Accession Number : ADP002470

Title :   Electrodiffusion of Charge-Compensating Ions in Alpha-Quartz,


Personal Author(s) : Martin,J. J. ; Bossoli,R. B. ; Halliburton,L. E. ; Subramaniam,B. ; West,J. D.

Report Date : 1983

Pagination or Media Count : 5

Abstract : Electrodiffusion (sweeping) is a post-growth treatment which allows the selective exchange of charge compensating interstitial ions in quartz. This technique is employed commercially to enhance the radiation hardness of the material used for quartz oscillator crystals. Nearly all quartz contains A13+ ions substituting for Si4+. Adjacent interstitial alkali ions or protons provide the necessary charge compensation for these A13+ ions. Additional unidentified sites also trap protons to form the OH--related defects which are responsible for several IR absorption bands. When thermally released from their trapping sites, the interstitials can migrate along the relatively large Z axis channels. Therefore, if the sample is heated with an electric field applied along the Z axis, the ions can be swept out and replaced either by protons from the surrounding atmosphere or by the desired alkali from a salt electrode. This process also modifies some extended defects, as the etch tunnel density is reduced in hydrogen swept material.

Descriptors :   *Quartz, *Electrochemistry, *IOns, Interstitial, Crystal oscillators, Ionic current, Charge transfer, Substitution reactions

Distribution Statement : APPROVED FOR PUBLIC RELEASE