Structural study of Al_(1-x)Sc_xN Thin Films by Mapping of Large Volumes in Reciprocal Space

The recently discovered III-V semiconductor-based ferroelectric material AlScN opens a new paradigm for advancement in acoustoelectric and memory technology. Here we studied the Sc content-induced structural dynamics of Al_(1-x)Sc_xN thin films grown on GaN substrates. We have measured a large volume of reciprocal space of Al_(1-x)Sc_xN thin films with the help of a large area detector at Cornell High Energy Synchrotron Source. Our results reveal that the ‘c/a’ ratio decreases for Al_(1-x)Sc_xN with increasing Sc content. Additionally, a change in integral peak intensity is observed.Lowering the ‘c/a’ ratio with Sc content will increase the internal parameter u (length of metal-nitrogen bond parallel to the c-axis). Structurally, this flattening (reduction in c/a ratio) of the wurtzite-type (space group: P6₃mc) unit cell due to Sc-content, may lead to ferroelectric behavior. Our work provides new information on the Sc-content-induced structural dynamics of Al_(1-x)Sc_xN, which will help to create a platform for tuning ferroelectricity in the semiconductor.