Hafnium silicon oxide films prepared by atomic layer deposition

Hf–Si–O mixture films were fabricated by atomic layer deposition at 400 °C on Si(1 0 0) substrates. The deposition sequence for one hafnium silicon oxide submonolayer comprises surface reactions between Si(OC2H5)4 and HfCl4, followed by the hydrolysis step in order to effectively remove the residual ligands. The effective permittivity, leakage current, and capacitance–voltage behavior depended on the hafnium/silicon ratio and on the oxide/silicon interface quality. The dielectric quality can be modulated for various configurations of stacked layers with different hafnium to silicon ratios.