Design and fabrication of MEMS-based field emission electron emitters for multiple e-beam lithography
Date Issued
2008
Date
2008
Author(s)
Wu, Yu-Wei
Abstract
Currently, the lithography which has critical dimension small than 45nm and can be applied to industry is not presented. However, single beam e-beam lithography has been developed for years. If the disadvantage of low throughput can be overcome by extending single beam to multiple beams, it will be the next generation of lithography. This thesis is about MEMS design and fabrication of field emission device as the source of parallel electron beams. Silicon is chosen to be the material of field emission device. Fabrication of field emission device includes Si tips array, gated Si tips array, and anode plate. First, Si tips array are formed mainly by RIE. The effect of over-etched on the apex of Si tip is not evident. It has mainly effect on the shape and the uniformity of Si tips. The aspect ratio and the cone angle of apex can be modified by varying the pressure and the ratio of flow rate of etching gas and diluted gas. Second, for gated Si tips array, the standard fabrication process of etched-gate Si tips array is performed. The collapse of gate layer is observed. A possible fabrication process defining the gate aperture by PR spin coating is presented. Third, we design a fabrication process utilizing the “lift-off” technique for anode plate. By this anode plate, anode and cathode can be separated at micrometers, and the leakage current can be totally blocked ideally. The distance can be modified by varying the etched depth in the fabrication process. Finally, experimental field emission device is constituted by the Si tips and the anode plate. The experiment on field emission is performed in a vacuum system with residual gas pressure about 10-5torr. The results are analyzed by theory of field emission from metal to obtain field factor,β, effective emission area,α, and turn-on electric field, Estart. Reasonable data is obtained.
Subjects
silicon field emission array
silicon tips array
field emission
multiple e-beam lithography
reactive ion etching
Type
thesis
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