QUARTZ CRYSTAL AGING EFFECTS.

The purpose of this research is to reduce the aging and failure rates of quartz resonators, thereby increasing their reliability. Aging measurements at 85C of 84 resonators distributed among the frequencies, 81.9, 100, 250, 455, and 500 kilocycles, and among the edge finishes, optically polished, optically polished and etched, and state of the art, revealed little variation in aging rates that might be ascribed to the finish. A series of 10 Mc reliability units aged at 125C exhibited aging behavior dependent on the container type and the accompanying bakeout temperature used. A series of 176 aluminum and gold plated 3 Mc resonators were fabricated, and measured at 85C. A yield of 67 percent of units capable of meeting the specification less than 1 x 10 to the minus 8th powerweek after the first 30 days was obtained in spite of several different exploratory fabrication methods employed among the first fabricated resonators. Preliminary fabrication and aging studies of 5 Mc resonators, with aluminum annular ring electrodes, produced units with an average Q of 1,660,000 and very low aging rates. X-ray diffraction topography and SID studies have given valuable aid in analysing aging anomalies in the design of annular ring electrodes, and in the recognition of fundamental and inharmonic modes.