Ion-implantation issues in the formation of shallow junctions in germanium

✍ Scribed by E. Simoen; A. Satta; A. D’Amore; T. Janssens; T. Clarysse; K. Martens; B. De Jaeger; A. Benedetti; I. Hoflijk; B. Brijs; M. Meuris; W. Vandervorst

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 361 KB
• Volume: 9
• Category: Article
• ISSN: 1369-8001
• DOI: 10.1016/j.mssp.2006.08.067

✦ Synopsis

This paper provides an overview of the current state-of-the-art in the formation of shallow junctions in germanium by ion implantation, covering the issues of dopant activation, diffusion and defect removal. As will be shown, for the case of p + implantations, the application of rapid thermal annealing (RTA) to B implants yields good sheet resistance values, corresponding with activation levels well above the maximum solid solubility. A further improvement can be achieved by the use of a Ge pre-amorphization implant (PAI), which also removes the stable extended defects observed after high-dose B implantations. It will be shown that the formation of shallow n + junctions is a more challenging field due to the rather low dopant solubilities and high diffusivities. However, encouraging results will be reported on the application of laser and flash-lamp annealing of P implantations in Ge. Also point-defect engineering is shown to be successful in controlling the junction formation.