Growth model of Reversed Taper during Early Stage of D.C. Etching on Aluminum Oriented to (100)

The tunnel growth mechanism of aluminum foil was studied in order to control the etching morphology. The growth of tunnels with a reversed taper followed by the tapered tunnel growth was observed only in acid solution. We proposed a model of the self-corrosion of aluminum for the reversed taper growth, and verified it by comparison of the current efficiency with the measured value made by ICP-ES to the simulation obtained from the results of the reversely tapered tunnel structure. From results of the early tunnel growth with a reversed taper, we discussed the relation between the limit length of the tunnel and width of the tunnel. It was expected that a uniform length of the tunnels should be obtained by controlling the width at the tunnel mouth to the same size.