Effects of constant voltage stress (CVS) on gate stacks consisting of an ALD HfO2 dielectric with various interfacial layers were studied with time dependent sensing measurements: DC I–V, pulse I–V, and charge pumping (CP) at different frequencies. The process of injected electron trapping/de-trapping on pre-existing defects in the bulk of the high-κ film was found to constitute the major contribution to the time dependence of the threshold voltage (Vt) shift during stress. The trap generation observed with the low frequency CP measurements is suggested to occur within the interfacial oxide layer or the interfacial layer/high-κ interface, with only a minor effect on Vt. 相似文献
Bias-temperature instabilities (BTI) of HfO/sub 2/ metal oxide semiconductor field effect transistors (MOSFETs) have been systematically studied for the first time. NMOS positive BTI (PBTI) exhibited a more significant V/sub t/ instability than that of PMOS negative BTI (NBTI), and limited the lifetime of HfO/sub 2/ MOSFETs. Although high-temperature forming gas annealing (HT-FGA) improved the interface quality by passivating the interfacial states with hydrogen, BTI behaviors were not strongly affected by the technique. Charge pumping measurements were extensively used to investigate the nature of the BTI degradation, and it was found that V/sub t/ degradation of NMOS PBTI was primarily caused by charge trapping in bulk HfO/sub 2/ rather than interfacial degradation. Deuterium (D/sub 2/) annealing was found to be an excellent technique to improve BTI immunity as well as to enhance the mobility of HfO/sub 2/ MOSFETs. 相似文献
This paper describes procedure for estimation of travel time on signalized arterial roads based on multiple data sources with application of dimensionality reduction. Travel time estimation approach incorporates forecast of transportation nodes impendence and travel time on network links. Forecasting period is two hours and the estimation is based on historical data and real time data on traffic conditions. Travel time estimation combines multivariate regression, principal component analysis, KNN (k-nearest neighbours), cross validation and EWMA (exponentially weighted moving average) methods. When comparing estimation methodologies, relevantly better results were achieved by KNN method than with EWMA method. This is true for every time interval considered except for evening time interval when signalized arterial roads were uncongested. 相似文献
Product selectivity control for the synthesis of imidoylindoles and 4‐alkylidenedihydroquinazolines from N‐imidoyl‐o‐alkynylanilines via silver triflate‐catalyzed cycloisomerization or tetrabutylammonium fluoride‐promoted cyclization is described. The product selectivity depends mainly on the catalyst/promoter used, and on the substituents on the alkyne and amidine functions of the substrates.
Urethane (ethyl carbamate) which has long been used for commonly used drugs and has proven to be useful in the formation of products in every-day use, is volatile, and small amounts sublime spontaneously. Pregnant ICR mice were maintained in the vinyl chamber (45 liter) which was ventilated 4 times per hour. To inhale urethane gas, air was passed first through a glass bottle containing 500 g of crystalline urethane and then into the vinyl chamber. Concentration of the sublimed urethane gas in the chamber was 1.28 +/- 0.08 mg/l, and sublimed urethane gas produced significantly high incidence of chromosomal aberrations in the cells of whole embryo, when mice inhaled it for 48 h from day 9 to day 11 of pregnancy. High and significant incidence of chromosomal aberrations (36.0%) was detected in the embryo 3 h after urethane gas inhalation, but decreased to 5.3% at 24 h after exposure and showed no significant differences from controls after 48 h, while the incidence in bone marrow cells from the adult (pregnant) mice was lower (21.5%) at 3 h after exposure but a significant increase remained until 72 h after exposure. A majority of chromosomal aberrations was chromatid types. As a consequence of cellular damages by urethane gas inhalation during pregnancy, significantly high incidence of fetal deaths and congenital malformations (cleft palate, polydactyly, tail anomaly etc.) was induced in the offspring. Thus, we must be aware of the risk of volatile chemicals, because it is difficult to perceive and avoid hazardous exposure via respiration. 相似文献
Niobium oxides have been reported as an alternative to tantalum, and its oxide, for the production of capacitors, but these materials still require a further and exhaustive study. Understanding the dynamics of the oxidation process from NbO to Nb2O5 is essential to explain and control the properties of a niobium oxide based capacitors. In situ XRD analysis of NbO powders was performed from 100 to 1100 °C, which showed a temperature range where only amorphous phase is present. The capacitor anodes, formed from the same type of NbO powders, were then heat-treated in air from room-temperature (RT) to 550 °C and recorded with a video camera to see the colour shift. The presence of core–shell structures and the increase of the shell thickness/amount with temperature are visible in SEM. Finally, in situ spectroscopy studies were performed, in order to observe the interference spectra which are responsible for the observed colours. 相似文献
Studied common concepts regarding the equilibrium of objects in 3 experiments, using a total of 85 17–45 yr old Ss. Groups of Ss (including some experts in statics) were asked to solve problems like finding the resting position of objects suspended either by their center of gravity or at some point more or less removed from the center of gravity. Results show that, with few exceptions, Ss confused neutral equilibrium with the stable equilibrium that is assumed when the object is symmetrical with its vertical axis. This error is explained, together with the errors found in tasks in which objects were not suspended by their center of gravity, by the hypothesis that Ss conceive equilibrium as an equaling of the potential energy of gravity. The possibility that Ss' mistakes may be due to an impression of equilibrium connected to conditions of perfect symmetry is discussed, as is the hypothesis of the coexistence of naive and objective concepts in the human system of knowledge. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Non-equilibrium molecular dynamics calculations were performed in order to obtain the thermal conductivity coefficients of
InSb nanowires in comparison with the bulk system value. For bulk, the value obtained was 16 ± 2 Wm−1 K−1 which is in very good agreement with experimental value of 15 Wm−1 K−1, and the thermal conductivity of the nanowires were 0.54 ± 0.01 Wm−1 K−1 and 0.50 ± 0.01 Wm−1 K−1 for a 5 and 4 unit cells square cross-sectional nanowires, respectively, which is almost two orders of magnitude smaller.
This result is in agreement with other simulations performed for other materials. 相似文献