Dielectric strength of cross-linked thin-film poly(methyl methacrylate)

The dielectric strength of thin-film cross-linked PMMA was studied. A series of samples was fabricated using EBL. The samples were two overlapping Pd electrodes separated by a layer of cross-linked PMMA. The cross-linking was obtained by high-dose electron-beam irradiation of PMMA thin-film. The size of the overlap was
$1\times 1\ \mu \mathrm{m}^{2}$
and the crosslinked PMMA layer thickness was 90 nm. The IV characteristics of the samples were obtained, and the breakdown voltage measured was 32.5 V to 46.6 V with mean value 39.2 V, and median 38.9 V. The calculated dielectric strength of the thin-film cross-linked PMMA was 3.6 MV/cm to 5.2 MV/cm, with mean value 4.4 MV/cm and median 4.3 MV/cm. Additionally, PMMA thin films shrinkage under cross-linking was measured.