Electron Beam Melting and Refining State of the Art, Bakish Materials Corp. , In Press, 2000.

The Directed Vapor Deposition (DVD) process is characterized by EB high-rate evaporation of metals or compounds in a reactive or non-reactive way from a rod-fed crucible centered in a ring-shaped nozzle. A carrier gas stream through the nozzle forms a supersonic jet capable of focusing and conveying the vapor particles at high efficiency towards the substrate.

It is the basic task to be managed by the EB to propagate through the work chamber space, which has an enhanced pressure up to 50 Pa due to the carrier jet, and to reach the crucible with a sufficient power density. For this processing environment, a gun with a special pressure stage was designed. Its minimized opening requires automatic centering and focusing of the EB online.

In order to allow for deposition of alloys by simultaneous evaporation from multiple sources, a crucible with four rod fed pools was designed. Thus, the demands to the EB regarding spot size and positioning accuracy are high. Because of the low thermal inertia of the small crucible, the EB gun is equipped with a high-frequency beam deflection and dynamic focusing system. High-resolution intensity profiles for balancing the composition of the deposit can be programmed via a graphic pattern editor. The high voltage power supply employs medium frequency technology providing fast power control and arc suppression.

Moreover, the intended upgrade of DVD with dense plasma activation technology has triggered the development of a closed-loop system for optimal beam alignment with respect to the crucible.

The EB gun control is part of a Windows NT based plant control software. The user can operate the system in manual, service, or fully automatic recipe driven mode.