Study of the cracking of highly porous p+ type silicon during drying

O. Belmont, D. Bellet, Y. Bréchet

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Abstract

The origin of the cracking of highly porous silicon layers during drying is investigated. Optical and scanning electron microscopy observation allow us to observe the cracking occurrence. In situ x-ray diffraction experiments, under controlled vapor pressure of pentane, reveal that large capillary stresses occur at a vapor pressure P* during the controlled drying. These stresses lead to the cracking of the highly porous layer, which occurs for samples thicker than a critical thickness hc. Taking into account the mechanical properties of the material, a model based on energy balance is presented. This model predicts a layer thickness hc of cracking occurrence, showing that hc varies as (1-p)3LV2 (where γLV is the surface tension of the drying liquid and p is the porosity). This model is in good agreement with experimental data obtained with two liquids, water, and pentane, which have very different surface tension and also for two different porosities.

Original languageEnglish
Pages (from-to)7586-7591
Number of pages6
JournalJournal of Applied Physics
Volume79
Issue number10
DOIs
Publication statusPublished - 15 May 1996
Externally publishedYes

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