Distributions of kinetic pathways in strain relaxation of heteroepitaxial films

• Published in: Journal of materials research 2017-11, Vol.32 (21), p.3977-3991
• Main Authors: Andersen, Dustin, Hull, Robert
• Format: Article
• Language: English
• Subjects: Annealing; Applied and Technical Physics; Biomaterials; Computer simulation; Dislocations; Energy; Film growth; Fingerprinting; Germanium; High temperature; Inorganic Chemistry; Invited Feature Paper; Kinetics; Materials Engineering; Materials research; Materials Science; Misfit dislocations; Molecular beam epitaxy; Nanotechnology; Nucleation; Parameter sensitivity; Propagation; Sensitivity analysis; Silicon; Strain relaxation; Stress analysis
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2017.374

The kinetic relaxation pathways for strained heteroepitaxial films are mapped using a process simulator that integrates experimental and model descriptions of the energetic and kinetic parameters that define the nucleation, propagation, and interaction of strain relieving dislocations. This paper focuses on Ge x Si1−x /Si(100), but the methodologies described should be extendible to other systems. The kinetic pathways for strain evolution are plotted for film growth as functions of the primary kinetic parameters: growth temperature, growth rate, and initial lattice mismatch, generating relaxation surfaces for parameter pairs. Sensitivity analyses are presented of how deviations from mean parameters disperse the resultant relaxation surfaces. Finally, multi-parameter “fingerprinting” of the dislocation array is shown to illustrate how fundamental kinetic mechanisms—particularly dislocation nucleation mechanisms—define the final dislocation array. The overarching goal is to establish a robust framework for predicting, interrogating, and optimizing strain relaxation pathways and underlying mechanisms, for misfit dislocations in strained heteroepitaxial films.