Application of Low Energy STEM with the In-lens Cold FE-SEM

Y Orai,M Konno,S Okada,H Ito,T Sunaoshi,T Ogashiwa

doi:10.1088/1742-6596/522/1/012020

Abstract

We have developed a high resolution STEM imaging method using accelerating beam voltages of 30 kV and less. In this study, we examined and determined the low accelerating voltage parameters necessary for obtaining lattice resolution in STEM images, using the cold field emission scanning electron microscope (CFE-SEM), Hitachi SU9000. We also investigated and optimized the objective lens conditions for optimum lattice fringe imaging. The STEM images and associated Fourier transform image obtained at 30 kV show the Si (222) lattice fringes and reflection spots, corresponding to the d-lattice spacing of 0.157 nm. The STEM images and associated Fourier transform image at 15 kV show the Si (111) lattice fringes and reflection spot, corresponding to the d-lattice spacing of 0.314 nm.

Highlights

There is an increasing demand to achieve high resolution STEM imaging at low accelerating voltage to obtain acceptable contrast intensity in observation of nanometer order structure of materials consisting of low atomic number elements [1]
The Si (111) lattice fringes were imaged and the reflection spots corresponding to 0.314nm were successfully confirmed
These results confirmed that an in-lens Cold FE SEM system is useful for structural characterization for most material with minimal radiation beam damage

Summary

Introduction

There is an increasing demand to achieve high resolution STEM imaging at low accelerating voltage to obtain acceptable contrast intensity in observation of nanometer order structure of materials consisting of low atomic number elements [1]. The combination of the cold field emission scanning electron microscope (CFE-SEM) with in-lens objective lens was one the most suitable configurations to achieve high resolution STEM imaging at low acceleration voltage below 30kV due to the benefit of a small energy spread and small spherical aberration relative to the conventional type SEM.

Results

Conclusion