The characteristics of HfO 2 films grown on Si substrates using a tetrakis-diethyl-amino-hafnium precursor by the remote plasma atomic layer deposition (RPALD) and direct plasma ALD (DPALD) methods were investigated by physical and electrical measurement techniques. The as-deposited HfO 2 layer from RPALD exhibits an amorphous structure, while the HfO 2 layer from DPALD exhibits a clearly visible polycrystalline structure. Medium energy ion scattering measurement results indicate that the interfacial layer consists of the interfacial SiO 2-x and silicate layers. These results suggested that the stoichiometric change in the depth direction could be related to the energetic reactant in a state of plasma used in the plasma ALD process, resulting in damage to the Si surface and interactions between Hf and SiO 2-x. The as-deposited HfO 2 films using RPALD have the better interfacial layer characteristics than those using DPALD. A metal-oxide-semiconductor capacitor fabricated using the RPALD method exhibits electrical characteristics such as equivalent oxide thickness (EOT) of 1.8 nm with an effective fixed oxide charge density (Q f,eff) of ∼4.2×10 11 q/cm 2 and that for DPALD has a EOT (2.0 nm), and Q f,eff(∼-1.2×10 13 q/cm 2).
Bibliographical noteFunding Information:
This study was supported by the National Program for Tera-level Nano-devices of the Ministry of Science and Technology as one of the 21st Century Frontier Programs.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)