Through silicon via (TSV) is one of the most important technologies used in three dimension (3D) packaging. The void-free filling of TSV can be achieved by adding additives into the electrolyte bath during the electrodeposition process. This paper focuses on the effects of three types of commercial additives (the suppressor, the leveler and the accelerator) and analyses additives’ interaction on electroplating through experimental investigations. The results showed that the suppressor, the leveler and the accelerator all have chemical behaviour of inhibition in different degrees to the copper electroplating. The interaction experiments of additives in pairs indicated that the suppressor absorbed on the cathode surface was gradually displaced by the accelerator as the concentration of the accelerator increased; the accelerator and the leveler presented a competitive adsorption relationship; the suppressor and the leveler had a synergistic effect for electroplating inhibition especially under high potential and low suppressor concentration. Experiments of micro via filling by electrodeposition have been conducted to investigated the effects of singular additive and multiple additives on the filling process of the micro vias.

Solar-blind ultraviolet photodetectors have potential applications in space communication, ozone hole monitoring and missile tracking. Amorphous Ga ₂ O ₃ (a-Ga ₂ O ₃ ) films are deposited by a simple radio frequency magnetron sputtering at different deposition temperatures. Fully transparent devices on a quartz substrate are fabricated with high responsivity, wide detection range and good repeatability. With the increase of Ga ₂ O ₃ deposited temperature, the concentration of oxygen vacancy increases accordingly, leading to a wide detection range from 250 to 325 nm and high responsivity (138 A W ⁻¹ at 5 V bias). The underlying mechanism has been discussed and analyzed. Our results should advance the application of a-Ga ₂ O ₃ -based ultraviolet photodetectors and other relevant devices.

This Letter proposes a circularly polarized (CP) light GaN micro-LED which is integrated with functional metasurfaces. The one-dimensional metallic nanograting can achieve a high transverse electric (TE) reflectivity ( R T E ) and extinction ratio (ER) of TE and transverse magnetic (TM) waves, which is highly polarized output for micro-LEDs. Besides, the nanograting, which is integrated on the bottom of the GaN layer, can also support a resonant cavity, together with the top distributed Bragg reflector, which can shape the radiation pattern. By optimizing the structure parameters of nanograting, the R T E achieves over 80%, and the ER reaches higher than 38 dB at 450 nm for the GaN micro-LED. Additionally, the metasurface, which acts as a quarter-wave plate, was investigated to control the phase delay between the polarization state of the electric wave in two orthogonal components. Finally, the circular shape of the transmitted pattern denotes the high performance of the metasurface which is integrated in the micro-LED for CP light emission. The work reported in this Letter might provide potential application in a 3D polarized light display.

Several methods that could effectively increase the strength of heavy aluminum bonding wire and broaden the scope for high-power IGBT module applications with a high degree of integration have been proposed. In this work, a series of finite element analysis has been carried out to study the thermomechanical reliability of bonding wire/ribbon under different conditions. The effects of structural loop parameters, bonding wire materials, bonding ribbon, and polymer coating are discussed based on simulation results, and the primary cause for the effect of geometric parameters has been developed. It is worth noticing that the reliability of the heavy bonding wires increases with the increase in Young's modulus and Poisson's rate in a polymer coating. This present study provides new insights into the thermomechanical behaviors of heavy bonding wire/ribbon, as well as a practical guide for designing an optimal structural loop shape and selecting an appropriate material of bonding wires or polymer, which will accelerate functional applications in industries.

The chip-level degradation and packaging-level degradation of SiC MOSFET coupled and affected each other in the degradation process of PCT. The degradation parameters monitored online are the result of coupling action of multiple failure mechanisms. The degradation features are more complex to distinguish. In this work, the reliability issues of the SiC MOSFET module were investigated by power cycling test (PCT) in saturation mode and body diode mode with the constant current and constant junction temperature swing (Δ T_j ) control strategies. The failure sites and its underlying failure mechanisms were distinguished by comparing the trends of online precursors via monitoring the Kelvin source and common source, with the help of static parameters and failure analysis. And the relationship between failure mechanisms and the trends of online aging precursors of two monitoring positions was clarified, based on the comprehensive analysis of chip and packaging-related failures. Besides, the competitive failure or interaction of chip-related and packaging-related degradation was discussed, which accelerated the failure of devices under tests (DUTs). Furthermore, the root cause of the difference in lifetime and failure modes under different PCT conditions was explored.