Helium-induced nanocavities in silicon: Formation and properties

Sanjay Rangan, S Ashok, G. Chen, D. Theodore

Research output: Contribution to journalConference articlepeer-review


Nanocavities in Si formed by He ion implantation and anneal are of interest for impurity gettering and localized lifetime control, an in layer splitting techniques used in wafer bonding. With sequential thermal anneal following cascade He implantation (40-160 keV, 2 × 1015 - 4 × 1016 cm-2) we have obtained multiple cavity layers. Transmission electron microscopy data reveal that, under isothermal anneal, the cavity shape changes from a distinct, aligned hexagonal geometry to a rounded spheroidal shape with increasing anneal time. Deep level transient spectroscopy (DLTS) measurements of the cavity region show broad minority carrier (electron in p-type Si) peaks indicative of the presence of defect clusters. Unusual capacitance-temperature (C-T) characteristics with steps and hysterisis are also seen, reflecting metastable behavior arising from change in structural configuration of the cavity defects.

Original languageEnglish (US)
Pages (from-to)255-261
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume4746 I
StatePublished - Jan 1 2002
EventPhysics of Semiconductor Devices - Delhi, India
Duration: Dec 11 2001Dec 15 2001

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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