Search results for "high-k"

Electrochemically Prepared High-k Thin Films for Resistive Switching Devices

Anodization and anodic oxides

2018

Anodizing is a low-temperature, low-cost electrochemical process allowing for the growth, on the surface of valve metals and valve metal alloys, of anodic oxides of tunable composition and properties. This article is an overview on theoretical aspects concerning the general aspects of the kinetics of growth of barrier and porous anodic oxides and some of their present and possibly future technological applications of anodic oxides. The first part of the article is devoted to anodic oxide growth models, from Guntherschulze and Betz work (in 1934) to the more recent results on barrier and porous oxide films. The second part is focused on industrial processes to fabricate anodic oxides and the…

Profiling of traps in SiO2/Al2O3 gate stack by the charge pumping technique

2006

In this paper, we present our results on the distribution and generation of traps in a SiO 2 /A1 2 O 3 transistor. The investigation has been carried out by using charge pumping measurements, both variable voltage and frequency techniques, and constant voltage stress. By increasing the amplitude of the gate pulse we observe an increase of the charge recombined per cycle closely related to the contribution of shallow traps near the SiO 2 /Al 2 O 3 interface. By reducing the pulse frequency we measure an increase in the charge pumping current due to traps located deeper in the Al 2 O 3 . By combining charge pumping and constant voltage stress measurements, we found that the traps are mostly g…

Hot carrier effects in n-MOSFETs with SiO2/HfO2/HfSiO gate stack and TaN metal gate

2009

Charge trapping and trap generation in field-effect transistors with SiO2/HfO2/HfSiO gate stack and TaN metal gate electrode are investigated under uniform and non-uniform charge injection along the channel. Compared to constant voltage stress (CVS), hot carrier stress (HCS) exhibits more severe degradation in transconductance and subthreshold swing. By applying a detrapping bias, it is demonstrated that charge trapping induced degradation is reversible during CVS, while the damage is permanent for hot carrier injection case. © 2008 Elsevier B.V. All rights reserved.

Low-Temperature Atomic Layer Deposition of High-k SbOx for Thin Film Transistors

2022

SbOx thin films are deposited by atomic layer deposition (ALD) using SbCl5 and Sb(NMe2)3 as antimony reactants and H2O and H2O2 as oxidizers at low temperatures. SbCl5 can react with both oxidizers, while no deposition is found to occur using Sb(NMe2)3 and H2O. For the first time, the reaction mechanism and dielectric properties of ALD-SbOx thin films are systematically studied, which exhibit a high breakdown field of ≈4 MV cm−1 and high areal capacitance ranging from 150 to 200 nF cm−2, corresponding to a dielectric constant ranging from 10 to 13. The ZnO semiconductor layer is integrated into a SbOx dielectric layer, and thin film transistors (TFTs) are successfully fabricated. A TFT with…

Fabrication and characterization of barium silicate ultrathin films as an alternative gate oxide

2008

Down-scaling of elementary CMOS elements requires the replacement of SiO2 as a gate oxide. By the identification of the formation conditions of barium silicate in direct contact of a silicon substrate, this study revealed a potential candidate. First of all, a reaction between Ba and SiO2 leading to the formation of barium silicate as been evidenced by in-situ XPS and SR-PES analyses. Then, barium silicate films have been elaborated by oxygen and barium co-deposition at 580 °C. Thermal treatments under vacuum showed that barium silicate was thermally stable up to 900 °C. TEM and SIMS ex-situ analyses revealed a sharp interface with the substrate. Finally, an experimental setup dedicated to …

Influence of oxide substrates on monolayer graphene doping process by thermal treatments in oxygen

2019

Abstract The structural and the electronic properties of monolayer graphene made by chemical vapor deposition and transferred on various oxide substrates ( SiO 2 , Al 2 O 3 , and HfO 2 ) are investigated by Raman Spectroscopy and Atomic Force Microscopy in order to highlight the influence of the substrate on the features of p-doping obtained by O 2 thermal treatments. By varing the treatment temperature up to 400 °C, the distribution of the reaction sites of the substrates is evaluated. Their total concentration and the consequent highest doping available is determined and it is shown that this latter is linked to the water affinity of the substrate. Finally, by varing the exposure time to …

Distribution and generation of traps in SiO2/Al2O3 gate stacks

2007

In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/ Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. (C) 2007 Elsevier Ltd. All rights reserved.

Electrochemical Oxidation of Hf-Nb Alloys as a Valuable Route to Prepare Mixed Oxides of Tailored Dielectric Properties

2018

Metal oxides with high dielectric constant are extensively studied in the frame of substituting SiO2 as gate dielectric in nanoelectronic devices. Here, high-k mixed HfO2/Nb2O5 oxides are prepared by a facile electrochemical route starting from sputtering-deposited Hf–Nb alloys with several compositions. Transmission electron microscopy, grazing incidence X-ray diffraction, and glow discharge optical emission spectroscopy are employed to study the oxide structures, disclosing a crystalline–amorphous transition of the electrochemically prepared oxides by increasing the Nb content. Photo-electrochemical measurements allow the observation of optical transitions ascribed to localized states ins…