Comprehensive Study on Negative Capacitance Effect Observed in MOS(n) Capacitors With Ultrathin Gate Oxides

Chang, Shu-Jau; Hwu, Jenn–Gwo

doi:10.1109/ted.2010.2102033

Cited by 14 publications

(8 citation statements)

References 31 publications

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“…Such an effect could explain the origin of the measured negative capacitance. 26,27 Further, the existence of anomalies in both the forward-and reverse-bias regions suggests that the interface states were distributed throughout the entire band-gap of Nb:STO. Because the amplitudes of the excess capacitance and capacitance/conductance hysteresis were more pronounced in the negative-bias region, subsequent measurements will focus on investigating the details of frequency-dependent admittance under different negative DC biases.…”

Section: Resultsmentioning

confidence: 99%

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions

Bourim

Kim

2014

ECS J. Solid State Sci. Technol.

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In this study, we investigated the resistive switching (RS) behavior of Pt/Nb-doped SrTiO 3 (Pt/Nb:STO) single-crystal junctions in air and vacuum. We performed steady-state electrical characterizations: the direct current (DC) current-voltage relationship and relaxation current-time dependence under an applied voltage step. The ideality factor of the junction suggested the existence of interface states and tunneling current. We observed that the relaxation current followed the Curie-von Schweidler law; electrical conduction was dominated by a space-charge-limited current based on charge recombination at the interface states. The dynamic electric response was obtained using an alternating current (AC) conductance technique. The carrier lifetime at the interface traps was largely dependent on the resistance state and the ambient environment. Thus, surface potential modification by charge capture/release at the interface traps played a crucial role in the RS of our junctions. Additionally, the ambient effect showed that oxygen desorption (adsorption) at the Nb:STO surface increased (decreased) the interface state density. Finally, an RS model based on interface states in Pt/Nb:STO was proposed.Many investigations have studied the resistive switching (RS) phenomena of thin-film and single-crystal metal oxides. 1-17 Schottky junctions composed of conducting electrodes and Nb-doped SrTiO 3 (Nb:STO) single crystals often exhibit strong rectifying transport characteristics, accompanied by a large hysteresis, i.e., bistable RS nature, without the need for any initial forming process. 8-17 Such single-crystal-based systems have less ambiguity in their transport properties, whereas thin films (mostly polycrystalline) present complications originating from the samples' microstructure and chemical imperfections. 1-7 Several models have been put forward to explain the RS memory effects. Coupled electron-ion dynamics is believed to play a key role in many of these models. As widely accepted, the migration of oxygen vacancies under the influence of an electric field is similar to the behavior of mobile dopants, in that the local conductivity and potential profile at the interface are affected, resulting in the formation of bi-stable resistance states. The resulting vacancy clusters often form localized conducting paths to induce RS (i.e., 'conducting filaments'). 1-6 Fujii et al. 8 discussed variations in the Schottky barrier height (SBH) from charge carriers trapped at interface states as the origin of RS. Shang et al. 9 reported little change in the SBH; however, the resistance states of their RS junctions were affected by trap-assisted tunneling. Lee et al. 10 reported that local barrier height fluctuations depend on the resistance state; however, the mean SBH is nearly constant, as indicated by internal photoemission spectra. Li et al. 11 claimed that SBH inhomogeneity and deep levels in the depletion layer play a crucial role in RS. Recently, Buzio et al. 12 and our research group 13 examined the effect of ambient condit...

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Section: Resultsmentioning

confidence: 99%

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions

Bourim

Kim

2014

ECS J. Solid State Sci. Technol.

