Electron beam induced decomposition of cadmium chloride thin films with potential resist application

The radiolysis of vacuum-deposited thin films of cadmium chloride on silicon substrates has been studied in the energy range from 1 to 5 keV. Phase-locked mass spectrometry was used for the in situ monitoring of the evolution of the decomposition products, chlorine and cadmium, as a function of substrate temperature, current density, film thickness, and beam energy, for pure and doped films. Ellipsometric thickness and refractive index measurements, and scanning electron microscope examination of the morphology of irradiated films were carried out. The decomposition kinetics have been analyzed in terms of a model in which a fraction of the radiation-generated electron-hole pairs participate in the thermally activated decomposition reaction sequence at the film surface. A potential lithographic scheme has been established, in which decomposition patterns generated onto the films are transferred onto the SiO2 underlayer by reactive ion etching, with a resolution approximately equal to the film grain size