| AVS 62nd International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF+AS+NS+SA-ThA |
| Session: | Thin Film: Growth and Characterization, Optical and Synchrotron Characterization II |
| Presenter: | Xuyang Zhou, The University of Alabama |
| Authors: | X. Zhou, The University of Alabama T. Kaub, The Univeristy of Alabama R.L. Martens, The Univeristy of Alabama G.B. Thompson, The University of Alabama |
| Correspondent: | Click to Email |
During the post coalescence portion of thin film deposition, thin film stress is related to the grain size and adatom mobility of the depositing material. This stress state can be regulated by the mobility of atoms into or out of these grain boundaries. Using Fe(Cr) alloy thin films as a case study, the stress evolution during growth was investigated as a function of Cr content up to 8 at.%. During the deposition of the elemental films, each film grew with a tensile stress state on a Si wafer because of their low adatom mobility. Upon alloying 4 at.% Cr to the Fe film, the as-deposited grains grew from ~40 nm (pure Fe) to ~65 nm (Fe-04Cr), resulting in a stress relaxation from ~200 GPa*nm to 50 GPa*nm at a thickness of 300 nm. As the Cr content increased further, the grains refined back towards ~ 50 nm in size resulting in a recovery of the higher tensile stress condition. The reduction of the grain size is contributed to Cr solute segregation to the grain boundaries, clustering, and ultimately precipitation at the boundaries. The real-time stress evolution during growth will be discussed in terms of the inferred microstructural evolution of the film using post-mortem atom probe tomography and transmission electron microscopy characterization. The results of which address how segregating behavior can be used as a means of thin film stress engineering.