Presentation Information
[2P27]The confinement of electron beam angle of field emitters by optimizing the size of base tip and nano-protrusion fabricated by field-assisted oxygen etching
*Junki Shima1, Tatsuo Iwata1, Shigekazu Nagai1 (1. Graduate School of Engineering, Mie University)
Field emitters with higher brightness are required for electron microscopes with high spatial resolution. To improve the brightness of field emitters, we fabricated W-field emitter with nano-protrusion of 6.7 nm on a base with an approximately 50 nm radius of curvature by field-assisted oxygen etching. The fabricated emitter was characterized by measurements of I-V and energy distribution of field-emitted electrons. Experimental values of emission current and opening half-angle of the electron beam from the emitter were 10 nA and 7.24-10.0°, respectively, when the applied voltage was 1000 V. A simulation of the electron trajectory for the tip shape using the electron optical simulation software SIMION agrees with the opening half-angle of 6.6°. The simulation for varying the tip shape suggest that the opening half-angle could be reduced to a smaller value by using large base radius, large shank angle, and low protrusion height.