Photon energy dependence of synchrotron radiation induced growth suppression and initiation in Al chemical vapor deposition II. Surface analysis by Auger electron spectroscopy

We analyzed the photochemical reaction of dimethyl aluminum hydride on Si and SiO2 surfaces as a function of photon energy using synchrotron radiation. Al LVV chemical shifts in the Auger electron spectra were clearly different, depending on whether core or valence electrons were excited. When high-energy photons were used to excite the core electrons, aluminum carbide was formed on the Si surface. On the other hand, when low energy photons, which can only excite valence electrons, were utilized, metallic aluminum was formed on the Si and SiO2 surfaces. These results were consistent with the previously reported photon energy dependence of CVD characteristics. That is, when AlC was formed with core electron excitation, growth was suppressed, and negative projection patterning was achieved. On the other hand, when Al was formed with valence electron excitation, growth was initiated and positive patterning was performed on the SiO2 surface. We proposed a model which explained how the Al growth was controlled by the surface layers formed by photochemical reaction, and why growth suppression and initiation changed with the excitation photon energy.