Morphological instability of heteroepitaxial growth on vicinal substrates: A phase-field crystal study

• Published in: Journal of crystal growth Vol. 318; no. 1; pp. 18 - 22
• Main Authors: Yu, Yan-Mei, Backofen, Rainer, Voigt, Axel
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2011; Elsevier
• Subjects: A1. Computer simulation; A1. Growth models; A1. Morphological stability; A1. Stress; A1. Substrates; A3. Liquid-phase epitaxy; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal growth; Defects and impurities in crystals; microstructure; Dislocations; Exact sciences and technology; Film growth; Instability; Linear defects: dislocations, disclinations; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Liquids; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of metals and alloys; Physics; Stability; Strain; Structure of solids and liquids; crystallography; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Thin films; A1. Stress; A3. Liquid-phase epitaxy; A1. Computer simulation; A1. Growth models; A1. Morphological stability; A1. Substrates; LPE; Phase diagrams; Digital simulation; Theoretical study; Computerized simulation; Crystal field; Interconnections; Film growth; Dislocations; Thin films; Morphology; Growth mechanism; Phase equilibria; Stress effects; Heteroepitaxy; Instability
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.08.047

We investigate morphological instability of heteroepitaxially grown thin films on vicinal substrates with the phase-field-crystal (PFC) model. The PFC model is tuned to have a sharp transition between solid and liquid. Thus, steps, terraces and kinks can be clearly identified. The substrate is modeled by an external pining potential. Varying vicinal angle and misfit between substrate and film a phase-diagram for morphological instability of the strained thin film near equilibrium is constructed. The morphology of the growing strained thin film follows the equilibrium morphological phase-diagram, but indicates less critical mismatch strain for dislocation formation. For small mismatch strains, the step-flow and the step-bunching modes contribute to the coherent film growth on the vicinal substrate, whereas for large mismatch strains, the strong non-coherent film growth tendency is caused due to the increased possibility of the mismatch dislocation formation, as companied by the island growth on the hill-and-valley facetted structures. Our simulation results demonstrate interconnection of the steps, the islands, and the mismatch dislocations during the heteroepitaxial growth on the vicinal substrate.