Strategy to obtain epitaxial aluminum scandium nitride thin films with reduced defect densities by magnetron sputtering
Abstract
AlScN-based bulk acoustic wave resonators with enhanced performance have become attractive for meeting the demanding requirements of the 5G telecommunication industry. For resonators to have better performance, AlScN films exhibiting epitaxy, high crystalline quality, high electric insultation, and low number of abnormally oriented grains are desired. In this study, we systematically change the total sputter power and investigate the structural, optical, and electrical properties of the resulting Al1−xScxN films. Our findings demonstrate that increasing the total sputter power results in Al1−xScxN films with low abnormally oriented grains, reduced sub-bandgap absorption, and lower leakage currents—predominantly due to reduced nitrogen vacancies. Based on these results, we argue that a higher growth rate promotes the growth of Al1−xScxN with reduced impurity levels. Furthermore, by depositing Al0.7Sc0.3N on epitaxial AlN, we demonstrate that epitaxial AlScN can be achieved while improving its crystal quality by ≈36%.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (9)
Balasubramanian Sundarapandian
Fraunhofer Institute for Applied Solid State Physics IAF 1 , Tullastr. 72, D-79108 Freiburg,
Ali Yassine
Institute for Sustainable Systems Engineering (INATECH), University of Freiburg 2 , Freiburg im Breisgau,
Mohit Raghuwanshi
Fraunhofer Institute for Applied Solid State Physics IAF 1 , Tullastr. 72, D-79108 Freiburg,
Patrik Straňák
Fraunhofer Institute for Applied Solid State Physics IAF , 79108 Freiburg,
Evelin Fisslthaler
Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology and Graz Center for Electron Microscopy 3 , Graz,
Mario Prescher
Fraunhofer Institute for Applied Solid State Physics IAF , 79108 Freiburg,
Mohamed Yassine
Power Electronics, Institute for Sustainable Systems Engineering INATECH, University of Freiburg , Emmy-Noether-St. 2, D-79110 Freiburg im Breisgau,
Lutz Kirste
Fraunhofer Institute for Applied Solid State Physics IAF , 79108 Freiburg,
Oliver Ambacher
Power Electronics, Institute for Sustainable Systems Engineering INATECH, University of Freiburg , Emmy-Noether-St. 2, D-79110 Freiburg im Breisgau,