This letter presents a compact, low-loss flexible filter based on a double-interdigital coupling stepped-impedance resonator (SIR) and through-polyimide via (TPV) technology. With a fractional bandwidth (FBW) of 12.5% at 2.5 GHz, the filter achieves a low insertion loss of 1.8 dB in the flat state and only 1.95 dB under bending. Its electrical performance remains highly stable under deformation, while the structure attains a 40% size reduction over the state-of-the-art designs, offering a promising solution for wearable wireless systems demanding flexibility and spectral selectivity.

Spin-polarized edge states in two-dimensional materials hold promise for spintronics and quantum computing applications. Constructing stable edge states by tailoring two-dimensional semiconductor materials with bulk-boundary correspondence is a feasible approach. Recently layered NiI₂ is suggested as a two-dimensional type-II multiferroic semiconductor with intrinsic spiral spin ordering and chirality-induced electric polarization. However, the one-dimensional spin-polarized edge states of multiferroic materials down to monolayer limit has not yet been studied. We report here that monolayer NiI₂ was successfully synthesized on Au(111) by molecular beam epitaxy. Spin-polarized scanning tunneling microscopy/spectroscopy experiments visualize orientation-selective spin-polarized edge states in monolayer NiI₂ islands. By performing first-principles calculations, we further confirm that spin-polarized edge states are selectively aligning along the Ni-terminated edges rather than the I-terminated edges. Our result will provide the opportunity to tune edge states by selected orientation and to develop spintronic devices in two-dimensional magnetic semiconductors.

The electromigration (EM) can introduce voids and hillocks in through-silicon vias (TSVs) and redistributed layer (RDL) interconnects, increasing the risks of short-circuit and open-circuit failures and thereby severely affecting the reliability of chiplet systems. In this article, the EM failure mechanism of the interconnects under electrical–thermal–stress multiphysics coupling is investigated, and a novel method for EM lifetime prediction based on coupled multiphysics modeling and finite element simulation is proposed. The implementation of dynamic failure simulation through element activation/deactivation technology employs a 20% void area ratio as the interconnect failure criterion, allowing for quantitative lifetime prediction. The consistency between the experimental and simulation results demonstrated the accuracy and effectiveness of the proposed lifetime prediction method. The overall prediction error is reduced by 11% with the state-of-the-art EM prediction method. Furthermore, based on this method, the effect of different interposer materials and TSV radii on interconnect EM is investigated. The evidence exhibits that using diamond as an interposer material can significantly mitigate interconnect EM phenomenon and enhance the reliability of the whole structure compared with silicon and glass. Furthermore, increasing the radius of TSV enhances EM resistance in interconnects, with each $1~\mu $ m increase in radius extending the average interconnect lifetime by 12.75 h. Finally, the sensitivity analysis of diffusion-related constants further validates the robustness of the proposed model to critical parameters.

The cubic BN (c-BN)/diamond heterostructure proposed recently to possess 2-D electron gas (2DEG) could be a solution to diamond n-type field-effect transistors (FETs). However, the growth of c-BN/diamond system is still challenging. This work theoretically investigates the electronic transport property of c-BN/diamond heterostructure and explores its potential in electronic devices fields. The 2DEG sheet density in the heterointerface is calculated considering the effects of Schottky barrier height and modulation doping (MD) in c-BN barrier layer. The 2DEG mobility is the sum of five possible scattering mechanisms. The results show that the 2DEG mobility of c-BN/diamond heterostructure could be higher than 3000 cm $^{\text{2}}$ / $\text{V}\cdot\text{s}$ at room temperature for 2DEG sheet density of $\sim$ 10 $^{\text{12}}$ cm $^{-\text{2}}$ with a Schottky barrier of 1.1 eV and the undoped c-BN barrier thickness of 20 nm. Acoustic phonon (AC) scattering is the main scattering mechanism of the 2DEG for relatively large range of the c-BN layer thickness at room temperature. Remote surface roughness (RSR) scattering could dominate with very thin c-BN layer ( $<$ 6 nm) if dense 2DEG was available even without MD, or otherwise, the MD scattering could dominate for thin c-BN layer if 2DEG mainly originated from the doping ionization. The temperature-dependent 2DEG mobility is determined by the phonon scatterings for temperature higher than $\sim$ 100 K.

For accurate estimation of the thermal characteristics of AlGaN/GaN high electron mobility transistors on diamond, the anisotropic thermal conductivities of polycrystalline diamond (PCD) and GaN with their thickness dependences are included in the finite element simulation model, of which the PCD thermal conductivity k_PCD is calculated through detailed analyses of the grain sizes in the directions parallel and vertical to the interface and relative phonon-grain boundary scatterings. In addition, the GaN thermal conductivity k_GaN is the result of an approximate solution of the phonon Boltzmann transport equation. To investigate the effects of anisotropic GaN and PCD thermal conductivity, four cases of thermal conductivity models are compared: anisotropic k_GaN and k_PCD, anisotropic k_GaN with constant k_PCD, constant k_GaN with anisotropic k_PCD, and constant k_GaN and k_PCD. Then the maximum channel temperature simulated from the four above-mentioned models and the errors relative to the case of anisotropic k_GaN and k_PCD are investigated with respect to thermal boundary resistance, GaN layer thickness, gate pitch, heat source width, and power dissipation. The results show that the combination of anisotropic k_PCD and constant k_GaN overestimates the maximum channel temperature rise, and using constant k_PCD and anisotropic k_GaN underestimates the maximum channel temperature rise for almost all the simulations in the text. However, the channel temperature stemming from constant k_PCD and k_GaN is generally closer to the case with anisotropic PCD and GaN thermal conductivity.