Improving electrical characteristics of W/HfO 2 /In 0.53 Ga 0.47 As gate stacks by altering deposition techniques

D. Zade*, K. Kakushima, T. Kanda, Y. C. Lin, P. Ahmet, K. Tsutsui, A. Nishiyama, N. Sugii, E. Y. Chang, K. Natori, T. Hattori, H. Iwai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of controlling InGaAs substrate temperature during electron beam deposition of HfO 2 on electrical characteristics of W/HfO 2 /n-In 0.53 Ga 0.47 As capacitors are investigated. It is found that by depositing a thin HfO 2 layer at the interface when substrate temperature is raised to 300 °C, frequency dispersion at depletion and accumulation conditions is reduced and interface state density is lowered regardless of the HfO 2 thickness. Cross-sectional transmission electron microscopy images have revealed that the formation of mesoscopic voids in the InGaAs substrate near the interface is suppressed with HfO 2 deposition at 300 °C at the interface. A band diagram with an additional bulk trap energy level has been proposed to explain the frequency dispersion and conductance peaks at accumulation condition.

Original languageEnglish
Pages (from-to)1109-1112
Number of pages4
JournalMicroelectronic Engineering
Volume88
Issue number7
DOIs
StatePublished - 1 Jul 2011

Keywords

  • Bulk trap
  • Frequency dispersion
  • High-k
  • InGaAs
  • Interface state density

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