Browsing by Subject "Nanometer scale metrology"

Two different bio transfer standards (BTS), composed of fatty acid bilayers, NanoRuler and NanoStar were developed. NanoRuler consists of a nanometer scale staircase with eight steps that are 5 nm tall each and NanoStar is designed to have topological structure with sharp edge and three height planes 5 nm elevated with respect to each other. With NanoRuler nanometer vertical calibration from 5 nm to 40 nm is possible and NanoStar allows the evaluation of the instrument transfer function (ITF). Due to the soft nature of the standards, the topographical stability was researched. Thus, an investigation of the topographical stability of three NanoRulers and one NanoStar across 24 months was done by measuring the surface topography with a custom-built Scanning White Light Interferometer (SWLI). The BTS were measured over 100 times during the experiments and were stored in laboratory conditions. The step heights of the structures were calculated with a histogram method and the surface roughness of the samples was evaluated using the Sq parameter. The step height analysis method was compared to the standard method (ISO 5436-1) where applicable and no notable differences were found. In both roughness and step height data no linear or non-linear trends were found, and the step heights compared well with the literature values. For NanoRuler the step heights were 4.9 nm, 10.1 nm, 15.1 nm, 20.1 nm, 25 nm, 30.1 nm, 35.1 nm and 40.2 nm and the respective stabilities were 0.3 nm, 0.3 nm, 0.6 nm, 0.9 nm, 1.3 nm, 1.6 nm, 2.1 nm, and 2.5 nm. For NanoStar the step heights were -5.1 nm and 5.2 nm with stabilities 0.3 nm and 0.4 nm respectively. The NanoRuler had a surface roughness stability of 0.02 nm whereas NanoStar had a roughness stability of 0.01 nm. After 24 months both BTS types preserved their topographical structure and no issues with surface topographical stability were observed.