Improvement of the porous silicon sacrificial-layer etching for micromachining applications

M. Navarro, Jose Maria López-Villegas, Josep Samitiera, Juan Ramon Morante, Joan Bausells

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    12 Citations (Scopus)


    Using porous silicon (PS) as a sacrificial layer, freestanding structures with a large distance to the bulk can be obtained. The very high specific surface area of PS allows its removal using dilute alkaline solutions. However, a critical equilibrium between a non-violent and a complete etch reaction is necessary. A solution to this problem is a multi-step etching process using solutions of different concentrations. To avoid this disadvantage, different technological conditions are studied in order to optimize the removal of the PS by using a one-step process with a 0.1% KOH solution. The effects of adding ethanol, ultrasonic stirring and polarization during the etching process are evaluated. Optimization of the etching procedure allows good-quality freestanding polysilicon structures featuring a smooth substrate surface to be obtained. © 1997 Elsevier Science S.A.
    Original languageEnglish
    Pages (from-to)676-679
    JournalSensors and Actuators, A: Physical
    Issue number1-3
    Publication statusPublished - 1 Jan 1997


    • Micromachining
    • Porous silicon
    • Sacrificial-layer etching


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