The electrical and physical properties of reactively sputtered HfO 2 thin films on predeposited Hf metal layer were investigated. Compared with a conventional deposition process, i.e., direct deposition of HfO2 on a Si substrate, the HfO2/Hf stacked capacitor exhibits excellent electrical characteristics such as capacitance equivalent thickness (CET) as thin as 1.3 nm with lower leakage current of 2×10 -5(A/cm2) at -1 V gate bias. Based on the structural analysis as well as the electrical characteristics, the interfacial layer thickness is found to be controllable with minimum CET and higher permittivity by optimizing the thickness ratio between HfO2 and Hf. This improvement in electrical characteristics can be explained by the blocking of oxygen diffusion through HfO2 films into the Si substrate due to oxidation of the Hf metal layer itself.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)