Template-Stripped, Ultraflat Gold Surfaces with Coplanar, Embedded Titanium Micropatterns

Ultraflat gold surfaces with coplanar, embedded titanium micropatterns, exhibiting extremely low roughness over the entire surface, have been obtained by a modified template-stripping procedure. Titanium is deposited onto photolithographically predefined regions of a silicon template. Following photoresist lift-off, the entire surface is backfilled with gold, template stripping is conducted, and an ultraflat micropatterned surface is revealed. Atomic force microscopy confirms a roughness of <0.5 nm RMS on both Ti and Au regions, with a topographically indistinguishable gold–titanium interface. Detailed surface-chemical maps of the patterned surfaces have been obtained by means of imaging X-ray photoelectron spectroscopy (i-XPS) as well as time-of-flight secondary-ion mass spectrometry (ToF-SIMS). They confirm the presence of well-separated Ti and Au regions, with a chemical contrast that is sharp (as determined by ToF-SIMS) and complete (as determined by i-XPS) across the Ti–Au interface. Thus, a surface ...