Low motional resistance ring-shaped contour-mode aluminum nitride piezoelectric micromechanical resonators for UHF applications

This paper reports experimental results on a new class of ring-shaped, contour-mode aluminum nitride piezoelectric resonators that span a frequency range from 223 MHz to 656 MHz showing high quality factors in air (Q/sub max/=2,900 at 472.7 MHz), low motional resistance (ranging from 56 to 205 /spl Omega/), and center frequencies that can be lithographically tuned. These resonators achieve the lowest value of motional resistance ever reported for contour-mode resonators and combine it with high Q factors, therefore truly enabling the fabrication of arrays of microresonators with different frequencies on a single chip. Uncompensated temperature coefficients of frequency of only approximately -25 ppm//spl deg/C were also recorded for these resonators.