The research project “System and process development for the atomic layer deposition of aluminum-based thin films for barriers, actuators, and electronics – MultiALD” is working on new methods to produce thin films based on trimethylaluminum (TMA) using atomic layer deposition (ALD).

Partners from industry and research in Saxony are involved:

• scia Systems GmbH from Chemnitz
• FAP Forschungs- und Applikationslabor Plasmatechnik GmbH
• InfraTec GmbH from Dresden
• the Center for Micro and Nano Technologies at University of Technology Chemnitz
• and the Fraunhofer Institute for Electronic Nano Systems in Chemnitz.

The project MultiALD uses the various possibilities offered by the starting material trimethylaluminum, which feature specific, adjustable properties. The materials are applied to arbitrarily shaped surfaces using atomic layer deposition and analyzed for two specific applications. The ALD process produces well-known materials such as aluminium oxide (Al₂O₃) and aluminium nitride (AlN). In addition, organic-inorganic hybrid materials, known as alucones, are being designed and newly developed.

Highly transparent humidity barriers for MEMS

One key application is the deposition of multi-layer ultra-thin coatings as humidity barriers. Even small amounts of ambient humidity can lead to the degradation of sensitive microelectronic components. In addition to providing protection against humidity, the barrier targeted in the project should also offer high optical transparency, e.g., for IR detectors. The aim of the work is therefore to develop a highly transparent material system that combines reliable protection with excellent optical properties.

Piezoelectric layers made of crystalline AlN

Another focus of research is aluminum nitride (AlN) on structured surfaces. Crystalline AlN is a piezoelectric material. It can be stretched or compressed by applying an electrical voltage. This characteristic is used to move and precisely control micromechanical components (MEMS). To achieve this, the project is developing a specialized process for plasma-assisted atomic layer deposition to deposit AlN in its crystalline phase.

The MultiALD project helps companies and research institutions in Saxony develop new trimethylaluminum-based technologies for different applications in just one production unit.