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Purpose Concerning the radiation effects on the three-dimensional (3D) packaging in space environment, this study aims to investigate the influence of the total dose effect on the transmission characteristics of high-frequency electrical signals using experimental and simulation methods. Design/methodology/approach This work carries out the irradiation test of the specimens and measures their S21 parameters before and after irradiation. A simulation model describing the total dose effect was built based on the experimental test results. And, the radiation hardening design is evaluated by the simulation method. Findings The experimental results demonstrate that the S21 curve of the interconnection decreases with the increase of the irradiation dose, indicating that the total dose effect leads to the decline of its signal transmission characteristics. According to the simulation results, decreasing the height of the through silicon via (TSV), increasing the radius of the TSV, reducing the length of Si and increasing the number of grounded through silicon via have positive effects on improving the radiation resistance of the interconnection structure. Originality/value This work investigates the effect of radiation on the transmission characteristics of interconnection structures for 3D packaging and proposes the hardening design methods. It is meaningful for improving the reliability of 3D packaging in space applications.

Purpose The purpose of this paper is to investigate the effects of Sn-Ag-x leveling layers on the mechanical properties of SnBi solder joints. Four Sn-Ag-x (Sn-3.0Ag-0.5Cu, Sn-0.3Ag-0.7Cu, Sn-0.3Ag-0.7Cu-0.5 Bi-0.05Ni and Sn-3.0Ag-3.0 Bi-3.0In) leveling layers were coated on Cu pads to prepare SnBi/Sn-Ag-x/Cu solder joints. The microstructure, hardness, shear strength and fracture morphology of solder joints before and after aging were studied. Design/methodology/approach The interfacial brittleness of the SnBi low-temperature solder joint is a key problem affecting its reliability. The purpose of this study is to improve the mechanical properties of the SnBi solder joint. Findings Owing to the addition of the leveling layers, the grain size of the ß-Sn phase in the SnBi/Sn-Ag-x/Cu solder joint is significantly larger than that in the SnBi/Cu eutectic solder joint. Meanwhile, the hardness of the solder bulk in the SnBi/Cu solder joint shows a decrease trend because of the addition of the leveling layers. The SnBi/Cu solder joint shows obvious strength drop and interfacial brittle fracture after aging. Through the addition of the Sn-Ag-x layers, the brittle failure caused by aging is effectively suppressed. In addition, the Sn-Ag-x leveling layers improve the shear strength of the SnBi/Cu solder joint after aging. Among them, the SnBi/SACBN/Cu solder joint shows the highest shear strength. Originality/value This work suppresses the interfacial brittleness of the SnBi/Cu solder joint after isothermal aging by adding Sn-Ag-x leveling layers on the Cu pads. It provides a way to improve the mechanical performances of the SnBi solder joint.

Nanostructured transition metal oxides are promising anode materials for lithium-ion batteries. Nevertheless, the problem of high volume expansion rate limits its further application. In this paper, we present a 3D hierarchical SnO2 hollow nanotubes material by calcining C@SnS2 materials in the air. This structure combines the advantages of both the hollow nanotubes and the outer staggered nanosheets structure, in which the hollow nanotube can provide more lithium ion transport channels, the space between the tubes can buffer the volume change, and the staggering nanosheets structure can effectively improve the relative specific surface area of the material and improve the storage capacity. As a result, the SnO2 hollow nanotubes anode exhibits the highly reversible capacity of 1079 mAh g−1 at a current density of 100 mA g−1, while the reversible specific capacity of 770 mAh g−1 was obtained after 100 cycles. The research results obtained in this work provide a feasible strategy for synthetic nanoscale transition metal oxide as high-performance lithium anode material.

In this study, porous metals (Ni, Cu) with the porosity of 110 and 500 ppi were, respectively, added into the SnBi solder joint to obtain the SnBi@P–Cu and SnBi@P–Ni composite solder joints. To ensure the bonding quality between the solder layers and the Cu substrates, a low pressure of 0.1 MPa was conducted during the soldering process. The microstructure and shear behavior of the composite solder joints were investigated. With the addition of 110 ppi porous metals, the microstructures of the solder joints are mainly composed of porous metals and SnBi solder matrix. As the porosity of P–Cu and P–Ni metals increases to 500 ppi, the concentration of the SnBi matrix decreases sharply in the solder joints. The cross-sectional microstructures of the solder joints present a uniform morphology of P-metals and intermetallic compound (IMC). Here the IMC is Cu6Sn5 in the SnBi@P–Cu joint, but (Ni, Cu)3Sn4 and (Cu, Ni)6Sn5 in the SnBi@P–Ni joint. The shear strength of the SnBi solder joint increases significantly with the addition of porous metals. The average shear strength of SnBi@110P–Cu reaches 85.28 MPa, which is the highest among the investigated solder joints.

Metal foam with excellent ductility was added into nano-Ag sintered joint to obtain the composite sintered joint with a sandwich structure of sintered Ag/metal foam/sintered Ag. The microstructure, shear behavior and fracture morphology of the composite sintered joint were investigated in this study. Experimental results indicate that the addition of ductile metal foam enhances the plasticity of composite sintered joint. As the number of pores of Cu foam increased from 110 to 500 per inch, the shear strength increased from 8.28 to 11.26 MPa. The composite sintered joint with 110ppi (pores per inch) Ni foam showed a higher shear strength than the other composite sintered joints did because of the higher Young’s modules and shear modules of Ni foam. In the Ni foam@nano-Ag composite sintered joint, cracks appeared at the interface between the metal foam and the nano-Ag sintered structure because of the mismatch of coefficient of thermal expansion (CTE). Compared with the Ni foam, the addition of Cu foam effectively depressed the generation of cracks at the interface between the metal foam and the nano-Ag sintered structure.

