Porosifi silicon wafer

Fig. 1 Common process flows for electrochemically etched (porosified) silicon wafers...

Porosifying controlled areas of a silicon wafer enables porous silicon to be integrated with silicon circuitry or MEMS devices within chip-based products. Although porous sihcon particles (microparticles and nanoparticles) can be derived from anodized wafers (see handbook chapters Milling of Porous Silicon Microparticles and Photoluminescent Nanoparticle Derivatization Via Porous Silicon ), this route is only viable for low-volume high-value product areas, as in some medical therapy applications (see handbook chapter Drug Delivery with Porous Silicon ). 

Other studies have also analyzed the degradation of pSi layers in SBFs [68, 78]. Both, inductively coupled plasma (ICP) and mass spectroscopy (MS) measurements of solutions containing porosified wafers were used to determine the amount of dissolved pSi from 64%, 83% and 88% porosity layers over 24h at different pH levels. Triplicate experiments were performed on five different buffered solutions with pH values of 2, 4, 6, 7 and 8, after which ICP-MS was used to determine the amount of silicon in solution at different time points [68]. At pH 7, medium-porosity (62%) pSi showed almost no dissolution at 6h, and very little at 24 h. Both, high (83%) and very high (88%) -porosity films showed an exponential increase in silicon dissolution over time, with a maximum of 61.3 7.6% for high-porosity films and 45.5 3.3% for very high-porosity films [68] (Figure 11.12). Dissolution at 6 and 24h under different pH conditions showed a positive correla-... 

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