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Wet etching of Silicon nitride (Si3N4) by phosphoric acid (H3PO4) is one of the key steps in the semiconductor fabrication process, especially for three‐dimensional integrated circuits (ICs). Unfortunately, few systematic studies of phosphoric acid etching of Silicon nitride are available. Summarizing how various factors affect etching and determining the reaction mechanism behind the etching process will help further optimize the etching process. In this work, how the boiling point of hydrous phosphoric acid solutions depends on phosphoric acid concentration is firstly investigated. Next, the etching of over 100 samples of Silicon nitride by H3PO4 at different concentrations and temperatures is systematically studied. The results show that the etching rate increases nearly linearly in both temperature and H3PO4 concentration, while temperature play more important role as compared to concentration. For each concentration, the reaction rate is maximal at the boiling point of the hydrous H3PO4 solution. Moreover, the etching rate of 85 wt % phosphoric acid is analyzed using the Arrhenius equation, yielding an apparent activation energy Ea=57.28 KJ/mol. Finally, a mechanism of Silicon nitride etching in phosphoric acid is proposed which explains the prior studies well. This work contributes to precisely control semiconductor processing for three‐dimensional ICs. [ABSTRACT FROM AUTHOR]

The modulation of the surface of silicon stimulates its applications in optics (antireflection surface, solar cells, and photoelectric devices). In this work, an appropriate ratio of the O2 to SF6 plasma through reactive ion etching generated a double-layer Silicon nanograss (upper layerflocculent SiOxFy passivation; lower layerpointy silicon spike) on the surface of the silicon wafer. The height and density of Silicon nanograss can be controlled through process parameters (pressure, O2/SF6 ratio, and RF power), mask spacing, and a variety of assistant substrates. The underlying formation mechanisms of Silicon nanograss disclosed that the sputtering of Al substrate acts as a micromask, i.e., primarily responsible for the formation of Silicon nanograss. Considering an in-depth study, a simple, low-cost, and CMOS-compatible method for wafer-level preparation of Silicon nanograss is provided. Specifically, the Silicon nanograss exhibited excellent antireflection and enhanced absorption properties. This work contributes to micro-nano surface science accompanied by optical applications. [ABSTRACT FROM AUTHOR]

White-feather broiler chickens are the dominant species in global poultry meat production. Yet there is growing concern about their health, quality, and growth efficiency. While feed additives, often antibiotics or synthetic chemicals, are used to maintain the health of the animals, drug resistance limits their use. Litsea cubeba (Lour.) Pers., a traditional Chinese herb with antibiotic-like benefits but without the risk of drug resistance, has not yet been explored as an additive to broiler diets. In the present study, broilers of the AA+ hybrid strain were randomly divided into three groups of 16: a control group (regular feed), a low-dose group (1.25 g/kg added L. cubeba extract), and a high-dose group (2.50 g/kg added L. cubeba extract). After 35 days, we found that the extract had no effect on growth. However, gut flora analysis revealed that both doses of the extract had a positive influence on amino acid content and minor unsaturated fatty acids, thus improving the flavor and nutritional value of the meat. These findings suggest that L. cubeba extract, at either dose, could serve as a sustainable alternative to antibiotics, thus reducing the risk of drug resistance while improving meat quality, nutrition, and flavor., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Luo, Bi, Xu, Shan, He, Wang, Zhou, Yu, Jiang, Yang, Yu, Gao, Wei, Du, Liu and Fang.)