Time-of-flight elastic recoil analysis of ion beam modified nitrocellulose thin films

Abstract

The erosion properties of nitrocellulose (C 6H 7N 3O 11) thin films on Si have been studied under exposure to 270 keV H, He, C, and Ar ions. Time-of-flight elastic recoil spectrometry has been applied to determine the atomic composition of the films as a function of deposited charge. All exposed films exhibit an initial removal of N and O consistent with RONO 2 bond breaking, proceeding at a rate that appears to depend on the density of electronic excitation. A non-volatile, carbon-rich residue remains after prolonged exposure to H, He, and C ions, while the film is effectively removed under Ar irradiation. Experimental evidence supports the proposition that binary collisions are an important mechanism affecting desorption of the H and C components. The results are consistent with a suggestion that complete volatilization of the film is determined by the nuclear stopping power of the incident ion.