Ionhyphen;implanted Se in GaAs

摘要

Electrical measurements are combined with the technique of secondaryhyphen;ion mass spectrometry (SIMS) in order to experimentally analyze and correlate the diffusion and activation of ionhyphen;implanted selenium in GaAs. A theory is presented based on the assumption of four chemically different species of selenium: (1) substitutional selenium, (2) interstitial selenium, (3) selenium complexed with a gallium vacancy, and (4) precipitated selenium. It is proposed that the interaction between these four species dictates the resulting redistribution and electrical activation of ionhyphen;implanted layers. The factors governing these interactions are investigated, and it is speculated that only substitutional selenium is a shallow donor. In addition, it is speculated that the species responsible for redistribution of impurity profiles is the seleniumhyphen;gallium vacancy complex. Precipitates and interstitial selenium appear to neither diffuse nor act like donors in GaAs. A model is developed which formalizes these observations in a set of five coupled differential equations. By employing a minimum number of simplifying assumptions, we are able to extract quantitative predictions from this model which accurately describe not only our experimental results but those of other workers.