Vacuum deposition techniques electron beam evaporation

Vacuum deposition techniques, such as sputtering, electron beam evaporation, and plasma deposition are common. Photopolymerization and laser-assisted depositions are used for preparation of specialized layers, particularly in the fabrication of sensing arrays. Most commercial instruments have thickness monitors (Chapter 4) that allow precise control of the deposition process. 

The most widely used vacuum deposition techniques are evaporation and sputtering, often employed for smaller substrates. In the evaporation process, heating the metal by an electron beam or by direct resistance produces the vapours. The system is operated at a very high vacuum (between 10-5 and 10 6 Torr) to allow a free path for the evaporant to reach the substrate. The rate of metal deposition by evaporation processes varies from 100 to 250,000 A min h These processes can be operated on a batch or a continuous scale. On the other hand, in the case of the sputtering technique, the reaction chamber is first evacuated to a pressure of about 10-5 Torr and then back-filled with an inert gas up to a pressure of 100 mTorr. A strong electric field in the chamber renders ionisation of the inert gas. These inert gas ions... 

Porous structure of the outer support surface has been modified by deposition of the additional layer of metal Ni. Two vacuum condensation techniques have been used for nickel deposition dc ion magnetron sputtering and electron beam evaporation. To produce coatings on tubes additional installation for dc sputtering has been designed. 

New techniques are being applied to develop miniaturized sensor arrays such as screen printing for thick film and electron beam evaporation, thermal vacuum deposition, and pulsed laser deposition for thin-film technique. Microfabrication techniques were used to prepare a sensor array for use in a voltammetric e-tongue by depositing gold (Au), platinum (Pt), iridium (Ir), and rhodium (Rh) on a silicon wafer. 

ZnO films can be prepared by many techniques, including chemical vapour deposition (CVD) [135], electron beam evaporation [136], molecular beam epitaxy (MBE) [137], pulsed laser deposition (PLD) [138], sol-gel [139], spray pyrolysis [140], sputtering [141] and chemical bath deposition [142]. Thermal oxidation of metallic Zn [143-149], ZnS or ZnSe [150-153] films has been used to prepare ZnO films. The Zn precursor films were deposited onto the substrates (glass, sapphire or Si) by magnetron sputtering, thermal/ electron-beam evaporation or filtered cathodic vacuum arc technique. Oxidation treatment was normally conducted in air or oxygen atmospheres in a wide temperature range typically from 300 to 1000°C. 

Little attention has been devoted to the study of carbon layers prepared by the simplest deposition technique - flash evaporation. By flash evaporation carbon layers of different thickness can be produced for routine SEM and TEM electron microscopy. In general, there is a need for these layers to be fine grain, even coating, with uniform and controllable layer thickness. Flash deposition is distinguished from other techniques (e.g. vacuum evaporation, ion beam) by short deposition time and low total power input. The thickness of flash prepared carbon layer should be controlled, but at present none of the conventional methods in general use allows precise and reproducible deposition and layer thickness... 

---