What is e-beam evaporation?

What is e-beam evaporation?

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.

What kind of voltage source is necessary for performing e-beam evaporation?

5.3. It is performed by applying a high voltage across a gas at low pressure, usually argon at ~ 1 Pa, to create a plasma which consists of electrons and gas ions in a high-energy state.

Why electron beam is used in evaporation?

The electron beam is accelerated to a high kinetic energy and focused towards the starting material. The kinetic energy of the electrons is converted into thermal energy that will increase the surface temperature of the materials, leading to evaporation and deposition onto the substrate.

How sputtering is different from electron beam evaporation?

E-beam evaporation, another thermal evaporation process, uses an electron beam to focus a large amount of energy onto the source material in a water-cooled copper hearth or crucible. E-beam evaporation has a better deposition rate than sputtering or resistive thermal evaporation.

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.

Which is disadvantage of electron beam evaporation?

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. Evaporation is based on the concept that there exists a finite “vapor pressure” above any material.

What is the difference between evaporation and sputtering?

What is the advantage of sputtering over evaporation?

– Higher energy with sputtering produces higher packing densities and better adhesion if stresses are low. – Greater variety of materials including alloys and mixtures can be sputtered than evaporated.

How does an e-beam evaporator work?

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 the principle of sputtering?

The principle of Sputtering is to use the energy of a plasma (partially ionized gas) on the surface of a target (cathode), to pull the atoms of the material one by one and deposit them on the substrate.

Why are e-beam deposition rates so high?

The E-beam has the advantage of being able to achieve high deposition rates and thicker films because of its large supply of deposition material in the chamber. The substrate receiving the film is far removed from the energies of the vapor source and so the deposition process is gentler on the sample.

How is physical sputtering used in e-beam evaporation?

E-beam evaporation allows the evaporation of a wider range of metals with higher melting points. Physical sputtering uses ionized gases (Ar) to move material from the target to the substrate. Dielectric films (SiO2, Si3N4, Al2O3) can be produced from dielectric targets and RF power or else reactively sputtered in mixtures of Ar and O2.

What happens to the target material during evaporation?

Evaporation is a form of physical vapor deposition in which a target material is heated in high vacuum. The heated target material will then melt and evaporate or sublime to transform into the gaseous phase.

Why do Evaporated materials deposit on the substrate?

Evaporated materials deposit nonuniformly if the substrate has a rough surface (as integrated circuits often do). Because the evaporated material attacks the substrate mostly from a single direction, protruding features block the evaporated material from some areas. This phenomenon is called “shadowing” or “step coverage.”