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In this letter, a high performance quasi-vertical GaN-on-Si Schottky barrier diode (SBD) was fabricated by combing in-situ p-GaN layer with hydrogen plasma treatment and controlled diffusion as edge terminations (ETs), where the main junction region of Schottky contact is emerged by pattern etching the top p-GaN layer. The p-n junction with higher barrier height can screen the Schottky contact from high electric field induced by field crowding effect. The hydrogen plasma treatment and controlled diffusion applied to the p-GaN layer further reduces the electric field crowding effect near the p-n junction edge via a gradient junction termination extension structure. As a result, the breakdown voltage of the edge p-GaN terminated SBD with H treatment and diffusion is significantly boosted from 140 V in conventional SBD to 500 V with optimized fabrication process. The on/off current ratio of the diode is as high as 1011@±3 V. The forward current density is 1.45 kA/cm2@3 V and the specific on-resistance is 1.57 $\text{m}\Omega \cdot $ cm2.

In silicon carbide (SiC) planar insulated-gate bipolar transistor (IGBT), a large distance between neighboring p-bodies is beneficial to enhance the on-state conductivity modulation, but will expose the gate oxide to high electric field in off-state. With p-bodies placed closer, the gate oxide field is reduced, but the conductivity modulation is suppressed. In this work, a new SiC planar IGBT with oxide shield is proposed and studied by TCAD simulations. The proposed SiC IGBT achieves improved trade-off between on-state voltage drop $(V_{\mathrm{ ON}})$ and maximum gate oxide electric field $(E_{\text {ox-m}})$ . When a quite larger distance between neighboring p-bodies is adopted in the proposed SiC IGBT, a low $V_{\mathrm{ ON}}$ is obtained, while the $E_{\text {ox-m}}$ can be kept at a small value with the oxide shielding structures protecting the gate oxide. Switching characteristics are also studied, and the proposed SiC-IGBT delivers much better trade-off between turn-off energy loss $(E_{\mathrm{ OFF}})$ and $V_{\mathrm{ ON}}$ than the conventional SiC planar IGBT.

A discrete GaN power transistor’s substrate is typically connected to its source electrode. However, on the GaN-on-Si power IC platform, the high-side transistor (HS-transistor) and low-side transistor (LS-transistor) share a common substrate that cannot be simultaneously connected to both source electrodes of the two transistors. Thus, the termination of the common substrate remains an undecided issue. In this work, comprehensive TCAD simulations are exploited to reveal the influences of various substrate termination schemes. It is found the common substrate inevitably leads to severe degradation in the dynamic ${R} _{\mathrm{ ON}}$ due to back-gating effects. The mechanisms for the degradations vary with the substrate termination scheme, and will be discussed in detail. To address these issues, we propose a new GaN power IC platform on an engineered bulk silicon substrate, and study the new platform with TCAD simulations. The proposed platform provides a local electrical substrate (a p+ island) for each GaN power transistor. The source electrode of each GaN transistor is connected to its local electrical substrate, while all devices share a common mechanical substrate. The junctions between the local substrates and the underlying n-layer provide an effective isolation between GaN transistors. The back-gating effects are completely suppressed for the GaN integrated bridge circuit.

In this work, we studied the mechanisms and switching properties of AlGaN/GaN high-electron-mobility-transistors (HEMTs) passivated by amorphous-SiNx and monocrystal-like AlN. The effects of interface traps and polarization charges on current collapse are investigated by TCAD simulations and experimental characterizations. Surface/interface deep levels can be compensated by both shallow donor-like traps (SiNx passivation) and polarization charges (AlN passivation) at passivation/heterostructure interface, but with different levels of effectiveness under fast switching conditions. SiNx-passivation introduces shallow donor-like trap states with short time constant that favors a fast emission of trapped electrons in the access region and suppressed current collapse, but nevertheless exhibits more severe time-dependent recovery of dynamic on-resistance. For AlN passivation, interface traps are compensated by the fixed positive polarization charges and the off-state depletion region (in the 2DEG channel) is formed predominantly by electric-field effect, leading to an immediate accumulation of high channel electron concentration after switching the HEMT devices back to on-state and instant response of drain current to gate and drain bias. The field plate structure is necessary in SiNx-passivated devices for both current collapse suppression and electric field alleviation. With AlN passivation, the field plate can be solely designed for achieving more uniform electric field distribution for gate reliability concern without the concern of current collapse.

Developments in high-speed railways have seen them become the mainstay of passenger transport systems in China, satisfying the increasing demand for rapid access to numerous locations. In practice, the operation of the network is a vital feature of the Chinese High-speed Railway (CHR), enabling the provision of through services while allowing indirect services via major hubs. The generation of travel plan sets in a large-scale, complex high-speed railway network is an important issue, as it is the foundation and key to those travel service systems where people can inquiry about their travel plans. This paper describes a method of generating all alternative travel plans that are potentially attractive to passengers. The inherent problem is first modeled for any journey between a given origin and destination pair, and then a spatiotemporal network is constructed. For each journey, a direct set of travel plans without transfers is extracted from the train timetable data. The construction of indirect travel plans is more complicated, and a two-stage generation method is proposed: (i) compute the $K$ -shortest paths using the improved Yen* algorithm to identify transfer node(s), and (ii) connect train services according to the train timetables. Furthermore, the reliability of a specific travel plan with transfers is determined by mapping the buffer time as a reliability measure. Finally, the proposed method is tested on the CHR network using the 2019 train timetable.

Optical remote sensing images have the advantages in clear visual characteristics and strong interpretability. Unfortunately, cloud coverage limits the quality and availability of optical images in practical applications. In contrast, synthetic aperture radar (SAR) images provide all-day and all-weather imaging, which can serve as effective auxiliary information for cloud removal. Existing cloud removal methods are difficult to obtain high-fidelity cloud-free results due to the insufficient spectral and spatial information exploration in the multitemporal SAR and optical images. In this letter, we propose a multidiscriminator supervision-based dual-stream interactive network (MDS-DIN) for cloud removal. Specifically, we first design a dual-stream interactive learning module to take full advantage of the complementary information between multitemporal SAR and optical images. Moreover, we specially design an adaptive weight fusion module (AWFM) to adaptively allocate fusion weights to the dual-stream results by considering the discriminative features in spectral and spatial levels. In addition, multidiscriminator is used to jointly optimize overall networks for high-fidelity cloud removal. Experiments on simulated and real datasets demonstrate the competitive performance of our proposed method. [ABSTRACT FROM AUTHOR]