Simulations of Silicon Microstructure for Preconcentration of Metallic Ions

Abstract

This work presents the simulation results of the fluid flow behavior inside a preconcentrator microstructure. The preconcentrator was implemented in silicon using reactive ion etching, SF6 based, to define the channels and anodic bonding between silicon and borosilicate glass for sealing. The preconcentrator design takes in account the enhancement of surface to area ratio, by dividing the flow until it reaches 50 um channels. The internal flow was analyzed using the commercial package ANSYS/FLOTRAN. Vortex formation was not observed under the simulation conditions and resolution, for water flow of 100 μl/min. The flow is essentially laminar and velocity changes (variations) can be observed, that can influence the residence time of the species inside the microstructure and, consequently, the diffusion/adsorption mechanisms.