Wet chemical etching mechanism of silicon

Michael Curt Elwenspoek, U. Lindberg, H. Kok, L. Smith

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    We review what can be said on wet chemical etching of single crystals from the viewpoint of the science of crystal growth. Starting point is that there are smooth and rough crystal surfaces. The kinetics of smooth faces is controlled by a nucleation barrier that is absent on rough faces. The latter therefore etch faster by orders of magnitude. The analysis of the diamond crystal structure reveals that the {111} face is the only smooth face in this lattice - other faces might be smooth only because of surface reconstruction. In this way we explain the minimum of the etchrate in KOH:H2O in the [Left angle bracket]001[Right Angle Bracket] direction. Two critical predictions concerning the shape of the minimum of the etchrate close to [Left angle bracket]001[Right Angle Bracket] and the transition from isotropic to anisotropic etching in HF:HNO3 based solutions are tested experimentally. The results are in agreement with the theory.
    Original languageUndefined
    Number of pages6
    Publication statusPublished - 25 Jan 1994
    EventIEEE Workshop on Micro Electro Mechanical Systems, MEMS 1994 - Oiso, Japan
    Duration: 25 Jan 199428 Jan 1994
    Conference number: 1994


    WorkshopIEEE Workshop on Micro Electro Mechanical Systems, MEMS 1994
    Abbreviated titleMEMS


    • EWI-14077
    • IR-56026

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