Lateral Structures of Buried Interfaces in ABA-Type Triblock Copolymer Films

Abstract

The lateral structure of an ABA-type triblock copolymer polyparamethylstyrene-block-polystyrene-blockpolyparamethylstyrene at the buried silicon substrate interface is studied as a function of different substrate surface treatments. With grazing incidence small-angle neutron scattering (GISANS), high interface sensitivity is reached. With GISANS, the orientation and degree of order of the morphology are probed. The powderlike oriented lamellar structure in the bulk orients along the surface normal in the vicinity of the substrate. A modification of the short-ranged interface potential of the substrate introduces a lateral stretching of this lamellar structure of up to 8% as compared to the bulk. The decay in stretching toward the volume structure is probed with depth profiling. It extends at least up to a distance of 51 nm from the solid surface.

Grazing-incidence small-angle neutron scattering from structures below an interface

“…In the majority of the studies (Mü ller-Buschbaum et al, 2008;Als-Nielsen et al, 1994;Prieve & Walz, 1993;Dosch et al, 1986;Wolff et al, 2014;Al-Hussein et al, 2013;Parratt, 1954;Dietrich & Wagner, 1984;Gutfreund, 2011), the penetration depth can be expressed as…”

Grazing incidence small-angle neutron scattering: challenges and possibilities

“…29 When the neutron beam enters through a transparent substrate, such as silicon Grazing incidence small-angle neutron scattering P Müller-Buschbaum (Si), D is the distance from the Si-polymer interface into the polymer (as depicted in the inset of Figure 2). 33 The highly nonlinear behavior of D (a i ) is illustrated in Figure 2 for the polymer film under investigation. The probed depth changes significantly for an incident angle close to the critical angle a c For a i oa c , surface or interface sensitivity is achieved using a very limited scattering depth.…”

“…For example, incident angles of 0.075, 0.162 and 0.2131 at the triblock copolymer-Si interface (marked with arrows in Figure 2b) produce scattering depths of 24, 31 and 51 nm, respectively. 33 Nanostructures at the free surface of the polymer film A series of GISANS experiments were conducted to investigate deviations from L bulk at the surface of the triblock copolymer film P(pMSb-Sd-b-pMS). A neutron beam (wavelength 0.6 nm) entered the polymer from the polymer-air surface at different incident angles: Grazing incidence small-angle neutron scattering P Müller-Buschbaum a i ¼ 0.067, 0.162, 0.306, 0.417, 0.465 and 0.7191.…”

“…As mentioned above, the neutron beam needs to enter through the substrate in these experiments. 33 As for the structures at the free surface of polymer films, depth sensitivity is achieved by varying the incident angle (see Figure 2b). Critical angles for the polymersubstrate interface are typically smaller than critical angles for the free surface of the films because the SLD difference between the polymer film and the substrate is smaller than that between polymer and air (SLD(air) ¼ 0).…”

Probing Relief Terraces in Destabilized Thin Films of an Asymmetric Block Copolymer with Grazing-Incidence Small-Angle X-ray Scattering

“…Such a feature was also reported in the morphological study of triblock copolymer thin films on various types of substrates by using grazing incident small-angle neutron scattering (GISANS). 27 They attributed the feature to variances in ordering of nanodomains at surface and buried in bulk. On the basis of the feature appearing in the Figure 6, we proposed a scenario to interpret the discrepancy in the ordering of nanostructures for thin films on polar (SiO x /Si and PMMA-SiO x /Si) and nonpolar substrates (PS-SiO x / Si).…”