Electron Optical Properties of Microcolumn with Field Emitter

We present the electron optical properties of a newly designed microcolumn. The microcolumn consists of an objective lens and an electron gun, which is composed of a microscale field emitter and a condenser lens. An acceleration lens was used as the objective lens. Each component was optimized to maximize its own function while minimizing its impact on the functions of the other components. The current–voltage characteristics of each electrode were evaluated. The current variation characteristics of each electrode indicated that each optimized structure could be used to control the electron beam. The objective lens could also focus the electron beam to a diameter of approximately 40 µm at a working distance of 2 mm and 400× magnification when no acceleration electric field was applied between the microcolumn and the anode.