Field emission (FE) properties of carbon related materials such as carbon nanotubes, carbon nanofibers, and graphite nanoneedles are currently assessed as excellent FE cathode materials which can be operated under non-ultrahigh vacuum condition for various applications. Indeed, Matsumoto et al have reported about a cold cathode SEM with a graphite nanoneedle cathode [1]. We are developing a compact FE-SEM equipped with a multiwall carbon nanotubes (MWNTs) bundle cathode and a Butler electrostatic lens as a condenser lens. The preliminary results are reported in this paper. Figure 1 shows a schematic diagram of compact FE-SEM we developed. A MWNTs bundle produced by arc discharge in helium gas was adhered to a top of tungsten hairpin filament by a conducting paste. The Butler lens consisted of an extraction and a focusing electrode was placed in front of the MWNTs bundle cathode. A ballast resistor was connected to the extraction electrode in order to stabilize an emission current. To obtain a fine probe beam, the electron beam passing through a deflector followed by the Butler lens was focused by means of an objective lens made of a permanent magnet. The adoption of these two lenses brought about downsizing to our FE-SEM column, and a distance between the cathode and the sample stage was only 192mm.
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