Chapter 3 - Fabrication of Nanoscale Structures using STM and AFM

Abstract

The fabrication of nanoscale structures using scanning tunneling microscopy (STM) and atomic force microscopy (AFM) is a field of relatively active research since the inception of these techniques. A unique advantage of these scanning probe techniques is the ability to manipulate matter down to the atomic level and to form structures not possible by other means. More recently, attempts have been made to develop more technologically interesting structures for use in device production. Techniques, such as dip-pen lithography or thermomechanical indentation are adaptable to such an array geometry and may eventually yield viable device applications. Two additional variations of AFM include TappingMode (or intermittent mode) and non-contact mode. In both cases, the cantilever is vibrated at its resonance frequency (50-500 kHz) during scanning. In non-contact AFM, the cantilever never touches the surface and is primarily affected by longer-range forces. These forces can be detected by a shift in the resonance frequency of the relatively "soft" cantilever. This mode is often used in ultrahigh vacuum (UHV) conditions where there should be no surface water meniscus forces that can cause "jump-to-contact" of the tip to sample.