Abstract: Near net shape free standing articles can be produced by chemical vapor deposition techniques when a suitable substrate is suspended in a chemical vapor deposition zone according to the disclosed technique. By suspending such substrates from linear suspension supports such as ropes, cables and wires, multiple near net shape articles can be produced with substantial manufacturing cost savings over previously employed techniques.

Abstract: A method of forming a light weight, closed-back mirror. The mirror is formed as a monolithic construction by the use of chemical vapor deposition techniques. A first deposition forms sheets of the material, which are machined to the proper size to form reinforcing ribs. A sacrificial mandrel is formed with grooves to receive the ribs in their assembled positions. The upper surface of the mandrel is in proximity to the rear edges of the ribs to form a substantially continuous surface. The mandrel and ribs are then subjected to a chemical vapor deposition process which forms a first coating upon the outer face of the mandrel, forming a back plate and side wall. The mandrel is then turned over, and the base is removed by machining to expose the front edges of the ribs. This process leaves islands of mandrel material between the ribs to form a substantially continuous surface. The mandrel and ribs are then subjected to a chemical vapor deposition process.

Abstract: A method of bonding a first silicon carbide part to a second silicon carbide part is provided. The first silicon carbide part provides a receiving female joint member and the second silicon carbide part provides an insertion male joint member. The male and female members each have facing sidewalls substantially parallel to a direction in which the male member is inserted into the female member. The male and female joint members are configured to provide an average gap(s) between the facing sidewalls of the joint members which is up to about 0.003 inch (0.76 mm). The female joint member further has reservoir means for containing silicon when the male joint member is fully inserted into the female joint member, the reservoir means being in fluid communication with the gap(s). The reservoir means is filled with solid-state silicon, e.g., in powder form.

Abstract: A semiconductor protection tube is a ceramic tube with a layer of silicon carbide covering at least a portion of the tube adjacent an open front end of the tube and extending forward of the open end to form a hollow, closed-end tip. The protection tube is formed by providing the ceramic tube, inserting a mandrel through the tube to extend forward of the front end, and depositing silicon carbide by chemical vapor deposition over at least a front portion of the ceramic tube and over the forward-extending portion of the mandrel. Subsequent removal of the mandrel completes the production of the protection tube.

Abstract: A semiconductor protection tube is a ceramic tube with a layer of silicon carbide covering at least a portion of the tube adjacent an open front end of the tube and extending forward of the open end to form a hollow, closed-end tip. The protection tube is formed by providing the ceramic tube, inserting a mandrel through the tube to extend forward of the front end, and depositing silicon carbide by chemical vapor deposition over at least a front portion of the ceramic tube and over the forward-extending portion of the mandrel. Subsequent removal of the mandrel completes the production of the protection tube.

Abstract: .beta.-silicon carbide which is optically transmitting in the visible and infrared regions is produced by chemical vapor deposition. Deposition conditions are temperatures within a 1400.degree.-1500.degree. C. range, pressure 50 torr or less, H.sub.2 /methyltrichlorosilane molar ratios of 4-30 and a deposition rate of 1 .mu.m or less.

Abstract: .beta.-silicon carbide which is optically transmitting in the visible and infrared regions is produced by chemical vapor deposition. Deposition conditions are temperatures within a 1400.degree.-1500.degree. C. range, pressure 50 torr or less, H.sub.2 /methyltrichlorosilane molar ratios of 4-30 and a deposition rate of 1 .mu.m or less.

Abstract: A susceptor for rapid thermal processing for epitaxial deposition upon semiconductor wafers. The susceptor includes an outer supporting ring upon which the wafer rests. This outer ring is preferably formed of a monolithic mass of silicon carbide, and most preferably high purity .beta.-phase (face-centered cubic) silicon carbide. The wafer is supported upon a small wafer shoulder on the ring. To prevent deposition upon the rear or bottom face of the wafer, a blocker shoulder is also provided in the ring, below the wafer shoulder, and a blocker is placed upon this shoulder. The blocker is preferably formed of quartz, and simply rests upon the shoulder. In this manner the ring and blocker may expand at different rates upon the rapid temperature changes, and the blocker or ring may be replaced.

Abstract: A uniform dosimetry of vapor phase trimethylindium is provided by dissolving trimethylindium in a C.sub.3 -C.sub.5 trialkylindium and bubbling an inert carrier gas through the solution.

Abstract: Silicon carbide is produced by chemical vapor deposition at temperatures from 1340.degree.-1380.degree. C., deposition chamber pressures of 180-200 torr, H.sub.2 /methyltrichlorosilane ratio of 4-10 and deposition rate of 1-2 .mu.m/min. Furthermore, H.sub.2 supplied as a part of the gas stream contains less than about 1 part per million (ppm) O.sub.2 gas, and various means are provided to exclude particulate material from the deposition chamber. The silicon carbide is polishable to <5 .ANG. RMS as measured on a Talystep mechanical profiler and has a thermal conductivity of at least about 300 W/mk. The silicon carbide is particularly suitable for applications where high polishability and thermal conductivity is desired, such as hard disc drives and read/write heads of head-disc assemblies, and also optical apparatus which require a very high polish.

