Dynamic terrain following: nvCPD scanning technique improvement

• Main Author: Pyekh, Yury B.
• Published: Georgia Institute of Technology 2010
• Subjects: Voice coil; Fringe field; Kelvin probe; Surfaces (Technology) Analysis; Volta effect
• Online Access: http://hdl.handle.net/1853/34826

There is a large number of measurement techniques that is used for a surface inspection and a characterization of different types of materials. One of these techniques is a contact potential difference (CPD) scanning technique. In this project a non-vibrating contact potential difference (nvCPD) method is utilized to measure a work function and a topographical structure of a sample surface. A sample is mounted on a spindle that rotates at high speed. A nvCPD sensor detects work-function variations during movement above the sample surface. There are certain factors that create difficulties during the measurement process. A nonplanar sample surface, the spindle wobble and an incline of a mounted sample impede the safe (without impacting the surface) scanning at a close distance. The goal of this thesis was to implement a height sensor as a feedback device to dynamically control and adjust a CPD sensor flying height. Since a CPD signal is inversely proportional to the flying height, minimization of this height will enhance the signal magnitude, the signal-to-noise ratio and the resolution of measurements.