International Business Machines Corporation

Joseph M Blum

Kevin K Chan

James Cleary McGroddy

Jerome J Cuomo

Ernest Bassous

Billy L Crowder

Zeev A Weinberg

Istvan Lovas

Alan D Wilson

William Francis Kane

Constantino Lapadula

Bruce Bumble

Robert C McIntosh

Angela C Lamberti

Joao R Conde

Eric Gung Lean

The present invention relates to a low-pressure chemical vapor deposition (LPCVD) process for depositing silicon dioxide. In particular, the present invention describes a process involving a pre-cleaning step in which all impurities are removed from the substrate followed by a LPCVD step performed at temperatures of between 200.degree. C. and 300.degree. C. The process of the present invention is intended to replace higher temperature LPCVD and thermal processes for depositing silicon dioxide. More particularly, the present invention involves a process in which a substrate is washed using a predetermined cleaning process. The substrate is then exposed to a dilute hydrofluoric acid solution which removes native oxide and contaminants from the surface. Next, the substrate is rinsed with, for example, de-ionized water or ultra-clean water to remove any hydrofluoric acid or other residue from the previous process steps. A layer of material, for example, silicon dioxide, is then deposited using a low-pressure chemical vapor deposition process in which the gas flow comprises silane, oxygen and nitrogen at temperatures below 300.degree. C. Oxide qualities approaching those of thermally grown oxides having been achieved.

High-throughput, low-temperature process for depositing oxides

A high-efficiency, low-temperature, plasma-enhanced chemical vapor deposition (PECVD) system for growing or depositing various types of thin films on substrate surfaces, or etching such surfaces, using substrates of materials such as silicon, plastic, etc. The system uses a hollow-cathode-effect electron source with a surrounding confining electrode to create a plasma at the substrate surface to insure that the density of reactive species is both enhanced and localized at the substrate surface thus causing the rate of growth of the films, or the etch rate, to increase so that the process can take place at much lower temperatures and power levels. A particular embodiment involves the growing of hydrogenated amorphous silicon (a:Si:H), at room temperature, on silicon using a tubular reactor containing a cylindrical electrode lining the inside of the reactor walls acting as a counter electrode for an rf-powered, substrate-supporting electrode near the center of the reactor. A set of silicon wafers, on which the amorphous silicon is grown, is mounted on the latter electrode. The reaction gases (silane) flowing between the electrodes are decomposed in a plasma excited by an rf power source (13.56 MHz) connected to the substrate-supporting electrode. With the use of appropriate deposition parameters (silane flow rate, pressure, applied power and frequency, and substrate spacing) room temperature growth of a-Si:H is achieved at growth rates up to 15 .ANG./sec, while keeping a low hydrogen concentration (.about.10%) and the bonded hydrogen in the Si-H monohydride configuration.

Plasma enhanced chemical vapor processing system using hollow cathode

The method of fabrication of a monolithic silicon membrane structure in which the membrane and its supporting framework are constructed from a single ultra thick body of silicon. The fabrication sequence includes the steps of providing a doped membrane layer on the silicon body, forming an apertured mask on the silicon body, and removal of an unwanted silicon region by mechanical grinding and chemical etching to provide a well opening in the silicon body terminating in the doped membrane.

Monolithic silicon membrane device fabrication process

An injection laser, which is chemically etched to provide mirror-like surfaces, also is provided with a chirped diffraction grating. The latter grating, which is etched in the injection laser, combines with the chemically etched sides to provide laser emission in a direction substantially parallel to the current flowing through the laser. As an alternative to the chirped diffraction grating, waveguides are included in the resulting folded cavity laser. Either of the above structures relaxes the fabrication tolerance in the inclined surfaces etched in the laser relative to known folded cavity lasing structures.

Folded cavity injection laser

A method for improving the current confinement capacity of a double heterojunction laser by using a high energy implantation of oxygen in the regions of an injection laser surrounding the active region of such laser so as to make such regions semi-insulating.

Method of making a double heterojunction diode laser

Growing community of inventors

Yorktown Heights, NY, United States of America

Joseph M Blum