Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Ion beam
Summary
An ion beam is a type of charged particle beam consisting of ions. Ion beams have many uses in electronics manufacturing (principally ion implantation) and other industries. A variety of ion beam sources exists, some derived from the mercury vapor thrusters developed by NASA in the 1960s. The most common ion beams are of singly-charged ions.
Ion current density is typically measured in mA/cm^2, and ion energy in eV. The use of eV is convenient for converting between voltage and energy, especially when dealing with singly-charged ion beams, as well as converting between energy and temperature (1 eV = 11600 K).
Most commercial applications use two popular types of ion source, gridded and gridless, which differ in current and power characteristics and the ability to control ion trajectories. In both cases electrons are needed to generate an ion beam. The most common electron emitters are hot filament and hollow cathode.
In a gridded ion source, DC or RF discharge are used to generate ions, which are then accelerated and decimated using grids and apertures. Here, the DC discharge current or the RF discharge power are used to control the beam current.
The ion current density that can be accelerated using a gridded ion source is limited by the space charge effect, which is described by Child's law:
where is the voltage between the grids, is the distance between the grids, and is the ion mass.
The grids are placed as closely as possible to increase the current density, typically . The ions used have a significant impact on the maximum ion beam current, since . Everything else being equal, the maximum ion beam current with krypton is only 69% the maximum ion current of an argon beam, and with xenon the ratio drops to 55%.
In a gridless ion source, ions are generated by a flow of electrons (no grids). The most common gridless ion source is the end-Hall ion source. Here, the discharge current and the gas flow are used to control the beam current.
One type of ion beam source is the duoplasmatron.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related courses (13)
MSE-619: Nanofabrication with focused electron and ion beams
Nanofabrication with focused charged particle beams (SEM, FIB) and their applications such as lithography, gas assisted deposition / etching, and milling are discussed and the limitations of these pro
MSE-609: 21Intro Scanning electron microscopy techniques
Modern Scanning Electron Microscopes, when combined with Focused Ion Beams (Dual beam FIB-SEM), provide a larger number of multimodal imaging and analysis/characterisation modes at the nano- and micro
MSE-704: 3D Electron Microscopy and FIB-Nanotomography
The principles of 3D surface (SEM) reconstruction and its limitations will be explained. 3D volume reconstruction and tomography methods by electron microscopy (SEM/FIB and TEM) will be explained and
Related publications (225)