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The performance and lifetime of silicon carbide (SiC) devices are directly affected by the quality of SiC epitaxial films. On the one hand, the quality of SiC epitaxial films is affected by the quality of substrates. For examples, the stacking faults (SF) in substrates penetrate into the epitaxial layer, forming bar-shaped stacking faults (BSF), and the threading screw dislocation (TSD) penetrate into the epitaxial layer to form pits or Frank-type stacking faults (Frank SF). On the other hand, the quality of SiC epitaxial films is also influenced by the epitaxial growing process. For examples, basal plane dislocation (BPD) in the substrate form Σ-basal plane dislocation (Σ-BPD) in the epitaxial layer under thermal stress or other unstable conditions, the TSD and threading edge dislocation (TED) in the substrate may be etched and derived into pits, and SF and silicon droplets may also be produced. Therefore, high quality SiC substrates and optimized epitaxial growing process are both crucial for obtaining high-quality silicon carbide epitaxial wafers. In this article, based on the SiC epitaxial films grown on 6 inch SiC substrates batch-produced by TankeBlue Company, the defects reproducing process in substrates during epitaxial growing were analyzed, and the formation mechanism and controlling technology of common defects such as BPD, SF, silicon droplets and pits were overviewed. The generation mechanism of Σ-BPD and its eliminating methods were also explored. Finally, we obtained the mass-production technologies of SiC epitaxial films with good thickness and concentration uniformity, and low defect density, which are qualified for making 650 and 1 200 V SiC-based MOSFETs. [ABSTRACT FROM AUTHOR]

The distributed energy supply system with efficient coupling of electric, hydrogen and thermal energy integrates the advantages of electricity, hydrogen, and thermal energy, which can significantly improve energy efficiency and reduce environmental pollution. In order to achieve the fine control of the model, a control model of the distributed energy supply system based on alternating direction multiplier method (ADMM) is proposed. According to the characteristics of multi-agent electric-hydrogen-thermal system, a double-layer optimal scheduling model is developed, and the adaptive alternating direction multiplier method is proposed to solve it. The experiment results show that the iteration times of the proposed algorithm fluctuate around 43. When the sample size was 40,000 times, the average iteration time of the model was 0.11 s, respectively, showing a relatively stable performance. The total carbon emission reduction of the energy system in the experimental park reached 4.53 tons within 24 hours, and the corresponding carbon trading income was 546.18 yuan. The results verify the applicability and potential of the model in both environmental and economic win-win aspects, and provide an important theoretical and practical reference for optimizing distributed energy management and promoting low-carbon transition. [ABSTRACT FROM AUTHOR]

The current energy system in chemical parks faces problems such as unstable energy supply, low energy use efficiency, and environmental pollution. The study optimises the integrated energy system of a chemical park by constructing a model to improve the efficiency of energy use, reduce energy costs, and promote the application of environmentally friendly energy sources. The results of the study show that the proposed strategy improves the operational efficiency of the system. Under different light intensity and temperature conditions, the system stability reaches 98% and 97%, respectively. Practical application analysis further proves the effectiveness of the model, for example, the day-ahead maximum error power of the electric load is reduced to 160 kW, the average error rate is reduced to 5.5%, and in real-time forecasting, the average error rate of all load types is generally lower than that of day-ahead forecasting. The optimised system not only significantly reduces the energy cost and improves the efficiency of energy use, but also ensures a high degree of reliability and environmental adaptability of the system, providing an efficient, economical, and environmentally friendly energy solution, which has important research significance and application value. [ABSTRACT FROM AUTHOR]