Modeling growth rate of HfO2 thin films grown by metal–organic molecular beam epitaxy

HfO2 dielectric layers were grown on the p-type Si (100) substrate by metal–organic molecular beam epitaxy (MOMBE). Hafnium-tetra-butoxide, Hf(O·t-C4H9)4 was used as a Hf precursor and Argon gas was used as a carrier gas. The thickness of the HfO2 film and intermediate SiO2 layer were measured by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The properties of the HfO2 layers were evaluated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high frequency (HF) capacitance–voltage (C–V) measurement, and current–voltage (I–V) measurement. C–V and I–V measurements have shown that HfO2 layer grown by MOMBE has a high dielectric constant (k) of 20–22 and a low-level of leakage current density. The growth rate is affected by various process variables such as substrate temperature, bubbler temperature, Ar and O2 gas flows and growth time. Since the ratio of O2 and Ar gas flows are closely correlated, the effect of variations in O2/Ar flow ratio on growth rate is also investigated using statistical modeling methodology.