Interface Characterization of HfO2/GaSb MOS Capacitors with Ultrathin Equivalent Oxide Thickness by Using Hydrogen Plasma Treatment

Ming Li Tsai, Jun Yu Ko, Shin Yuan Wang, Chao-Hsin Chien

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


We investigate p-type GaSb MOS capacitors with various HfO2 thicknesses grown using an atomic layer deposition. GaSb surfaces treated with ex-situ chemical solution and in situ remote hydrogen plasma are inspected. After a series of etching steps, the GaSb surfaces exhibit smooth topography, indicating that this combination of treatments is capable of realizing ultrathin dielectric deposition. After etching processes, the ultrathin (approximately 3 nm) HfO2 layer deposited successfully on GaSb exhibit high-permittivity (approximately 21) properties as well as equivalent oxide thickness (EOT) of 0.75 nm, which can be attributed to the flat surface. To the best of our knowledge, the EOT of GaSb capacitor prepared using the exploited approach is record low. Furthermore, we find that the interlayer present after hydrogen plasma treatment and forming gas annealing could efficiently passivate interface state density and achieve high C-V modulation. Compared with the benchmark of gate leakage current versus EOT, the electrical performance with low gate leakage current of the GaSb MOS capacitors demonstrates the high feasibility of the proposed treatments.

Original languageEnglish
Article number7515183
Pages (from-to)3459-3465
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number9
StatePublished - 1 Sep 2016


  • Capacitor
  • dielectric interface
  • equivalent oxide thickness (EOT)
  • gallium antimonide
  • hafnium oxide
  • hydrogen plasma
  • Surface treatment

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