In this paper, a newfound and simple silicon bulk micromachining process based on metal-assisted chemical etching (MaCE) is proposed which opens a whole new field of research in MEMS technology. This method is anisotropic and by controlling the etching parameters, deep vertical etching, relative to substrate surface, can be achieved in micrometer size for 〈1 0 0〉 oriented Si wafer. By utilizing gold as a catalyst and a photoresist layer as the single mask layer for etching, 60 µm deep gyroscope micromachined structures have been fabricated for 2 µm features. The results indicate that MaCE could be the only wet etching method comparable to conventional dry etching recipes in terms of achievable etch rate, aspect ratio, verticality and side wall roughness. It also does not need a vacuum chamber and the other costly instruments associated with dry etching techniques.

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The authors report on Coulomb blockade effect in the PtSi/porous Si Schottky barrier. A model of two-dimensional multi-tunnelling junction (2D-MTJ) can explain the blockade characteristic of this barrier. Using the SIMON simulator, the electrical characteristics of the proposed model were investigated. The results show that simulated current-voltage curves achieve a reasonable fit with the measured data and the present model can be used to study the PtSi/porous Si Schottky barrier behaviour. In accordance with both the studies, Coulomb blockade phenomenon is observed in current oscillation and single-electron effect of this device at low temperatures (5 K) is justified using the 2D-MTJ model. In addition, it indicates that by increasing the current value with temperature and for high drain voltages, PtSi/porous Si Schottky barrier behaves like a single island single-electron tunnelling (SET) junction as previously reported by Raissi et al.