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
High dynamic range pixel structure
Social network user data advertising
Cytokine biomarkers as predictive biomarkers of clinical response for Glatiramer acetate
Multi-wired antenna for mobile apparatus
Method and system for network configuration for virtual machines
Lightning-protective explosion-preventive fastener
  Randomly Featured Patents
Thermal head and method of manufacturing the same, and heat-sensitive recording method
Floor nozzle for vacuum cleaners
Thermal mass flow rate sensor having fixed bypass ratio
Method and system for managing channels in a wireless network
Novel organofunctional (ketoximino) silanes and room temperature, vulcanizable compositions containing the same
Scatterometer and a method for observing a surface
Thermal bend actuator with conduction pad at bend region
Shipping package containing coiled fastener packages
Chrysanthemum plant named Triumph
Inflatable pillow