Depletion and Depolarizing Effects in Ferroelectric Thin-Films and Their Manifestations in Switching and Fatigue

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In this work, an AlGaN/GaN high electron mobility transistor (HEMT) with a large positive threshold voltage (VTH) is demonstrated, based on a digitally recessed barrier combined with a p-type NiO/SiO2 gate dielectric stack to form a recessed tri-junction HEMT (TJHEMT). Digital etching precisely recesses both the AlGaN barrier and sidewalls of the fins with nanometer-scale control, which combined with an additional depletion from p-type NiO/SiO2 gate dielectric stack, results in a VTH up to 1.5 V at 1 μA/mm.

We consider the problem of finding the optimal time to switch between two measurable cash-flow streams. A complete characterization of the set of solutions is obtained in terms of adjoint variables which measure the available gain from deviations. An iterative procedure for the computation of the adjoint variables is provided. The results are generalized to multiple switching times, multiple cash-flow streams, switching costs, as well as switch-triggered cash-flow streams that arise in equipment-replacement

We report the significant improvement obtained by a non-uniform gate capacitance made by appropriate combination of high-k and low-k regions over the tunneling and the channel regions of a heterostucture TFET (called HKLKFFET). In addition to significantly enhanced ION and subthreshold swing, we find that this structure offers great improvements for the dynamic switching energy (66% saving) and propagation delay (similar to 3 x fast operation) compared to a heterostructure TFET (HeTFET) due to the reduction

Silicon has been, and continues to be, the material support of integrated circuit (IC) technology-the enabling tool of one of the most impressive technological, industrial and social revolution of mankind. Silicon (both in monocrystalline and polycrystalline form as well as epitaxial silicon, silicon on insulator and silicon on nothing) has grown with IC technology for its ability to match the numerous and complex needs of microelectronics. In recent years, however, IC technology is experiencing problems of

Strontium barium niobate thin films have been deposited by pulsed laser deposition on (111)-textured Pt films, p-doped Si(I 00) and Nb doped STO (SrTiO3) single crystals. The deposition parameters were optimized for obtaining phase pure (001)-oriented films from stochiometric targets. The samples were annealed in oxygen to improve top electrode adhesion and reduce oxygen vacancies. The SBN/substrate interfaces were investigated by means of TEM combined with EDAX chemical analysis. Growth on silicon resulted

In this article an experimental method of characterization and modeling of ferroelectric materials is presented. The reversible and irreversible contributions of polarization are separated. The measurements of these effects are performed simultaneously giving a perfect separation. Investigations on switching behavior under different electric field strengths permit final representation of totally irreversible effects by a two-dimensional (2D) function. This function, a Preisach-type density, allows us to ext

We report ac susceptibility data on RuSr2(Eu,Ce)(2)Cu2O10-y (Ru-1222, Ce content x=0.5 and 1.0), RuSr2GdCu2O8 (Ru-1212), and SrRuO3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and "inverted" hysteresis loops. Neither Ru-1212 nor SrRuO3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the da

L-mode to H-mode (LH) transitions are observed in a large variety of plasma conditions in TCV Ohmic plasmas. The power flowing through the separatrix at the LH transition differs by up to a factor of two from the predicted H-mode threshold power. Variations in this deviation are due to the large operational domain covered by the transitions as well as from the different scenarios identified to access the H-mode regime. LH. transitions obtained during the plasma current ramp at low plasma current, elongation

Devices in mobile ad hoc networks work as network nodes and relay packets originated by other nodes. Mobile ad hoc networks can work properly only if the participating nodes cooperate in routing and forwarding. For individual nodes it might be advantageous not to cooperate, though. The new routing protocol extensions presented in this paper make it possible to detect and isolate misbehaving nodes, thus making it unattractive to deny cooperation. In the presented scheme, trust relationships and routing decis

Leakage conduction of Pt-Pb(ZrXTi:(1-X))O-3-Pt capacitors is studied by means of different measuring techniques and analyzed in terms of semiconductor properties of the system. Based on the experimental data, it is concluded that two different regimes of carrier injection (with the critical electric field of the crossover between these regimes being independent of the measuring technique) are responsible for true leakage conduction in Pt-Pb(ZrXTi1-X)O-3-Pt films. For interpretation of the experimental resul

The study of semiconductor interfaces and of solid interfaces in general requires novel instrument capable to investigate the lateral fluctuations of properties on a microscopic scale. We present the first result of a major effort in that framework, whose main objective is the exploitation of the unique characteristics of free electron laser (FEL) infrared sources. The background was provided by our previous development of FEL-based techniques to measure interface barriers with high accuracy and reliability

The classic Preisach model is used to describe a general hysteretic behaviour, and as most nonlinear systems, its output contains higher harmonics. A Fourier analysis of a specific class of weighting functions for the Preisach model relates some free parameters with the frequency contents of the output. This enables an identification of the parameters from higher harmonics, by which hysteretic losses can be separated from losses in linear elements.

The effects of niobium doping on the hysteresis parameters of sol-gel Pb-1.1-x/2(Zr0.53Ti0.47)(1-x)NbxO3 (0 < x < 0.05) have been reported fbr two sets of films with analogous grain size and degree of (111) texture but with different surface microstructures. For both sets, a strong continuous decay of the remnant and maximum polarizations and slope of the hysteresis loop at the coercive field was observed with increasing niobium concentration. The held dependence of the remnant polarization for any given ni

The fatigued state of Pt-PZT-Pt ferroelectric capacitors (FECAP) was investigated by means of piezoelectric coefficient, polarisation charge and permittivity measurements. The suppression of switching polarisation P-r(s) appears to be the result of freezing of ferroelectric domains without affecting the lattice dielectric properties. The frozen polarised domains show a preferential orientation which is related td the electrode interface asymmetry. The fatigue mechanism in thin films is not assisted by a gro

Low-frequency noise measurements have been performed in the linear range of the I-V characteristics of pseudomorphic Al0.3Ga0.7As/In0.25Ga0.75As/GaAs high electron mobility transistors (HEMTs) grown by molecular beam epitaxy with different channel thicknesses. The results obtained show that the 1/f noise in such devices depends greatly on channel thickness. It is controlled by the penetration of the electron wavefunction into the barrier as well as by Coulombic effects for thin channels and by the increase

In the present study, piezoelectric, conductivity and dielectric measurements have been performed on virgin and fatigued ferroelectric PZT thin films prepared by spin-on sol-gel deposition process on Si/SiO2/Ti/Pt substrates. By fatiguing, the polarisation shows a strong exponential degradation, the hysteresis loops of the piezoelectric coefficient d(33) become smaller and asymmetric and the polarisation-induced asymmetry of the conductivity at low voltage and the relative permittivity both decrease. The en

Depletion and Depolarizing Effects in Ferroelectric Thin-Films and Their Manifestations in Switching and Fatigue

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