Resistance Standards Research Articles

Electronic nanolithography as a basic nanoavionics technology

The need for further development of electronic components of aviation and rocket-space information and commu-nication systems towards nanoelectronics brings nanolithography to the forefront as its basic technology. A promis-ing nanolithography method is electron nanolithography (ENL). Advantages of ENL: 1) potential resolution - less than 2 nm, 2) possibility of direct recording without the use of masks, 3) possibility of using standard film resistors, 4) low density of defects in circuits, 5) controllability using electric and magnetic fields, 6) possibility use of ready-made industrial installations (microscopes, lithographs for masks). This review examines the principles of con-struction, the history of creation and the current state of ENL, with an emphasis on its features, as well as its classi-fication and stages of development. In addition, one of the main problems of ENL that requires a solution is con-sidered – the development of special electronic resists and methods for increasing their resolution and sensitivity.

The enhanced antiferromagnetic interaction and tunable temperature coefficient of resistivity in antiperovskite compounds Mn3−xCoxAgN (0≤x≤0.2)

The magnetic and electric evolution with the substitution level of Co element has been investigated in Mn[Formula: see text]CoxAgN. The DC magnetic measurements demonstrate that the substitution of Co for Mn enhances the antiferromagnetic (AFM) interaction and weakens the magnetic irreversibility at low temperature. The strengthening of AFM order in Mn[Formula: see text]CoxAgN has been attributed to the enhanced Co–Mn AFM interaction and weakened Co–N–Mn ferromagnetic (FM) interaction. Additionally, with the gradual increase of Co content, the temperature coefficient of resistivity (TCR) in paramagnetic (PM) region changes from a positive one to a negative one gradually. When [Formula: see text], the TCR value is only [Formula: see text]5[Formula: see text]ppm/K, which is one magnitude smaller than that of conventional standard resistor materials. The negative TCR phenomenon is closely associated with the Co-element-induced lattice disorder, which leads to the weak localization of conduction electrons.

Digital Impedance Bridge for Four-Terminal-Pair AC Resistor Calibration up to 20 kHz

For this study, a substitution principle-based impedance bridge has been developed to calibrate AC resistors in a four-terminal-pair (4TP) configuration. The calibration is performed in the full complex plane for resistances ranging from 100 mΩ to 400 Ω and frequencies of between 50 Hz and 20 kHz. The automated bridge is based on four resistors associated with two high-impedance stages. The balancing of the bridge is achieved by means of PXI modules. The bridge is automatically balanced via a simplex top-down algorithm. The new bridge is primarily used for the measurement chain of AC standard resistors defined in a 4TP configuration at LNE, which are used for routine customer calibrations. The traceability of LNE’s standard resistors when defined in a 4TP configuration is ensured by a measurement chain from a 1 kΩ reference resistor using the new bridge. The reference resistor was calibrated previously via comparison with a calculable resistor up to 20 kHz. The bridge was validated via comparison with calibration results obtained in 1983 and 2009. For a resistor of 1 Ω at 1 kHz, the uncertainty of the series resistance variation and the phase shift are less than 6 µΩ/Ω (k = 1) and 6 µrad (k = 1), respectively.

Evaluation of the effects of leakage current in the calibration of standard resistors between two dc resistance bridges and a digital sampling impedance bridge

This article discusses calibrations results of standard resistors performed with two commercially available equipment and a digital sampling impedance bridge developed at Inmetro. One of the commercial bridges uses the current comparison method and the other the potentiometric method with a binary voltage divider. Calibration was performed with standard resistors of 10 kΩ and 100 kΩ with significant leakage current. This study showed divergent results between each methodology. A specific methodology was used to estimate the leakage resistance of these resistors. This study contributes to establish criteria for correction and/or inclusion of uncertainty components in resistors calibrated in these methodologies.

Memristor-Assisted Background Calibration for SAR ADCs: A Feasibility Study

This paper proposes a memristor-assisted sign-based background calibration scheme for analog-to-digital converters (ADCs). The scheme was implemented and validated in a 12-bit asynchronous successive approximation register (SAR) ADC, which consists of a hybrid binary weighted/R-2R digital-to-analog converter (binary/R-2R DAC) and other peripheral circuits. This hybrid DAC, in which one redundancy bit is introduced, is built with a memristor and standard polysilicon resistors. The proposed calibration technique can detect the errors caused by DAC mismatches and correct them by adjusting the resistance of the memristor (memristance) in a feedback loop. The implemented circuit takes the memristor’s advantages such as small area and resistance switching property. The proposed scheme has been designed and simulated in a standard 180 nm CMOS process. Eventually, a monolithic CMOS/memristor chip will be fabricated with the CMOS part processed at a standard foundry and the memristors integrated through post-CMOS processing in house. Simulation results demonstrate the feasibility of exploiting memristors to improve the linearity of high-resolution SAR ADCs. The designed calibration scheme can effectively reduce the integral non-linearity (INL) and differential non-linearity (DNL) of the 12-bit SAR ADC.

