Process
Focused electron beam of scanning electron microscope (SEM) or scanning transmission electron microscope (STEM) is commonly used. Focused ion beam can be applied instead, but then the process is called ion beam-induced deposition (IBID). The precursor material is gas, liquid or solid. Liquid or solids are gasified prior to deposition, usually through vaporization or sublimation, and introduced, at accurately controlled rate, into the high-vacuum chamber of electron microscope. Alternatively, solid precursor is sublimated by the electron beam itself.
When deposition occurs at high temperature or involves corrosive gases, specially designed deposition chamber is used; it is isolated from the microscope, and the beam is introduced into it through a micrometre-sized orifice. Small orifice size maintains differential pressure in the microscope (vacuum) and deposition chamber (no vacuum). Such deposition mode has been used for EBID of diamond.
The electron beam is scanned over desired shape resulting in deposition of material. The scanning is usually computer controlled. The deposition rate depends on the partial pressure and is of the order 10 nm/s.
Read more about this topic: Electron Beam-induced Deposition
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