No abstract

About 20 Å of hafnium were deposited on silicon substrates using the electron beam evaporation technique. Two types of samples were investigated. In one type, the substrate was kept at the ambient temperature. After the deposition, the substrate temperature was increased to 100, 200, and 300∘C. In the other type, the substrate temperature was held fixed at some value during the deposition. For this type, the substrate temperatures used were 100, 200, 300, 400, 500, 550, and 600∘C. The samples were characterized in situ by the technique of X-ray photoelectron spectroscopy. No trace of elemental hafnium is observed in the deposited overlayer. Also, there is no evidence of any chemical reactivity between the overlayer and the silicon substrate over the temperature range used. The hafnium overlayer shows a mixture of the dioxide and the suboxide. The ratio of the suboxide to dioxide is observed to be more in the first type of samples. The spectral data indicate that hafnium has a strong affinity for oxygen. The overlayer gets completely oxidized to form HfO2 at substrate temperature around 300∘C for the first type of samples and at substrate temperature greater than 550∘C for the second type.

The Si3N4 sample was grown by chemical vapor deposition on a Si substrate at 900 °C using a mixture of SiH4, NH3, and H2 gases. Prior to deposition the Si wafer was cleaned in HCl vapor at about 1050 °C. The formation of Si3N4 was checked by x-ray diffraction. This sample was analyzed by x-ray photoelectron spectroscopy. The XPS data in the Si 2s, Si 2p, N 1s, and N KVV Auger regions are presented. A wide range of binding energy values for these constituents has been reported in the literature [see C. D. Wagner, D. E. Passoja, H. F. Hillery, T. G. Kinisky, H. A. Six, W. T. Jansen, and J. A. Taylor, J. Vac. Sci. Technol. 21, 933 (1982); J. A. Taylor, Appl. Surf. Sci. 7, 168 (1981); and T. N. Wittberg, J. R. Hoenigman, W. E. Moddeman, C. R. Cothern, and M. R. Gulett, J. Vac. Sci. Technol. 15, 348 (1978)]. The present data will serve as a reference for CVD Si3N4 film which has wide applications in semiconductor technology.

No abstract