Total Ionizing Dose Response of Hafnium-Oxide Based MOS Devices to Low-Dose-Rate Gamma Ray Radiation Observed by Pulse CV and On-Site Measurements

Yifei Mu, Ce Zhou Zhao, Qifeng Lu, Chun Zhao, Yanfei Qi, Sang Lam, Ivona Z. Mitrovic, Stephen Taylor, Paul R. Chalker

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12 Citations (Scopus)


This paper reports on the low-dose-rate radiation response of Al-HfO2/SiO2-Si MOS devices, where the gate dielectric was formed by atomic layer deposition with 4.7 nm equivalent oxide thickness. The degradation of the devices was characterized by a pulse capacitance-voltage (CV) and on-site radiation response techniques under continuous gamma (γ) ray exposure at a relatively low-dose-rate of 0.116 rad(HfO2)/s. A significant variation of the flat-band voltage shift of up to ± 1.1 V under positive and negative biased irradiation, with the total dose of up to 40 krad (HfO2) and the electric field of ∼0.5 MV/cm, has been measured on the HfO2-based MOS devices using the proposed techniques, not apparent by conventional CV measurements. The large flat-b and voltage shift is mainly attributed to the radiation-induced oxide trapped charges, which are not readily compensated by bias-induced charges produced over the measurement timescales of less than 5 ms. Analysis of the experimental results suggest that both hole and electron trapping can dominate the radiation response performance of the HfO2-based MOS devices depending on the applied bias. No distinct loop width variation has been found with irradiation in all cases.

Original languageEnglish
Article number7762951
Pages (from-to)673-682
Number of pages10
JournalIEEE Transactions on Nuclear Science
Issue number1
Publication statusPublished - Jan 2017


  • ALD
  • gamma irradiation
  • hafnium oxide
  • low-dose-rate
  • oxide trapped charges
  • pulse CV

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