Optically stimulated diffusion in ultra-shallow junction formation

Y. Kondratenko, C. T.M. Kwok, R. Vaidyanathan, E. G. Seebauer

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Formation of pn junctions in advanced Si-based transistors employs rapid thermal annealing after ion-implantation in order to increase the activation of dopants. There has long been suspicion that the strong lamp illumination required for this procedure may nonthermally influence the diffusion of dopants. Identification of such effects is difficult in conventional RTA geometries because lamps provide both heating and photo stimulation, and because the interpretation of conventional dopant diffusion experiments is impeded by complex dopant-defect interactions. We have circumvented these problems with a new experimental design in which heating and illumination can be decoupled. Data interpretation has been simplified by examining the motion of isotopically labelled 30Si tracer in an epitaxial 28Si matrix using SIMS depth profiling, and more recently with dopants such as arsenic in standard ion-implanted Si. Results for self-diffusion show that for n-type Si, self-diffusion rates are increased nonthermally by more than an order of magnitude for modest illumination intensities of roughly 1 W/cm2. Diffusion rates for silicon self-diffusion are shown to change by factors of up to 25 in response to optical fluxes on the order of 1 W/cm2. Results depend on doping type; the rates of both interstitial formation and migration are affected in the case of n-type material. There is no comparable effect for p-type material, however. Significant effects appear for boron as well in standard implantation experiments.

Original languageEnglish (US)
Title of host publicationIon Implantation Technology 2008 - 17th International Conference on Ion Implantation Technology, IIT 2008
EditorsEdmund G. Seebauer, Amitabh Jain, Yevgeniy V. Kondratenko, Susan B. Felch
PublisherAmerican Institute of Physics Inc.
Number of pages4
ISBN (Electronic)9780735405974
StatePublished - 2008
Event17th International Conference on Ion Implantation Technology, IIT 2008 - Monterey, United States
Duration: Jun 8 2008Jun 13 2008

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other17th International Conference on Ion Implantation Technology, IIT 2008
Country/TerritoryUnited States


  • Annealing
  • Dopant diffusion enhancement
  • Illumination effects
  • Photo stimulated diffusion
  • Ultra-Shallow junctions

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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