To address the insufficient utilization of heat flow and the limited adaptability to spatially nonuniform thermal distributions, a low-temperature co-fired ceramic (LTCC)-based radially partitioned longitudinal–transverse micro-thermoelectric generator ( $\mu $ -TEG) is proposed. The proposed design responds to the dominant heat-flow direction and temperature-gradient intensity according to the spatial characteristics of the heat source. A high-density $\Pi $ -type vertical thermocouple array is constructed in the central region, where the heat flux is highly concentrated, to enhance the direct utilization of the vertical temperature gradient. In the peripheral region, where heat gradually spreads in-plane, arc-shaped Y-type thermocouple arrays are introduced to expand the capture range of lateral heat flow. The designed device contains $144~\Pi $ -type pairs and 162 Y-type pairs, while the experiments give an average open-circuit voltage of $59.949~\pm ~3.553$ mV and an average matched-load power of $140.831~\pm ~16.974~\mu $ W; the highest measured voltage reaches 69.368 mV. The simulated junction temperature difference is approximately 0.3 of the applied temperature difference for the baseline contact conductance used in the model. By synergistically integrating transverse and longitudinal heat-harvesting pathways, the proposed design provides a viable solution for self-powered electronic systems operating under nonuniform thermal gradients.
In this work, a monolithic 3-D SRAM–DRAM memory (M3D-SD) based on amorphous indium–gallium–zinc-oxide (IGZO) back-end-of-line (BEOL) integration on silicon is demonstrated for high-density and low-standby-power last-level cache (LLC) applications. An optimized atomic layer deposition (ALD) process with tailored indium composition and low-hydrogen gate/interlayer dielectrics (ILDs) enables stable multilayer IGZO transistors. The monolithic 3-D (M3D)-SD integrates IGZO/Si hybrid SRAM with vertically stacked IGZO 2T0C DRAM, enabling ultralow-latency (~10 ns) and energy-efficient (~9.08 fJ) SRAM–DRAM communication. System-level evaluations using Transformer and ResNet-50 workloads demonstrate 4– $6\times $ speedup and 6.4– $8.4\times $ reduction in off-chip memory access, highlighting M3D IGZO integration as a promising route toward high-density and energy-efficient LLC-oriented memory hierarchies.
An equivalent circuit model and a nonlinear beam–wave interaction analysis method for folded-waveguide (FWG) traveling-wave tubes (TWTs) are proposed. A unit cell of the FWG slow wave structure (SWS) is represented by a lumped circuit, from which a second-order passive transmission matrix and a third-order active transmission matrix are derived to calculate the voltage and current distributions in the SWS. The dispersion relation is incorporated into the matrix elements, while the required high-frequency parameters are directly extracted from computational electromagnetic (CEM) simulations. The interaction field is reconstructed from the gap voltage obtained by the transmission matrix calculation, with all spatial harmonics included. The space-charge field is calculated using a simplified disk model. A corresponding 1-D large-signal code is developed and validated using E-band and D-band FWG TWTs. The proposed model provides detailed information on nonlinear beam–wave interaction, and the predicted saturated output power and gain agree well with CST particle-in-cell (PIC) simulations, while deviations from the experimental measurements are discussed.
The development of ZrO2-based high- $k$ capacitors has driven the continuous scaling down of the metal-insulator-metal (MIM) capacitors in modern integrated circuits such as those in RF applications, analog and mixed-signal (AMS) applications, and dynamic random access memories. In this article, we focused on the strong voltage dependence of capacitance typically existed in the TiN/ZrO2/TiN structures. Employing NH3 plasma treatment allows the doping of nitrogen of different doses to the topmost part of the dielectrics, which effectively suppresses the voltage dependence of the C–V curves and increases the overall dielectric constants. Landau theory analysis and first-principles calculations suggest that the primary origin of the C–V anomaly is the built-in electric field caused by the nonuniform nitrogen doping at the bottom of the dielectric, which results from the interfacial interdiffusion between the dielectric and the bottom electrode during fabrication. By moderate nitrogen doping on the top of the dielectric, the built-in electric field is neutralized, and the ionic polarization is further enhanced. This work provides insights to the formation and mitigation of the C–V anomaly common in high- $k$ capacitors, and demonstrates a practical application of the classical Landau theory in guiding the design and optimization of the state-of-the-art capacitor technologies.
