Date of Award

12-2006

Level of Access

Campus-Only Thesis

Degree Name

Master of Engineering (ME)

Department

Engineering Physics

Advisor

William Unertl

Second Committee Member

Robert Lad

Third Committee Member

Susan McKay

Abstract

UV/ozone cleaning of new silicon Atomic Force Microscopy (AFM) probes with nominal tip radii of 15nm has been studied and its effects on the adhesion force between the tip and the substrate (mica/gold) have been analyzed. The purpose of this thesis was to implement this cleaning technique in AFM experiments by studying its effectiveness and suitability for cleaning probes. As cleanliness plays a major role in topography, friction and adhesion studies, an easy to use, effective and in situ cleaning technique is needed for cleaning AFM probes prior to starting an experiment. We have observed that when the tip undergoes a UV/Ozone treatment in ambient conditions (relative humidity 10-30%), the adhesion between the tip and the substrate is greatly increased relative to the adhesion force before treatment. At relative humidity < 1%, no significant change in the adhesion force had been observed after the tip treatment, leading to the conclusion that water on the tip enhances the cleaning process due to the presence of hydroxyl groups. In all of the experiments, the adhesion force has been monitored as a function of time immediately after the tip treatment, in order to observe how long the tip-surface adhesion remains constant following the UV/Ozone treatment. The effectiveness of UV/Ozone in removing organic surface contaminants had been demonstrated by Fourier Transform Infrared Spectroscopy (FTIR) experiments where the spectra show that five minutes of UV/ozone cleaning are enough to remove the hydrocarbon contaminants present on the surface.

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