Implementation of instantaneous comparison methods in temperature gradient evaluation of stirred liquid temperature baths

Temperature gradient is an important performance indicator of a stirred liquid bath. Its evaluation requires measuring the temperature differences between different bath positions. A common way to do that is to place two SPRTs at two positions and measure their resistances against a standard resistor (R SPRT1/R S and R SPRT2/R S) sequentially (the sequential method). A drawback of this method is the existence of a time gap between the two measurements rendering the results susceptible to temporal temperature variation. The instantaneous comparisons method offers a better solution by measuring the resistance ratio of two SPRTs directly (R SPRT1/R SPRT2) and deriving their temperature difference at the same moment eliminating the time gap. To implement this method at the Standards and Calibration Laboratory (SCL) of Hong Kong, the resistance ratio of SPRT1 to a standard resistor (R SPRT1/R s) is firstly measured to determine the initial bath temperature. After that, the resistance ratios of SPRT1 to SPRT2 (R SPRT1/R SPRT2) are measured with the two SPRTs placed at different positions and immersion depths in the bath. This paper describes the derivation of the temperature difference from the SPRT resistance ratio using the ITS-90 reference equations and the estimation of the measurement uncertainties. The potential of reducing the uncertainties of measured temperature gradient by leveraging the correlation of the two SPRTs calibrated at the same set of temperature fixed points is discussed. The paper also compares the calibration results obtained by the instantaneous comparisons method and the sequential method.

Application of Statistical Tools to Optimize a Dual Source Electrical High Dc Resistance Bridge

At the Istituto Nazionale di Ricerca Metrologica (INRIM), a commercial dual source high resistance bridge has been optimized by means of the application of statistical tools and of the analysis of measurements distributions. These tools help to achieve the best precision for resistance ratio measurements in the range 10 TΩ ÷ 100 TΩ. A measurement procedure consisting of multiple steps, in which at each one the value of the resistor under calibration is updated and has been considered the best one. With this procedure, at the third step, the lowest standard deviation of the mean and the measurements distribution approximately normal are obtained regardless of the settle time, of the resistance ratio, of the measurement voltages and of the resistors under comparison. This comes from the achievement of the white noise regime and from a bridge balance close to the ideal. This measurement procedure therefore allows also to achieve the lowest measurement uncertainty due to the minimization of the type A uncertainty. The Allan variance and the power spectral density were used to identify the white noise analyzing the detector readings. Strict triangulation rules were also established and applied to validate both the measurement process and the chosen model to extrapolate the values of the standard resistors at low voltages.

Metrological assessment of DC current comparator resistance bridges

Direct-current comparator bridges (DCC) are the working horses of primary resistance metrology in the intermediate resistance range. Having a ratio accuracy reaching 10-7 or better, they allow the realization of resistance scales and the calibration of artifact standard resistors for customers. In this paper we compare the performances of three commercial DCC bridges, by performing measurements on resistors in decadal ratios (1Ω to 10kΩ) of very high stability in a thermostated environment. The results show that the three bridges give mutually compatible results within the manufacturer’s specifications, therefore mutually validating the bridges; nevertheless, the readings time series show quite different statistical behavior, with internal correlations, making an evaluation of the Type A measurement uncertainty not trivial.

AFRIMETS.EM-S3: Bilateral comparison between NMISA and KEBS on resistance standards at 1 Ω, 10 Ω, 100 Ω, 1 kΩ and 10 kΩ

Main textThis is a follow-up comparison between NMISA and KEBS of AFRIMETS.EM-S1 (resistance standards at 1 Ω, 10 Ω, 100 Ω, 1 kΩ, and 10 kΩ), published in KCDB in February 2022. This follow-up comparison uses a different set of standard resistors from the main comparison. After completion of the supplementary comparison (AFRIMETS.EM-S1), KEBS was not satisfied with their comparison results because they did not support their required measurement capabilities. KEBS purchased a new resistance measurement system as part of the corrective action and requested a follow-up bilateral comparison with NMISA. This report describes the detailed findings and results of the comparison in terms of behaviour of travelling standards, methods used by participants and measurement results.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Accuracy and precision when deriving sea-ice thickness from thermistor strings: a comparison of methods

