Practical precursor aspects for electron beam induced deposition

The purity of a structure made with electron beam induced deposition (EBID) is a the major concern when creating micro and nano-scale functionalities, for example for rapid prototyping. Substantial research focuses on the improvements of the purity using chemical vapor deposition (CVD) based precursors. However, from a practical point of view, many other aspects of a precursor are very relevant in the design of a process and the actual use of a tool for EBID. To a large extent, these precursor-related characteristics will determine whether or not a precursor can successfully be applied. Some of these characteristics include: vapor pressure range, transition behavior, chemical stability, pyrolitic thresholds, release of corrosive ligands during deposition, toxicity, commercial availability, compatibility with the instrument and operator safety. These characteristic are discussed in more detail here in order to understand what an ideal EBID precursor may be. Although some parameters such as toxicity or flammability seem less important, in practice they can be a road block for application unless the main instrument, such as a regular scanning electron microscope (SEM), is adapted accordingly.