Modeling temperature dependency (6 &amp;#x2013; 400K) of the leakage current through the SiO&lt;inf&gt;2&lt;/inf&gt;/high-K stacks

Vandelli, Luca; Padovani, Andrea; Larcher, Luca; Southwick, Richard G.; Knowlton, William B.; Bersuker, G.

doi:10.1109/essderc.2010.5618204

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…This hints on a reducing number of defects in the layer counteracting and surpassing the effect of physical thickness reduction. Defects can enhance both the charge carrier transport through and the injection of carriers into the dielectric film . This was shown in earlier studies for similar films .…”

Section: Discussionsupporting

confidence: 51%

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films

Grimley

Schenk

Sang

et al. 2016

Adv Elect Materials

340

280

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of crucial relevance for the performance of ferroelectric memories. [ 12,13 ] The phenomenon of wake-up refers to the transition from a pinched hysteresis with a low remanent polarization P r to an open (depinched) hysteresis during a certain amount of initial switching cycles. Internal bias fi elds [ 12 ] have recently been shown to account for this behavior and have been speculated to be caused by charged oxygen vacancies at top and bottom electrodes. [ 5,7 ] The phenomenon of polarization fatigue is characterized by a gradual decrease in P r with continued application of switching cycles beyond wake-up. [ 14,15 ] Despite the importance of these phenomena, they have yet to be thoroughly explained for these rather new ferroelectrics. To address this lack of understanding, we chose a combined approach of sophisticated electrical and structural analysis. We report the fi rst impedance spectroscopy measurements of ferroelectric-doped HfO 2 thin fi lms using TiN-Gd:HfO 2 -TiN metal-ferroelectric-metal (MFM) capacitors at different stages of cycling lifetime. These fi ndings are then correlated to aberration-corrected atomicresolution scanning transmission electron microscopy (STEM) measurements. Direct evidence for the evolution of multiple aspects of fi lm structure during fi eld cycling is shown to underlie the observed electrical behavior. ResultsThe electrical response of the Gd:HfO 2 MFM capacitors exhibits typical behavior of HfO 2 ferroelectrics. Figure 1 a shows the manifestation of both wake-up and fatigue in the polarization hysteresis whereas Figure 1 b depicts the evolution of P r throughout the course of continuous fi eld cycling. Besides the aforementioned changes in the polarization-voltage ( P -V ) hysteresis (loop opening and P r increase followed by a decrease in P r ), the slopes of the saturated hysteresis branches hint at changes in relative permittivity of the fi lm. These changes become even more apparent when measuring the small-signal capacitance as a function of applied bias voltage. As expected from the P -V hysteresis, the peaks in the butterfl y-like hysteresis in relative permittivity ε r that result from additional domain wall capacitance during polarization switching [ 16 ] fi rst increase Since 2011, ferroelectric HfO 2 has attracted growing interest in both fundamental and application oriented groups. In this material, noteworthy wake-up and fatigue effects alter the shape of the polarization hysteresis loop during fi eld cycling. Such changes are problematic for application of HfO 2 to ferroelectric memories, which require stable polarization hystereses. Herein, electrical and structural techniques are implemented to unveil how cyclic switching changes nanoscale fi lm structure, which modifi es the polarization hysteresis. Impedance spectroscopy and scanning transmission electron microscopy identify regions with different dielectric and conductive properties in fi lms at different cycling stages, enabling development of a structural model to explain the wake-up and fatigue phenomen...

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Section: Discussionsupporting

confidence: 51%

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films

Grimley

Schenk

Sang

et al. 2016

Adv Elect Materials

340

280

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“…This is consistent with SRIM modeling, which shows that the density of radiation-induced vacancies in the HfO ECM devices considered here is approximately cm at 1.5 Grad proton irradiation. This is comparable to the intrinsic trap density for that material system ( -cm [10], [30]- [32]). Similar field screening would also result in higher measured values of .…”

Section: Resultsmentioning

confidence: 62%

Superior TID Hardness in TiN/HfO$_{2}$/TiN ReRAMs After Proton Radiation

Wang

Butcher

et al. 2012

IEEE Trans. Nucl. Sci.

