Physical and electrical characteristics of Hf02/Hf films deposited on silicon by atomic layer deposition

The HfO₂/Hf stacked film has been applied as the gate dielectric in MOS devices. The HfO₂ thin film was deposited on p-type (100) silicon wafers by atomic layer deposition (ALD) using TEMAH and O₃ as precursors, Prior to the deposition of HfO₂ film, a thin Hf metal layer was deposited as an intermediate layer. The deposition temperature of HfO₂ thin film was 350degC and its resulted thickness was 15 nm. Round-type MOS capacitors have been fabricated on HfO₂/Hf/Si substrates with 200 nm-thick Pt top electrodes. We investigated and then compared the growth of inter layer between the HfO₂/Hf/Si and the HfO₂/Si structures during temperature annealing. The interfacial layer in our HfO₂/Hf/Si structure was changed as the HfSiO film. The Hf metal layer sandwiched in the HfO₂/Si structure was effectively suppressed to grow interfacial SiO₂ layer. The MOS capacitance of the HfO₂/Hf/Si structure was bigger than that of HfO₂/Si structure. The dielectric constant in our structure is ~ 19.