課題別成果報告 -詳細-

Atomic-Layer-Deposition of High-k Gate Dielectrics for Scaled MOSFETs
Shiyang Zhu and Anri Nakajima

Atomic layer deposition (ALD) of high-κ gate dielectrics (HfO₂ and Si-nitride) on both Si and Ge substrates were systematically studied. HfO₂ thin films grown from tetrakis(diethylamino)hafnium and water have almost stoichiometric components and Al/ALD-HfO₂/p-Si capacitors have comparable electrical properties with respect to the recently reported data. MOSFETs with the ALD-HfO₂ gate dielectrics were successfully demonstrated using a simplified process. ALD-HfO₂ on Ge substrates suffers a relatively large leakage current and the Al/ALD-HfO₂/p-Ge capacitors exhibit relatively large hysteresis and frequency-dependency. Nevertheless, the performance of our ALD-HfO₂ on Ge is still comparable to the reported data. For comparison, ALD of Si-nitride films on Si and Ge substrates from SiCl4 and NH3 precursors was studied. Moreover, reliability of MOSFETs with ultrathin gate dielectrics was also studied.