Structural and dielectric properties of thin ZrO[sub 2] films on silicon grown by atomic layer deposition from cyclopentadienyl precursor.

ZrO[sub 2] thin films with thicknesses below 20 nm were deposited by the atomic layer deposition process on Si(100) substrates at 350 °C. An organometallic precursor, Cp[sub 2]Zr(CH[sub 3])[sub 2] (Cp=cyclopentadienyl, C[sub 5]H[sub 5]) was used as the zirconium source and water or ozone as oxygen source. The influence of oxygen source and substrate pretreatment on the dielectric properties of ZrO[sub 2] films was investigated. Structural characterization with high-resolution transmission electron microscopy was performed to films grown onto HF-etched or native oxide covered silicon. Strong inhibition of ZrO[sub 2] film growth was observed with the water process on HF-etched Si. Ozone process on HF-etched Si resulted in interfacial SiO[sub 2] formation between the dense and uniform film and the substrate while water process produced interfacial layer with intermixing of SiO[sub 2] and ZrO[sub 2]. The effective permittivity of ZrO[sub 2] in Al/ZrO[sub 2]/Si/Al capacitor structures was dependent on the ZrO[sub 2] layer thickness and oxygen source used. The interfacial layer formation increased the capacitance equivalent oxide thickness (CET). CET of 2.0 nm was achieved with 5.9 nm ZrO[sub 2] film deposited with the H[sub 2]O process on HF-stripped Si. The ozone-processed films showed good dielectric properties such as low hysteresis and nearly ideal flatband voltage. The leakage current density was lower and breakdown field higher for the ozone-processed ZrO[sub 2] films. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]