Browsing by Author "Chiu, J. P."

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A Comparative Study of NBTI and RTN Amplitude Distributions in High-kappa Gate Dielectric pMOSFETs
(2012-02-01)
Chiu, J. P.
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Chung, Y. T.
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Wang, Tahui
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Chen, Min-Cheng
;
Lu, C. Y.
Random telegraph noise (RTN) and negative bias temperature (NBT) stress-induced threshold voltage (V-t) fluctuations in high-kappa gate dielectric and metal-gate pMOSFETs are investigated. We measured RTN amplitude distributions before and after NBT stress. RTN in poststressed devices exhibits a broader amplitude distribution than the prestress one. In addition, we trace a single trapped charge-induced Delta V-t in NBT stress and find that the average Delta V-t is significantly larger than a Delta V(t)caused by RTN. A 3-D atomistic simulation is performed to compare a single-charge-induced Delta V-t by RTN and NBTI. In our simulation, the probability distribution of a NBT trapped charge in the channel is calculated from the reaction-diffusion model. Our simulation confirms that the NBT-induced Delta V-t indeed has a larger distribution tail than RTN due to a current-path percolation effect.
Investigation of Post-NBT Stress Current Instability Modes in HfSiON Gate Dielectric pMOSFETs by Measurement of Individual Trapped Charge Emissions
(2009)
Ma, H. C.
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Chiu, J. P.
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Tang, C. J.
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Wang, Tahui
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Chang, C. S.
Bipolar charge detrapping induced current instability in HfSiON gate dielectric pMOSFETs after negative bias and temperature stress is studied by using a fast transient measurement technique. Both single electron and single hole emissions are observed, leading to post-stress current degradation and recovery, respectively. The NBT stress voltage and temperature effect on post-stress current evolution is explored. Clear evidence of electron and hole trapping in NBT stress is demonstrated. A bipolar charge trapping/detrapping model and charge detrapping paths based on measured charge emission times are proposed.
Program Charge Effect on Random Telegraph Noise Amplitude and Its Device Structural Dependence in SONOS Flash Memory
(2009)
Chiu, J. P.
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Chou, Y. L.
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Ma, H. C.
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Wang, Tahui
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Ku, S. H.
Nitride program charge effects on random telegraph noise (RTN) in SONOS flash cells are investigated. We measure and simulate RTN amplitudes in floating gate flash, planar SONOS, and FinFET SONOS cells. We find that a planar SONOS has a wide spread in RTN amplitude after programming while a floating gate flash cell has identical RTN amplitude in erase and program states. The spread of program-state RTN amplitudes in a planar SONOS is attributed to a current-path percolation effect caused by random discrete nitride charges. The program-state RTN spread can be significantly reduced in FinFET SONOS.
Program Trapped-Charge Effect on Random Telegraph-Noise Amplitude in a Planar SONOS Flash Memory Cell
(2009-11-01)
Ma, H. C.
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Chou, Y. L.
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Chiu, J. P.
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Wang, Tahui
;
Ku, S. H.
Program-charge effects in a SONOS Flash cell on the amplitude of random telegraph noise (RTN) are investigated. We measure RTN in 45 planar SONOS cells and 40 floating-gate (FG) cells in erase state and program state, respectively. We find that a SONOS cell has a wide spread in RTN amplitudes after programming, while an FG cell has identical RTN amplitudes in erase and program states at the same read-current level. A 3-D atomistic simulation is performed to calculate RTN amplitudes. Our result shows that the wide spread of program-state RTN amplitudes in a SONOS cell is attributed to a current-path-percolation effect caused by random discrete nitride charges.
Use of Random Telegraph Signal as Internal Probe to Study Program/Erase Charge Lateral Spread in a SONOS Flash Memory
(2010)
Chou, Y. L.
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Chiu, J. P.
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Ma, H. C.
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Wang, Tahui
;
Chao, Y. P.
A novel random telegraph signal (RTS) method is proposed to study the lateral spread of injected charges in program/erase of a NOR-type SONOS flash memory. The concept is to use RTS to extract an interface trap position and to detect a local potential variation near the trap due to injection of program/erase charges. By using this method, we find that CHISEL program has a broader charge distribution than CHE program. A mismatch of CHE program electrons and band-to-band erase holes is observed directly from this method.