Surface and interfacial properties of the ultra-thin HfO2 gate dielectric deposited by ALD

In this work, the surface and interfacial properties of the ultra-thin HfO₂/SiO₂ gate stack dielectrics fabricated on the p-type Si (100) substrates by atomic layer deposition is studied. Grazing incidence x-ray diffraction result manifests the HfO₂ film is almost ideal amorphous phase. Atomic force microscopy images reveal that the surface roughness of the HfO₂ is extremely small and the surface presents a good uniformity. Transmission electron microscopy shows the thickness of the dielectric layers are 2.8 nm and 0.7 nm respectively. X-ray photoelectron spectroscopy indicates that the adventitious impurities carbon and nitrogen are keeping out of the dielectric layers and the interfacial layer SiO₂ can suppress the formation of the hafnium silicates. All the properties show that the atomic layer deposition can deposit HfO₂/SiO₂ gate stack dielectrics with high performance.