Preamorphization Techniques for Shallow Junctions in SI

  • J. Imschweiler
  • H. A. Hefner
Conference paper


Due to dopant channeling during ion implantation into crystalline silicon, shallow junctions are difficult to achieve. The scope of this study was to investigate the preamorphization technique as a tool to prevent channeling during transistor fabrication. Implantation of heavy ions such as Si+ and Ge+ offers the possibility of amorphizing a desired region in a highly controllable way. The preamorphization experiments were carried out using these species of atoms. In both cases boron channeling was found to be completely suppressed. In the case of Si+ preamorphization transistors show significant leakage currents due to a high density of residual stacking faults and dislocation loops inside the active region. In the case of Ge+ preamorphization complete recrystallization of the amorphized layer was obtained. No stacking faults or dislocation loops could be observed by TEM analysis after a two-step low temperature annealing process. A slight improvement of the peak value of the transit frequency was obtained for the preamorphized transistors.


Transmission Electron Microscopy Analysis Rapid Thermal Annealing Dislocation Loop Amorphized Layer Bipolar Transistor 
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Copyright information

© ECSC, EEC, EAEC, Brussels and Luxembourg 1990

Authors and Affiliations

  • J. Imschweiler
    • 1
  • H. A. Hefner
    • 1
  1. 1.TTELEFUNKEN electronic GmbHHeilbronnGermany

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