Cathode Electron Sources For Cold Field Emission: Fabrication Methodology For Discretely Patterned High aspect Ratio Silicon Nanotips

The development of high aspect ratio electron sources for use in Cold Field Emission (CFE) is an area of research interest with a wide range of potential applications from electron microscopy to CFE X-ray sources for computed tomography in the medical field. The development of cathode electron sources that are capable of electron emission at room temperature is attractive because of their ability to produce bright high current electron beams with less energy spread than their Thermionic or Schottky equivalents. These parameters are impacted by the sharpness of the emitter’s apex, creating the desire for high aspect ratio emitters. Additionally, there is a desire for a low-cost fabrication methodology for CFE emitters patterned in discrete arrays of known distances. The discrete arrays of emitters would minimize the Debye screening effect, further enhancing field emission. Discrete arrays of CFE emitters would also streamline the extraction of meaningful I-V data used to characterize the performance of the emitters due to the pre-quantized nature of the arrays. The void challenge area that this study is addressing is gaining nanoscale resolution with microscale equipment. The void challenge area will be handled by investigating and optimizing photolithography, soft lithography, microsphere lithography, Reactive Ion Etching, and Oxidative Sharpening