Bilayer Silver Precipitation in Glass Formed by Alternate Doping of Silver and Sodium Ions and Additive Voltage Application

Abstract

The solid-state ion exchange method enables to dope metal ions to alkali-containing glass surfaces. When silver is used as a dopant material, a silver precipitation layer is formed in the silver-doped area by additive voltage application. Because of the high electrical conductivity, the precipitation layer can be used as an internal wiring in a glass substrate. In this study, we tried to form bilayer wiring in a glass substrate. For the bilayer precipitation, two silver-doped areas are necessary to be separated by a silver-undoped area. Therefore, silver, sodium and silver ions were sequentially doped to a borosilicate glass surface. To prevent silver ions being mixed into the sodium-doped area, the diffusion behaviors of two ionic species were numerically analyzed. The temperature dependences of their diffusion coefficients were also determined by comparing experimental and numerical results carried out under various temperature conditions. Calculated results showed that low temperature doping of sodium ions to silver-doped area is preferable. By adopting suggested conditions, the formation of electrically-insulated two silver precipitation layer was achieved.