Improving Interface State Density and Thermal Stability of High-κ Gate Stack Through High-Vacuum Annealing on Si0.5Ge0.5

Wei Li Lee, Cheng Yu Yu, Jun Lin Zhang, Guang Li Luo, Chao-Hsin Chien*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We fabricated HfO2-based gate stacks on epi-Si0.5Ge0.5 substrates and investigated the effect of thermal treatment on their structural and electrical properties at varying temperatures and pressures in oxygen ambient. The thermal treatment process led to severe degradation of interface quality as the temperature increased. Material analyses indicated that annealing in oxygen ambient resulted in oxygen diffusion from the high-κ material to the SiGe surface, causing undesirable SiGe reoxidation. In high-vacuum annealing, an interface state density of approximately 1.4 × 1011 eV-1 cm-2 and a thermal stability of up to 500 °C were achieved for the gate stack on SiGe.

Original languageEnglish
Article number8667385
Pages (from-to)678-681
Number of pages4
JournalIEEE Electron Device Letters
Volume40
Issue number5
DOIs
StatePublished - 1 May 2019

Keywords

  • SiGe channel
  • high-vacuum annealing (HVA)
  • interface passivation

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