A precise knowledge of landfast sea-ice (fast-ice) thickness is relevant to many different disciplines. Sea Ice Monitoring Stations (SIMS) are used to measure time series of fast-ice thickness at a location. SIMS measure ice and ocean temperature via thermistor strings with many different methods for extracting sea-ice thickness from temperature existing. This study investigates: if thickness results from temperature recorded by SIMS of different designs, and analysed with different methods are comparable; which methods are recommended for their robustness, precision and accuracy and how they compare to independent thickness measurements; how otherwise unuseable data can be salvaged through specific SIMS designs. We present an analysis of fast-ice thickness calculated from SIMS deployed in McMurdo Sound, Antarctica and in the Chukchi Sea near Utqiaġvik, Alaska, over two decades. We find that median thicknesses derived by different methods agree within 1 ± 1.5 cm for McMurdo Sound and 2 ± 3 cm for Utqiaġvik. Thus, it is possible to confidently compare data collected from different stations and analysed with different methods. The vertical gradient of sea-ice temperature gives the best results for fast-ice thickness during the growth season and including standard resistors in a thermistor string can reduce potential data loss due to noise.

Precise high resistance comparison between the NMIJ traveling dual source bridge and the NIST adapted Wheatstone bridge

A precise high resistance comparison was performed between the traveling dual source bridge developed by the National Metrology Institute of Japan (NMIJ) and the adapted Wheatstone bridge of the National Institute of Standards and Technology (NIST) from 10 MΩ to 100 TΩ at NIST. The NMIJ traveling bridge was shipped to NIST Gaithersburg and was installed right next to the NIST bridge and these bridges alternately measured the resistance ratio of the high resistance standards, without moving the location of the resistors inside the temperature controlled air-bath. Having the bridges and resistance standards in the same location for the comparison decreased the transportation and temperature coefficient effects on the resistance standards, contributing to the excellent agreement of the measured values. The NMIJ traveling bridge used an 8.5-digit digital multimeter and a relay switch box to determine a resistance ratio by measuring the ratio of the voltages applied to the resistors. The comparison was started from 10 MΩ based on the same 1 MΩ standard resistor calibrated using a NIST two-terminal cryogenic current comparator bridge, and standard resistors from 10 MΩ to 100 TΩ were calibrated by repeating 10:1 scaling measurements with both systems. Excellent agreement was obtained within the uncertainty of all resistance ranges and the difference between both systems was less than 1 μΩ Ω−1 up to 1 TΩ and the degrees of equivalence for 10 TΩ and 100 TΩ were less than 6 μΩ Ω−1.

New impedance bridge at LNE for the two terminal-pair AC resistor calibration up to 20 kHz

This paper presents the evolution of LNE’s impedance bridge (Wheatstone bridge) used to calibrate AC resistors defined in the two terminal-pair configuration. A new automated Wheatstone bridge, based on four resistances, was developed to operate in the full complex plane for resistances ranging from 400 Ω to 2 MΩ and for frequencies up to 20 kHz. A commercial dual precision arbitrary waveform generator supplies the bridge and PXI modules achieve the balance. Phase and frequency synchronization solutions between the arbitrary waveform generator source and the PXI modules were used. The choice of these instruments allows the bridge to be easily automated and to benefit from recent progress in the development of digital-analog converters, in particular those with high frequency sampling rates and resolution. The bridge is mainly dedicated to realize the periodic calibration of LNE’s standard resistors, used for routine customer calibrations. The traceability of LNE’s standard resistors is ensured, firstly, by the calibration of a 1 kΩ resistor by comparison to a calculable resistor up to 20 kHz. Then, this resistor is used as a reference element to ensure the traceability of all LNE’s standard resistors using the new bridge. The validation was done by comparing the results obtained, for some resistors with very low drift, with those obtained during calibrations performed in 1983, 1995 and 2009. For resistors of 1 kΩ in a 1:1 ratio, the expanded uncertainty of series resistance variation and argument are, respectively, less than 1.3 µΩ Ω−1 (k = 1) and 1.2 µrad (k = 1), up to 20 kHz.

