Quartz Crystal Hermeticity

Precision quartz crystals must operate reliably for many years under sometimes adverse conditions including large ambient temperature variations and exposure to moisture and other environmental contaminants. If the quartz blank and electrode are exposed to moisture, oxygen or other foreign materials the crystal can exhibit widely changing performance including excessive long term frequency changes (aging), increasing resistance, degrading phase noise, unstable frequency vs temperature stability and other problems. It is important therefore that the crystal is made using processes that minimize surface and internal package contaminants and that the crystal enclosure be suitably sealed to prevent the entrance of any foreign materials over the expected operating life.