Passivation Properties of Atomic-Layer-Deposited Hafnium and Aluminum Oxides on Si Surfaces

This paper studies the chemical and field effect passivation properties of silicon surfaces by thin hafnium oxide
$(\hbox{HfO}_{2})$
and aluminum oxide
$(\hbox{Al}_{2}\hbox{O}_{3})$
layers grown by chemical-vapor-based atomic layer deposition method. Using a rigorous metal–oxide–semiconductor model and results from capacitance–voltage measurements, the density of fixed charges
$(N_{f})$
and the density of interface traps
$(D_{\rm it})$
at the
$\hbox{HfO}_{2}\hbox{/}\hbox{Si}$
and
$\hbox{Al}_{2}\hbox{O}_{3}\hbox{/}\hbox{Si}$
interfaces were obtained. Microwave photoconductivity decay measurements were used to characterize interface recombination velocities at these interfaces.