Effective Failure Analysis Approach in Uncovering Circuit Level Continuity Defects

This research was proposed to utilize sputtering system to fabricate sensing material of electronics nose of humidity sensor, and expected to use it in nano and multiple biosensor system with intelligent functions in new generation. The first test was material measurement for zinc oxides (ZnO) deposited on (100) Si substrate in variable thin film thickness and epitaxial growth time. The second test was that the variable growth time will be selected to study characteristics of the sensing material in humidity sensors by measurement of resistance and capacitance. The ZnO nanostructure-like were synthesized on silicon wafer with native buffer layer by the DC sputtering method, and the optimum growth conditions based on growth temperature, oxygen flow rate, and growth time, have been found. We discussed some issue of growth rate, resistivity of thin film, and crystalline of nanostructure, and also explained the sensing mechanism of ZnO hexagonal nanostructure in impedance measurement. It is experimentally demonstrated that the ZnO hexagonal nanostructures have potential growth by DC sputtering growth method on silicon wafer with native oxidation at room temperature. This grown ZnO epitaxial layers would be used in application of sensors.

A quasi-optical method for measuring the surface resistance of a metallic thin film is described. This resistance is derived from measurements of the forward tilt of a surface wave which propagates on the thin metallic film. In order to verify the results, ellipsometry is used. The measurements were made at a wavelength of 10.6 mu m at ambient temperature. The surface resistance of an Au film was measured to be 16 times higher than the classical surface resistance. >

An improved image type sapphire resonator was developed for accurate measurement of surface resistance of a single piece of high temperature superconductor thin film. The surface resistances of two DC spurting yttrium-barium-copper oxide (YBCO) thin films were measured by TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">011</sub> mode of this resonator. TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">012</sub> mode of this resonator was also used in the measurement for the determination of the frequency dependence of the surface resistance of the HTS thin film. The high accuracy in the R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> measurement of this resonator is comparable to the one of conventional two-resonator method, while the process is much simpler. The ability for measuring surface resistance of a single HTS thin film and characterizing the frequency dependence of R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> of this sapphire resonator is remarkable.

Resistance noise measurement: A better diagnostic tool to detect stress and current induced degradation

Carbon nanotube (CNT) thin film-based devices are expected to have better uniformity and reproducibility compared with single-tube devices due to statistical averaging. In this work, thin film resistors (TFR) were prepared from CNT dispersions and their nonuniformity estimated by multipoint, two-terminal resistance (TTR) measurements. I-V measurements were done for determining the nature of metal-CNT contact. For estimation of contact resistance, transmission line measurements (TLM) were carried out. Reduction of CNT-TFR nonuniformity was achieved using di-methyl formamide (DMF). Scanning electron microscopy and electrical measurements imply that DMF improves debundling of single-walled nanotubes, reduces the resistance and improves homogeneity of subsequently prepared thin films.

We report on a novel method and system for investigation of hydrogenated nanocrystalline silicon (nc-Si:H) thin films' piezoresistive effect, and a measurement system for gauge factor of nc-Si:H thin films is designed based on four-point bending method. nc-Si:H thin film resistor is deposited onto glass beam by plasma-enhanced chemical vapor deposition (PECVD) technique. Fractional strain of strained nc-Si:H thin films is measured by PSD sensor based on laser triangulation method, and relative change in resistance of strained nc-Si:H thin films is read out by Wheatstone bridge, when nc-Si:H thin film resistor is under a uniform stress. All signals, including converted and conditioned signal outputting from PSD sensor and output of Wheatstone bridge, are acquired by PXI data acquisition system with industry's most accurate 7½-digit digital multi-meter, and then gauge factor of nc-Si:H thin films is achieved by programming. The experimental results show that the measurement system for nc-Si:H thin films' gauge factor has solved the problem of thin film materials' gauge factor measurement, and based on the system the level of automation, precision and efficiency in measurement has been improved, and more importantly, the measurement system has provided the experimental basis for investigation of nc-Si:H thin films' piezoresistive effect.

Thickness dependence of resistivity in In-Bi thin films

Benzene is an important air pollutant and a key chemical feedstock for the synthesis of cyclohexane. Because of the small difference of 0.6°C in their boiling points, the separation of benzene and cyclohexane is extremely challenging. Here, we report the high adsorption of benzene at low pressure and efficient separation of benzene/cyclohexane, achieved by the control of pore chemistry of two families of robust metal-organic frameworks, UiO-66 and MFM-300. At 298 K, UiO-66-CuII shows an exceptional adsorption of benzene of 3.92 mmol g−1 at 1.2 mbar and MFM-300(Sc) exhibits a high selectivity of 166 for the separation of benzene/cyclohexane (v/v = 1/1) mixture. In situ synchrotron X-ray diffraction and neutron powder diffraction, and multiple spectroscopic techniques reveal the binding mechanisms of benzene and cyclohexane in these materials. We also report the first example of direct visualization of reversible binding of benzene at an open Cu(II) site within metal-organic frameworks.

In programmes 2 and 3 we established the main body of theory needed to analyse circuits containing direct voltage and current generators and resistors. We saw how a very wide range of circuit problems could be reduced, by the use of Thevenin and Norton’s theorems, to the analysis of two simple forms: the potential divider and the current splitter. In programme 4 we investigated the nature of time-varying waveforms (voltages and currents which are not direct but whose values change with time) and learnt that sinusoidally varying signals in particular are very widely used in circuit design. In programme 4 we saw how the mathematical properties of such waveforms could be represented by a vector-like ‘phasor notation’ and went on to see how this notation could be used in circuit analysis.

