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TG-FTIR coupled analysis to predetermine effective precursors for laser-activated and electroless metallized materials
摘要： Copper compounds can be used as additives to elaborate polymer materials, which after laser-induced ablation can be directly metallized on the irradiated surface area. In this work, three [Cu(l-tyr)2]n (l-tyr = l-tyrosine) (A), [Cu(bpy)3][CrO4]·7.5H2O (bpy = 2,2′-bipyridine) (B) and [Cu(bpy)2(O2SO2)]·CH3OH (C) copper(II) complexes were evaluated. The complexes were mixed at 20 mass% with polyurethane resin to form the coatings. The coatings were irradiated with ArF excimer laser and electroless metallized. It was found that only complex A was effective metallization precursors. Thermal properties of the copper(II) complexes were considered as crucial for defining effective precursors. TG-FTIR coupled analysis was applied to predetermine thermal properties of the compounds, which can be responsible for effective metallization. It was found that the main reason for unsuccessful metallization of the coatings containing complexes B or C was release of lattice H2O or CH3OH molecules in crystal structures, respectively, which affected ablation of the coatings. Appropriate model of laser ablation was also proposed.
关键词： Copper(II) complexes,Polymer coating,Electroless metallization,Laser modification,TG-FTIR coupled analysis
更新于2025-09-11 14:15:04
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Annealing Impact on Interface Properties of Sprayed Al2O3-Based MIS Structure for Silicon Surface Passivation
摘要： Aluminum oxide (Al2O3) films of different thicknesses were deposited on quartz and silicon (100) substrates by an ultrasonic spray method from a solution of aluminum acetylacetonate dissolved in N,N-dimethylformamide with different molar concentrations. The optical, morphological and electrical properties were investigated. Increasing the molar concentration leads to a refractive index decrease, an increase in the optical band gap from 5.26 eV to 5.52 eV and a change in the surface roughness of the films. The electrical parameters at the Al2O3/Si interface such as the flat band voltage (VFB), effective charge density (Qeff) and interface trap density (Dit) were explored as a function of the molar concentration, film thickness and heat treatment. The latter, done by two annealing processes, namely, the post deposition annealing (PDA) and post metallization annealing (PMA) on the structure, lead to remarkable interface properties. It was found that the positive flat band voltage VFB shift is correlated with the generation of negative effective charge during PMA. A decrease of the Dit distribution in the PMA samples with no significant effect in the case of PDA samples was clearly observed for different molar concentrations. Furthermore, as the Al2O3 film thickness decreases, Dit decreases in both PDA and PMA samples while the relatively high density Qeff and its negative charge polarity were obtained for thinner films. A noticeable passivation effect on the Al2O3/Si interface has been confirmed on samples that underwent the annealing process. These findings related specifically to the interface properties are promising for silicon surface passivation, in particular for solar cells applications.
关键词： Al2O3,surface passivation,ultrasonic spray,post-metallization annealing,post-deposition annealing
更新于2025-09-10 09:29:36
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GeSn surface preparation by wet cleaning and in-situ plasma treatments prior to metallization
摘要： GeSn, a group IV binary alloy, is currently of high interest. Its use is envisioned in two kinds of applications: (i) as a source/drain compressive stressor in order to boost the hole mobility in short gate length Ge channel p-type MOSFETs [1] and (ii) as a direct-band-gap material for Si photonics, provided that the Sn content is higher than 10%, typically [2]. However, the fabrication of GeSn-based components faces major technological issues. First of all, as the lattice mismatch between Sn and Ge is large (14%) and the solubility of Sn in Ge low at thermodynamic equilibrium (< 1%), specific conditions have to be used for the epitaxial growth of high Sn content GeSn layers. Moreover, the fabrication of efficient ohmic contacts to receive and deliver power and signals is challenging. Ni-stanogermanides are currently under investigation in order to benefit from low contact resistivity (Rc) and sheet resistance (Rsh) in GeSn-based devices. The surface preparation of such metastable alloys will then be an unavoidable step. Whatever the targeted application, wet cleaning is indeed mandatory to remove particles, organic materials, metallic impurities and native oxides from the surface. Literature data on GeSn surface preparation prior to metallization is currently scarce [3], [4]. Based on the existing knowledge on pure germanium, we will likely have to cope with a high dissolution in oxidant solutions (GeO2 dissolution in water) and unstable surface preparations (high reactivity upon air and oxygen exposure). Ex-situ wet cleanings will likely suffer from a fast native oxide regrowth on the GeSn surface. In-situ plasma treatments in a chamber connected to the metal deposition chamber itself, i.e. without any air break, should enable to get rid of that problem. In this work, after a characterization of the native oxide formed upon air exposure of Ge0.85Sn0.15 alloys, we investigate the impact of i) wet chemistries, ii) plasma treatments and iii) “wet + plasma” combinations on GeSn surface oxide removal.
