収差補正走査透過型電子顕微鏡を用いたサブナノオーダー分析の現状

摘要

Scanning transmission electron microscopy (STEM) is a powerful tool for not only imaging but also elemental composition and chemical bonding analysis by energy dispersive X-ray spectroscopy (EDX) and electron energy-loss spectroscopy (EELS) with nanometer spatial resolutions. The technique of spherical aberration correction has recently been developed, and angstrom spatial resolutions have been achieved for EDX and EELS measurement as well as imaging. I also introduce other recent trends in STEM related techniques. Low acceleration voltage has often been adopted in order to reduce electron radiation damage. Recent monochrometer has achieved 0.2 eV energy resolution for EELS measurement, which enables us to analyze chemical bonding in more detail.A new type of silicon drift detector (SDD) improves the sensitivity of EDX 10 times higher than conventional detectors. These recent technologies are not independently implemented but combined in an ultimate system which can promote diverse applications of STEM.%走査透過型電子顕微鏡(Scanning transmission electron microscopy: STEM)は，通常のTEMと同様に対象物の形状や寸法をナノオーダーで捉えたり，結晶構造の解析をしたりするだけでなく，特性X線分光法（Energy dispersive X-ray spectroscopy: EDX),電子線エネルギー損失分光法(Electron energy-loss spectroscopy: EELS)という周辺機能によってナノオーダーの空間分解能で組成·状態分析ができる有用なツールである.