Characteristics of stress-induced defects under positive bias in high-k/InGaAs stacks

The introduction of InGaAs as a channel material for complementary metal-oxide-semiconductor technology presents major challenges in terms of the characterization of the various defects that affect the performance and reliability. Understanding the generation of defects by constant voltage stresses is crucial in terms of their concentration profiles and energy levels. In particular, we want to understand the real nature of the defects responsible for the dispersion of C-V in strong accumulation. Here, we show that the degradation under positive bias of metal/Al2O3/n-InGaAs capacitors reveals two contributions depending on the temperature that affects the C-V curves in a different way. Based on features of stressed C-V curves, it is possible to estimate the onset point of the distribution of border traps near the midgap condition. The results suggest that these defects are strongly related to the characteristics of the InGaAs substrate.Fil: Palumbo, Félix Roberto Mario. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Winter, R.. Technion - Israel Institute of Technology; IsraelFil: Krylov, I.. Technion - Israel Institute of Technology; IsraelFil: Eizenberg, M.. Technion - Israel Institute of Technology; Israe

Characteristics of the dynamics of breakdown filaments in Al2O3/InGaAs stacks

In this paper, the Al2O3/InGaAs interface was studied by X-ray photoelectron spectroscopy (XPS) after a breakdown (BD) event at positive bias applied to the gate contact. The dynamics of the BD event were studied by comparable XPS measurements with different current compliance levels during the BD event. The overall results show that indium atoms from the substrate move towards the oxide by an electro-migration process and oxidize upon arrival following a power law dependence on the current compliance of the BD event. Such a result reveals the physical feature of the breakdown characteristics of III-V based metal-oxide-semiconductor devices.Fil: Palumbo, Félix Roberto Mario. Comisión Nacional de Energía Atómica; Argentina. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Shekhter, P.. Technion - Israel Institute of Technology; IsraelFil: Cohen Weinfeld, K.. Technion - Israel Institute of Technology; IsraelFil: Eizenberg, M.. Technion - Israel Institute of Technology; Israe

Hf-based high-k dielectrics for p-Ge MOS gate stacks

The physical and electrical properties of the gate stack high-k/Al2O3/GeO2/p-Ge were studied in detail, where the high-k is either HfO2 or alloyed HfO2 (HfZrOy, HfGdOx, or HfAlOx). Electrical measurements combined with x-ray photoelectron spectroscopy chemical bonding analysis and band alignment determination were conducted in order to assess the suitability of hafnium-based high-k for this kind of gate stacks, with emphasis on low density of interface states and border traps. HfAlOx was found to be the most promising high-k from those studied. The authors have also found that the current- voltage trends for the various systems studied can be explained by the band alignment of the samples obtained by our x-ray photoelectron spectroscopy analysis.Fil: Fadida, Sivan. Technion - Israel Institute of Technology; IsraelFil: Palumbo, Félix Roberto Mario. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nyns, Laura. Imec; BélgicaFil: Lin, Dennis. Imec; BélgicaFil: Van Elshocht, Sven. Imec; BélgicaFil: Caymax, Matty. Imec; BélgicaFil: Eizenberg, Moshe. Technion - Israel Institute of Technology; Israe

Reducing Memory Cost of Exact Diagonalization using Singular Value Decomposition

We present a modified Lanczos algorithm to diagonalize lattice Hamiltonians with dramatically reduced memory requirements, {\em without restricting to variational ansatzes}. The lattice of size $N$ is partitioned into two subclusters. At each iteration the Lanczos vector is projected into two sets of $n_{{\rm svd}}$ smaller subcluster vectors using singular value decomposition. For low entanglement entropy $S_{ee}$, (satisfied by short range Hamiltonians), the truncation error is expected to vanish as $\exp(-n_{{\rm svd}}^{1/S_{ee}})$. Convergence is tested for the Heisenberg model on Kagom\'e clusters of 24, 30 and 36 sites, with no lattice symmetries exploited, using less than 15GB of dynamical memory. Generalization of the Lanczos-SVD algorithm to multiple partitioning is discussed, and comparisons to other techniques are given.Comment: 7 pages, 8 figure

Influence of the spatial distribution of border traps in the capacitance frequency dispersion of Al2O3/InGaAs

In this paper, the capacitance frequency dispersion in strong accumulation of capacitance voltage curves has been studied for different high-k dielectric layers in MOS stacks. By studying experimental data at low (77 K) and room temperature (300 K), in oxides with different density of defects, it was possible reflect the spatial distribution of the defects in the capacitance frequency dispersion. The experimental data show that while at room temperature, the capacitance dispersion is dominated by the exchange of carriers from the semiconductor into oxide traps far away from the interface, at low temperature the oxide traps near the Al2O3/InGaAs interface are responsible for the frequency dispersion. The results indicate that the capacitance dispersion in strong accumulation reflect the spatial distribution of traps within the oxide, and that dielectric/semiconductor conduction band offset is a critical parameter for determining the capacitance dispersion for Al2O3/InGaAs based gate stacks.Fil: Palumbo, Félix Roberto Mario. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Aguirre, Fernando Leonel. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Pazos, Sebastián Matías. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Krylov, Igor. Technion - Israel Institute of Technology; IsraelFil: Winter, Roy. Technion - Israel Institute of Technology; IsraelFil: Eizenberg, Moshe. Technion - Israel Institute of Technology; Israe

Degradation characteristics of metal/Al2O3/n-InGaAs capacitors

Implementation of new materials in Metal-Oxide-Semiconductor stacks requires capabilities to predict long-time degradation as well as the impact of process changes on degradation processes. In this work, the degradation under constant voltage stress of metal gate/Al2O3/InGaAs stacks is studied for different pre-dielectric deposition treatments. The results show that the degradation, particularly under negative bias, is strongly affected by the oxide-semiconductor surface treatment of the samples. Two contributions (interface states and bulk traps) dominate depending on the stress conditions. Surface treatment with NH4OH shows a better quality of the interface in term of interface states; however, it contributes to generation of positive charge on the dielectric layer.Fil: Palumbo, Félix Roberto Mario. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Inbar, Moshe. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

On the Determination of ∣Vub∣|V_{ub}| from Inclusive Semileptonic Decay Spectra

We propose a model independent method to determine $|V_{ub}|$ from the energy spectrum of the charged lepton in inclusive semileptonic $B$ decays. The method includes perturbative QCD corrections as well as nonperturbative ones.Comment: LaTeX, 19 pages, 8 figures appended after \end{document} as uu-encoded and compressed .eps files, uses epsf, Technion-PH-94/9, CERN-TH.7308/9