Multilayered ALD HfAlOx and HfO2 for high-quality gate stacks

Md Nasir Uddin Bhuyian, Durgamadhab Misra

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

This paper has demonstrated a high-quality HfO2- based gate stack by depositing atomic-layer-deposited HfAlOx along with HfO2 in a layered structure. In order to get a multifold enhancement of the gate stack quality, both Al percentage and distribution were observed by varying theHfAlOx layer thickness and its location in the gate stack. It was found that < 2% Al/(Al + Hf)% incorporation can result in up to 18% reduction in the average EOT along with up to 41% reduction in the 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, the dielectrics with Al/(Hf+Al)%<2% showed resistance to stressinduced flatband voltage shiftΔVFB, and stress-induced leakage current. The time-dependent dielectric breakdown characteristics showed a higher charge to breakdown and an increase in the extracted Weibull slope β, which further confirms an enhanced dielectric reliability for devices with < 2% Al/(Al + Hf)%.

Original languageEnglish (US)
Article number7088592
Pages (from-to)229-235
Number of pages7
JournalIEEE Transactions on Device and Materials Reliability
Volume15
Issue number2
DOIs
StatePublished - Jan 1 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Safety, Risk, Reliability and Quality
  • Electrical and Electronic Engineering

Keywords

  • Equivalent oxide thickness (EOT)
  • HfAlO
  • Interface state density (D)
  • Stress-induced flatband voltage shift (ΔV)
  • Stress-induced leakage current (SILC)
  • Time-dependent dielectric breakdown (TDDB)

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