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
PublisherIEEE
Conference LocationLake Tahoe, CA
Abstract

We have begun an investigation of the electrical properties of thin film HfO₂ deposited via atomic layer deposition (ALD) using Hf(NO₃)₄ and H₂O as precursors. Excellent uniformity was achieved on H-terminated Si with better than 1% variation in Cmax over a 6" wafer. Since the most widely used ALD precursor for HfO₂, HfCl₄, requires an initial SiO₂ layer for uniform growth, uniform deposition directly on H-terminated Si is an advantage of using Hf(NO₃)₄. The effective dielectric constant of thin (< 10 nm) films was in the range of κeff = 10-12. The "bulk" dielectric constant of the HfO₂ was found to be κHfO₂ ∼ 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 SiO₂. HfO₂ films showed low leakage (10³-10⁶ times less than SiO₂ of equivalent CET) and good equivalent breakdown strength. The relative leakage benefit of HfO₂ over SiO₂ decreased with decreasing effective thickness. Electron trapping was observed under constant voltage stressing.

DOI10.1109/IRWS.2002.1194244