Browsing by Author "Su, P. C."

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Correlation between SET-State Current Level and Read Disturb Failure Time in a Resistive Switching Memory
(2018-01-01)
Su, P. C.
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Jiang, C. M.
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Wang, C. W.
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Wang, Tahui
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電子工程學系及電子研究所
The relationship between SET-state current level and read-disturb failure time in a tungsten oxide RRAM is characterized and modeled. Our result shows that read voltage induced reduction of oxygen vacancy density in tungsten oxide follows a power law dependence on cumulative read-disturb time. The power factor is independent of SET-state current level. Read disturb failure time is considerably improved by several orders of magnitude as SET-state current level increases a few times. An analytical model to correlate SET-state current level and read disturb failure time is proposed. Since SET-state current level is related to a cross-section of a conductive filament in an oxide, our model is developed based on a relationship between oxide area and critical oxide trap (oxygen vacancy) density from an oxide breakdown model. The validity of the proposed model is supported by experiment results.
Investigation of Factors Affecting SET-Disturb Failure Time in a Resistive Switching Memory
(2016)
Su, P. C.
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Chung, Y. T.
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Chen, M. C.
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Wang, Tahui
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電子工程學系及電子研究所
Factors affecting SET-disturb failure time (tau(f)) in a tungsten oxide resistive switching memory including SET/RESET cycling stress, resistance window in operation and SET-disturb voltage are investigated. A SET-disturb failure time in high resistance state (HRS) may degrade by orders of magnitude in a post-cycling cell. The degradation is attributed to the formation of a current percolation path of cycling stress-generated traps. A one-dimensional percolation model is proposed for the tau(f) degradation. The dependence of tau(f) on resistance window in operation is characterized. We find that tau(f) is greatly affected by the current level of LRS. The strong LRS dependence of tf is attributed to a small Weibull slope of tau(f). In addition, we perform statistical characterizations of tau(f) at different SET-disturb voltages. A relationship between tau(f) and a SET-disturb voltage in a stressed cell is given.
Investigation of Random Telegraph Noise Amplitudes in Hafnium Oxide Resistive Memory Devices
(2014-01-01)
Chung, Y. T.
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Liu, Y. H.
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Su, P. C.
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Cheng, Y. H.
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Wang, Tahui
Statistical characterization of two-level random telegraph noise (RTN) amplitude distribution in a hafnium oxide resistive memory has been performed. We find that two-level RTN in HRS exhibits a large amplitude distribution tail, as compared to LRS. To investigate an RTN trap position in a hafnium oxide film, we measure the dependence of electron capture and emission times of RTN on applied read voltage. A correlation between an RTN trap position and RTN amplitude is found. A quasi-two-dimensional RTN amplitude simulation based on trap-assisted electron sequential tunneling is developed. Our study shows that RTN traps in a rupture region of a hafnium oxide film are responsible for an RTN large-amplitude tail in HRS mostly.