USING MICROMACHINING, MOLECULAR SELF-ASSEMBLY, AND WET ETCHING TO FABRICATE 0.1-1-MU-M-SCALE STRUCTURES OF GOLD AND SILICON

A combination of molecular self-assembly and micromachining was used to pattern the surface of thin films of gold with 0.1-1-mum-sized regions of monolayers formed from HO(CH2)2SH and CH3(CH2)15SH. Selective, wet chemical etching of gold supporting patterned, self-assembled monolayers resulted in the formation of microstructures of gold on substrates of silicon or glass. Using this procedure, it is possible to construct electrically conducting wires of gold with cross sections as small as 200 nm X 25 nm and lengths greater-than-or-equal-to 15 mum. Complex and closely spaced microstructures, such as parallel and collinear wires separated by <1 mum, can also be fabricated. Microstructures of gold served as masks for wet etching of silicon (aqueous solutions of 2 M KOH) and were used to form multilayer structures of gold and silicon. This method of microfabrication is a simple one, can be performed in any wet chemical laboratory, and, we believe, can be scaled to smaller dimensions.