Mass Density of Polystyrene Thin Films
Abstract
Neutron reflectivity measurements on polystyrene thin films (6.5 to 79.0 nm thick) supported on silicon substrates indicate that the mass density is near the bulk value regardless of film thickness. To account for possible inaccuracies arising from sample misalignment, reflectivity measurements were made both from the free-surface and silicon-substrate sides of the thin film, a method termed twin reflectivity. For films spin coated on the hydrogen-terminated silicon surface the relative uncertainty in the density measurement was on the order of one percent, but for films spin coated onto the silicon native-oxide surface the analysis was more difficult because of subtleties in data fitting due to the oxide layer. Nevertheless, within the limits of greater uncertainty, these films also showed no systematic change in density with thickness.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.A1311W