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 throughput thin film characterization and defect detection
Light-emitting diode devices
Local access to data while roaming with a mobile telephony device
Personal IP toll-free number
Tactile output device for computing device notifications
Use of endogenous promoters in genetic engineering of Nannochloropsis gaditana
  Randomly Featured Patents
Process for producing olefins
Transition fault testing for a non-volatile memory
2-phenoxy-6-thienylmethyloxypyridine derivative and herbicidal composition containing same
Electronic devices having thermodynamic encapsulant portions predominating over thermostatic encapsulant portions
Fuel cell component sealant
Active lamp pulse driver circuit
Athermal process for the concentration of Garcinia extract
Form keys and method for thermoforming undercuts in foam parts
Method and system to interface internet protocol (IP) based wireless devices with networks
Low specific gravity silicone rubber golf club grip