Here, the Ag/amorphous Bi3.15Nd0.85Ti3O12/Pt resistive switching memories were designed and prepared, and the total ionizing dose (TID) effects of 60Co γ-ray on the Ag/amorphous Bi3.15Nd0.85Ti3O12/Pt resistive switching memories were investigated. The results show that the resistance in low resistance state (LRS), resistance in high resistance state (HRS), and set voltage are almost immune to a TID up to 1 Mrad(Si), whereas the reset voltage and forming voltage are impacted slightly. The good radiation immunity is related to the metallic conductive filaments and the amorphous Bi3.15Nd0.85Ti3O12 matrix. These results suggest that the Ag/amorphous Bi3.15Nd0.85Ti3O12/Pt devices show potential for radiation-hard electronics applications.

To improve the reliability of SnBi solder joints, Ag and porous Cu were used as additives to obtain SnBi-xAg@P-Cu/Cu (x = 0, 0.4, 1 wt%) solder joints. The effect of porous Cu addition on the microstructure, IMC layer, shear behavior and hardness of the solder joints during isothermal aging was studied. The experimental results indicate that there are some areas enclosed by Cu frames in the SnBi-xAg@P-Cu/Cu solder joints. Compared with the SnBi-xAg/Cu solder joints, these areas show a more refined microstructure and higher hardness than the other areas do. After being aged at 100 °C for 600 h, the hardness of the solder bulks showed an increasing trend due to the coarsening of the microstructure. The addition of porous Cu improves the shear strength of the SnBi-xAg/Cu solder joints before and after aging. Among them, SnBi-0.4Ag@P-Cu/Cu shows the highest shear strength. After isothermal aging, the shear fracture transferred from the solder bulk to the soldering interface in the SnBi and SnBi-0.4Ag solder joints. The addition of porous Cu has a positive effect on suppressing the crack propagation in the solder joints. Therefore, the fracture position is mainly located in the solder bulks in the SnBi-xAg@P-Cu/Cu solder joint.

In this paper, the epitaxial hexagonal LuFeO3 (h-LuFeO3) thin films with c-axis-oriented single phase, smooth surface were grown on YSZ (111) substrates by pulsed laser deposition method. Furthermore, a structural distortion of increased lattice constant of c is found in the epitaxial h-LuFeO3 thin films. Moreover, the epitaxial h-LuFeO3 thin films show room-temperature ferromagnetism. The coercive field and remnant magnetization of the epitaxial h-LuFeO3 thin film decrease with the increase in the test temperature from 50 to 300 K. The study would be of benefit to the room-temperature single-phase multiferroic materials.

Perovskite solar cells have excellent photoelectric properties, but their physical mechanism of anti-irradiation is still incomplete. In this work, we investigate the photoelectrical properties of mixed cation perovskite solar cells by performing electron irradiation experiments, characterization measurements (i.e. photoluminescence spectra, UV–vis absorption spectra, and quantum efficiency spectra), and Monte Carlo simulation analysis. It is found that the electrical performance of solar cells degrades more severely with increasing electron irradiation fluence. Specifically, the open-circuit voltage independent of the electron irradiation is attributed to the stability of perovskite materials. The short-circuit current density (alternatively, photoelectric conversion efficiency) of irradiated solar cells decreases because two main reasons: the blackening of the glass substrate hampers the short-wavelength light to reach the photosensitive layer, and the Au electrode has a large number of recombination centers to shorten the carrier lifetime. It is suggested that the mixed cation perovskite solar cell has anti-electron irradiation performance by adopting the anti-irradiation glass and electrode.

In order to improve the mechanical behavior of the low-temperature [Formula: see text] (SnBi) lead-free solder joint, the [Formula: see text] (SACBN) solder ball with the diameter of 400 [Formula: see text]m was pre-soldered on Cu to obtain the SnBi/SACBN/Cu composite joint. The microstructure and shear behavior of the solder joints were investigated. Experimental results indicate that SnBi solder is well bonded on the SACBN bump due to the elemental diffusion and dissolution between the molten SnBi and solid SACBN bump during the soldering process. The addition of the SACBN bump shows a significant effect on the formation and growth of the [Formula: see text]-Sn grains in the SnBi bulk. Compared with the SnBi/Cu joint, the SnBi bulk in the composite joint shows enlarged [Formula: see text]-Sn dendritic grains. Meanwhile, the interfacial intermetallic compound (IMC) layer transforms from Cu6Sn5 into (Cu, Ni)6Sn5. Among these three solder joints, the shear strength of the SACBN/Cu joint is the highest, reaching 86.7 MPa. The shear strength of the SnBi/Cu solder joint is enhanced by the SACBN bump from 68.2 MPa to 75.2 MPa. Additionally, the addition of the SACBN bump shows a positive effect on suppressing the brittleness of the SnBi/Cu solder joint.