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

The HfO
₂
/Hf stacked film has been applied as the gate dielectric in MOS devices. The HfO
₂
thin film was deposited on p-type (100) silicon wafers by atomic layer deposition (ALD) using TEMAH and O
₃
as precursors, Prior to the deposition of HfO
₂
film, a thin Hf metal layer was deposited as an intermediate layer. The deposition temperature of HfO
₂
thin film was 350degC and its resulted thickness was 15 nm. Round-type MOS capacitors have been fabricated on HfO
₂
/Hf/Si substrates with 200 nm-thick Pt top electrodes. We investigated and then compared the growth of inter layer between the HfO
₂
/Hf/Si and the HfO
₂
/Si structures during temperature annealing. The interfacial layer in our HfO
₂
/Hf/Si structure was changed as the HfSiO film. The Hf metal layer sandwiched in the HfO
₂
/Si structure was effectively suppressed to grow interfacial SiO
₂
layer. The MOS capacitance of the HfO
₂
/Hf/Si structure was bigger than that of HfO
₂
/Si structure. The dielectric constant in our structure is ~ 19.