关键词： surface preparation,GeSn,metallization,wet cleaning,plasma treatments
更新于2025-09-09 09:28:46
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Thermal Shock Performance of DBA/AMB Substrates Plated by Ni and Ni–P Layers for High-Temperature Applications of Power Device Modules
摘要： The thermal cycling life of direct bonded aluminum (DBA) and active metal brazing (AMB) substrates with two types of plating—Ni electroplating and Ni–P electroless plating—was evaluated by thermal shock tests between ?50 and 250 ?C. AMB substrates with Al2O3 and AlN fractured only after 10 cycles, but with Si3N4 ceramic, they retained good thermal stability even beyond 1000 cycles, regardless of the metallization type. The Ni layer on the surviving AMB substrates with Si3N4 was not damaged, while a crack occurred in the Ni–P layer. For DBA substrates, fracture did not occur up to 1000 cycles for all kind of ceramics. On the other hand, the Ni–P layer was roughened and cracked according to the severe deformation of the aluminum layer, while the Ni layer was not damaged after thermal shock tests. In addition, the deformation mechanism of an Al plate on a ceramic substrate was investigated both by microstructural observation and ?nite element method (FEM) simulation, which con?rmed that grain boundary sliding was a key factor in the severe deformation of the Al layer that resulted in the cracking of the Ni–P layer. The fracture suppression in the Ni layer on DBA/AMB substrates can be attributed to its ductility and higher strength compared with those of Ni–P plating.
关键词： DBA,cracking,Ni–P electroless plating,Ni electroplating,reliability,grain boundary sliding,AMB,thermal shock test,roughness,metallization
更新于2025-09-09 09:28:46
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Nanoelectronics and Materials Development || Epitaxial Cu3Ge Thin Film: Fabrication, Structure, and Property
摘要： In this paper, the fabrication and electrical property characterization of epitaxial Cu3Ge thin film are performed. By adjusting deposition parameters, the crystallinity of the as‐grown Cu3Ge thin films is improved, with the formation of twins within it. The average work function of epitaxial Cu3Ge thin film is measured to be ～4.47 + 0.02 eV, render‐ ing it a desirable mid‐gap gate metal for applications in complementary metal‐oxide semiconductor (CMOS) devices. The present study therefore shows an epitaxial Cu3Ge thin film that is promising for applications.
关键词： sapphire,semiconductor metallization,Cu3Ge thin film,pulsed laser deposition,twin
更新于2025-09-09 09:28:46
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Gallium Oxide || Ohmic contacts to gallium oxide
摘要： The deposition of a metal onto a semiconductor surface to provide low contact resistance, high-reliability electrical contacts without adversely affecting the device during the metallization process is one of the most important challenges in device fabrication. Consequently, a fundamental understanding of how contacts work is essential for successful device manufacturing and commercialization. The physics of carrier transport across the metal-semiconductor junction renders metal contacts either rectifying (a.k.a. Schottky) or nonrectifying. A nonrectifying contact whose relationship between current and voltage has a low interfacial contact resistance Rc, and is preferably linear, is referred to as an Ohmic contact. Achieving low contact resistance Rc (Ω mm) or contact resistivity ρc (Ω cm2) has required a great amount of investigation for every relevant semiconductor material in the past. Typically, the successful formation of an Ohmic contact has relied on three constituent requirements: highly or degenerately doped semiconductor, choice of metallization, and thermal annealing. In the case of silicon, for instance, diffusion processes have been the topic of much early work but ultimately the control and reproducibility of ion implantation have rendered it an industry standard. For compound semiconductor heterostructure devices based on GaAs or GaN, the presence of a two-dimensional electron gas (2DEG) has necessitated a multilayer metallization deposition and annealing scheme, the details of which took many years to optimize. Particularly in the case of III-nitride high electron mobility transistors (HEMTs), Ohmic contacts were relatively easy to make on heteroepitaxal GaN due to its high dislocation density as the barrier height was reduced through defect-assisted formation of metal-nitride alloys during the anneal. Subsequent breakthroughs in GaN crystal growth, however, resulted in several orders of magnitude lower dislocation density homoepitaxial GaN, and naturally the contact resistance obtained under identical process conditions was higher [1]. Regrowth techniques to provide n+-doped GaN have become commonplace as a result.
