Oxidation kinetics of $$\hbox {ZrO}_2$$ ZrO 2 films on Si by differential scanning calorimetry

Abstract

Differential scanning calorimetry (DSC) technique is employed to study the growth kinetics of zirconium dioxide where oxidation of a 23 nm-thick Zr film, deposited on Si (100) substrate using dc sputtering system, is studied in $$\hbox {O}_2$$ ambient. The activation energy, derived from the DSC data is 1.36 eV and the diffusion coefficient of oxygen in Zr is estimated as $$1.625 \times 10^{-6} \exp (-\frac{1.36~\hbox {eV}}{k_BT}) {\mathrm{m}}^2/{\mathrm{s}}$$ . The results indicate a parabolic temperature dependence of the $$\hbox {ZrO}_2$$ growth with time. From isothermal measurements, it is further observed that the diffusion coefficient of oxygen in Zr, in logarithmic scale, varies linearly with temperature upto 870 $$^{\circ }\hbox {C}$$ beyond which the linear dependence is continued with a different slope. Such a change in slope is due to the change in diffusion coefficient of $$\hbox {O}_2$$ in ZrSi, $$\hbox {ZrSi}_2$$ and Si leading to formation of interfacial $$\hbox {SiO}_2$$ layer and Zr–Silicate at higher temperature. Synchrotron-based grazing incidence X-ray diffraction study on the $$\hbox {ZrO}_2$$ samples, oxidized in furnace at different temperatures, also corroborates the above observation.