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Resistive switching properties of valence change memory (VCM) resistive-random-access-memory (ReRAM) devices (TiN/HfO /TiN) are investigated after exposure to proton radiation with total ionizing doses (TID) of 1.5, 3, and 5 Grad(Si) and compared to similar measurements from electrochemical metallization memory (ECM) ReRAM devices (Pt/HfO :Cu/Cu). The TiN/HfO /TiN ReRAMs show significantly superior TID radiation-hardness compared to Pt/HfO :Cu/Cu ReRAMs: 1) All devices remained functional after radiation; 2) switching parameters including average , , , showed minimal or no degradation; and 3) TID radiation enhanced the uniformity of resistive switching among all VCM devices. The superior radiation responses of the VCM ReRAM devices relative to ECM ReRAMs result from the distinct conduction filament (CF) formation mechanisms. For the VCM ReRAM system, the radiation-induced vacancy density does not serve to inhibit the trap-assisted tunneling associated with the Hf-rich CF formation kinetics. On the contrary, vacancy-promoted charge trapping promotes VCM CF stability. In strong contrast, proton-induced vacancies for the ECM ReRAMs inhibit the formation of the metallic filament through internal field reduction due to charge trapping. The comparison of TID effects suggests that HfO -based VCM ReRAMs can be made radiation immune to a TID up to 5 Grad(Si) and may be highly suitable for rad-hard electronics applications.Index Terms-Hafnium oxide, rad-hard, resistive switching, total ionizing dose.

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“…However, we suspect that also other reliability issues, such as the drain current RTN (20,21), involve the same type of oxide defects and rely on the same charge capture and emission processes. This hypothesis is supported by a number of studies that link NMP processes to drain noise (22,23) and the gate leakage (24)(25)(26) but disregard the possible existence of metastable states. Interestingly, recent publications (19,(27)(28)(29) report that the drain and gate current noise is sometimes correlated (see Fig.…”

Section: Introductionmentioning

confidence: 89%

“…10, the state 1 ′ is split into the states 1 ′ s and 1 ′ p where subscripts s and p indicate whether the hole is located in the substrate or in the poly-gate, respectively. In previous works (24,25,44), the TAT current is usually modeled as…”

Section: Trap-assisted Tunnelingmentioning

confidence: 99%

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(Invited) Multiphonon Processes as the Origin of Reliability Issues

Goes

Toledano-Luque²,

Schanovsky

et al. 2013

ECS Trans.

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Recently, correlated drain and gate current fluctuations have been observed in nano-scaled MOSFETs, indicating that their occurrence is linked to the same defect. One explanation for this observation can be given by the multi-state defect model, which has been developed to describe the hole capture and emission processes involved in the bias temperature instability (BTI). This model relies on a combination of metastable defect states and nonradiative multi-phonon transitions. Our detailed investigations demonstrate that the observed gate current fluctuations and their correlation with the drain noise can be well reproduced using a TAT mechanism based on the multi-state model.

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Modeling temperature dependency (6 – 400K) of the leakage current through the SiO<inf>2</inf>/high-K stacks

Cited by 12 publications

References 10 publications

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films

Superior TID Hardness in TiN/HfO$_{2}$/TiN ReRAMs After Proton Radiation

(Invited) Multiphonon Processes as the Origin of Reliability Issues

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Modeling temperature dependency (6 &#x2013; 400K) of the leakage current through the SiO<inf>2</inf>/high-K stacks

Cited by 12 publications

References 10 publications

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO2 Thin Films

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO2 Thin Films

Superior TID Hardness in TiN/HfO$_{2}$/TiN ReRAMs After Proton Radiation

(Invited) Multiphonon Processes as the Origin of Reliability Issues

Contact Info

Product

Resources

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Modeling temperature dependency (6 – 400K) of the leakage current through the SiO<inf>2</inf>/high-K stacks

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films

Structural Changes Underlying Field‐Cycling Phenomena in Ferroelectric HfO₂ Thin Films