Papers by Andrzej Dziedzic
Metrology and Measurement Systems, Jun 1, 2015
Studies of noise properties of thick-film conducting lines from Au or PdAg conductive pastes on L... more Studies of noise properties of thick-film conducting lines from Au or PdAg conductive pastes on LTCC or alumina substrates are reported. Experiments have been carried out at the room temperature on samples prepared in the form of meanders by traditional screen-printing or laser-shaping technique. Due to a low resistance of the devices under test (DUTs), low-frequency noise spectra have been measured for the dc-biased samples arranged in a bridge configuration, transformer-coupled to a low-noise amplifier. The detailed analysis of noise sources in the signal path and its transfer function, including the transformer, has been carried out, and a procedure for measurement setup self-calibration has been described. The 1/f noise component originating from resistance fluctuations has been found to be dominant in all DUTs. The analysis of experimental data leads to the conclusion that noise is produced in the bends of meanders rather than in their straight segments. It occurs that noise of Au-based laser-shaped lines is significantly smaller than screen-printed ones. PdAg lines have been found more resistive but simultaneously less noisy than Au-based lines.
Metrology and Measurement Systems, Mar 1, 2014
IEEE Conference Proceedings, 2016
Proc. 39th Int. Spring Seminar on Electronics Technology, Pilsen (Czechia), 2016
This study presents electrical behavior of TiO 2 :Nb thin films with niobium concentration up to ... more This study presents electrical behavior of TiO 2 :Nb thin films with niobium concentration up to 13 at. %. The layers were deposited on Corning 7059 glass substrates by unipolar dc pulse magnetron co-sputtering from TiO 2 and Nb composite target. Manufactured films underwent thermal treatment in the ambient air up to the 873 K. Dependencies between the temperature and electrical conductivity as well as thermoelectric force were determined within the range of 300-578 K. An amorphous TiO 2 :Nb films with optical transparency of about 50% in the visible range and resistivity higher than 8 Ωcm were achieved directly after deposition for the target power density discharge in the range of 4.7-5.8 W/cm 2. During the post process air thermal treatment a rapid resistivity decrease (over 1000) was observed up to final value of 1.5×10-3 Ωcm at 300 K. Moreover the conversion from n-type semiconductivity to metallic conductivity was observed.
2016 39th International Spring Seminar on Electronics Technology (ISSE), 2016
This study presents electrical behavior of TiO2:Nb thin films with niobium concentration up to 13... more This study presents electrical behavior of TiO2:Nb thin films with niobium concentration up to 13 at. %. The layers were deposited on Corning 7059 glass substrates by unipolar dc pulse magnetron co-sputtering from TiO2 and Nb composite target. Manufactured films underwent thermal treatment in the ambient air up to the 873 K. Dependencies between the temperature and electrical conductivity as well as thermoelectric force were determined within the range of 300-578 K. An amorphous TiO2:Nb films with optical transparency of about 50% in the visible range and resistivity higher than 8 Ωcm were achieved directly after deposition for the target power density discharge in the range of 4.7-5.8 W/cm2. During the post process air thermal treatment a rapid resistivity decrease (over 1000×) was observed up to final value of 1.5×10-3 Qcm at 300 K. Moreover the conversion from n-type semiconductivity to metallic conductivity was observed. Simultaneously the layers exhibited the substantial increase in the transparency and decrease in Seebeck coefficient from -160 μV/K to -35 μV/K. Electrical behavior of the films where examined with the use of NiCrSi/Ag thin films contacts pads according to Kelvin method.
Electronics, 2021
The monitoring of processor temperature is crucial to increase its efficiency. One of the novel a... more The monitoring of processor temperature is crucial to increase its efficiency. One of the novel approaches is use the information not only about the CPU (Central Processing Unit) thermal state, but also about changing environmental conditions. The additional temperature difference sensor to monitor thermal changes in the processor environment is necessary. The sensor dedicated for active heat sink, often used inside laptops, was designed, fabricated and investigated. To fulfill the requirements and to match to the specific shape of the active heat sink, the hybrid sensor was proposed. It was composed of six thermocouples and fabricated using thick-film and LTCC (Low Temperature Cofired Ceramic) technology combined with wire thermocouples. Thick-film/LTCC flat substrates with thermoelectric paths ensured good thermal contact between the sensor and the monitored surface. The thermoelectric wires allowed adjusting the sensor to the complicated shape of the active heatsink. Three differ...
