Positive temperature coefficient of impact ionization in strained-Si

Niamh S. Waldron, Arthur J. Pitera, Minjoo L. Lee, Eugene A. Fitzgerald, Jesús A. del Alamo

Research output: Contribution to journalArticlepeer-review


We have experimentally studied impact ionization (II) in the strained-Si layer of a strained-Si/SiGe heterostructure. Our key finding is that the impact ionization multiplication coefficient has a positive temperature coefficient which is opposite to that of bulk Si. Furthermore, the temperature dependence of the multiplication coefficient has been found to be exponential in nature. Our experimental work shows that the combination of a strong and positive temperature dependence of the II coefficient and the significant self-heating that this structure suffers from results in an overall impact ionization rate that is more than an order of magnitude higher than that of reference Si devices operating under identical bias conditions.

Original languageEnglish (US)
Pages (from-to)1627-1633
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number7
StatePublished - Jul 2005
Externally publishedYes


  • Impact ionization
  • Self-heating
  • Stained-Si

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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