摘要:
A continuous, adhering film of polycrystalline diamond is grown on a grape substrate from diamond crystallites nucleated at a metal layer on the substrate when subjected to a microwave activated plasma of hydrogen and a carbon containing gas. Pyrolytic graphite and cured graphite adhesive are effective and other forms of graphite may be effective. Effective metals are chromium, nickel, and titanium. Diamond nucleation apparently occurs at crystallites of metal carbides nucleated by carbon from the plasma so that other carbide forming metals may be effective. Metal not nucleated as the carbide is, apparently, etched away by the plasma; and the diamond film is effectively deposited directly on the graphite since the diamond film is not contaminated by the metal even at the graphite interface where carbide contamination was less than 0.2 percent from a 2500 .ANG. chromium film. The diamond film deposition occurs at substrate temperatures as low as 650.degree. C. and may be facilitated by a positive voltage bias of the substrate relative to an enclosing vacuum chamber wall. Partial coating of a graphite surface with the metal results in diamond deposition only at the coated portion. A grid of diamond film has thus been deposited on graphite by application of a nickel screen to the graphite, and diamond film may be deposited in a desired pattern by masking the substrate to deposit the metal at selected substrate portions.
摘要:
Nucleation of diamond crystallites is initiated on electrically nonconducting substrates and on semiconducting substrates at a temperatures of 650.degree. C. or lower by providing atoms of a metal in a plasma formed by activation, as by microwave energy in a vacuum chamber, of a mixture of hydrogen and a carbon containing vapor. A continuous, adhering film of polycrystalline diamond is then grown on the substrate from the nucleated crystallites. The nucleation is effective when the substrate has a positive electric potential relative to a wall of the chamber. Positive and negative dopants may be provided in the vapor to give a semiconducting film. The nucleation and film growth are effective at the relatively low substrate temperatures so that dopant diffusion and substrate damage occurring at the usual, higher diamond film deposition temperatures are avoided. Atoms of chromium, titanium, and nickel are particularly effective and may be provided by a metalorganic compound in the vapor or by a solid material which is etched by the plasma and may be the pure metal or its oxide, nitride, or alloy. The solid material may be provided as an open vessel or on a ring within which the substrate is placed or as a coating deposited on the substrate. A partial coating of the solid material results in the diamond film being selectively deposited only on the uncoated portion.
摘要:
Preexisting elements are bonded by placing a sol-gel solution between juxtapositioned surfaces of the elements and sintering a gel formed from the solution at a temperature, which does not damage the elements, to form a sol-gel derived bonding material. The elements may be constructed of glasses, metals, infrared transmissive materials, or diamond, and bonded by sintering at about 300.degree. C. The bonding material may be resistant to high temperature and may have properties, such as refractive index, selected by varying the composition of the sol-gel solution. Optical and electronic articles are constructed by preparing a mandrel conforming to a substrate, which may be of arbitrary shape; depositing a coating on the mandrel; bonding the coating to the substrate with a sintered sol-gel; and removing the mandrel, as by etching. Diamond films formed by chemical vapor deposition at temperatures destructive to optical and microelectronic materials are thus mounted on variously shaped elements of these materials for protection against erosion and high temperatures and to provide low friction and high thermal conduction. Tetraethyl orthosilicate used as a sol-gel precursor gives a silica bonding layer effective at up to 800.degree. C. Other precursors may be used, and a titania sol-gel precursor provides a matching index of refraction for zinc sulfide or zinc selenide substrates. An intermediate layer, as of sputter deposited metal selected to accommodate thermal expansion differences, may be disposed between an element to be bonded and the bonding material.
摘要:
Coatings for a diamond surface of an optical element control reflections and oxidation at the surface. Transmissive element coatings effective in the infrared and at up to 800.degree. C. have a first layer of amorphous hydrogenated silicon deposited directly on the diamond and have a second layer of aluminum nitride, yttrium oxide, hafnium oxide or other refractory oxide deposited directly on the first layer. The first layer may be relatively thin and for adhesion only with the second layer constructed of an oxide and having a thickness selected to control reflection, or the thicknesses of both layers may be selected together to control reflection with the proportion of hydrogen in the first layer varied to select its refractive index.
摘要:
In depositing an adhering, continuous, polycrystalline diamond film of optical or semiconductor quality on a substrate, as by forming on the substrate a layer of a refractory nitride interlayer and depositing diamond on the interlayer without mechanical treatment or seeding of the substrate or the interlayer, the substrate is heated in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon, and the size of deposited diamond crystallites and their rate of deposition selectively varied by a bias voltage applied to the substrate.
摘要:
An apparatus and method for imparting wide angle low reflection on any high reflective surfaces through resonant excitation of plasmonic leaky mode of a nanocavity.
摘要:
In depositing an adhering, continuous, polycrystalline diamond film on a substrate by forming a refractory nitride interlayer on the substrate and depositing diamond on the interlayer in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon, the crystal orientation of the deposited diamond, or , is selected by controlling the pressure in the chamber. Preferably, relatively higher microwave power is utilized at higher pressures.
摘要:
An adhering, continuous, polycrystalline diamond film is deposited on a z sulfide substrate by forming a refractory nitride interlayer directly on the substrate and then depositing diamond on the interlayer in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon. The diamond film may be of optical quality and may be deposited without mechanical treatment or seeding of the zinc sulfide substrate or the nitride interlayer. However, diamond deposition may be facilitated by abrasion of the interlayer before diamond deposition.
摘要:
An adhering, continuous diamond film of optical or semiconductor quality is deposited on a substrate by forming on the substrate a layer of a nitride and then depositing diamond on the nitride without mechanical treatment or seeding of the substrate or the nitride. A substrate of silicon or silicon carbide has been used by depositing a layer of silicon dioxide directly on the substrate and then directly depositing the nitride layer on the silicon dioxide. A polycrystalline diamond film has been deposited by heating the substrate and nitride layer in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon with the nitride being a refractory nitride to withstand the temperature at which the diamond is deposited. Deposition of the diamond is facilitated by adding oxygen to the mixture after a sufficient thickness of diamond is deposited to protect the nitride layer from oxidation.