Chemical interaction between atomic-layer-deposited $HfO2$ thin films and the Si substrate Available to Purchase

$HfO2$ thin films were deposited on Si wafers using an atomic layer deposition technique at temperatures ranging from 200 to 400 °C with $HfCl4$ as the precursor and $H2O$ as the oxidant. The time-dependent interfacial-layer growth behavior was dependent on the deposition temperature. The interfacial layer grew with increasing deposition time at 200 °C. However, the film thicknesses decreased with increasing deposition time after reaching a certain maximum value at 300 and 400 °C due to the enhanced dissolution of $SiOx$ into the growing films at these temperatures. Post-annealing at 800 °C under a $N2$ atmosphere resulted in the precipitation of a Si-rich interfacial layer even for the initially interfacial layer free films. This had the effect of reducing the capacitance density of the films.