The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr∕O∕W Schottky gun. At the pressure of less than 1×10−9Pa, the authors observed stable emission of 20nA, which generates the specimen current of 5pA required for scanning electron microscopes.

We prepared Zn(octylethylenediamine(= oct-en))2Cl2 and found that its solubilities to benzene and chloroform are appreciably enhanced with an addition of water. This solubilizaiton can be attributed to the formation of reverse micelles. Vapor pressure osmometry(VPO) showed appreciable aggregations in benzene solutions, and 13C and 2H NMR relaxations for the zinc complex and water molecules, respectively, suggest their extensive motional restrictions in benzene and chloroform solutions by the aggregations.

This report describes the characteristics for the development of a compound lens that consists of a single pole-piece objective lens and an electrostatic bipotential lens. By applying a relatively small voltage of around 1 kV to the specimen and the bipotential lens, the image quality for low acceleration voltage is improved to a condition better than with just a single pole-piece lens. Even if the wafer is tilted to a large angle, the electric field near the specimen does not become asymmetrical, and there is no occurrence of astigmatic aberration or a reduction of the secondary electron signal. Therefore, 300 mm diameter wafers can be tilted with large angles to observe patterns, particles and defects with high-resolution SEM. Lastly, when the specimen is not tilted, a topographic image of the specimen surface can be obtained by detecting the secondary electron with dual detectors.

For developing electron microscopes mounted with a single-atom electron source, we constructed a practical gun chamber of an extreme high vacuum (XHV), and demonstrated excellent characteristics of its emission beams; the stable beam with the current fluctuation of ∼0.8 % was observed at the total current of 20 nA in the XHV of 1 × 10 −9 Pa.

As is well known, it is not so easy to operate a conventional transmission electron microscope for observation of magnetic materials. The reason is that the instrument requires re-alignment of the axis and re-correction of astigmatism after each specimen shift, as the lens field is greatly disturbed by the specimen. With a conventional electron microscope, furthermore, it is impossible to observe magnetic domains, because the specimen is magnetized to single orientation by the lens field. The above mentioned facts are due to the specimen usually being in the lens field. Thus, special techniques or systems are usually required for magnetic material observation (especially magnetic domain observation), for example, the technique to switch off the objective lens current and Lorentz microscopy. But these cannot give high image quality and wide magnification range, and furthermore Lorentz microscopy is very complicated.