Low Voltage Electron Microscopy: Principles and Applications

Chapter 8

What's Next? The Future Directions in Low Voltage Electron Microscopy

David C. Bell¹ and Natasha Erdman²

¹School of Engineering and Applied Sciences, Harvard University, USA

²JEOL USA Inc., USA

8.1 Introduction

With the advances in electron gun design, aberration corrected optics and improvements in the sensitivity of recording images and obtaining analytical information, the future for low voltage electron microscopy is looking very promising. Rather than having custom designed SEMs and TEMs, the experience with lower voltage instruments have motivated instrument manufacturers to include these advances with the design of traditional systems. For example, the advent and incorporation of special aberration correctors required improvements in high voltage power supplies and electron optics, these improvements have typically been carried over to non-corrected systems.

In the case of SEMs, the improved operation at primary beam voltages below 1 kV, for example, now means that most FEG-SEM's can easily operate at 0.1–0.5 kV with good performance. Some may say that the catch up is now being done with the detectors to improve upon the efficiency of SE and BSE detection and analytical capabilities. TE and STEM have of course benefited greatly from the incorporation of spherical aberration correctors; now the next step is taking place, the detector design and performance improvements. For TEM the big push is to replace CCD CMOS technology for the imaging array with direct electron ...