Improvement of thermal stability and electrical performance in HfSiO gate dielectrics by nitrogen incorporation

We have investigated the electrical properties and the thermal stability in terms of crystallization by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS) in Hf-silicate (HfSiO) and nitrided Hf-silicate (HfSiON) gate dielectric. It is shown that for films with nitrogen incorporation, HfSiON films have superior thermal stability compared to the corresponding HfSiO films. The excellent electrical properties with maximum dielectric constant (17.1 and 18.7) and the smallest oxide-charge density (5.6×1011 and 2.2×1010 cm−2) and leakage current density (1.3×10−6 and 5.9×10−7 A/cm2 at Vg=−1 V) were obtained after 900 and 950°C annealing for HfSiO and HfSiON films, respectively, which indicates that the electrical performance of HfSiO gate dielectrics had a larger improvement through nitrogen incorporation.