The mechanism for the suppression of leakage current in high dielectric TiO2 thin films by adopting ultra-thin HfO2 films for memory application.

Autor: Seo, Minha, Ho Rha, Sang, Keun Kim, Seong, Hwan Han, Jeong, Lee, Woongkyu, Han, Sora, Seong Hwang, Cheol
Předmět:
Zdroj: Journal of Applied Physics; Jul2011, Vol. 110 Issue 2, p024105, 7p
Abstrakt: The electrical leakage current of thin rutile structured TiO2 films deposited by atomic layer deposition on a Ru electrode was enormously reduced by depositing an extremely thin HfO2 (< 1 nm) on top. The sacrifice of the capacitance density by the HfO2 was minimized. The leakage mechanism analysis on the Pt/TiO2/Ru and Pt/HfO2/TiO2/Ru structures revealed that the improvement in leakage current was attributed to the reduction of defect (trap) density in the TiO2 film. The interfacial potential barrier height for electron transport in thinner (∼ 10 nm) TiO2 films was lower than that of thicker (∼ 20 nm) TiO2 films, which resulted in a higher leakage current in these films. The capping of ultra-thin (∼ 0.7 nm) HfO2 films effectively increased the potential barrier height, and the leakage current was decreased accordingly. The leakage current behavior was systematically analyzed from quantum mechanical transport simulations. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index