We have measured the surface resistance R, in polycrystalline films of YBCO and BSCCO deposited in our laboratory as well as oriented films made by other laboratories by codepostion techniques. The R, of YBCO and BSCCO has been measured in the frequency range between 0.5 and 40 GHz using a stripline resonator technique. R, for the films is nearly proportional to the square of the applied frequency over the entire measurement range. The magnitude of R, is, however, strongly dependent on the film microstructure. Our measurements at 1 GHz and 4 K show that randomly oriented films have R, ~ 10~3 Ω (close to Cu) while oriented large-grain films have markedly lower R, ~ 2 x 10-6 Ω, approaching the R, of superconducting Nb. The magnitude of R, rises to ~ 2 Ω and ~ 10-3 Ω at 40 GHz for the randomly oriented and preferentially oriented films, respectively. An effective penetration depth, λeff, has been determined from R, using local electrodynamics. We find that λeff is dependent on film microstructure and is ~ 5 µm for high-R, films, decreasing to ~ 5000 Å for low-R, films. The smaller values of Ωeff calculated for oriented films are of similar magnitude to values of the YBCO penetration depth (~ 2000 Å) reported in the literature. The use of the stripline resonator technique for temperature and magnetic field dependent i Measurements of R, will also be discussed.

Sn-doped Ge2Sb2Te5 thin films deposited onSi(100)/SiO2 substrates by rf magnetron sputtering areinvestigated by a differential scanning calorimeter, x-ray diffractionand sheet resistance measurement. The crystallization temperatures ofthe 3.58 at.%, 6.92 at.% and 10.04 at.% Sn-dopedGe2Sb2Te5 thin films have decreases of 5.3, 6.1and 0.9°C, respectively, which is beneficial to reduce theswitching current for the amorphous-to-crystalline phase transition.Due to Sn-doping, the sheet resistance of crystallineGe2Sb2Te5 thin films increases about 2–10 times,which may be useful to reduce the switching current for theamorphous-to-crystalline phase change. In addition, an obviousdecreasing dispersibility for the sheet resistance of Sn-dopedGe2Sb2Te5 thin films in the crystalline state hasbeen observed, which can play an important role in minimizingresistance difference for the phase-change memory cell element arrays.

This paper presents fault modeling and analysis for open defects in a synchronizer that is implemented by two D flip-flops. Open defects are injected into any node of the synchronizer, and HSPICE is used to perform circuit analysis. The major purpose of this analysis is to find all possible faults that might occur in the synchronizer by open defects. The results obtained can be used to develop methods for testing the interfacing circuits between different clock domains which are implemented with the synchronizer.

Stable platforms of host-guest catalysts are indispensable in the field of heterogeneous catalysis, however, clarifying the specific effect of host remains challenging. Herein, polyoxometalate (POM) is encapsulated in three types of UiO-66(Zr) with different controlled densities of defects by the aperture opening and closing strategy at ambient-temperature. It is found that catalytic activity of POM for oxidative desulfurization (ODS) at room temperature is turned on when encapsulated in the defective UiO-66(Zr), and the sulfur oxidation efficiency shows an obvious increasing trend (from 0.34 to 10.43 mmol g-1 h-1 ) with the increased concentration of defects in UiO-66(Zr) host. The as-prepared catalyst with the most defective host displays ultrahigh performance which removed 1000ppm sulfur with exceptionally diluted oxidant at room-temperature within 25min. The turnover frequency can reach 620.0 h-1 at 30°C, which surpassed all the reported MOFs based ODS catalysts. A substantial guest/host synergistic effect mediated by the defective sites in UiO-66(Zr) is responsible for the enhancement. Density functional theory calculations reveal that OH/OH2 capped on the open Zr sites of host UiO-66(Zr) can decompose H2 O2 to OOH group and enables the formation of WVI -peroxo intermediates that determine the ODS activity.

Highly permselective and durable membrane materials have been sought for energy‐efficient C3H6/C3H8 separation. Mixed‐matrix membranes (MMMs) comprising a polymer matrix and metal–organic frameworks (MOFs) are promising candidates for this application; however, rational matching of filler‐matrix is challenging and their separation performances need to be further improved. Here, we propose a novel strategy of “defect engineering” in MOFs as an additional degree of freedom to design advanced MMMs. MMMs incorporated with defect‐engineered MOFs exhibit exceptionally high C3H6 permeability and maintained C3H6/C3H8 selectivity, especially with enhanced stability under industrial mixed‐gas conditions. The gas transport, sorption, and material characterizations reveal that the defect sites in MOFs provide the resulting MMMs with not only ultrafast diffusion pathways but also favorable C3H6 sorption by forming complexation with unsaturated open metal sites, confirmed by in situ FT‐IR studies. Most importantly, the concept is also valid for different polymer matrices and gas pairs, demonstrating its versatile potential in other fields.

Three UiO-66 samples were prepared by solvothermal synthesis using the defect engineering approach with benzoic acid as a modulator. They were characterized by different techniques and their acidic properties were assessed by FTIR spectroscopy of adsorbed CO and CD3CN. All samples evacuated at room temperature contained bridging μ3-OH groups that interacted with both probe molecules. Evacuation at 250 °C leads to the dehydroxylation and disappearance of the μ3-OH groups. Modulator-free synthesis resulted in a material with open Zr sites. They were detected by low-temperature CO adsorption on a sample evacuated at 200 °C and by CD3CN even on a sample evacuated at RT. However, these sites were lacking in the two samples obtained with a modulator. IR and Raman spectra revealed that in these cases, the Zr4+ defect sites were saturated by benzoates, which prevented their interaction with probe molecules. Finally, the dehydroxylation of all samples produced another kind of bare Zr sites that did not interact with CO but formed complexes with acetonitrile, probably due to structural rearrangement. The results showed that FTIR spectroscopy is a powerful tool for investigating the presence and availability of acid sites in UiO-66, which is crucial for its application in adsorption and catalysis.