Parallel Plasma Field Directed Sputter Sharpening of Field Emitters

Many of the current methods to sharpen field emitters are time consuming and can only process one field emitter at a time. In this thesis, a method is proposed to parallel process multiple field emitters using a DC glow discharge plasma as the ion source in conjunction with field directed sputter sharpening methodology. With field directed sputter sharpening, a positive voltage bias is applied to the field emitter and impinging ions are repelled away from the apex of the tip to the shank of the tip. This produces a very sharp tip with radius of curvature of approximately 1 nm. A plasma system was designed and built, and tungsten tips for use in scanning tunneling microscopy (STM) applications were sputtered with argon ions. The result is that as the tip voltage bias to plasma voltage bias ratio is increased above approximately 0.1, the cone angle of the tungsten tip decreases. The radius of curvature of the tip also decreases, but the result is not always consistent and does not reach the same order of magnitude as the result achieved by field directed sputter sharpening with an ion gun. This result shows much promise and further work is necessary to refine the process and achieve consistent results