Successive approximation type resistance to digital converter

Successive approximation type direct resistance to digital converter (SAR RDC) topology is presented here. The conventional SAR type ADC is augmented with an additional opamp inverting summer and a standard resistance such that the digital output of the SAR directly indicates the value of an unknown resistance connected between the output of the digital to analog converter of the SAR RDC and the inverting input of the added inverting summer. Analysis of the proposed technique presented here helps select proper components at the design stage itself to obtain minimal errors in the measurement of the unknown resistor. The major advantage of the proposed scheme is that it retains the basic architecture of an SAR ADC and hence can be implemented with all available SAR ADC architectures, including the ability to install ‘auto-ranging’. An added advantage is that the value of the unknown resistor is determined in terms of a standard resistor and hence good accuracy is easily obtained. Simulation studies and results obtained from a prototype SAR RDC built and tested, establish the efficacy of the proffered technique. The results indicate a worst-case error of < ±0.2% and no missing codes.

The Measurement Uncertainty in Determining of Electrical Resistance Value by Applying Direct-Comparison Method

This paper considers the unknown electrical resistance (measurand) as the numerical result of the measurement that was carried out by means of the well-known direct comparison measurement method using an appropriate standard resistor and voltmeter. In the literature, this measurement method is also referred to as a series comparison method. This method of measurement is one of the indirect methods and is suitable for measuring low resistance. This paper presents two approaches for evaluating the unknown electrical resistance and its associated combined standard uncertainty. The entire process of evaluating the combined standard uncertainty that is associated with the measurand and the standard uncertainties that are associated with the analyzed input quantities has been entirely performed in accordance with the applicable international recommendations and guidelines for the uncertainty of measurement. The analyzed approaches for evaluating the combined standard uncertainty are designed to be universal and valid both for the mutually non-correlated input quantities and for the mutually correlated input quantities, which can be obtained from a single observation, or repeated observations or by other means. This paper can substantially contribute to the measurements in electrical engineering and education.

Investigation of Power Consumption Effect of Various Memristor Emulators on a Logic Gate

Memristor, also known as memory resistor, is considered as the fourth passive electronic element expressing the relationship between magnetic flux and electric charge. One of the most important features of the memristor is that it has low power consumption. Minimizing power consumption is an important issue in the electronic circuits. However, the fact that the memristor element was not yet fully manufactured has led researchers to design memristor-like emulator circuits. These circuits, which approximate the memristor properties, are realized by combining the other existing electronic elements. In this paper, a basic NAND logic gate is considered and the change in power consumption when using a memristor instead of the standard resistor in the gate circuit is examined. For this purpose, the NAND logic circuit was constituted for four different memristor emulators, and the power consumption values of these circuits were obtained by simulation and experiments. These values are compared with the power consumption values of NAND circuits obtained by using standard resistors equivalent to the memristor resistance. The results clearly show that the memristor gate circuits reduce power consumption compared to standard resistive gate circuits.

Impact of Thermo-Mechanical Stress Due to Probing and Wire Bonding on CUP Devices

Recently, the circuit under pad (CUP) designs are getting very popular because they could save lots of silicon especially for high-density and high-complexity applications. Polysilicon is a material widely used in many electronic device components. When such devices are placed underneath the bond pads, it is highly expected not to show any change in the electrical behavior due to any kind of thermo-mechanical stresses such as probing or wire bonding mainly during the process of packaging. This article presents a detailed investigation of such impacts on a polysilicon resistor placed underneath the bond pads. The standard meander-shaped polysilicon resistor was used as a test vehicle. In this article, different stress-causing factors such as probing insertions, probing temperature, and wire bond materials were investigated in detail. The impact of such thermo-mechanical stresses is simulated using Comsol to understand the stress phenomenon and for qualitative analysis. Then, the wafer-level silicon testing was carried out to quantify the impact of such thermo-mechanical stresses using a standard design of experiments (DOEs). The impact in terms of change in resistance of the polysilicon resistor of two different widths (5 and 0.42 μm) for two different bond pad metal options viz. Middle thickness metal (METMID) (thickness of 880 nm) and thick metal (METTHK) (thickness of 3000 nm) was investigated. The percent change in resistance was observed to be very negligible after multiple probing attempts and probe temperatures. However, after wire bonding, up to ~14% change in resistance was observed when copper was used as the wire bonding material. Nevertheless, this percent change was still well within the reliability specification limit set by Joint Electron Device Engineering Council (JEDEC), which is widely used in the industry. This detailed investigation will help CUP designers choose the correct back end of line (BEOL) metal options and also wire bonding material upfront and accordingly plan their design margins.

