1 F NOISE IN ETCHED GROOVE SURFACE-ACOUSTIC-WAVE (SAW) RESONATORS/

Measurements of 1/f (or flicker) frequency fluctuations in SAW resonat ors fabricated with etched groove reflectors on single crystal quartz have shown that the observed noise levels vary inversely with device s ize. These measurements were made on sixteen 450 MHz resonators of fou r different sizes. The 1/f noise levels were also evaluated on twenty- eight other SAW resonators ranging in frequency from 401 to 915 MHz. T his additional data provides valuable information on the dependence of the flicker noise levels on resonator frequency. A model based on loc alized, independent velocity fluctuations in the quartz is proposed wh ich correctly fits the observed size and frequency dependence of the m easured 1/f noise levels. This model suggests that the velocity fluctu ations originate in small regions (much less than approximately 5 mum in diameter) randomly distributed throughout the quartz with an averag e separation of about 5 mum between independent (incoherent) sources. The magnitude of the localized fractional velocity fluctuation, DELTAu psilon/upsilon, averaged over a 5 micron cube is on the order of 1 x 1 0(-9).