Thin-film deposition

Thin-film deposition is any technique for depositing a thin film of material unto a substrate or onto previously deposited layers. "Thin" is a relative term, but most deposition techniques allow layer thickness to be controlled within a few hundred nanometers, and some allow one layer of atoms to be deposited at a time.

AIT offers services to perform Physical Vapor Depositions, more specifically, E-Beam Evaporation and Sputtering.

Physical Vapor Deposition

PVD uses mechanical (sputtering) or thermodynamic (E-Beam) means to produce a thin film of solid. An everyday example is the formation of frost. Since most engineering materials are held together by relatively high energies, and chemical reactions are not used to store these energies, our physical deposition systems require a low-pressure vapor environment to function properly.

The material to be deposited is placed in an energetic, entropic environment, so that particles of material escape its surface. Facing this source is a cooler surface which draws energy from these particles as they arrive, allowing them to form a solid layer. The whole system is kept in a vacuum deposition chamber, to allow the particles to travel as freely as possible. Since particles tend to follow a straight path, films deposited by physical means are commonly directional, rather than conformal.

AIT's processes are below:

• E-beam Evaporation: The Balzer Evaporation System fires a high-energy beam from an electron gun to boil a small spot of material; since the heating is not uniform, higher vapor pressure materials can be deposited. Our evaporator system has a 650mm (25.5 in) chamber with the capability to deposit 4 separate materials without breaking vacuum. We keep our system in a class 1000 clean room and rigorously control the environment to ensure an amicable working area.

• Sputtering relies on a plasma (Argon) to knock material from a "target" a few atoms at a time. The target can be kept at a relatively low temperature, since the process is not one of evaporation, making this one of the most flexible deposition techniques. It is especially useful for compounds or mixtures, where different components would otherwise tend to evaporate at different rates.