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Title: Impact of Lanthanum on positive-bias temperature instability - insight from first-principles simulation
Authors: Gu, Chen Jie
Ang, Diing Shenp
Keywords: DRNTU::Science::Chemistry::Physical chemistry::Electrochemistry
Issue Date: 2013
Source: Gu, C. J., & Ang, D. S. (2013). Impact of Lanthanum on positive-bias temperature instability - insight from first-principles simulation. ECS transactions, 53(3), 193-204.
Series/Report no.: ECS transactions
Abstract: The impact of lanthanum (La) on positive-bias temperature instability (PBTI) is examined via first-principles simulation of the electronic properties of the oxygen vacancy (VO) and vacancy-interstitial (VO-Oi) paired defects in the hafnium dioxide (HfO2) gate dielectric. The purpose is to understand the recently reported retardation of PBTI recovery in La-doped HfO2 gate n-MOSFETs, indicating that La doping has made part of the stress induced electron trapping become more permanent. Simulation results show that the formation energy of both defects are significantly decreased by La doping, implying that these defects are more readily formed in the La-doped HfO2 as compared to the undoped counterpart. The higher density of VO’s should increase PBTI effect, contrary to the experimental observation of a reduced PBTI effect. The discrepancy may be reconciled by the smaller gate current in the La-doped n-MOSFET, believed to be due to the larger tunneling barrier that results from La dipoles at the HfO2/SiOx interface. With a smaller gate current, electron trapping – the main mechanism of PBTI – is correspondingly reduced. But the trap state of VO in the La-doped HfO2 remains as shallow as that in the undoped counterpart and could not account for the reduction in the PBTI recovery observed experimentally. On the other hand, the trap state of the VO-Oi defect is found to be much deeper, and the greater ease of its formation in the La-doped HfO2 could explain the reduced PBTI recovery observed experimentally.
DOI: 10.1149/05303.0193ecst
Rights: © 2013 The Electrochemical Society. This paper was published in ECS Transactions and is made available as an electronic reprint (preprint) with permission of The Electrochemical Society. The paper can be found at the following official DOI: []. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
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