Ion-implanted Se in GaAs

• Published in: Journal of applied physics Vol. 51; no. 8; pp. 4130 - 4138
• Main Authors: Lidow, A., Gibbons, J. F., Deline, V. R., Evans, C. A.
• Format: Journal Article
• Language: English
• Published: 01.01.1980
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.328232

Electrical measurements are combined with the technique of secondary-ion mass spectrometry (SIMS) in order to experimentally analyze and correlate the diffusion and activation of ion-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 ion-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 selenium-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.