Proc. 39th International Spring Seminar on Electronics Technology (ISSE), 2016
Modeling, simulation and analyses of temperature distribution in a heat-sink are presented in thi... more Modeling, simulation and analyses of temperature distribution in a heat-sink are presented in this paper. Laboratory model of processor - source of heat was designed and realized. Four different heaters were fabricated as thick-film resistors screen-printed on alumina substrate. Temperature distribution was monitored using experimental measurements as well as numerical simulations. A measurement system consists of measuring table with structure (heater), heat-sink and two pyrometers, DC power supplies, data acquisition unit and computer. The experimental results were comparable to the results of numerical simulations carried out for similar processor/heat-sink system. This confirm the correctness of the used simulation model. On this basis the numerical analyses were extended - the influence of various factors (such as shape and size of the heat-sink, the presence of the cooling fan) on the heat distribution in the system was investigated. As a result the information useful in optimization process of the heat-sink was collected.
Materials Science-Poland, 2016
The aim of this work was to elaborate two-dimensional behavioral modeling method of thick-film re... more The aim of this work was to elaborate two-dimensional behavioral modeling method of thick-film resistors working in low-temperature conditions. The investigated resistors (made from 5 various resistive inks: 10 resistor coupons, each with 36 resistors with various dimensions), were measured automatically in a cryostat system. The low temperature was achieved in a nitrogen-helium continuous-flow cryostat. For nitrogen used as a freezing liquid the minimal temperature possible to achieve was equal to −195.85 °C (77.3 K). Mathematical model in the form of a multiplication of two polynomials was elaborated based on the above mentioned measurements. The first polynomial approximated temperature behavior of the normalized resistance, while the second one described the dependence of resistance on planar resistors dimensions. Special computational procedures for multidimensional approximation purpose were elaborated. It was shown that proper approximation polynomials and sufficiently exact ...
Acta Polytechnica Hungarica, 2020
The thermovoltaic effect describes the formation of electromotive force (EMF) in the absence of a... more The thermovoltaic effect describes the formation of electromotive force (EMF) in the absence of an external temperature gradient (in contrast to the conventional Seebeck phenomenon, which requires the creation of a temperature gradient between two semiconductor or metal connectors). In the presented research, the structure of a microgenerator using a thermovoltaic effect was proposed, in which the transport of hot electrons through an oxide insulating barrier lead to the accumulation of charge carriers and the formation of inter-layer potential. The microgenerator structures were fabricated in a multi-stage magnetron sputtering process. Planar structures were fabricated, consisting of thin layers of heavily doped degenerate semiconductor (SiC:Zr:B, Ge:Au, Ge:Ta:V, TiO 2 :Nb) with a silicon dioxide (SiO 2) insulation barrier and a second siliconmetal based electrode (Ta, Mo, NiCr). The thermovoltaic effect was observed in all of the structures, and the value of the generated electromotive force (thermovoltaic voltage) and the value of effective power was determined. The presented preliminary results show that the concept of constructing of asymmetric multi-layer junction structures can be used to fabricate microgenerators using a thermovoltaic effect.
In the paper results of experimentally determined values of diffusion and recombination related c... more In the paper results of experimentally determined values of diffusion and recombination related components of diode dark saturation corresponding to double-diode model (DEM) for CI(G)S and CdTe are presented. Obtained values result from considering of p-n junction physical basics as well from numerical simulations. Presented examples show a discrepancy between diffusion and recombination dark current components derived using both methods. The reason for this discrepancy is discussed. Work has been partially done within EC-funded BIPV-CIS 6FP project and Internal University Grant (Grant no 12/332116/2008).
Materials (Basel, Switzerland), Jan 12, 2018
This paper describes the design, manufacturing and characterization of newly developed mixed thic... more This paper describes the design, manufacturing and characterization of newly developed mixed thick-/thin film thermoelectric microgenerators based on magnetron sputtered constantan (copper-nickel alloy) and screen-printed silver layers. The thermoelectric microgenerator consists of sixteen thermocouples made on a 34.2 × 27.5 × 0.25 mm³ alumina substrate. One of thermocouple arms was made of magnetron-sputtered constantan (Cu-Ni alloy), the second was a Ag-based screen-printed film. The length of each thermocouple arm was equal to 27 mm, and their width 0.3 mm. The distance between the arms was equal to 0.3 mm. In the first step, a pattern mask with thermocouples was designed and fabricated. Then, a constantan layer was magnetron sputtered over the whole substrate, and a photolithography process was used to prepare the first thermocouple arms. The second arms were screen-printed onto the substrate using a low-temperature silver paste (Heraeus C8829A or ElectroScience Laboratories ESL...
