Electrical and materials properties of $ZrO2$ gate dielectrics grown by atomic layer chemical vapor deposition Available to Purchase

Structural and electrical properties of gate stack structures containing $ZrO2$ dielectrics were investigated. The $ZrO2$ 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 $ZrO2$ films were polycrystalline with either a cubic or tetragonal crystal structure. An amorphous interfacial layer with a moderate dielectric constant formed between the $ZrO2$ 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 $10−5 A/cm2$ at a bias of −1 V from flatband, which is significantly less than that seen with $SiO2$ dielectrics of similar EOT. A hysteresis of 8–10 mV was seen for ±2 V sweeps while a midgap interface state density $(Dit)$ of $∼3×1011$ states/cm eV was determined from comparisons of measured and ideal capacitance curves.