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“…5(a). The LNU in SiO 2 and high-k gate dielectrics has been observed in the MOS structures [19]- [25]. The rough silicon surface can result in nonuniform thickness in SiO 2 .…”

Section: A Lateral Nonuniformity-induced C-v Frequency Dispersion Inmentioning

confidence: 96%

Surface Nonuniformity-Induced Frequency Dispersion in Accumulation Capacitance for Silicon MOS(n) Capacitor

Lin

Hwu

2016

IEEE Trans. Electron Devices

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Frequency dispersion in accumulation capacitance is observed in Al/SiO 2 /n-Si structured MOS with an ultrathin oxide layer (2.8 nm) grown on roughened silicon surface. The measured accumulation capacitance shows a 14.9% (26.9%) decrease at 1-kHz measurement frequency, and a 50.3% (69.2%) decrease at 10-kHz measurement frequency for partially nonuniform (fully nonuniform) sample. This phenomenon can be attributed to the lateral series resistance in the surface accumulation layer due to the interaction between nonuniformly distributed electrons. By taking into account the effect of nonuniformity-induced lateral series resistance, the accumulation C-V can be reproduced from a simplified model with a carefully chosen effective series resistance R s,eff . The extracted R s,eff is found to be frequency dependent and the value increases with a larger percentage of the nonuniform area. On the other hand, for p-type MOS, inconspicuous frequency dispersion in accumulation capacitance but apparent distortion in C-V profiles is observed. The possible mechanisms for the phenomenon are discussed.

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“…In fact, the yields of the charges at the D it to the measurements at low-frequencies result in obtaining excessive C and G/ω values at these frequency ranges [32]. The peak, NC, and inductive behavior (IB) are the other anomalies experimentally observed, and they are reported in the literature several times for different materials [33][34][35][36][37][38][39][40][41][42][43]. Although the observation of NC behavior for different materials has different explanations related to their internal properties, there should be general principles for the explanation of NC for all types of structures.…”

Section: Introductionmentioning

confidence: 96%

Investigation of photon-induced effects on some diode parameters and negative capacitance of the Schottky structure with Zn-doped organic polymer (PVA) interface

Tanrıkulu

2022

Phys. Scr.

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Variation in the electrical parameters depending on illumination and the formation of negative capacitance (NC), and inductive behavior (IB) of Schottky structures interlaid with Zn:PVA, were executed by current/impedance-voltage (I/Z-V) measurements in the dark and under 200 mW/cm2 illuminance. To designate the voltage or calculation method effects on the ideality factor (n), barrier height (BH-B), and series resistance (Rs), these parameters were extracted from different methods. These parameters extracted through the Thermionic-emission (TE) theory, Ohm's law, Norde and Cheung functions were compared with each other. The reverse bias ln(IR) – VR0.5 plots were also drawn to designate the validity of Poole-Frenkel and Schottky emissions. In Z-V measurements, NC and related IB phenomena were observed at 500 kHz-fixed frequency in the dark and under illuminance. The interface states (Dit) variation depending on energy and voltage was obtained using current and capacitance measurements and related equations. The calculations of the diffusion-potential (VD), acceptor-atoms (NA), Fermi-energy (EF), and B(C-V) values were performed by fitting the observed linear in the reverse bias C-2-V plot. A detailed analysis of NC and IB was performed via the drawn C/G/-I plots for positive voltages. All experimental results show that the used calculation method, illumination, and voltage are highly effective on the electrical parameters.

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Comprehensive Study on Negative Capacitance Effect Observed in MOS(n) Capacitors With Ultrathin Gate Oxides

Cited by 14 publications

References 31 publications

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions

Surface Nonuniformity-Induced Frequency Dispersion in Accumulation Capacitance for Silicon MOS(n) Capacitor

Investigation of photon-induced effects on some diode parameters and negative capacitance of the Schottky structure with Zn-doped organic polymer (PVA) interface

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Comprehensive Study on Negative Capacitance Effect Observed in MOS(n) Capacitors With Ultrathin Gate Oxides

Cited by 14 publications

References 31 publications

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO3Single-Crystal Schottky Junctions

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO3Single-Crystal Schottky Junctions

Surface Nonuniformity-Induced Frequency Dispersion in Accumulation Capacitance for Silicon MOS(n) Capacitor

Investigation of photon-induced effects on some diode parameters and negative capacitance of the Schottky structure with Zn-doped organic polymer (PVA) interface

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Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions

Interface State Effects on Resistive Switching Behaviors of Pt/Nb-Doped SrTiO₃Single-Crystal Schottky Junctions