Effect of Electrode Configuration on the Frequency and Quality Factor Repeatability of RF Micromechanical Disk Resonators

A statistical evaluation of the standard deviations of the resonance frequencies and quality factors of polysilicon surface-micromachined micromechanical disk resonators with fully-surrounding and split electrode configurations has been conducted by fabricating and measuring a large quantity (>400) of devices. Through this analysis, respective single-wafer resonance frequency standard deviations as low as 642 ppm for fully-surrounding electrode devices; and 984 ppm for two-port split electrode devices; have been measured. Respective average quality factor standard deviations for fully surrounding electrode devices of 5.6% in vacuum; and 3.9% in air; have also been obtained. The standard deviations for both frequency and Q of each resonator type are well within values needed to achieve the -3% percent bandwidth requirements for filters presently used in the RF front-ends of wireless communication devices without trimming.