電子光学装置用ダイヤモンド電子源の作製とエネルギー分散評価

抄録

Diamond that shows low or negative electron affinity has good electron emission properties. The authors are developing a diamond electron source, which is suited for electron optics instruments such as electron beam exposure systems and electron microscopes. As a result of thermionic emission evaluations, an electron emission current of practical level (116 μA at 600^oC) was obtained. The energy spread of an electron beam generated by thermionic emission was measured as 0.23 eV (FWHM), the value of which was lower than those of a LaB₆ cathode and a ZrO/W cathode measured together. The result of field emission evaluations, a practical beam current (459 pA) and stability (6%rms for 10 h) for scanning electron microscope (SEM) was obtained. The energy spread of over 200 pA of a high current electron beam generated by field emission was about the same as that of a tungsten field emission cathode. It was found that an unprecedentedly high current and high convergence electron source can be made by using diamond.