![]() ![]() It requires more stringent handling and safety precautions, especially to protect manufacturing personnel. Highly toxic fluorine gas (F 2, diatomic fluorine) is a climate neutral replacement for nitrogen trifluoride in some manufacturing applications. The annual reporting of NFģ production, consumption, and waste emissions by large manufacturers has been required in many industrialized countries as a response to the observed atmospheric growth and the international Kyoto Protocol. NFģ has not been subject to significant use restrictions. Modern abatement systems can substantially decrease atmospheric emissions. A sizeable fraction of the reactants are wasted into the exhaust stream and can ultimately be emitted into Earth's atmosphere. The utilization efficiency of the chemicals applied in plasma processes varies widely between equipment and applications. As a somewhat more thoroughly consumed etching and cleaning agent, NF 3 has also been promoted as an environmentally preferable substitute for SF The greater abundance of negatively-charged free radicals thus generated can yield higher silicon removal rates, and provide other process benefits such as less residual contamination and a lower net charge stress on the device being fabricated. ![]() In addition to serving as an etchant in device fabrication, NFģ is also widely used to clean PECVD chambers.ģ dissociates more readily within a low-pressure discharge in comparison to perfluorinated compounds (PFCs) and sulfur hexafluoride ( SFĦ). They can be used as well to remove tungsten silicide, tungsten, and certain other metals. The resulting fluorine radicals are the active agents that attack polysilicon, silicon nitride and silicon oxide. In these applications NFģ is initially broken down within a plasma. Nitrogen trifluoride is primarily used to remove silicon and silicon-compounds during the manufacturing of semiconductor devices such as LCD displays, some thin-film solar cells, and other microelectronics. Mixtures of NF 3 and B 2H 6 are explosive even at cryogenic temperatures, reacting to produce nitrogen gas, boron trifluoride, and hydrofluoric acid. NF 3 reacts with fluorine and antimony pentafluoride to give the tetrafluoroammonium salt: It converts to tetrafluorohydrazine upon contact with metals, but only at high temperatures: It is compatible with steel and Monel, as well as several plastics. ![]() It oxidizes hydrogen chloride to chlorine: This difference arises from the fluorine atoms acting as electron withdrawing groups, attracting essentially all of the lone pair electrons on the nitrogen atom. By contrast, ammonia is basic and highly polar (1.47 D). It is nonbasic with a low dipole moment of 0.2340 D. It is supplied in pressurized cylinders.ģ is slightly soluble in water without undergoing chemical reaction. It is prepared in modern times both by direct reaction of ammonia and fluorine and by a variation of Ruff's method. Alone among the nitrogen trihalides it has a negative enthalpy of formation. ![]() It proved to be far less reactive than the other nitrogen trihalides nitrogen trichloride, nitrogen tribromide and nitrogen triiodide, all of which are explosive. After first attempting the synthesis in 1903, Otto Ruff prepared nitrogen trifluoride by the electrolysis of a molten mixture of ammonium fluoride and hydrogen fluoride. It is a rare example of a binary fluoride that can be prepared directly from the elements only at very uncommon conditions, such as an electric discharge. Nitrogen trifluoride did not exist in significant quantities on Earth prior to its synthesis by humans. Its atmospheric burden exceeded 2 parts per trillion during 2019 and has doubled every five years since the late 20th century. Nitrogen trifluoride is also an extremely strong and long-lived greenhouse gas. It finds increasing use within the manufacturing of flat-panel displays, photovoltaics, LEDs and other microelectronics. 3) is an inorganic, colorless, non- flammable, toxic gas with a slightly musty odor. ![]()
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