Research On Electron Beam Nanolithogrpahy Based On AFM

Scanning probe microscopy (SPM) has evolved into a powerful tool for imaging with nanometer-scale resolution and analyzing a variety of surface in the past two decades, which is advantageous to be done in vacuum, in atmosphere, or in liquid. Fabrication of nanostructures based on SPM as an extension to SPM imaging, referred to as scanning probe nanofabrication (SPN) is an emerging technique undertaken at labs in the past ten years that comprises manipulation of atom or molecule in a bottom-up paradigm and Scanning Probe Lithography (SPL) in a top-down paradigm.In Chapter One, in the light of decentralized experimentaL data in this respect, the author, classify in an analytic approach the literature concerned as electrical SPL, mechanical SPL, thermal SPL, and optical SPL in terms of different mechanisms of interplay between a probe and a surface of a sample, after describing the most important of this type of microscopy, i.e., scanning tunneling microscopy and atomic force microscopy. Of all these SPL methods, the principles of five special SPL methods are illustrated, respectively. The common problems existing in SPL are given and prospects of application of these SPL techniques to manufacturing nanometer-scale devices are analyzed. All this has laid a strong foundation for selecting a subject of maskless AFM nanolithography, i.e., field-induced oxidation of Si semiconductor.In Chapter Two, a high-intensity current between a probe tip and a sample is discussed first. Electrical intensity between them is simulated using Matlab software after an electrical model is introduced, thus theoretically analyzing the effect of tip radii, tip-sample separation, radii at the sample, and biases on the morphology of field-induced oxidation.In Chapter Three, the mechanism responsible for scanning probe field-induced oxidation in ambient air is attributed to an electrochemical process, i.e., anodic oxidation or anodization, after the analyses is given of a surface of a sample exposed to air. The effects of biases, tip speeds on morphology of field-induced oxidation, areintroduced and deduced in the form of kinetics formula of oxidation growth.In Chapter Fourth, field-induced oxidation of hydrogen-passivated Si (Si:H)using contact-mode (CM) AFM in air at room temperature is investigated. The morphology of oxidation lines are analyzed as a result of different biases, tip speeds. And hence the aforesaid kinectics formula is validated. Finally, oxygen ion is considered as a prerequisite to succeed in this SPL after the discussion is carried out on CM-AFM field-induced oxidation of Si:H.In Chapter Five, the author sums up this dissertation, points out creative points inherent in this dissertation, and propose a lot of perspective tasks to be further studied.