Atomic and Electronic Structure Investigations of HfO2/SiO2/Si Gate Stacks Using Aberration-Corrected STEM

Abstract

Aberration correction in scanning transmission electron microscopy represents a major breakthrough in transmission electron microscopy, enabling the formation of sub-Angstrom probe sizes. Thus, electron microscopy achieved single atom sensitivity. Here, we show how this technique with its unique spatial resolution in combination with high-resolution electron energy-loss spectroscopy can be used to investigate atomic and electronic structures of semiconductor interfaces with single atom sensitivity. We employ a Si/HfO2/SiO2/Si high-k dielectric interface to show the presence of single Hf atoms in the SiO2 interlayer. Furthermore, we demonstrate how local dielectric properties and local band structure information can be obtained by electron energy-loss spectroscopy.