Engineering Glass Passivation Layers -Model Results

Abstract This paper presents a new fail mechanism for laser-marking induced die damage. Discovered during package qualification, silica spheres – commonly used as fillers in the molding material, was shown to act as a propagation medium that promote the direct interaction of the scribing laser beam and the die surface. Critical to the understanding of the fail mechanism is the deprocessing technique devised to allow layer by layer examination of the metallization and passivation layers in an encapsulated silicon die. The technique also made possible the inspection of the molding compound profile directly on top of the affected die area.

Download Full-text

Studies on a Novel Qualification Method of Silicon Nitride Layer

ISTFA 2016: Conference Proceedings from the 42nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2016p0186 ◽

2016 ◽

Author(s):

Younan Hua ◽

Bingsheng Khoo ◽

Henry Leong ◽

Yixin Chen ◽

Eason Chan ◽

...

Keyword(s):

Silicon Nitride ◽

Silicon Substrate ◽

Nitride Layer ◽

Passivation Layer ◽

Wafer Fabrication ◽

Wafer Surface ◽

Si3n4 Layer ◽

Silicon Nitride Layer ◽

Passivation Layers ◽

Pinhole Test

Abstract In wafer fabrication, a silicon nitride (Si3N4) layer is widely used as passivation layer. To qualify the passivation layers, traditionally chemical recipe PAE (H3PO4+ HNO3) is used to conduct passivation pinhole test. However, it is very challenging for us to identify any pinholes in the Si3N4 layer with different layers underneath. For example, in this study, the wafer surface is Si3N4 layer and the underneath layer is silicon substrate. The traditional receipt of PAE cannot be used for passivation qualification. In this paper, we will report a new recipe using KOH solution to identify the pinhole in the Si3N4 passivation layer.

Download Full-text

MoS2 Based Photodetectors: A Review

Sensors ◽

10.3390/s21082758 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2758

Author(s):

Alberto Taffelli ◽

Sandra Dirè ◽

Alberto Quaranta ◽

Lucio Pancheri

Keyword(s):

Electric Fields ◽

Spectral Range ◽

Performance Metrics ◽

Transition Metal Dichalcogenides ◽

Visible Spectral Range ◽

Detector Performance ◽

Strong Light ◽

Near Ultraviolet ◽

Passivation Layers ◽

Low Dimensional

Photodetectors based on transition metal dichalcogenides (TMDs) have been widely reported in the literature and molybdenum disulfide (MoS2) has been the most extensively explored for photodetection applications. The properties of MoS2, such as direct band gap transition in low dimensional structures, strong light–matter interaction and good carrier mobility, combined with the possibility of fabricating thin MoS2 films, have attracted interest for this material in the field of optoelectronics. In this work, MoS2-based photodetectors are reviewed in terms of their main performance metrics, namely responsivity, detectivity, response time and dark current. Although neat MoS2-based detectors already show remarkable characteristics in the visible spectral range, MoS2 can be advantageously coupled with other materials to further improve the detector performance Nanoparticles (NPs) and quantum dots (QDs) have been exploited in combination with MoS2 to boost the response of the devices in the near ultraviolet (NUV) and infrared (IR) spectral range. Moreover, heterostructures with different materials (e.g., other TMDs, Graphene) can speed up the response of the photodetectors through the creation of built-in electric fields and the faster transport of charge carriers. Finally, in order to enhance the stability of the devices, perovskites have been exploited both as passivation layers and as electron reservoirs.

Download Full-text

An Overview on Anodes for Magnesium Batteries: Challenges towards a Promising Storage Solution for Renewables

Nanomaterials ◽

10.3390/nano11030810 ◽

2021 ◽

Vol 11 (3) ◽

pp. 810

Author(s):

Federico Bella ◽

Stefano De Luca ◽

Lucia Fagiolari ◽

Daniele Versaci ◽

Julia Amici ◽

...

