Multi-layered nanocavities in silicon with sequential helium implantation/anneal

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

Research output: Contribution to journalConference articlepeer-review

14 Scopus citations


Nanocavities in Si formed by He ion implantation and anneal are of interest for impurity gettering in Si technology, localized lifetime control in power devices, and in layer splitting techniques used in wafer bonding. We have obtained multiple cavity layers with cascade He implants (40-160 keV, 2 × 1015-4 × 1016 cm-2) by the use of sequential thermal anneals. This behavior is intimately related to the vacancy generation process necessary for cavity formation. 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 measurements of the cavity region show broad minority carrier (electron in p-type Si) peaks indicative of the effect of defect clusters. They also exhibit metastable behavior under temperature cycling, suggestive of change in structural configuration of the cavity defects.

Original languageEnglish (US)
Pages (from-to)417-421
Number of pages5
JournalNuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
StatePublished - May 2003
Event13th International conference on Ion beam modification of Mate - Kobe, Japan
Duration: Sep 1 2002Sep 6 2002

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Instrumentation


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