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Polycrystalline (1− x )Ta 2 O 5 − x TiO 2 thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600 °C. During crystallization, a thin interfacial SiO 2 layer was formed at the (1− x )Ta 2 O 5 − x TiO 2 /Si interface. Thin films with 0.92Ta 2 O 5 –0.08TiO 2 composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1 MHz were 9 and 0.015, respectively, for films annealed at 900 °C. The interface trap density was 2.5×10 11 cm −2 eV −1 , and flatband voltage was −0.38 V. A charge storage density of 22.8 fC/μm 2 was obtained at an applied electric field of 3 MV/cm. The leakage current density was lower than 4×10 −9 A/cm 2 up to an applied electric field of 6 MV/cm. |
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