Multi-layered gate for a CMOS imager
AssigneeMicron Technology, Inc.
InventorHoward E. Rhodes
Life of this patent
Estimating the term…
Abstract
A multi-layered gate for use in a CMOS or CCD imager formed with a second gate at least partially overlapping it. The multi-layered gate is a complete gate stack having an insulating layer, a conductive layer, an optional silicide layer, and a second insulating layer, and has a second gate formed adjacent to it which has a second conductive layer that extends at least partially over the surface of the multi-layered gate. The multi-layered gate has improved insulation, thereby resulting in fewer shorts between the conductive layers of the two gates. Also disclosed are processes for forming the multi-layered gate and the overlapping gate.
Claims66
A pixel sensor cell for use in an imaging device, said pixel sensor cell comprising:
- a photosensitive region of a first conductivity type formed on a substrate;
- a floating diffusion region of a second conductivity type formed in the substrate and spaced from said photosensitive region;
- a first insulating layer formed on said substrate;
- a first gate formed on said first insulating layer over said photosensitive region, said first gate comprising a first conductive layer on a first portion of said first insulating layer, a second insulating layer on the first conductive layer, and insulating spacers for defining structure in said substrate, said insulating spacers being formed on the sides of said first gate;
- and
- a second gate formed on a second portion of said first insulating layer, said second portion of said first insulating layer overlying said structure in said substrate, and said second gate comprising a semitransparent conductive layer formed on said second insulating layer and extending at least partially over said first gate.
A pixel sensor cell for use in an imaging device, said pixel sensor cell comprising:
- a photosensitive region of a first conductivity type formed in a substrate;
- a floating diffusion region of a second conductivity type formed in the substrate and spaced from said photosensitive region;
- a first insulating layer formed on the substrate;
- a first gate formed on said first insulating layer over said photosensitive region, said first gate comprising a first conductive layer on said first insulating layer, a second insulating layer on the first conductive layer, and insulating spacers formed on the sides of said first gate;
- and
- a second gate formed on said first insulating layer, said second gate comprising a semitransparent conductive layer formed on said first insulating layer and extending at least partially over said first gate.
A pixel sensor cell for use in an imaging device, said pixel sensor cell comprising:
- a photosensitive region of a first conductivity type formed in a substrate;
- a floating diffusion region of a second conductivity type formed in the substrate and spaced from said photosensitive region;
- a first insulating layer formed on the substrate;
- a first gate formed on said first insulating layer over said photosensitive region, said first gate comprising a first conductive layer on said first insulating layer, a second insulating layer on the first conductive layer, and insulating spacers formed on the sides of said first gate;
- and
- a second gate formed on said second insulating layer, said second gate comprising a semitransparent conductive layer formed on said second insulating layer and extending at least partially over said first gate.
Dependencies are inferred from the claim text.