International Business Machines Corporation

Other

San-Mei Ku

Paul J Tsang

Michael R Poponiak

Reinhard Glang

Klaus D Beyer

Robert Otto Schwenker

Victor J Silvestri

Russell C Lange

Shao-Fu S Chu

Kathleen Anne Perry

Wen-Yuan Wang

Janet M Sickler

Andrie S Yapsir

John L Deines

Alfred Schmitt

Bao-Tai Hwang

Rosemary Christie

Charles A Pillus

Joseph F Shephard

William N Jacobus, Jr

A method for isolating areas of silicon from a substrate 50 includes the steps of: providing a buried N+ region 52 in the substrate; forming an intrinsic epitaxial layer 12 onto the N+ region; etching trenches 18, 20 through the intrinsic epitaxial layer to thereby form a desired isolation region 16 of intrinsic epitaxial material; laterally etching a cavity 22 underneath the desired isolation region; and, forming an insulation layer 24 of insulation material along the bottom of the desired isolation region exposed by the former etching steps.

Buried air dielectric isolation of silicon islands

A method of forming a semiconductor device on a body of semiconductor material having a first doped region of a first conductivity type, comprising the steps of: forming a stud over the first doped region; using the stud as a mask to form a second doped region of a second conductivity type in the surface of the first doped region adjoining the stud; forming a sidewall of insulating material on the stud; forming a first device contact within the sidewall; and forming a second device contact over the second doped region adjoining the sidewall, such that the first and second electrical contacts are separated by the sidewall. In accordance with an embodiment of the present invention, the step of forming the second device contact includes the steps of forming a layer of conductive material generally conformally over the first doped region and the stud, and then planarizing the layer of conductive material to a height equal to or less than that of the sidewalls. The second contact is thus self-aligned with the first and second doped regions and the first device contact. The method of the present invention can be utilized to fabricate bipolar transistors, insulated gate transistors, and BICMOS logic including both types of transistors. It can further be used to fabricate any other type of semiconductor device which utilizes the self-aligned, closely spaced device regions and contacts of the present invention.

Process of making BiCMOS devices having closely spaced device regions

A method of forming semiconductor device contacts includes the steps of: providing a semiconductor substrate having at least two features thereon whereat it is desired to make electrical connections; forming a layer of etch stop material having a first etch characteristic over each of the features; forming a layer of dielectric material having a second etch characteristic over each of the features; simultaneously etching at least two vias through the layer of dielectric material using an etchant selective to the layer of dielectric material so as to substantially stop on the layer of etch stop material, the at least two vias including a via over each of the features; and extending the vias through the layer of etch stop material so as to expose the features for subsequent electrical connections.

Method of forming contacts to a semiconductor device

A semiconductor process for fabricating bipolar devices of one type and extendible to include bipolar devices of a second type in the same epi-layer. The process protects selected surfaces of the epi-layer against deleterious processes associated with the formation of future emitter/contact regions for the devices. Subsequently, such emitter/contact regions are formed beneath such protected surfaces and contribute to enhanced device performance. The process also provides improved planarization of an insulating layer on the epi-layer by chemical-mechanical polishing. The planarization in conjunction with a mask formed in the insulating layer facilitates the formation of self-aligned emitter/base regions to appropriate thicknesses for high performance devices.

Self-aligned polysilicon emitter and contact structure for high

Disclosed is a method of forming in a monocrystalline silicon body an optimum recessed oxide isolation structure with reduced steepness of the bird's neck. Starting from a monocrystalline silicon body, there is formed thereon a layered structure of first silicon dioxide, polycrystalline silicon, second silicon dioxide and silicon nitride, in that order. The layers are patterned to form openings in the structure at the areas where it is desired to form the oxide isolation pattern within the silicon body. The exposed areas of the silicon body are anisotropically reactive ion etched to an initial portion of the desired depth obtaining the corresponding portion of the trench having substantially vertical walls. Then by chemical etching the trench is extended to a final portion of the desired depth obtaining inwardly sloped walls in the final portion. The body is then thermally oxidized until the desired oxide isolation penetrates to the desired depth within the silicon body.

Method of forming recessed oxide isolation with reduced steepness of the

A method for fabricating polycrystalline silicon resistors is described which includes deposition of a polycrystalline silicon layer of very fine grain size upon an insulator surface, followed by ion implantation of boron equal to or slightly in excess of the solubility limit of the polycrystalline silicon. This ion implantation is normally done using a screen silicon dioxide surface layer. The structure may be annealed at temperatures of between about 800.degree. C. to 1100.degree. C. for 15 to 180 minutes to control the grain size of the polycrystalline silicon layer, homogenize the distribution of the boron ions throughout the entire film thickness and to raise the concentration of the boron in the silicon grains to the solid solubility limit. The suitable electrical contacts are now made to the polycrystalline silicon layer to form the resistor.

Process for fabricating polycrystalline silicon film resistors

A method for forming monocrystalline silicon carbide on a silicon substrate by converting a portion of the monocrystalline silicon substrate into a porous silicon substance by anodic treatment carried out in an aqueous solution of hydrofluoric acid, heating the resultant substrate to a temperature in the range of 1050.degree. C to 1250.degree. C in an atmosphere that includes a hydrocarbon gas for a time sufficient to react the porous silicon and the gas, thereby forming a layer of monocrystalline silicon carbide on the silicon substrate.

Process for forming monocrystalline silicon carbide on silicon substrates

In integrated circuit fabrication, a method is provided for simultaneously forming two regions of the same conductivity-type such as the base and isolation regions. In one embodiment, an epitaxial layer of one conductivity-type is formed on a substrate of opposite conductivity-type, after which dopant ions of the opposite conductivity-type are introduced into the epitaxial surface areas which are to provide the base and isolation regions, and in addition, the isolation regions are bombarded with non-dopant ions having a maximum atomic number of two, e.g., hydrogen or helium ion while the base regions are appropriately masked and remain umbombarded, said bombardment is carried out at temperatures below 300.degree. C, preferably room temperature. The bombardment is preferably carried out so that the non-dopant ions are implanted primarily in regions below the isolation regions. Next, the wafer is heated at a temperature at a range of from 600.degree. - 900.degree. C which is substantially below normal drive-in diffusion temperatures for unbombarded doped regions. The heating to be maintained for a period sufficient to drive-in diffuse the bombarded isolation regions through the epitaxial layer into contact with the substrate but is insufficient to drive-in the unbombarded base regions to such a depth.

Method of proton-enhanced diffusion for simultaneously forming

Disclosed is a semiconductor light emitting diode (LED) array in which 'cross-talk' between adjacent diodes in the array is minimized. The disclosed LED arrays have an absorbing layer on the backside of the devices and/or a guard ring region surrounding each device in order to absorb spurious reflections within the semiconductor crystal. Disclosed also is a method of making improved light emitting diodes (LED's).

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Poughkeepsie, NY, United States of America

San-Mei Ku