators in which a suspended metal electrode allows for improved Q [11], a proposed switched BAW filter [12], and co-integration of metal contact switches with micromachined resonators [13]. However, none of these techniques demonstrate the ability to switch the piezoelectric resonance either on and off or in frequency.…”

Nanoscaled piezoelectric aluminum nitride contour-mode resonant sensors

“…The number of fingers, their length (also known as aperture of the transducer) and the film thickness are used to set the equivalent impedance of the device. Quality factors, Q, ranging between 1,000 and 3,000 in air have been demonstrated [20]. A maximum of 2.2 % has been experimentally recorded for the electromechanical coupling, k t 2 , of the AlN resonant transducer [21].…”

Nonlinear dynamics in aluminum nitride contour-mode resonators

“…[http://dx.doi.org/10.1063/ 1.4861461] In the past several years, aluminum nitride (AlN) contour mode resonators (CMRs) have received a great deal of attention as a candidate technology for the monolithic integration of high-quality passive elements in radio frequency (RF) circuits. [1][2][3][4][5][6][7] AlN CMRs consist of a film of AlN sandwiched between two metal patterned layers. The resonator considered in this work is a rectangular device excited by interdigitated electrodes on the top layer, see Figure 1.…”