Electron Technology Conference 2016, 2016
Results of fabrication as well as electrical and stability characterization of thick-film high oh... more Results of fabrication as well as electrical and stability characterization of thick-film high ohmic resistors are described in this paper. Five commercially available resistive compositions with sheet resistance of 1, 10, and 100 MΩ/sq were applied. The best properties were obtained for the lowest sheet resistance pastes, for which voltage coefficient of resistance (VCR) was lower than 3 ppm/V and hot temperature coefficient of resistance (HTCR) below 50 ppm/°C. Effect of resistor length on sheet resistance and impact of termination material were analyzed. High voltage pulse stress at 2 kV had negligible influence on resistors’ properties.
Microelectronics International
Purpose The paper focuses on design, fabrication and characterization of electromagnetic microgen... more Purpose The paper focuses on design, fabrication and characterization of electromagnetic microgenerators with integrated rectifying circuits to convert AC output signal to DC one. The work includes research on simulation of voltage-rectifying circuits, including charge pump, realization of the experimental printed circuit board (PCB) with selected electronic circuits and the execution of the final structure with integrated rectifying circuit. Measurements were performed on these circuits. Design/methodology/approach Electromagnetic microgenerators include multipole permanent magnets secured on rotor three-phase brushless direct current (BLDC) motor and planar multilayer multiple coils. These were fabricated using low temperature co-fired ceramics (LTCC) technology. In our experiment, six rectifying circuits were simulated and tested with a structure consisting of eight layers of coils and with an outer diameter of 50 mm fabricated earlier. Findings The microgenerator with Graetz bri...
Thick-film heaters are used very often in many types of sensors, especially gas sensors. Such hea... more Thick-film heaters are used very often in many types of sensors, especially gas sensors. Such heater should be characterised by good stability and reliability as well as uniform or programmed temperature distribution in gas sensing layer area. The last condition is very important for sensitivity and selectivity of sensors. Thick-film sensors are typically made on alumina substrate. In this case heater is placed on the opposite side of the substrate than gas sensitive film. LTCC technology allows construction of three-dimensional devices with buried components. The heater can be made inside LTCC structure, close to the gas sensitive material placed on the top. T he heater is protected from the harsh environment. Thermal properties of elements made on alumina are widely described in literature. However, temperature analysis of LTCC buried heating elements is very rear. This paper presents surface temperature distribution analysis of gas sensor made in LTCC technology. Sensors with buried and surface heater on LTCC ceramics have been made. Laser cutting has been used for fine meander patterning of unfired Pt pad. The width of fired Pt tracks has been equal to 150 m with 80 m distances between them. Thermal investigations by Finite Elements M ethod (FEM) as well as thermovision inspection have been performed. Thermal and electrical properties (up to 500°C) of elements made on substrates with different thermal properties i.e. alumina and LTCC ceramics (with buried and surface heater) have been compared. The homogeneous temperature distribution has been received on the desired surface part of investigated LTCC structure thanks to theoretical (FEM) and experimental (thermovision) methods.
Microelectronics Reliability, Jun 1, 2008
This paper describes manufacturing process as well as thermoelectric properties and long-term sta... more This paper describes manufacturing process as well as thermoelectric properties and long-term stability of planar and three-dimensional (3-D) thermoelectric structures made in thick-film/LTCC technology. Screen-printed thick-film thermocouples based on PdAg, Ag and Ni inks were manufactured and investigated. Seebeck coefficient and electrical output power were measured with the help of custom built automatic measuring system. Achieved results were compared with
Self-made and commercially available NTC thermistor compositions were investigated. The influence... more Self-made and commercially available NTC thermistor compositions were investigated. The influence of kind of substrate as well as component configuration and placement on basic electrical properties (resistivity at room temperature, R(T) dependence) and long-term stability was analysed. The durability of LTCC and thick-film thermistors on short high-voltage pulses was described. Application of thermistors matrix for characterization of temperature distribution in LTCC and thick-film microcircuits was presented.
Microelectronics Reliability, 2005
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Papers by Andrzej Dziedzic