International Business Machines Corporation

Thomas O Sedgwick

Paul David Agnello

Tung-Sheng Kuan

Jerry M Woodall

Jerome Brett Lasky

Larry Alan Nesbit

Rodney T Hodgson

Scott R Stiffler

George D Pettit

John R Abernathey

Alec N Broers

Detlev A Gruetzmacher

Melvyn E Cowher

A method of maintaining an optimum pressure and purity level in a vessel having an inlet gas flow and an outlet gas flow during shutdown of the vessel that prevents imploding of the vessel when the inlet and outlet gas flows are discontinued. Gas from the vessel is directed to a containment portion in communication with the vessel. The pressure of the gas in the containment portion is monitored; the containment portion is backfilled with a purified inert gas when the monitored pressure drops to a predetermined lower level; and the containment portion is vented when the monitored pressure rises to a predetermined higher level. Apparatus for maintaining an optimum pressure and purity level in a vessel having an inlet gas flow and an outlet gas flow during shutdown of the vessel that prevents imploding of the vessel when the inlet and outlet gas flows are discontinued is also provided. The apparatus includes a containment portion adjacent to the vessel and in communication with the vessel for containing gas from the vessel, a back-pressure regulator and a conventional regulator for monitoring the pressure of the containment portion, a high-purity inert purge gas source in communication with the conventional regulator, adapted to backfill the containment portion with purified inert gas when the monitored pressure drops to a predetermined lower level, the back-pressure regulator adapted to vent the containment portion when the monitored pressure rises to a predetermined higher level.

Method and apparatus for preventing rupture and contamination of an

A system and method for growing low defect density epitaxial layers of Si on imperfectly cleaned Si surfaces by either selective or blanket deposition at low temperatures using the APCVD process wherein a first thin, e.g., 10 nm, layer of Si is grown on the surface from silane or disilane, followed by the growing of the remainder of the film from dichlorosilane (DCS) at the same low temperature, e.g., 550.degree. C. to 850.degree. C. The subsequent growth of the second layer with DCS over the first layer, especially if carried out immediately in the very same deposition system, will not introduce additional defects and may be coupled with high and controlled n-type doping which is not available in a silane-based system. Further, in order to achieve an optimal trade-off between the need for an inert ambience to promote silane reaction at low temperature and the need for a hydrogen ambience to prevent surface oxidation from inadvertant residual impurities, depositions are carried out in an ambience composed primarily of He but always containing some H.sub.2. Also, the relative deposition rates on a patterned surface of polycrystalline Si on insulator areas and single crystal Si on single crystal seed areas, when using the reactant silane, are dependent on the temperature of deposition and the relative concentrations of hydrogen and inert gas, e.g., helium, in the ambient gas, and can be controlled by regulating these parameters.

Comprehensive process for low temperature epitaxial growth

A system and method for growing low defect density epitaxial layers of Si on imperfectly cleaned Si surfaces by either selective or blanket deposition at low temperatures using the APCVD process wherein a first thin, e.g., 10 nm, layer of Si is grown on the surface from silane or disilane, followed by the growing of the remainder of the film from dichlorosilane (DCS) at the same low temperature, e.g., 550.degree. C. to 850.degree. C. The subsequent growth of the second layer with DCS over the first layer, especially if carried out immediately in the very same deposition system, will not introduce additional defects and may be coupled with high and controlled n-type doping which is not available in a silane-based system. Further, in order to achieve an optimal trade-off between the need for an inert ambience to promote silane reaction at low temperature and the need for a hydrogen ambience to prevent surface oxidation from inadvertant residual impurities, depositions are carried out in an ambience composed primarily of He but always containing some H.sub.2. Alternatively, instead of using He for H.sub.2 as the primary carrier gas when depositing Si from silane at low temperatures, DCS with a diborane additive may be used instead of silane in the normal hydrogen carrier. This modification permits DCS to be used in atmospheric pressure processes for Si deposition at low temperatures, which conventionally deposit Si selectively, to deposit blanket (non-selective) Si films over insulator and Si areas, and particularly such areas on a patterned wafer. Because the Si deposition rate is enhanced when diborane is added, significant non-selective deposition rates can occur down to 550.degree. C.

Comprehensive process for low temperature SI epit axial growth

A method of forming a thin silicon layer upon which semiconductor devices may be constructed. An epitaxial layer is grown on a silicon substrate, and oxygen or nitrogen ions are implanted into the epitaxial layer in order to form a buried etch-stop layer therein. An oxide layer is grown on the epitaxial layer, and is used to form a bond to a mechanical support wafer. The silicon substrate is removed using grinding and/or HNA, the upper portions of the epitaxy are removed using EDP, EPP or KOH, and the etch-stop is removed using a non-selective etch. The remaining portions of the epitaxy forms the thin silicon layer. Due to the uniformity of the implanted ions, the thin silicon layer has a very uniform thickness.

Method of producing a thin silicon-on-insulator layer

The disclosure provides for the use of a group II-VI compound semiconductor as a surface passivator to control recombination of charge carriers at the surface of a group III-V compound semiconductor by a localized heating step. It is theorized for practice of the invention that the control of the recombination of the charge carriers is achieved by chemical reaction of the II-VI compound with excess group V element. In particular the disclosure provides for the use of a capping layer of laser annealed ZnS as a passivating layer on a GaAs device.

Zinc-sulphide capping layer for gallium-arsenide device

A chemical vapor deposition (CVD) process is described for depositing magnetic oxides, such as garnets, having growth induced anisotropy sufficient to support stable bubble domains, even in very thin films. Organometallic source compounds are used together with low growth temperatures less than 900.degree. C. and high nozzle velocities in the range of 200-600 cm/sec. at room temperature. The oxidant gas mixture contains about 30-50 mol percent O.sub.2, rather than approximately 100 mol percent O.sub.2, as is usually used in CVD processes for depositing magnetic garnet films. The gas flow is transverse to the plane of the substrate onto which deposition is to occur, and is preferably perpendicular to the plane of the substrate. The individual source compounds are volatilized and carried by an inert gas, combined, then pre-mixed with oxygen in a nozzle without reaction at about 200.degree.-300.degree. C. The gas mixture is then passed at high velocity (200-600 cm/sec) onto a heated substrate. A novel nozzle-substrate arrangement is used which produces a favorable flow pattern and allows the source gas to be mixed with oxygen just immediately before it strikes the hot substrate. This yields optimum thickness and composition control for the particular substrate geometry used.

CVD Growth of magnetic oxide films having growth induced anisotropy

The disclosed method is one which provides an extremely thin substrate upon which there can be laid down a high resolution pattern of material such as metal by an electron beam fabrication technique. The latter technique is one wherein a resist is placed on the surface of the substrate. Thereafter, an electron beam is utilized to expose the resist in the desired pattern. The exposed resist is then removed and the metal or other material is laid down on the locations where the resist has been removed. With the use of the very thin substrate, the amount and effect of electron backscattering is substantially minimized whereby the consequent decrease of resolution due to exposure of the resist with the backscattered electrons is effectively eliminated. Accordingly, the resist exposure can be confined to much narrower widths than heretofore possible with known electron beam fabrication techniques.

Growing community of inventors

Croton-on-Hudson, NY, United States of America

Thomas O Sedgwick