UV degradability of polysilanes for nanoresists examined by electron spectroscopies and photoluminescence

Abstract

The aim of this study was to elucidate the degradation mechanisms in polysilanes, especially one-dimensional polysilylenes, with respect to the search for suitable resists for silicon industrial nanotechnologies. To this end we used the combined methods of photoelectron spectroscopies — PES (UPS and XPS) and photoluminescence — PL. Films of aryl-methyl-substituted polysilane chain, poly[methyl(phenyl)silylene] (PMPSi), prepared by casting from benzene solution, were analysed by X-ray and UV-induced photoelectron spectroscopy. Photoelectron spectra were recorded from the pristine PMPSi surface and after the UV photodegradation. Pronounced changes were found in the HeI induced photoelectron spectra indicating redistribution of filled Si 3s-like and Si 3p-like states. The photodegradation by UV radiation for two different degradation wavelengths λ = 266 and 355 nm was examined also by PL. We concentrated on the PL study in the region of the σ*-σ excitonic deexcitation after major degradations, studying the disorder and dangling bonds (DB) created by the degradation process. The results of both complementary methods are interpreted in accordance with our recent paper [1], with the degradation process explained by two competing phenomena, i.e. the energy dependent exciton transport by diffusion process and Si-Si bond scission.