Toward non destructive high resolution thermal methods for electric charge measurements in solid dielectrics and components (original) (raw)
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The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films.
Journal of Optoelectronics and Advanced Materials
This work concerns the use of the thermal step method (TSM) for measuring electric charge in metal-oxyde-semiconductor (MOS) structures used in micro and nano-electronics, The TSM is a non destructive method for quantifying and localizing the electric charge in solid insulating materials and structures. Its principle is the application of a low thermal step to a short-circuited or dc-biased sample and the analysis of a current response, which depends on the charge present in the device. An adaptation of the technique (so far used in thick insulating materials and structures for electrical engineering) to short-circuited and biased MOS devices, is described. Results obtained on biased MOS structures and their correlation with classical capacitance-voltage (C-V) measurements are given. Estimations, by the TSM, of the amount of charge trapped in the oxide and. of the space charge penetration depth in the silicon substrate are presented.
Thin Film Thermoelectric Characterization Techniques
Annual Review of Heat Transfer, 2013
The key thin film thermoelectric characterization techniques are described. Due to the small dimensions, a careful examination of electrical and thermal paths in the device is necessary. We describe both in-plane and cross-plane measurement methodologies. Sample requirements for four-probe and van der Pauw methods for in-plane electrical conductivity measurement are discussed. The in-plane Seebeck coefficient is characterized under a temperature gradient which generates a voltage. Precise measurements of temperature and voltage at the same location in the sample are very important. For the cross-plane electrical conductivity, the modified transmission line method is evaluated. To eliminate parasitic contact and substrate resistances, several samples with varying thicknesses are required. Two approaches, a DC method and the 3ω method, are described in detail for the cross-plane Seebeck coefficient characterization. Next, we focus on the transient Harman method to directly measure the cross-plane thermoelectric figure of merit of a thin film. The device requirements for reducing parasitic heat losses and current nonuniformity are presented. Thermoreflectance imaging can be used together with transient Harman in order to extract electrical and thermal conductivities and the Seebeck coefficient simultaneously. Finally, Z-meters are described for directly determining the figure of merit and efficiency of a thermoelectric element or module under a large temperature gradient. Recent developments have significantly reduced thermal and electrical parasitics, as well as radiation heat loss in the system, enabling ZT measurement of legs as thin as one hundred microns. 4 leakage. Alternatively, micro-heaters fabricated on the sample can be utilized as thermometers, but careful calibration of the heater resistance as a function of temperature is essential. The thermal resistance of the insulating layer separating the micro-heater from the thermoelectric device should also be taken into account. In addition to the standard DC measurements, where a steady-state temperature gradient is created across the thin-film, the 3ω technique can be used to obtain the cross-plane Seebeck coefficient of thin films 18 . This technique was originally developed for thermal conductivity measurements 19 , and is quite sensitive to temperature changes across the device under test. The Seebeck voltage generated in the cross-plane direction has a 2ω component proportional to the Joule heating; small thermoelectric voltages can be measured more accurately using this approach through the lock-in technique.
An Insight into Space Charge Measurements
International Journal of Plasma Environmental Science and Technology, 2017
This paper aims at giving an insight into the field of non-destructive methods for localizing and quantifying electric charges and field distribution in dielectrics. The fundamentals of the influence (or "stimuli") methods used for measuring space charge and polarization distributions in solid insulating structures are first presented. The possibilities offered today by these methods and their fallouts in the domains of dielectric materials, electrical engineering and electronics structures are then put into evidence using various supporting examples. Experimental setups and results obtained in recent years are reviewed, and perspectives of evolution of these methods are discussed. Challenges and expected achievements in the near future are brought into focus.
Determination of space charge distribution in thick dielectric samples
Journal of Electrostatics, 1989
A method for determining the space charge distribution on thick samples of dielectrics is presented. The method is based on measurements of the effective surface charge density on one side of a plane parallel sample, when the other side is simultaneously dissolved (or etched) in conducting or dielectric solvent. The space charge distribution can be obtained by differentiation of the surface charge density as a function of sample thickness. An important advantage of the method is the simplicity of the measuring circuit and its relatively high resolution. A possible application of the method was checked on wax electrets and a good agreement with literature data was obtained.
ECS Transactions, 2006
Non-contact electrical metrology offers a fast and cost saving monitoring of dielectrics in IC manufacturing process. This corona-Kelvin measuring technique has entered the maturity stage with about 400 tools installed in silicon IC-fabs. We discuss recent advancements that broaden the spectrum of monitoring parameters and enhance the precision of these measurements. We also discuss the current ongoing extension of corona-Kelvin metrology to the micro scale measurement on sites as small as 30µm x 30µm. This opens new possibilities for non-contact electrical testing of product wafers, rather than expensive process monitor wafers. Micromeasurement is illustrated using flash memory ONO structures and corona induced programming and erasing. 4 characteristics (6) facilitated by knowledge of EOT, that enables one to determine the inversion threshold voltage, V TH , and to extend the interface trap density D it spectra over a large range of surface barrier from accumulation into inversion. 4. high-field SASS (self-adjusting steady state) technique (7) and its application to measurement of tunneling leakage with "plus-minus" asymmetry that probes the composition of dielectrics via conduction-valence band offset asymmetry. 5. SASS charge injection phenomena in flash-memory structures. 6. finally, we discuss a micro-version of corona-Kelvin metrology (8) suitable for measurement on miniature test sites, even as small as 30µm x 30µm. By measuring scribe-line test sites or the cell areas, this micro-metrology version enables, for the first time to monitor product wafers.
Space charge distribution measurement methods and particle loaded insulating materials
Journal of Physics D: Applied Physics, 2006
In this paper the authors discuss the effects of particles (fillers) mixed in a composite polymer on the space charge measurement techniques. The origin of particle-induced spurious signals is determined and silica filled epoxy resin is analysed by using the laser-induced-pressure-pulse (LIPP), the pulsed-electroacoustic (PEA) and the laser-induced-thermal-pulse (LITP) methods. A spurious signal identified as the consequence of a piezoelectric effect of some silica particles is visible for all the methods. Moreover, space charges are clearly detected at the epoxy/silica interface after a 10-kV/mm poling at room temperature for 2 hours.
Optics Letters, 2019
Testing and characterization techniques intended for traditional electronics production are rarely compatible with modern large-area, thin film electronics manufacturing processes such as roll-to-roll fabrication. Online quality monitoring of conductive thin films is necessary for upscaling and maintaining high-yield production. Thermography has already shown its usefulness in this kind of applications but has suffered the lack of proper non-contact electrical heating. Now, a fully contactless quality inspection technique based on thermal imaging and induction heating is implemented and evaluated. This approach is capable to find out defected areas and to estimate conductivity degradation online with full coverage over conductive thin films.
A review of developments in thermal techniques for charge profile measurements in polymer electrets
A number of methods were evolved during last three decades to understand the internal charge profile of polymer electrets. These methods essentially are based on the propagation of heat or pressure waves inside the charged samples. In both cases, electrical signals are generated due to mechanical or dielectric changes caused by heat diffusion or propagation of a pressure discontinuity in the sample. The charge distribution can be obtained from the electrical response. This paper presents detailed information on the thermal techniques to probe the charge distributions in the thickness direction of the polymer electrets as well as a comprehensive review of thermal data analysis.