Effects of annealing temperature on sensing properties of Pt/HfO2/SiC Schottky-diode hydrogen sensor

Hafnium oxide (HfO 2) is successfully used as gate insulator for fabricating Metal-Insulator-SiC (MISiC) Schottky-diode hydrogen sensor. Sensors undergone N 2 annealing at different temperatures are fabricated for investigation. The hydrogen-sensing properties of these samples are compared with each other by taking the measurements at high temperature under various hydrogen concentrations using a computer-controlled measurement system. Experimental results show that sensitivity increases with the annealing temperature. Higher annealing temperature can enhance the densification of the HfO 2 film; improve the oxide stoichiometry; and facilitate the growth of a SiO 2 interfacial layer to give better interface quality, thus causing a remarkable reduction of the current of the sensor under air ambient. The effects of hydrogen adsorption on the barrier height and hydrogen-reaction kinetics are also investigated. © 2008 IEEE.published_or_final_versio

Enhanced sensing performance of MISiC schottky-diode hydrogen sensor by using HfON as gate insulator

MISiC Schottky-diode hydrogen sensor with HfON gate insulator fabricated by NO nitridation is investigated. The hydrogen-sensing characteristics of this novel sensor are studied by doing steady-state and transient measurements at different temperatures and hydrogen concentrations using a computer-controlled measurement system. Experimental results show that this novel sensor can rapidly respond to hydrogen variation and can give a significant response even at a low H 2 concentration of 48-ppm, e.g., a sensitivity of 81% is achieved at 450°C and 2.5 V, which is two times higher than its HfO 2 counterpart. The enhanced sensitivity of the device should be attributed to a remarkable reduction of the current of the sensor before hydrogen exposure by the NO nitridation because the NO nitridation can passivate the O vacancies in the insulator and facilitate the formation of a SiO 2 interlayer to suppress the leakage current associated with high-k materials. © 2006 IEEE.published_or_final_versio

Improved Sensing Characteristics of a Novel Pt/HfTiO2/SiC Schottky-Diode Hydrogen Sensor

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Improved performance of Pd/WO3/SiC Schottky-diode hydrogen gas sensor by using fluorine plasma treatment

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Improved Characteristics of InGaZnO Thin-Film Transistor by using Fluorine Implant

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Sensitivity analysis of permeability parameters of bovine nucleus pulposus obtained through inverse fitting of the nonlinear biphasic equation : effect of sampling strategy

Permeability controls the fluid flow into and out of soft tissue, and plays an important role in maintaining the health status of such tissue. Accurate determination of the parameters that define permeability is important for the interpretation of models that incorporate such processes. This paper describes the determination of strain-dependent permeability parameters from the nonlinear biphasic equation from experimental data of different sampling frequencies using the Nelder–Mead simplex method. The ability of this method to determine the global optimum was assessed by constructing the whole manifold arising from possible parameter combinations. Many parameter combinations yielded similar fits with the Nelder–Mead algorithm able to identify the global maximum within the resolution of the manifold. Furthermore, the sampling strategy affected the optimum values of the permeability parameters. Therefore, permeability parameter estimations arising from inverse methods should be utilised with the knowledge that they come with large confidence intervals

A comparison of MISiC Schottky-diode hydrogen sensors made by NO, N 2O, or NH 3 nitridations

MISiC Schottky-diode hydrogen sensors with gate insulator grown in three different nitridation gases (nitric oxide (NO), N 2O, and NH 3) are fabricated. Steady-state and transien-t-response measurements are carried out at different temperatures and hydrogen concentrations using a computer-controlled measurement system. Experimental results show that these nitrided sensors have high sensitivity and can give a rapid and stable response over a wide range of temperature. This paper also finds that N 2O provides the fastest insulator growth with good insulator quality and hence the highest sensitivity among the three nitrided samples. The N 2O- nitrided sensor can give a significant response even at a low H 2 concentration of 48-ppm H 2 in N 2, indicating a potential application for detecting hydrogen leakage at high temperature. Moreover, the three nitrided samples respond faster than the control sample. At 300°C, the response times of the N 2O, NO, and NH 3-nitrided sample to the 48-ppm H 2 in N 2 are 11, 11, and 37 s, respectively, as compared to 65 s for the control sample without the gate insulator. © 2006 IEEE.published_or_final_versio

On the voltage dependence of sensitivity for Schottky-type gas sensor

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Schottky-diode hydrogen sensor based on InGaN/GaN multiple quantum wells

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Sensing characteristics of a novel NH 3-nitrided schottky-diode hydrogen sensor

A novel NHi-nitrided Schottky-diode hydrogen sensor has been successfully fabricated Measurements have been performed to investigate the sensitivity, stability and response speed of the sensor at different temperatures and hydrogen concentrations. It can respond to hydrogen variation very quickly and can give significant response ewn at low hydrogen concentration. The studied device exhibits high sensitivity of 350 % at 300 °C when 800 ppm IJ in N2 gas is introduced. The sensitivity is 15 times greater than that of the Pt-SiC sensor. The excellent hydrogen-sensing characteristics of this novel sensor make it very suitable for detecting hydrogen leakage in high-temperature environment. The effects of hydrogen adsorption on the barrier height and hydrogen reaction kinetics are also investigated. ©2004 IEEE.published_or_final_versio