Weak Current Detection Based On AFM Electric-field Induced Oxidation Fabrication

Nanotechnology is a multi-disciplinary and newly emerging science field based on fundamental research and application explore, whose final aim is to fabricate specified functional products on the nanometer scale on the base of atoms and molecules. Nanofabrication is the key issue of nanotechnology, and also the critical event of achieving the invention of nanometer device. Since the invention of scanning tunneling microscope (STM) in 1980s, scanning probe microscope(SPM) has been developed rapidly. While SPM are usually used as measuring tools, they were also found to be able to modify the sample surface in the nanometer scale. Therefore, the nanofabrication technology based on SPM comes into being. Because of its ability of molecular manipulation and nanopatterning, this technique has attracted great attentions from research groups in the world.Although the research of field-induced oxidation by AFM has proceeded for more than a decade years, there still exists lots of problems in theory and experiment method. The aim of this dissertation is to make theoretical analysis and experimental research on the field emission current generated between tip and sample surface, analyzing the effect of fabrication parameters on the results of weak current during the process of dots and lines fabrication. The main contents include:Analyzing the basic theory of AFM field-induced oxidation and surface oxidation theory of Si;Studying the interior structure of Multimode SPM, building up a set of nanofabrication system to fabricate oxide structure of dot and line, and meanwhile monitoring the weak current generated between tip and sample surface;Studying the tunneling effect and the field emission effect occurring in the fabrication with AFM, providing theoretical basis for the weak current monitoring during nanofabrication process; Analyzing the effect of fabrication parameters (including bias voltage and exposure time) on the results of weak current detection during dot fabrication; Modifying the mode of voltage regulation, giving analysis of the results of weak current produced during the process of dots and lines fabrication; Modifying the mode of voltage regulation, comparing the relation of voltage and current between dots and lines;Evaluating the shape of nanoscale structure and analyzing the error.