Stoichiometry Reversal and Depth-Profiling in The Growth of Thin Oxynitride Films With N_2O on Si(100) Surfaces

摘要

Synchrotron based O 1s and N 1s photoabsorption spectroscopy have been used to determine the composition and thickness of oxynitride films grown in N_2O on a Si(100) surface. Core-level photoabsorption spectroscopy is shown to be a very sensitive probe capable of measuring surface coverages lower than 0.1 monolayers of N (6.5 x 10~(13) N atoms/cm~2). Film composition was monitored as a function of growth to demonstrate the stoichiometry reversal from primarily N terminated surfaces in thin films to nearly pure SiO_2 in films thicker than ～ 20 A. A sample with a 60 A oxynitride film was depth-profiled by etching in HF and was shown, via N 1s absorption spectroscopy, to have N segregation within 10 A above the Si/SiO_2 interface.