Keyword(s):

Reduction Potential ◽

Literature Analysis ◽

Organic Electrolytes ◽

Boron Clusters ◽

Passivation Film ◽

Metallic Magnesium ◽

Passivation Layers ◽

Magnesium Batteries ◽

Nanostructured Metal Oxides ◽

Nanostructured Metal

Magnesium-based batteries represent one of the successfully emerging electrochemical energy storage chemistries, mainly due to the high theoretical volumetric capacity of metallic magnesium (i.e., 3833 mAh cm−3 vs. 2046 mAh cm−3 for lithium), its low reduction potential (−2.37 V vs. SHE), abundance in the Earth’s crust (104 times higher than that of lithium) and dendrite-free behaviour when used as an anode during cycling. However, Mg deposition and dissolution processes in polar organic electrolytes lead to the formation of a passivation film bearing an insulating effect towards Mg2+ ions. Several strategies to overcome this drawback have been recently proposed, keeping as a main goal that of reducing the formation of such passivation layers and improving the magnesium-related kinetics. This manuscript offers a literature analysis on this topic, starting with a rapid overview on magnesium batteries as a feasible strategy for storing electricity coming from renewables, and then addressing the most relevant outcomes in the field of anodic materials (i.e., metallic magnesium, bismuth-, titanium- and tin-based electrodes, biphasic alloys, nanostructured metal oxides, boron clusters, graphene-based electrodes, etc.).

Download Full-text

Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18115921 ◽

2021 ◽

Vol 18 (11) ◽

pp. 5921

Author(s):

Haiyan Song ◽

Wei Liu ◽

Fansheng Meng ◽

Qi Yang ◽

Niandong Guo

Keyword(s):

Aqueous Solution ◽

Removal Efficiency ◽

Inhibitory Effect ◽

Ultrasonic Cavitation ◽

Zero Valent Iron ◽

Ultrasonic Pretreatment ◽

Nanoscale Zero Valent Iron ◽

Passivation Layers ◽

Initial Ph ◽

Two Phases

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42−, NO3−, and Cl− had a strong inhibitory effect on this process, while the presence of SO42− promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.

Download Full-text

Enhanced ion transport in Li2O and Li2S films

Chemical Communications ◽

10.1039/d1cc00557j ◽

2021 ◽

Author(s):

Simon Lorger ◽

Kai Narita ◽

Robert Usiskin ◽

Joachim Maier

Keyword(s):

Ion Transport ◽

Passivation Layers

Li2O and Li2S films show Li+ conductivities comparable to those of typical SEI passivation layers in batteries.

Download Full-text

Microbial-Driven Stabilisation of Archaeological Iron Artefacts

Corrosion and Materials Degradation ◽

10.3390/cmd2020015 ◽

2021 ◽

Vol 2 (2) ◽

pp. 274-292

Author(s):

Sarah James ◽

Edith Joseph

Keyword(s):

Health And Safety ◽

Chloride Content ◽

Key Factors ◽

Passivation Layers ◽

Archaeological Iron ◽

Initial Results ◽

Sulphur Species ◽

Partial Success ◽

Made In

The instability of iron artefacts is rooted in salt contamination during burial and damages associated with exposure to alternative oxygen levels and high relative humidity once excavated. While a combination of chemical and mechanical treatments is utilised to remove the harmful ions (chlorides, sulphur species) and excess bulky corrosion products, these methods can be hazardous for conservation staff’s health, have limited success, or require extensive treatment times. Bio-based treatments provide a potentially greener alternative for removing damaging corrosion and creating biogenic mineral passivation layers, thus remediating concerns over costs, duration, and health and safety. Pseudomonas putida mt-2 (KT2440) is capable of utilising iron under certain conditions and for phosphating mild steel; however, applications have not been made in the cultural heritage sector. To address the potential of using bacteria for conservation purposes, Pseudomonas was assessed for both the bioremediation of salt contaminates and the production of a passivation layer suitable for iron artefacts, with specific conservation concerns in mind. Key factors for optimisation include the role of agitation, chloride content, and oxygen content on bacterial growth and biomineralisation. The initial results indicate a growth preference, not reliance, for NaCl and agitation with partial success of bioconversion of a mineral source.

Download Full-text