ALDtekniikkaä

ALDtekniikkaä, often referred to as Atomic Layer Deposition (ALD), is a thin-film deposition technique that enables the controlled growth of materials layer by atomic layer. It is based on sequential, self-limiting surface chemical reactions. In a typical ALD process, gaseous precursors are pulsed into a reaction chamber in a specific sequence. Each pulse is followed by a purge step to remove any excess precursor and reaction byproducts.

The self-limiting nature of the reactions is key to ALD's precision. Once a precursor reacts with the surface, the reaction stops after one monolayer has formed, regardless of the duration of the precursor pulse or its concentration. This ensures that the film thickness can be controlled with sub-angstrom accuracy. The process is highly conformal, meaning it can deposit uniform films on complex 3D structures and inside nanoscale features with excellent step coverage.

ALD is utilized across various scientific and industrial fields. In the semiconductor industry, it is crucial for fabricating advanced microelectronic devices, including memory chips and logic transistors, where precise control over ultra-thin gate dielectrics and barrier layers is essential. It also finds applications in optics for creating anti-reflective coatings and optical filters, in catalysis for depositing highly dispersed catalyst nanoparticles, and in protective coatings for enhancing the durability and corrosion resistance of materials. Research continues to expand the range of materials that can be deposited using ALD, including oxides, nitrides, metals, and sulfides.