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

Abstract

This paper studies the chemical and field effect passivation properties of silicon surfaces by thin hafnium oxide <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(\hbox{HfO}_{2})$</tex></formula> and aluminum oxide <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(\hbox{Al}_{2}\hbox{O}_{3})$</tex></formula> 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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$(N_{f})$</tex></formula> and the density of interface traps <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(D_{\rm it})$ </tex></formula> at the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{HfO}_{2}\hbox{/}\hbox{Si}$</tex></formula> and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}\hbox{/}\hbox{Si}$</tex></formula> interfaces were obtained. Microwave photoconductivity decay measurements were used to characterize interface recombination velocities at these interfaces.