关键词： thermal annealing,semiconductor,metallization,gallium oxide,contact resistance,Ohmic contacts
更新于2025-09-09 09:28:46
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Polarization-Direction Dependence of Thermodynamic Stability of Ferroelectric BiAlO <sub/>3</sub> (0001) Polar Surfaces
摘要： Polar surfaces of ferroelectric oxides are of great importance for both fundamental and practical interest. In this report, we present a theoretical study to determine the thermodynamic stability and electronic properties of ferroelectric BiAlO3(0001) surfaces. According to the calculated surface phase diagram, we predict that the equilibrium stoichiometries are distinct for the oppositely polarized BiAlO3 surfaces under the same chemical conditions. In addition to nonstoichiometry of the surface chemical compositions, we find that anomalous filling of the surface states can also result in surface metallization in order to compensate the remarkable surface polarity. Besides providing atomic-scale understanding of the BiAlO3(0001) surfaces, we also put forward the practical implications in novel magnetoelectric devices and advanced surface chemistry.
关键词： Magnetoelectric devices,Surface chemistry,Thermodynamic stability,Surface metallization,BiAlO3(0001) surfaces,Electronic properties,Ferroelectric oxides
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - A 24-GHz Radar with 3d-Printed and Metallized Lightweight Antennas for UAV Applications
摘要： A 24-GHz frequency-modulated continuous-wave (FMCW) radar system and its possible use in airborne vehicles is presented in this paper. The focus of this paper is set on the ultralight antennas and their integration into radar systems for unmanned aerial vehicle (UAV) applications. For this purpose a radiator arrangement was designed and then 3d-printed twice out of plastics with various methods. Different metallization processes were used to establish conductivity afterwards. Particularly, one antenna was plated with a conventional method and one with a new metallization technique, which makes it feasible to cover a non conducting part with silver within seconds. The weight of the antenna is 7-8 times less, than compared to full metal antennas. Subsequently, both antennas were measured, characterized and compared to each other in terms of re?ection loss and beam pattern. It will be shown that the antenna metallized by the new technology can achieve 2-3 dB better results in return loss than the conventionally plated one in the 24-GHz ISM band. Also it will be shown that both prototypes are similar regarding their gain. Moreover, the antennas were mounted onto a radar, located on the UAV and then ?ight tests up to 120 meters have been performed. These results were recorded, processed and evaluated ?nally.
关键词： horn antenna,airborne application,drones,Jet MetalTM,UAV,additive manufacturing,3d-printing,metallization,radar measurements,FMCW radar
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Reactive Silver Ink as a Novel Low-Temperature Metallization: Monitoring Corrosion
摘要： Reactive silver ink (RSI) forms low-resistivity (<5 μΩ?cm) metallization at temperatures below 100 °C –enabling lower resistive losses for thermally sensitive solar cells while drastically reducing Ag usage compared to other low-temperature Ag pastes. However, before adoption of the technology many reliability related questions must be addressed. Ag-based metallizations are susceptible to corrosion by acetic acid formed in encapsulated modules, resulting in increased resistive losses. Here we report on corrosion of three types of metallizations; high-firing-temperature Ag paste (HT Ag Paste), low-temperature Ag paste (LT Ag Paste), and RSI. We develop a method for exposing these metallizations to dilute acetic acid in concentrations comparable to those found in field- and damp heat-exposed modules. We find that HT Ag and RSI are quickly affected by acetic acid exposure after only 24 h. Interestingly, Raman spectroscopy suggests the formation of AgCl or AgCH3COO on HT Ag Paste, dissolution of AgCH3COO from RSI, and LT Ag Paste remains relatively unchanged throughout 2936 h of exposure to diluted acetic acid.
关键词： low temperature metallization,silver usage,metallization,silver,corrosion
更新于2025-09-04 15:30:14
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Formation of silver films for advanced electrical properties by using aerosol deposition process
摘要： A simple room temperature aerosol deposition (AD) process was used to fabricate silver thick films for high efficiency metallization that can be applied to decrease the resistance–capacitance delay and increase the signal propagation speed in integrated circuits. To obtain more advanced performance than aerosol-deposited silver films reported in previous studies, experimental parameters (orifice size of nozzle and gas consumption) that could directly affect electrical resistivity were optimized in advance. The proper small orifice size was selected for facilitated reduction of electrical resistivity by activating the percolation effect and making more conduction channels. High gas consumption also reduced the electrical resistivity of the silver films, forming plenty of metal clusters. Using experimental parameters that showed the lowest resistivity, silver thick films were fabricated via the AD process and their properties were analyzed. The results of the X-ray diffraction confirmed that the silver particles underwent impact-induced plastic deformation. As the film thickness was thickened up to 12 scans, the collided particles filled up the rough alumina substrate. After 12 scans, the silver films became densified due to severe plastic deformation of the as-deposited silver particles. Therefore, the growth mechanism suggests that most silver particles in the initial deposition step contribute to mechanical interlocking, and the subsequent particles could lead to film densification.
关键词： aerosol deposition,electrical resistivity,silver films,metallization,integrated circuits
更新于2025-09-04 15:30:14