Abstract
In this study, Al 0.8 Sc 0.2 N multilayer structures phase stability, interfacial quality, and piezoelectric response were tested before and after annealing in wide range of temperatures and times. The thicknesses and sequence of the layers in the structures are a replica of the design used for the fabrication of piezoelectric micromachined ultrasonic transducers (pMUTs). Al, AlSi (1%), Al/Mo, and Mo have been assessed to choose the most reliable top electrode (TE) material for the structures. The piezoresponse of the structure was estimated by measuring the deflection of piezocantilevers as a function of voltage applied over the film. Membrane deflection at resonance frequency for AlScN- and AlN-based pMUTs was simulated in COMSOL Multiphysics. It is found that the structure with Mo TE layer is stable after annealing at 800°C for 300 h and at 1000 °C for 100 h. None of the structures formed any phases at the interface between the electrode layer and AlScN. Membrane deflection for structures with AlScN as piezolayer is almost three times higher as compared to structures with AlN as piezolayer. Moreover, the pMUT membrane deflection increases after annealing of the structure.
Original language | English |
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Title of host publication | IUS 2020 - International Ultrasonics Symposium, Proceedings |
Publisher | IEEE Institute of Electrical and Electronic Engineers |
Number of pages | 4 |
ISBN (Electronic) | 978-1-7281-5448-0 |
ISBN (Print) | 978-1-7281-5449-7 |
DOIs | |
Publication status | Published - 7 Sep 2020 |
MoE publication type | B3 Non-refereed article in conference proceedings |
Event | IEEE International Ultrasonics Symposium, IUS - Las Vegas, United States Duration: 7 Sep 2020 → 11 Sep 2020 |
Conference
Conference | IEEE International Ultrasonics Symposium, IUS |
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Country | United States |
City | Las Vegas |
Period | 7/09/20 → 11/09/20 |
Keywords
- Aluminium Scandium Nitride
- pMUT
- thin-film deposition
- annealing