Midwest Research Institute

Y Simon Tsuo

John Roland Pitts

Jack L Stone

Eugene A Chernyshev

Eugene N Lebedev

Vadim G Gerlivanov

Vitali V Zadde

Nikolai N Korneev

Dmitry S Strebkov

Eugene P Belov

Eugene A Ryabenko

Satyen K Deb

Solomonida I Kleschevnikova

Akhsarbek B Pinov

Marc D Landry

A process for the preparation of high purity silane, suitable for forming thin layer silicon structures in various semiconductor devices and high purity poly- and single crystal silicon for a variety of applications, is provided. Synthesis of high-purity silane starts with a temperature assisted reaction of metallurgical silicon with alcohol in the presence of a catalyst. Alcoxysilanes formed in the silicon-alcohol reaction are separated from other products and purified. Simultaneous reduction and oxidation of alcoxysilanes produces gaseous silane and liquid secondary products, including, active part of a catalyst, tetra-alcoxysilanes, and impurity compounds having silicon-hydrogen bonds. Silane is purified by an impurity adsorption technique. Unreacted alcohol is extracted and returned to the reaction with silicon. Concentrated mixture of alcoxysilanes undergoes simultaneous oxidation and reduction in the presence of a catalyst at the temperature -20.degree. C. to +40.degree. C. during 1 to 50 hours. Tetra-alcoxysilane extracted from liquid products of simultaneous oxidation and reduction reaction is directed to a complete hydrolysis. Complete hydrolysis of tetra-alcoxysilane results in formation of industrial silica sol and alcohol. Alcohol is dehydrated by tetra-alcoxysilane and returned to the reaction with silicon.

Method of high purity silane preparation

The instant invention teaches a novel method for fabricating silicon solar cells utilizing concentrated solar radiation. The solar radiation is concentrated by use of a solar furnace which is used to form a front surface junction and back-surface field in one processing step. The present invention also provides a method of making multicrystallline silicon from amorphous silicon. The invention also teaches a method of texturing the surface of a wafer by forming a porous silicon layer on the surface of a silicon substrate and a method of gettering impurities. Also contemplated by the invention are methods of surface passivation, forming novel solar cell structures, and hydrogen passivation.

Method for processing silicon solar cells

A process for preparing a multiple level logic optical memory disks which are erasable upon heating when ion-beam hydrogenation is used for writing informatin on the disk. The process comprises depositing an amorphous film selected from the group consisting of silicon hydride, silicon carbon hydride and silicon nitrogen hydride on a glass substrate using plasma enhanced chemical vapor deposition at temperatures sufficient to ensure good adhesion and high film quality and an optical bandgap of between aboout 1.55 and about 2.0 eV; writing information on these disks by using a laser beam to selectively heat spots of the film to expel hydrogen and change the bandgap and optical absorption of the film; and using a laser beam at a sufficient nm wavelength in order to detect information stored on these disks.

Erasable, multiple level logic optical memory disk

A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

Oxygen ion-beam microlithography

Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing.

Hydrogen ion microlithography

Growing community of inventors

Golden, CO, United States of America

Y Simon Tsuo