Development of Electrical Quantities Primary Standards

The developments of primary standards for electrical quantities that practically realize the electrical units such as ampere (A), volt (V), ohm (Ω), and farad (F) are introduced in this manuscript. These quantities are achieved in consistency with their definitions. According to the new definition of ampere, current can be realized directly such as single electron transport (SET) pump or indirectly using Ohm’s law. For the SET pump, developments are ongoing as trials to obtain higher current values with lower associated uncertainty to be suitable for metrological applications. With the discoveries of the Effects of Josephson and quantum Hall, it has become possible to consider quantum electrical standards that relate the volt and ohm units to h and e through the Josephson and the von Klitzing constants, respectively. The dc programmable Josephson standard was developed to overcome the problems of conventional standards such as stability and noise immunity with lower cost. Developments are continuing on ac Josephson standards to improve performance and increase output voltages and frequencies. For ac voltage measurements for voltages up to 1000 V, thermal voltage converters are introduced to extend the traceability for measuring the ac voltages in the frequency range from 10 Hz to 100 MHz where quantum-based ac standards still have limitations. Thermal current converters are used as the most accurate and precise standard for measurement of ac currents. The realization of ohm is done by the quantum Hall effect through a quantum Hall resistance (QHR) standard. Developments are occurring to make it simpler, more precise and accurate. The efforts that have been made to increase the values of the resistance quantum hall standard to disseminate its accuracy to other standard resistors to help in industry are also introduced. The farad is practically achieved by the calculable cross-capacitor. The calculable capacitor acts as the ac impedance primary standard because it can transfer the traceability to other impedances by using bridges such as the quadrature bridge. The development is occurring on its displacement sensing system to allow greater accuracy.

Bias-induced impedance effect of the current-carrying conductors

&lt;p class="Abstract"&gt;The paper presents the previously unstudied properties of current-carrying conductors utilising impedance spectroscopy. The purpose of the article is to present discovered properties that are the significant context of impedance research. The methodology is based on the superposition of test signals and bias affecting the objects under study. These are the main results obtained in this work: the studied objects have an additional low-frequency impedance during the passage of an electric current; the bias-induced impedance effect (Z&lt;sub&gt;BI&lt;/sub&gt;-effect) is noticeably manifested in the range of 0.01 Hz … 100 Hz and it has either capacitive or inductive nature or both types, depending on the bias level (current density) and material types. The experiments in this work were done using open and covered wires made of pure metals, alloys, and non-metal conductors, such as graphite rods. These objects showed the Z&lt;sub&gt;BI&lt;/sub&gt;-effect that distinguishes them from other objects, such as standard resistors of the same rating, in which this phenomenon does not occur. The Z&lt;sub&gt;BI&lt;/sub&gt;-effect was modeled by equivalent circuits. Particular attention is paid to assessing the consistency of experimental data. Understanding the nature of this effect can give impetus to the development of a new type of instrument in various fields.&lt;/p&gt;

Improved non-contact variable-frequency AC impedance instrument for cement hydration and pore structure based on SVM calibration method

The non-contact alternating current (AC) impedance method is widely used in the study of electrochemical properties of cement-based materials,the instrument of this paper provide a new way for the study of pore structure of cement-based materials. Due to the loss of magnetic materials and the parasitic capacitance of measuring circuit, the ratio difference and phase difference of current sensor inevitably exit. Traditionally the standard resistor calibration method is used to determine the ratio error and phase error under different frequencies based on polynomial fitting (FT). In this paper, a machine-learning support vector machine (SVM) model is used to predict the calibration data with a small test sample. For the accuracy assessment, SVM model has the best comprehensive performance among FT, artificial neural network (ANN). The actual impedance test of typical cement-based materials under different frequencies is given and the results verify the excellent performance of SVM.

High-Throughput Measurement of the Contact Resistance of Metal Electrode Materials and Uncertainty Estimation

Low and stable contact resistance of metal electrode materials is mainly demanded for reliable and long lifetime electrical engineering. A novel test rig is developed in order to realize the high-throughput measurement of the contact resistance with the adjustable mechanical load force and load current. The contact potential drop is extracted accurately based on the proposed periodical current chopping (PCC) method in addition to the sliding window average filtering algorithm. The instrument is calibrated by standard resistors of 1 mΩ, 10 mΩ, and 100 mΩ with the accuracy of 0.01% and the associated measurement uncertainty is evaluated systematically. Furthermore, the contact resistance between standard indenter and rivet specimen is measured by the commercial DMM-based instruments and our designed test rig for comparison. The variations in relative expanded uncertainty of the measured contact resistance as a function of various mechanical load force and load current are presented.