Reliability of HfAlOx in multi layered gate stack

M. Nasir Bhuyian, D. Misra

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

1 Scopus citations

Abstract

This work has demonstrated a high quality HfO2 based gate stack by depositing HfAlOx along with HfO2 in a layered structure. In order to get multifold enhancement of the gate stack quality both Al percentage and distribution were observed by varying the HfAlOx layer thickness and it was found that < 2% Al/(Al+Hf)% incorporation can result in up to 18% reduction in average EOT along with up to 41% reduction in gate leakage current as compared to the dielectric with no Al content. On the other hand, excess Al presence in the interfacial layer moderately increased the interface state density (Dit). When devices were stressed in the gate injection mode at a constant voltage stress, dielectrics with Al/(Hf+Al)% < 2% showed resistance to stress induced flat-band voltage shift (ΔVFB), and stress induced leakage current (SILC). The time dependent dielectric breakdown (TDDB) characteristics showed a higher charge to breakdown and an increase in the extracted Weibull slope (β) that further confirms an enhanced dielectric reliability for devices with < 2% Al/(Al+Hf)%.

Original languageEnglish (US)
Title of host publication2015 IEEE International Reliability Physics Symposium, IRPS 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
PagesPI31-PI37
ISBN (Electronic)9781467373623
DOIs
StatePublished - May 26 2015
EventIEEE International Reliability Physics Symposium, IRPS 2015 - Monterey, United States
Duration: Apr 19 2015Apr 23 2015

Publication series

NameIEEE International Reliability Physics Symposium Proceedings
Volume2015-May
ISSN (Print)1541-7026

Other

OtherIEEE International Reliability Physics Symposium, IRPS 2015
Country/TerritoryUnited States
CityMonterey
Period4/19/154/23/15

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Keywords

  • Equivalent oxide thickness (EOT)
  • HfAlO
  • interface state density (Dit)
  • stress induced flat-band voltage shift (ΔVFB)
  • stress induced leakage current (SILC)
  • time dependent dielectric breakdown (TDDB)

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