Novel dual-metal gate technology using Mo-MoSix combination

Tzung Lin Li*, Wu Lin Ho, Hung Bin Chen, Howard C.H. Wang, Chun Yen Chang, Chen-Ming Hu

*Corresponding author for this work

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

A novel dual-metal gate technology that uses a combination of Mo-MoSix gate electrodes is proposed. An amorphous-Si/Mo stack was fabricated as a gate electrode for the n-channel device. It was thermally annealed to form MoSix. Pure Mo served as the gate electrode for the p-channel device. The work functions of MoSix and pure Mo gates on SiO2 are 4.38 and 4.94 eV, respectively, which are appropriate for devices with advanced transistor structures. The small increase in the work function (< 20 meV) and the negligible equivalent oxide thickness variation (< 0.08 nm) after rapid thermal annealing at 950 °C for 30 s also demonstrate the excellent thermal stabilities of Mo and MoSix on SiO2. Additional arsenic ion implantation prior to silicidation was demonstrated further to lower the work function of MoSixto 4.07 eV. This approach for modulating the work function makes the proposed combination of Mo-MoSix gate electrodes appropriate for conventional bulk devices. The developed dual-metal-gate technology on HfO2 gate dielectric was also evaluated. The effective work functions of pure Mo and undoped MoSixgates on HfO2 are 4.89 and 4.34 eV, respectively. A considerable work-function shift was observed on the high-κ gate dielectric. The effect of arsenic preimplantation upon the work function of the metal silicide on HfO2 was also demonstrated, even though the range of modulation was a little reduced.

Original languageEnglish
Pages (from-to)1420-1426
Number of pages7
JournalIEEE Transactions on Electron Devices
Volume53
Issue number6
DOIs
StatePublished - 1 Jun 2006

Keywords

  • Dual-metal gate
  • Molybdenum
  • Silicide
  • Thermal stability

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