Physical Vapor Deposition

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Physical vapor deposition

A physical deposition process consists of three steps: 1. Emission of the particles from a source 2. Their transport to the substrate 3. The condensation on the substrate

Physical vapor deposition
 a process by which a thin film of material is deposited on a

substrate according to the following sequence of steps: 1) the material to be deposited is converted into vapor by physical means; 2) the vapor is transported across a region of low pressure from its source to the substrate; and 3) the vapor undergoes condensation on the substrate to form the thin film

Typical set-up

 alloy targets are struck at an angle of 45o by a pulsed

and focused laser beam  the substrates are attached with the surface parallel to the target surface at a target-to-substrate distance of typically 2-10 cm

 Laser ablation of the target

Process (4 stages)

material and creation of a plasma  Dynamic of the plasma  Deposition of the ablation material on the substrate  Nucleation and growth of the film on the substrate surface

1. Laser ablation of the target material and creation of a plasma  The removal of atoms from the bulk material is done by

vaporization of the bulk at the surface region in a state of nonequilibrium  The surface of the target is then heated up and the material is vaporized  The temperature of the generated plasma plume is typically 10000 K

2. Dynamic of the plasma
The dependency of the plume shape on pressure can be described in three stages:  The vacuum stage, where the plume is very narrow and forward directed; almost no scattering occurs with the background gases  The intermediate region where a splitting of the high energetic ions from the less energetic species can be observed  High pressure region where we find a more diffusion-like expansion of the ablated material

3. Deposition of the ablation material on the substrate
The third stage is important to determine...
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