Improving Thermal Stability and Interface State Density of High-κ Stacks by Incorporating Hf into an Interfacial Layer on p-Germanium

Yi He Tsai, Chen Han Chou, An Shih Shih, Yu Hau Jau, Wen Kuan Yeh, Yu Hsien Lin, Fu-Hsiang Ko, Chao-Hsin Chien*

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

We propose a new HfGeOx interfacial layer (IL) for the high-κ gate-stacks on p-Type germanium substrate with improved thermal stability as compared with that of conventional GeOx IL. We inserted an additional HfO 2 layer after the formation of GeO x in the HfO 2 /Al 2 O 3 /GeOx/Ge gate-stack by using plasma-enhanced atomic layer deposition. Through the use of post-deposition annealing and post-metal annealing, the new system exhibited greater thermal immunity and was stable up to 600 °C. We speculate that the improvement originates from the formation of HfGeO x through the combination of HfO 2 and GeO x , according to the thermodynamic data. By incorporating Hf into interfacial layer, the fabricated high-κ gate-stack with an equivalent oxide thickness of 1.2 nm, a low interface states density (Dit) of approximately 3.3×10 11 eV -1 cm -2 , and an impressive gate leakage current of approximately 2.2×10 -6 A/cm 2 at V FBs -1V.

Original languageEnglish
Article number7577750
Pages (from-to)1379-1382
Number of pages4
JournalIEEE Electron Device Letters
Volume37
Issue number11
DOIs
StatePublished - 1 Nov 2016

Keywords

  • Aluminum oxide (Al O )
  • Equivalent oxide thickness
  • Germanium
  • Germanium oxide (GEO )
  • Hafnium oxide (HfO )
  • Plasma enhanced atomic layer deposition

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