Atomic layer deposition of HfO₂ films using carbon-free tetrakis(tetrahydroborato)hafnium and water

Journal Article · 19 June 2020 · Journal of Vacuum Science and Technology A

DOI: https://doi.org/10.1116/6.0000053 · OSTI ID:1660750

Choudhury, Devika ^[1]; Mandia, David J. ^[1]; Langeslay, Ryan R. ^[1]; Yanguas-Gil, Angel  ^[1]; Letourneau, Steven  ^[1]; Sattelberger, Alfred P. ^[1]; Balasubramanium, Mahalingam ^[1]; Mane, Anil U. ^[1]; Delferro, Massimiliano ^[1]; Elam, Jeffrey W. ^[1]

---

1. Argonne National Lab. (ANL), Argonne, IL (United States)

Thin hafnium oxide films were prepared by atomic layer deposition using a carbon-free precursor, tetrakis(tetrahydroborato)hafnium [Hf(BH₄)(₄)], and H₂O. Film growth was studied using an in situ quartz crystal microbalance and Fourier transform infrared spectroscopy measurements. Self-limiting growth was observed between 100 and 175 degrees C, but the thermal decomposition of the Hf precursor occurred at higher temperatures. The film properties were investigated using x-ray photoelectron spectroscopy, x-ray reflectivity, x-ray diffraction, ellipsometry, time-of-flight secondary ion mass spectrometry, and x-ray absorption spectroscopy. The as-deposited films were found to consist of an amorphous mixture of HfO₂ and B₂O₃, and had a lower density and lower refractive index compared to pure HfO₂ thin films. Finally, annealing the films to >750 degrees C yielded crystalline monoclinic HfO₂ with a density of 9g/cm³ and a refractive index of 2.10.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1660750
• Journal Information: Journal of Vacuum Science and Technology A, Vol. 38, Issue 4; ISSN 0734-2101
• Publisher: American Vacuum Society / AIPCopyright Statement
• Country of Publication: United States
• Language: English