ZEPPELIN
Ferroelektrisches Zirkonoxid für piezo- und pyroelektrische Bauelemente
Field of research:
- Duration:
- 01.07.2020 - 30.06.2023
- Project status:
- compleated
- Institutions:
- Department of Applied Sciences and Mechatronics
- Project management:
- Prof. Dr. Alfred Kersch
- Funding program:
- DFG Sachbeihilfen
- Third-party funding type:
- DFG
- Project type:
- Forschung
This DFG project is being carried out in collaboration with Namlab (TU Dresden) and RWTH Aachen. The aim is to transfer the large piezoelectric effect in ZrO2 and HfO2, which could previously only be realised in layers of a few 100 nm, to thicknesses of 1000-2000 nm.
In the piezoelectric effect, mechanical tension leads to the generation of an electric field or, conversely, an electric field leads to mechanical expansion. This transducer property is of enormous importance in engineering. Applications include actuators, motors, oscillators, sensors and energy harvesting. In an application that affects the general public, frequency filters based on thin film piezoelectrics are used in mobile communications. The most common piezoelectric materials are lead zirconium titanate (PZT) for actuators and aluminium nitride (AlN) for thin film acoustic wave resonators. Lead-free materials have been in development for many years in response to environmental standards. At the same time, the demands on the piezo coefficient have increased, especially in microelectronic applications such as frequency filters. The ferroelectric properties of zirconium and hafnium oxide were discovered about 10 years ago. The piezoelectric properties are so powerful that there is hope that these materials can be used for lead-free frequency filters. The pyroelectric properties are a different matter.
However, layers thicker than a few 100 nm tend to lose the required ferroelectric and piezoelectric properties. This is where the project comes in. Solving the problem will require a fundamental understanding of the material properties of thin films. This will be achieved using experimental data and simulations based on density functional theory. Munich University of Applied Sciences is responsible for the simulations. One possible approach to achieve the desired properties is specific doping, where the choice of the dopant is made with the help of the simulations.