What is e-beam evaporation technique?
E-Beam evaporation is a physical vapor deposition (PVD) technique whereby an intense, electron beam is generated from a filament and steered via electric and magnetic fields to strike source material (e.g. pellets of Au) and vaporize it within a vacuum environment.
How is an electron beam evaporator cooled during deposition?
Both the crucible and socket must be cooled. This is typically done by water circulation. In the case of ingots, molten liquid can form on its surface, which can be kept constant by vertical displacement of the ingot. The evaporation rate may be on the order of 10−2 g/(cm2·s).
Which is advantage of electron beam evaporation?
One of the advantages of E-Beam Evaporation is the ability to rotate several source materials into the path of the electron so that multiple thin films can be deposited sequentially without breaking vacuum.
What are the disadvantages of e-beam evaporation?
1.) Evaporation: Advantages: Highest purity (Good for Schottky contacts) due to low pressures. Disadvantages: Poor step coverage, forming alloys can be difficult, lower throughput due to low vacuum.
What is e evaporation?
E-Beam or Electron Beam Evaporation is a form of Physical Vapor Deposition in which the target material to be used as a coating is bombarded with an electron beam from a charged tungsten filament to evaporate and convert it to a gaseous state for deposition on the material to be coated.
What is thermal evaporation technique?
Thermal evaporation is a common method of physical vapor deposition (PVD). It is one of the simplest forms of PVD and typically uses a resistive heat source to evaporate a solid material in a vacuum environment to form a thin film. The material is heated in a high vacuum chamber until vapor pressure is produced.
How does electron beam deposition work?
Electron beam deposition is a method of using electron beams generated from an electron source in a vacuum to irradiate an evaporant material, and heating and evaporating it so that the evaporated material forms a thin film on a substance, such as a substrate or a lens.
Why is electron beam deposition technique used?
Of these two processes, The E-Beam Deposition technique has several clear advantages for many types of applications. It permits the direct transfer of energy with the Electron Beam to the target material to be evaporated making it ideal for metals with high melting points.
What are the advantages of an electron beam evaporator compared to a thermal evaporator?
1) Electron beam evaporation can heat materials to a higher temperature than thermal evaporation. This allows very high deposition rates and evaporation of high temperature materials and refractory metals such as tungsten, tantalum or graphite. 2) E-beam evaporation can deposit thinner films with higher purity.
What is the difference between sputtering and evaporation?
In thermal evaporation, the source material is brought to evaporation temperature either by the heat generated by the resistance of a metal container or by bombardment of a beam of high energy electrons. – Higher energy with sputtering produces higher packing densities and better adhesion if stresses are low.
What can electron beam evaporation be used for?
Electron beam evaporation can be applicable to all of the metals and alloys and can also be used for compounds such as oxides and zinc sulphide (ZnS), especially high melting point materials, for thin film fabrication.
How are electron beams generated in an EBPVD system?
Multiple types of evaporation materials and electron guns can be used simultaneously in a single EBPVD system, each having a power from tens to hundreds of kilowatts. Electron beams can be generated by thermionic emission, field electron emission or the anodic arc method.
How are metal vapors carried by the electron beam?
In the reactive evaporation process, the metal is evaporated from the ingot by the electron beam. The vapors are carried by the reactive gas, which is oxygen in case of metal oxides or acetylene in case of metal carbides. When the thermodynamic conditions are met, the vapors react with the gas in the vicinity of the substrate to form films.
How is the energy of an electron beam generated?
Electron beams can be generated by thermionic emission, field electron emission or the anodic arc method. The generated electron beam is accelerated to a high kinetic energy and directed towards the evaporation material.