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
Supplier capability methods, systems, and apparatuses for extended commerce
Display for gloves
Rules-based approach to transferring and/or viewing medical images
Context-sensitive views
System and method for seamlessly increasing download throughput
  Randomly Featured Patents
Apparatus for sensing button-pressed state and method therefor in mobile device
Image forming apparatus capable of forming glossy color image
Full-size optical sensor device having improved driving means
Cooling fan start-up control device for liquid crystal projector
Adjustable hinge adjustment tool
Print system, and printer and digital camera making up system
Control for variable geometry compressor
Tray-access door device and method
Capacitive pressure sensor with third encircling plate