Structural and electrical properties of thin Ho2O3 gate dielectrics

This paper describes the structural properties and electrical characteristics of thin Ho2O3 gate dielectrics deposited on silicon substrates by means of reactive sputtering. The structural and morphological features of these films after postdeposition annealing were studied by X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy. It is found that Ho2O3 dielectrics annealed at 700 °C exhibit a thinner capacitance equivalent thickness and excellent electrical properties, including the interface trap density and the hysteresis in the capacitance–voltage curves. Under constant current stress, the Weibull slope of the charge-to-breakdown of the 700 °C-annealed films is about 1.7. These results are attributed to the formation of well-crystallized Ho2O3 structure and the reduction of the interfacial SiO2 layer.