Study of poly-Si/TaSiN/Pt structure for stacked capacitors

摘要

Due to its high oxidation resistance, TaSiN is a promising candidate as an electrically conductive barrier layer for integration of high permittivity oxides in advanced memory devices. In this work, we report on the properties of TaSiN thin films deposited by reactive magnetron sputtering of a TaSi_2 target. We have mainly studied the influence of deposition pressure and power density on film properties (composition, density, resistivity). The oxidation resistance of TaSiN films has been investigated at typical conditions for crystallization of perovskite dielectrics. The as-deposited and annealed samples were characterized using Rutherford backscattering spectroscopy and nuclear reaction analysis for atomic composition and XPS for chemical bonding. To study oxidation resistance, films have been processed in ~(18)O_2. The concentration depth profiles of ~(18)O was measured after thermal treatments via the narrow resonances of ~(18)O(p,α)~(15)N at 151 keV (fwhm=100eV). The different results suggest that a pressure of 0.5 Pa, a power density of 2.63W/cm~2 and a gas flow ratio N_2/Ar of 5% allow to perform TaSiN films with high density, low resistivity and good oxidation resistance.