No chemical reactions take place at the substrate.

Metal layers are deposited by PVD techniques. Metal is obtained in vapor form which is then transported to the vapor surface where it nucleates and condenses.

PVD is widely used in SIC technology for deposition of semiconducting films, deposition of chrome masks etc.

• Typical steps in making thin films:

  Emission of particles from source (heat, high voltage . . .)

  Transport of particles to substrate

  Condensation of particles on substrate

• PVD is sometimes called "vacuum deposition" since very low-pressure environments are required for the transport of the gaseous species from the source to the film surface.

• Because of the very low pressures in these systems, very few gas-phase collisions occur.

Advantages:

1. PVD methods are more versatile than CVD as almost any material can be deposited.
2. Very few, if any, chemical reactions occur.
3. Little wafer damage.

Disadvantages:

1. No uniformity in thickness across a wafer, from wafer to wafer, and as film crosses non-planar topography.
2. Shadowing by surface topology
3. Poor step coverage.