Miniaturized homo-polar rotating liquid device on Si substrates

In this paper, the preliminary results on the fabrication of a miniaturized liquid-based homopolar micro-motor structure were reported. The fabrication has been carried out on Si wafers by means of a deep etching of the substrate using a hydrogenation assisted reactive ion etching technique. Little attention has been paid to liquid-based motors mainly due to fabrication limitations and ionic currents in the liquid. Both experimental and simulation method were conducted using SEM and COMSOL simulating tool. SEM was used for the cross-sectional structure of the sample and for this simulation a typical liquid like water has been used and the effect of conductivity and magnetic field has been investigated on the level and profile of the rotation. This simulation tool, however does not consider the electrolysis. As stated before, electrolysis was the main drawback for such liquid-based devices. The evolution of gas (mainly H2) was inevitable, although it was speculated to minimize this negative effect by incorporating nano-silver particles into the liquid to increase the "electron-current" rather than "ion-current" in the liquid. This work was being pursued and its findings were presented.