Resources Contact Us Home
Technique for elimination of polysilicon stringers in direct moat field oxide structure

Image Number 3 for United States Patent #4908683.

The problem of unwanted residual polysilicon stringers along the sidewalls of a field oxide layer employed in direct moat wafer processing is avoided by a processing scheme in which the sidewalls of the aperture in the field oxide layer are initially tapered prior to formation of the polysilicon layer to be used for the gate electrode(s). Because of the graduated thickness of the sidewalls of the field oxide layer, the thickness of the polysilicon layer formed thereon is substantially uniform over the entirety of the substrate. As a result, during subsequent masking of the polysilicon layer to define the gate electrode(s), all unmasked portions of the polysilicon are completely etched, leaving no residual material (e.g. stringers) that could be a source of device contamination. After the polysilicon gate has been delineated, the sloped sidewalls of the field oxide are removed (by anisotropic etching), so that the sidewalls of the apertures or windows of the field oxide layer will be perpendicular to the planar surface of the substrate, thus facilitating proper formation of dielectric (oxide) spacers therealong, which thereby provide separation between contact materials and the junction created by shallow ion implantation of dopants through the field oxide aperture.

  Recently Added Patents
Polymorphic forms of 3-(1-{3-[5-(1-methyl-piperidin-4-ylmethoxy)-pyrimidin-2-yl]-benzyl}-6-oxo- -1,6-dihydro-pyridazin-3-yl)-benzonitrile hydrochloride salt and processes of manufacturing t
Magnetic memory and method of manufacturing the same
Key management policies for cryptographic keys
Systems and methods for controlling registration of advancing substrates in absorbent article converting lines
Phase-change memory device having multiple diodes
Lithographic apparatus and device manufacturing method
Once daily formulations of tetracyclines
  Randomly Featured Patents
Method and buffer station for buffering documents
Method of, and apparatus for, transmitting data in a manufacturing machine comprising a plurality of production stations
Electrically conductive hot-melt silicone adhesive composition
Changing the fine chemical content in organisms by genetically modifying the shikimate pathway
Liquid detergent composition comprising selected alkylbenzene sulphonates and alkyl ether sulphates
Composition and process for treating metal
Apparatus and method for sharpening saw blades having planetary motion in transverse cutting
Electrocromic rearview mirror for an automobile improved in a water proof ability
High resolution magnetic resonance imaging of body cavities
Porphine-carbohydrate-fatty acid complexes as synthetic respiratory pigments