Comparative study of the interfacial characteristics of sputter-deposited HfO2 on native SiO2/Si (100) using in situ XPS, AES and GIXR

The HfO2/SiO2/Si, Hf/SiO2/Si and HfO2/Hf/SiO2/Si interfaces formed by rf magnetron sputtering deposition were comparatively investigated using in situ high resolution X-ray photoelectron spectroscopy, auger depth profiling and grazing incident X-ray reflectivity (GIXR). The reactive deposition of HfO2 directly on native SiO2/Si (100) leads to an extraordinarily thick Si-rich interface of about 3.33 run, which will limit the capacitance of high-kappa films. To suppress the growth of the unexpected interface, it has been found that the pre-deposition of Hf (about 1 nm) is effective. The Hf radicals reduce SiO2 to metallic Si to form HfO2 and partly result in HfSix. After subsequent reactive deposition of HfO2 on Hf/SiO2/Si stacks, the Hf-rich silicates interlayer is as thin as 1.88 mn, calculated as an equivalent thickness Of SiO2. All the XPS, AES depth profiling and GIXR results show a good coincidence with each other. Copyright (C) 2006 John Wiley & Sons, Ltd.