Cvd, Incorporated

Lee E Burns

Raymond L Taylor

Jitendra Singh Goela

Michael A Pickering

James C MacDonald

Kenneth F Tulloch

Alexander Teverovsky

Hemant D Desai

Hemandt D Desai

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. This forms a second coating upon the lower surface of the mandrel, used as the mirror face. To reduce weight, holes are drilled through the back plate, and the remaining, encapsulated, mandrel material is removed by oxidation.

Method of making lightweight closed-back mirror

The surface of a zinc selenide substrate is ground to curve in the opposite direction from that which occurs due to the bimetallic effect when zinc sulfide is deposited on a flat substrate by the chemical vapor deposition process. The bowing of the interface that occurs upon cooling of the hot laminate when the surface of the substrate is flat before deposition is compensated for by the pre-figured bowing. A distortion free window for the transmission of infra-red radiation is provided by this invention.

Process for an improved laminate of ZnSe and ZnS

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. The male joint member is inserted into the female joint member, and the first and second silicon carbide parts are heated to above the melting point of silicon for a time sufficient for the silicon to melt, whereupon molten silicon is drawn into the gap(s) between the facing sidewalls of the male and female joint members by capillary action. Subsequent cooling of the assembled parts solidifies the silicon, thereby securing the joint between the male and female members with solidified silicon forming a bond between the facing sidewalls of the male and female joint members.

Bonding of silicon carbide components

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.

Composite thermocouple protection tubes

.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.

Chemical vapor deposition-produced silicon carbide having improved

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.

Susceptor for semiconductor wafer processing

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 &lt;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.

Chemical vapor deposition furnace and furnace apparatus

Hard disc drives and read/write heads formed from highly thermally

Highly polishable, highly thermally conductive silicon carbide

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.

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Woburn, MA, United States of America

Lee E Burns