Thermal desorption of quartz crystals

Thermal desorption mass spectroscopy was used to measure the outgassing of water and ammonia from quartz wafers after different processing steps typically used in resonator fabrication. The activation energies of the two species were calculated and compared with a test bakeout. It was determined that the water could be represented well by multiple activation energies. The effect this has on bakeout parameters is discussed. Also discussed are the possible sites where water and ammonia may be bound to the quartz surface. It was determined that part of the ammonia that was detected in these experiments originates in the vacuum system. Although UV ozone cleaning is primarily used to remove carbonaceous contaminants, it was found to substantially reduce the amount of ammonia desorbing from quartz samples.