Microcontact Printing of Alkanephosphonic Acids on Aluminum: Pattern Transfer by Wet Chemical Etching

Microcontact printing (μCP) has been used to pattern octadecanephosphonic acid on the native oxide surface film of aluminum supported on silicon or on silicon nitride-coated silicon wafers. The patterned alkanephosphonic acid protects the Al2O3/Al film from etching in a solution containing phosphoric, acetic, and nitric acids and water in a ratio of 16:1:1:2 and allows the nonpatterned film to be removed selectively. The patterned Al2O3/Al structures resulting from etching are continuous and electrically conductive within each pattern, and separated patterns are electrically isolated. Resistance measurements of the patterned structures are presented. Using μCP, Schottky diodes of aluminum have been prepared on p-type Si(100). The Schottky diodes exhibit rectifying behavior, and the forward-bias current−voltage (I−V) and reverse-bias capacitance−voltage (C−V) characteristics are presented.