Comparison of ion tuning and conventional finish plate for high frequency fundamental mode AT crystals

Despite the number of companies working on them, the manufacture of inverted mesa crystals in large quantities has remained a cumbersome and relatively expensive art. We discuss several of the unique challenges surrounding the final frequency adjustment of high frequency fundamental mode crystals. The focus will be on a comparison between recently developed ion tuning processes and conventional finish plating techniques for high frequency fundamental crystal applications. The topics discussed will range from the difficulties associated with minimizing electrical performance degradations through final tune to the observation of a "unique", persistent frequency drift after finish plating.