Surface chemical mechanisms in atomic layer deposition of hard nitrides

Important results from the project

Our objective was to understand the surface chemical reactions that control the deposition of the hard material AlTiN, which is used to increase the performance of tools that cut metal, such as drills. Seco deposits AlTiN on tools using CVD (chemical vapor deposition), and by slowing down the process by alternately exposing the surface to molecules containing metals and nitrogen, we can study the surface chemistry. The measurements at MAX IV allowed us to see chemical bonds as they formed.

Expected long term effects

The surface chemical reactions are the key to controlling CVD of AlTiN. Our experiments at MAX IV contribute to a better picture of these reactions and as a piece of the puzzle for a more complete model of the surface chemistry. The model will help Seco in their quest to be able to control CVD of AlTiN. In a larger perspective, our results can also contribute to a better understanding for other industries, such as the semiconductor industry, which uses similar processes and materials.

Approach and implementation

We used APXPS (ambient pressure x-ray photoelectron spectroscopy) which allowed us to study the chemical environment, i.e., different bonds to other elements, for different elements in the sample while we were sending molecules towards the sample. The key here is "while". XPS normally requires measuring at extremely low pressures, but at MAX IV you can measure while adding gases, so you can see how the surface chemical reactions change the bonds on the surface in real time.