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Electrical Properties and Reliability of HfO2 Deposited via ALD using Hf(NO3)4 Precursor

TitleElectrical Properties and Reliability of HfO2 Deposited via ALD using Hf(NO3)4 Precursor
Publication TypeConference Paper
Year of Publication2002
AuthorsConley, J. F., Y. Ono, W. Zhuang, L. Stecker, and G. Stecker
Conference NameIEEE 2002 Integrated Reliability Workshop (IRW)
Pagination108 - 112
Date Published10/2002
Conference LocationLake Tahoe, CA

We have begun an investigation of the electrical properties of thin film HfO&#8322; deposited via atomic layer deposition (ALD) using Hf(NO&#8323;)&#8324; and H&#8322;O as precursors. Excellent uniformity was achieved on H-terminated Si with better than 1% variation in C<sub>max</sub> over a 6" wafer. Since the most widely used ALD precursor for HfO&#8322;, HfCl&#8324;, requires an initial SiO&#8322; layer for uniform growth, uniform deposition directly on H-terminated Si is an advantage of using Hf(NO&#8323;)&#8324;. The effective dielectric constant of thin (< 10 nm) films was in the range of κ<sub>eff</sub> = 10-12. The "bulk" dielectric constant of the HfO&#8322; was found to be κHfO&#8322; ∼ 15.9 and the effective interfacial layer thickness (assuming κ = 3.9) was calculated to be approximately one to two monolayers. Recent ESR results suggest this interfacial layer is not pure SiO&#8322;. HfO&#8322; films showed low leakage (10&#179;-10&#8310; times less than SiO&#8322; of equivalent CET) and good equivalent breakdown strength. The relative leakage benefit of HfO&#8322; over SiO&#8322; decreased with decreasing effective thickness. Electron trapping was observed under constant voltage stressing.