Atomic Layer Deposition
Atomic layer deposition (ALD) is a new technique making inroads into semiconductor manufacturing to produce thin films. ALD is a chemical vapor deposition technique where precursor molecules are pulsed into a chamber and react to cover the substrate. The precursor is selected so that it doesn’t react with itself, so that only a monolayer can react with the substrate. A purge gas is introduced to the chamber to remove unreacted precursor. A pulse of oxidant deposits oxygen and removes the precursor ligands, and another purge step is repeated. This series is repeated to build up a film. ALD is known for its ability to produce uniform, conformal films with precise control of thickness.
Film quality is influenced by the precursor and oxidant reactivity, precursor and oxidant pressure and time in the chamber, and substrate temperature. Ideally, film thickness scales with the number of growth cycles.
Our research involves growing entire fuel cells via ALD in one reaction chamber. We also study the precursor selection and design process via quantum simulations of precursor molecules.
