The construction of orientation-dependent crystal growth and etch rate functions II: Application to wet chemical etching of silicon in potassium hydroxide

E. van Veenendaal, J. van Suchtelen, W.J.P. van Enckevort, K. Sato, A.J. Nijdam, Johannes G.E. Gardeniers, Michael Curt Elwenspoek

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Abstract

In Part I we introduced a construction method for analytical orientation dependent growth and etch rate functions. In this article, this network construction principle is applied to wet chemical etching of silicon in concentrated aqueous potassium hydroxide. Detailed measurements of the etch rate as a function of crystal surface orientation are used to fit the phenomenological parameters in the network etch rate function. In this function, for each crystal facet, two surface processes are accounted for, etching through misorientation step flow and etching through nucleation of pits. The fitting procedure identifies additional mesoscopic, surface processes which influence the orientation dependence of the etch rate. These processes correspond to instabilities of the surface. In the {111} region step bunching occurs which evolves into microfaceting for larger inclination angles. Moreover, for certain experimental circumstances, the fast etching {110} region breaks up into a staircase structure of terraces. Additional network elements are defined to account for these instabilities. The step-bunching instability is treated using an ad hoc approach. With these amendments the experimental etch rate functions can be fitted to an accuracy of about 5% by a network function with nine parameters. This shows that it is possible to reproduce the essential features of an experimental growth or etch rate function using an analytical function with a limited number of physically meaningful parameters
Original languageUndefined
Pages (from-to)8732-8740
Number of pages9
JournalJournal of Applied Physics
Volume87
Issue number12
DOIs
Publication statusPublished - 15 Jun 2000

Keywords

  • IR-14624
  • METIS-111704
  • EWI-12965

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