Electrical and materials properties of ZrO[sub 2] gate dielectrics grown by atomic layer chemical vapor deposition.

Structural and electrical properties of gate stack structures containing ZrO[sub 2] dielectrics were investigated. The ZrO[sub 2] films were deposited by atomic layer chemical vapor deposition (ALCVD) after different substrate preparations. The structure, composition, and interfacial characteristics of these gate stacks were examined using cross-sectional transmission electron microscopy and x-ray photoelectron spectroscopy. The ZrO[sub 2] films were polycrystalline with either a cubic or tetragonal crystal structure. An amorphous interfacial layer with a moderate dielectric constant formed between the ZrO[sub 2] layer and the substrate during ALCVD growth on chemical oxide-terminated silicon. Gate stacks with a measured equivalent oxide thickness (EOT) of 1.3 nm showed leakage values of 10[sup -5] A/cm[sup 2] at a bias of -1 V from flatband, which is significantly less than that seen with SiO[sub 2] dielectrics of similar EOT. A hysteresis of 8-10 mV was seen for ±2 V sweeps while a midgap interface state density (D[sub it]) of ∼3x10[sup 11] states/cm eV was determined from comparisons of measured and ideal capacitance curves. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]