The characteristic length study of Si spirals during growth

• Published in: Computational materials science 2014-07, Vol.90, p.148-152
• Main Authors: Lin, En-Yu, Zhang, Yi-Xiong, Liao, Yan-Juan, Mo, Yun-Jie, Jiang, Shao-Ji
• Format: Article
• Language: English
• Subjects: Characteristic length; Cross-disciplinary physics: materials science; rheology; Diamond structure; Exact sciences and technology; Kinetic Monte Carlo simulation; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Physics; Si spiral film growth; Theory and models of film growth
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2014.04.015

Si spirals or screw-like geometries will be formed under a slow substrate rotation, with a larger-than-diameter pitch. Once the pitch is comparable to the diameter at a very rotational speed, the spiral structure will degenerate into pillars. The critical rotational speed is predicted according to this numerical relation. [Display omitted] •An elaborate on-lattice alignment of Si diamond structure represents as the framework of simulation.•A systematic 3D Kinetic Monte Carlo model of GLAD-grown Si spirals on the nanosphere-array substrate has been built.•A characteristic length (i.e., the pitch) is proposed to indicate the spiral growth during substrate rotation.•The critical rotational speed of translation from spirals to upright columns has been predicted.•The competition mechanism between the lateral growth and the vertical growth dominates the structure geometry. The growing transition of Si spirals by glancing angle deposition on the nanosphere-array substrate is investigated via the three-dimensional Kinetic Monte Carlo technique, based on the fine diamond lattice structure. We employed the pitch as the characteristic length to indicate the spiral growth during substrate rotation, and analyzed its dependencies on rotational speed and deposition rate. We found that the spiral arms broaden with increasing height during film growth, and the diameter of intrinsic structure can be obtained by fitting the growth exponent. Spirals or screw-like geometries will be formed under a slow substrate rotation, with a larger-than-diameter pitch. Once the pitch is comparable to the diameter at a very rotational speed, the spiral structure will degenerate into pillars. The critical rotational speed is predicted according to this numerical relation, and the competition mechanism between the lateral growth and the vertical growth is also proposed.