Atomic Layer Deposition

Introduction to atomic layer deposition

Atomic layer deposition (ALD) is a self-limited growth method that is characterized by alternating exposure of the growing film to chemical precursors, resulting in the sequential deposition of monolayers over the entire sample surface. ALD is ideally suited for coating nanostructures, because of its unique advantages:

• excellent conformality on 3D objects
• atomic level control of layer thickness and composition

The most important disadvantage is the limited deposition rate (at best a couple of nanometer / minute). However, this limitation becomes less relevant for the ultra-thin films that are required for coating nanostructures.

Plasma-enhanced ALD (PE-ALD), a variant of the conventional ALD, uses a plasma to generate reactive radicals, which are then used as a reactant in the process. Consequently, the plasma process depends less on the thermal energy available at the surface, which allows for film growth at lower temperatures and higher growth rates. Since 2006, a home-built integrated system for ALD/PE-ALD/PVD is operational at our lab.  

We have processes available for ALD coating of a wide range of different materials, including Al₂O₃, AlN, TiO₂, HfO₂, ZrO₂, Ru, Pt, Fe₂O₃, MnO_x, CoO_x, VN, ZnO, Ta₂(C)N, etc.

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