Browsing by Author "Wang, Bin-Wei"

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High-k shallow traps observed by charge pumping with varying discharging times
(2013-11-07)
Ho, Szu-Han
;
Chang, Ting-Chang
;
Lu, Ying-Hsin
;
Wang, Bin-Wei
;
Lo, Wen-Hung
In this paper, we investigate the influence of falling time and base level time on high-k bulk shallow traps measured by charge pumping technique in n-channel metal-oxide-semiconductor field-effect transistors with HfO2/metal gate stacks. N-T-V-high level characteristic curves with different duty ratios indicate that the electron detrapping time dominates the value of N-T for extra contribution of I-cp traps. N-T is the number of traps, and I-cp is charge pumping current. By fitting discharge formula at different temperatures, the results show that extra contribution of I-cp traps at high voltage are in fact high-k bulk shallow traps. This is also verified through a comparison of different interlayer thicknesses and different TixN1-x metal gate concentrations. Next, N-T-V-high level characteristic curves with different falling times (t(falling time)) and base level times (t(base level)) show that extra contribution of I-cp traps decrease with an increase in t(falling time). By fitting discharge formula for different t(falling time), the results show that electrons trapped in high-k bulk shallow traps first discharge to the channel and then to source and drain during t(falling time). This current cannot be measured by the charge pumping technique. Subsequent measurements of N-T by charge pumping technique at t(base level) reveal a remainder of electrons trapped in high-k bulk shallow traps. (c) 2013 AIP Publishing LLC.
Investigation of an anomalous hump in gate current after negative-bias temperature-instability in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors
(2013-01-07)
Ho, Szu-Han
;
Chang, Ting-Chang
;
Wu, Chi-Wei
;
Lo, Wen-Hung
;
Chen, Ching-En
This Letter investigates a hump in gate current after negative-bias temperature-instability (NBTI) in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors. Measuring gate current at initial through body floating and source/drain floating shows that hole current flows from source/drain. The fitting of gate current (I-g)-gate voltage (V-g) characteristic curves demonstrates that the Frenkel-Poole mechanism dominates the conduction. Next, by fitting the gate current after NBTI, in the order of Frenkel-Poole then tunneling, the Frenkel-Poole mechanism can be confirmed. These phenomena can be attributed to hole trapping in high-k bulk and the electric field formula Ehigh-k epsilon(high-k) = Q+E-sio2 epsilon(sio2). (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773479]
Investigation of extra traps measured by charge pumping technique in high voltage zone in p-channel metal-oxide-semiconductor field-effect transistors with HfO2/metal gate stacks
(2013-01-07)
Ho, Szu-Han
;
Chang, Ting-Chang
;
Wang, Bin-Wei
;
Lu, Ying-Shin
;
Lo, Wen-Hung
This letter investigates extra traps measured by charge pumping technique in the high voltage zone in p-channel metal-oxide-semiconductor field-effect transistors with HfO2/metal gate stacks. N-V-high level characteristic curves with different duty ratios show that the hole discharge time (t(base level)) dominates the value of extra traps. By fitting ln (N (t(base level) = 1 mu s) -N (t(base level))) - Delta t(base level) at different temperatures and computing the equation t = tau(0) exp (alpha(h,SiO2)d(SiO2) + alpha(h,HfO2)d(HfO2,trap)), the results show that these extra traps measured by the charge pumping technique at high voltage zone can be attributed to high-k bulk shallow traps. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773914]