Electrical surface modification and characterization of metallic thin films using scanning probe microscope (SPM) nanolithography method
This thesis focuses on local oxidation of metallic thin films using atomic force microscopy (AFM). The primary aim of this thesis is to investigate the growth kinetics of oxide forms of these metallic materials and characterize the resulted oxide structures. In this study, tantalum, hafnium and zirconium thin films were used to be oxidized via AFM. During this work, metallic thin films were grown on Si and SiOx substrates with DC magnetron sputtering method. Thin films were characterized via x-ray diffraction, scanning electron microscopy and atomic force microscopy. Oxidation experiments were performed under different environmental conditions to explore the effect of influential parameters; such as bias voltage, oxidation time and relative humidity, and line shape oxide structures were created on metallic films. Dimensional analysis of created oxide structures was carried out measuring height and line-width of oxide lines as a function of applied voltage, oxidation time and relative humidity. In addition to the dimensional analysis, electrical characterization of metal-oxides was performed via AFM electrical characterization methods which are two terminal I-V measurements, electric force microscopy and spreading resistance measurements. At the end of the thesis, the capability of this method to create lateral metal-oxide-metal junction was shown oxidizing a tantalum stripe and performing in-situ resistance measurement. Patterning of tantalum stripes was accomplished by standard photolithography process and lift-off technique.