Atomistic modelling of anisotropic etching of crystalline silicon

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Doctoral thesis (article-based)
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Date

2003-09-19

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en

Pages

41, [129]

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Dissertations / Laboratory of Physics, Helsinki University of Technology, 123

Abstract

An atomistic model for the simulation of anisotropic wet chemical etching of crystalline silicon is developed. Special attention is paid to the relation between the atomistic processes, the mesoscopic features of the surface morphology and the macroscopic anisotropy of the process, bridging the different length scales. The development of the atomistic model is made by direct comparison of atomistic kinetic Monte Carlo and Cellular Automaton simulations with experimental results, guided by first-principles calculations. The model explains the anisotropy of the etching process and the orientation-dependent surface morphology as two different manifestations of the same atomistic mechanisms, namely, the weakening of backbonds following OH termination of surface atoms and the existence of significant interaction between the terminating species (H / OH). The versatility of the atomistic model is demonstrated by the concentration and time dependence of the simulated under-etched structures and surface morphology. A substantial effort has been made to develop an efficient program in order to simulate the etching process in arbitrarily oriented, large, micrometer-scale systems in the presence (or absence) of masking patterns and considering the effects of temperature and etchant concentration. The program has a great potential for use in the optimization of the processing parameters in industrial applications.

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Keywords

anisotropic wet chemical etching, surface morphology, Monte Carlo, cellular automaton, mask, convex corner, crystalline silicon, activation energy, surface processing

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Parts

  • Gosálvez M. A., Nieminen R. M., Kilpinen P., Haimi E. and Lindroos V., 2001. Anisotropic wet chemical etching of crystalline silicon: atomistic Monte-Carlo simulations and experiments. Applied Surface Science 178, No. 1-4, pages 7-26. [article1.pdf] © 2001 Elsevier Science. By permission.
  • Gosálvez M. A., Foster A. S. and Nieminen R. M., 2002. Multiscale modeling of anisotropic wet chemical etching of crystalline silicon. Europhysics Letters 60, No. 3, pages 467-473. [article2.pdf] © 2002 EDP Sciences. By permission.
  • Gosálvez M. A., Foster A. S. and Nieminen R. M., 2002. Atomistic simulations of surface coverage effects in anisotropic wet chemical etching of crystalline silicon. Applied Surface Science 202, No. 3-4, pages 160-182. [article3.pdf] © 2002 Elsevier Science. By permission.
  • Gosálvez M. A., Foster A. S. and Nieminen R. M., 2003. Dependence of the anisotropy of wet chemical etching of silicon on the amount of surface coverage by OH radicals. Sensors and Materials 15, No. 2, pages 53-65.
  • Gosálvez M. A. and Nieminen R. M., 2003. Surface morphology during anisotropic wet chemical etching of crystalline silicon. New Journal of Physics 5, pages 100.1-100.28. [article5.pdf] © 2003 Institute of Physics Publishing Ltd. By permission.
  • Gosálvez M. A. and Nieminen R. M., 2003. Relation between macroscopic and microscopic activation energies in non-equilibrium surface processing. Physical Review E, in press. [article6.pdf] © 2003 by authors and © 2003 American Physical Society. By permission.

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Permanent link to this item

https://urn.fi/urn:nbn:fi:tkk-000767