Electrolysis of copper in solid silicon

Abstract

The diffusion of copper in silicon can be enhanced or retarded by application of an electric field. Transport measurements indicate that the copper diffuses with a single positive charge at temperatures around 1100°C. The amount of transport observed requires that a large fraction, possibly 50 per cent of the copper in solution, be positively charged and rapidly diffusing. On the basis of these results and the known slight electrical activity produced by copper in silicon at room temperature, we conclude that the charged, rapidly diffusing species of copper is interstitial. Similar experiments with Au and Fe in silicon show no field effect at 1100°C. It is found that copper in germanium diffuses rapidly with a positive charge at 700°C, in agreement with the results reported by F uller for higher temperatures.