Abstract: Silicon carbide is produced by chemical vapor deposition at temperatures from 1340.degree.-1380.degree. C., deposition chamber pressures of 180-200 torr, H.sub.2 /methyltrichlorosilane ratio of 4-10 and deposition rate of 1-2 .mu.m/min. Furthermore, H.sub.2 supplied as a part of the gas stream contains less than about 1 part per million (ppm) O.sub.2 gas, and various means are provided to exclude particulate material from the deposition chamber. The silicon carbide is polishable to <5 .ANG. RMS as measured on a Talystep mechanical profiler and has a thermal conductivity of at least about 300 W/mk. The silicon carbide is particularly suitable for applications where high polishability and thermal conductivity is desired, such as hard disc drives and read/write heads of head-disc assemblies, and also optical apparatus which require a very high polish.

Abstract: A process and apparatus for the manufacture of chemical vapor deposited silicon carbide which comprises conveying the reaction gases to a triangular chemical vapor deposition cell where material is deposited by chemical vapor deposition. The triangular cell provides a large surface area for deposition while occupying a minimum amount of the furnace floor surface area. The triangular cell has the added benefit in that deposited silicon carbide is of negligible thickness at the edges thereby permitting easy separation of material with a minimum of post deposition machining.

Abstract: Trialkylgallium is purified of group II B p-type impurities, particularly Zn, Hg, and Cd, by contacting the trialkylgallium with a metallic gallium-containing melt. Also, trialkylgallium can be produced by contacting a dialkyl group II B compound with a metallic gallium-containing melt.

Abstract: A process is disclosed for fabricating lightweight honeycomb type structures out of material such as silicon carbide (SiC) and silicon (S). The lightweight structure consists of a core to define the shape and size of the structure. The core is coated with an appropriate deposit such as SiC or Si to give the lightweight structure strength and stiffness and for bonding the lightweight structure to another surface. The core is fabricated from extremely thin ribs of appropriately stiff and strong material such as graphite. First, a graphite core consisting of an outer hexagonal cell with six inner triangular cells is constructed from the graphite ribs. The graphite core may be placed on the back-up side of a SiC faceplate and then coated with SiC to produce a monolithic structure without the use of any bonding agent. Cores and methods for the fabrication thereof in which the six inner triangular cells are further divided into a plurality of cells are also disclosed.

Abstract: A MOCVD process for depositing an arsenic-containing film or a phosphorous-containing film utilizing a diprimary phosphine or arsine or an unsaturated hydrocarbon phosphine or arsine.

Abstract: Periodic pulsing of the gaseous reactant flows during chemical vapor deposition of gradient index optical material markedly improves the refractive index homogeneity of the deposit with the frequency of the pulsing being variable over a wide range but the number and size of the inhomogeneities, or nodules, being significantly reduced at higher pulsing frequencies.

Abstract: A process to fabricate lightweigth ceramic mirrors, and in particular, silicon/silicon carbide mirrors, involves three chemical vapor deposition steps: one to produce the mirror faceplate, the second to form the lightweight backstructure which is deposited integral to the faceplate, and the third and final step which results in the deposition of a layer of optical grade material, for example, silicon, onto the front surface of the faceplate. The mirror figure and finish are fabricated into this latter material.

Abstract: Disclosed is a method for producing, from an aqueous basic composition, a primary arsine having one hydrocarbyl group bonded directly to As, the basic composition having been obtained from the combination of components comprising an alkali metal arsenite and a reactive hydrocarbyl halide by combining the aqueous composition with an acidic, nascent hydrogen-generating reducing agent to produce the primary arsine directly from the aqueous composition without isolation of the primary arsonic acid intermediate.

Abstract: A MOCVD process for depositing an arsenic-containing film utilizes an organoarsine compound having at least one As-As bond, in particular, diarsines and compounds having arsenic rings of 5 or 6 arsenic atoms.

Abstract: A process is disclosed by which the finish and figure of polished preshaped structures (such as mirrors) can be replicated directly by chemical vapor deposition, with only minor polishing of the replica being required to obtain a final product, and with the original substrate being reusable for further replication. Relevant conditions under which the process can be carried out are given. Featured in the process is a pretreatment step prior to the deposition of a layer of silicon carbide to form the replica, which pretreatment step involves the formation on the polished substrate of an oxide layer and a carbon layer of high finish and uniform thickness. The carbon layer allows easy separation of the substrate and replica which otherwise would be bound together.