The aging of bulk acoustic wave resonators, filters and oscillators

The aging of quartz crystal resonators, filters, and oscillators is reviewed, including such topics as the impacts of aging, typical aging characteristics, aging specifications, aging mechanisms, temperature dependence of aging, frequency and overtone dependence of aging, drive level dependence of aging, the effects of aging interruptions, the dependence of aging on material and mode type, state-of-the-art in low-aging oscillators, and aging acceleration effects. The aging mechanisms discussed include contamination transfer effects, stress effects, electrode effects, diffusion effects, changes in the quartz material, and circuit and other electrical changes. Isothermal and thermal step stress aging acceleration methods are reviewed.< >