Comparison of the Electrical Properties of High-k Gate Dielectric (HfO₂ and Al₂O₃) Films with Pt or n⁺-Polycrystalline-Silicon Gate

Abstract

Pt or Arsenic (As)-doped polycrystalline-silicon (poly-Si) gate/HfO₂ or HfO₂-Al₂O₃/p-type Si metal oxide semiconductor (MOS) capacitors were fabricated using an atomic-layer-deposition technique, and their compatibility with poly-Si gate was investigated using a comparison with the Pt gate. The HfO₂-Al₂O₃ stack film was found to have better As diffusion-blocking properties as a result of the rather thick amorphous interface layer including Al₂O₃ than that of the HfO₂ film. N⁺ doped poly-Si gate/HfO₂-Al₂O₃ MOS capacitors had a lower current density of −1.1× 10⁻⁹ A/cm² at −1 V resulting in a small hysteresis voltage due to the lower As penetration and thick amorphous interface layer. These results suggest that N⁺ doped poly-Si gate/HfO₂-Al₂O₃ MOS capacitors are compatible with the poly-Si gate, which is also comparable to the Pt gate.

Keywords:

• Pt
• poly-Si
• HfO₂
• Al₂O₃
• As
• penetration

ACKNOWLEDGEMENTS

This work was supported by the Korea Research Foundation (Grant No. KRF-2002-042-D00348), and Korean Ministry of Science and Technology through National Research Laboratories program and National R&D Project for Nano Science and Technology (M10214000097-02B1500-01500).