Dendrimer-mediated growth of very flat ultrathin Au films

Si wafers covered with a native oxide were used as substrates for growth of 12.5 nm of evaporated Au (Au/SiOx), and self-assembly of a dendrimer monolayer followed by the same thickness of Au (Au/dendrimer/SiOx). This paper presents evidence for very significant improvements in Au film quality when grown on a self-assembled monolayer of amine-terminated poly(amidoamine) (PAMAM) dendrimers (generation G8) on SiOx. An increase in surface hardness from 1.7 to 3 GPa, a decrease in surface roughness from about 1.2 to 0.4 nm and better adhesion are shown with a combination of XPS, X-ray reflectivity (XRR), AFM, and nanoindentation. The improvement in film quality may be explained by penetration of the deposited Au into the dendrimer adlayer. This interpenetration is confirmed by AFM profilometry and XPS analysis.