Determination of the local gold contact morphology on a photoactive polymer film using nanobeam GISAXS

Grazing incidence small-angle X-ray scattering is performed with a nanometer sized X-ray beam (nGISAXS) to probe the local gold contact morphology on a photoactive polymer film. By evaporation a 50 nm thick gold contact is installed on a diblock copolymer film, which consists of a non-conducting poly(styrene) (PS) and a semi-conducting poly(paraphenylene) (PPP) block. The region around the edge of the gold contact of 200 μm is probed with nGISAXS by scanning the sample position in steps of 1 μm with respect to the X-ray beam. The diblock copolymer film has a densely packed micellar structure with a characteristic distance between adjacent micelles of 19 nm which is unaffected by the gold deposition. The gold contact exhibits a tail region which extends its lateral dimension. For the full extended surface area of the gold contact with its tails an interdiffusion of gold into the diblock copolymer film is observed. For comparison imaging ellipsometry, atomic force microscopy and optical microscopy measurements are performed.