Solid-state imaging device with an electrically connected light shield layer
AssigneeSony Corporation
InventorsToshirou Kurusu, Hiromi Suzuki
Life of this patent
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Abstract
A solid-state imaging device. A hole accumulation layer is provided on the surface of a photosensor region. Voltage lower than the voltage of the hole accumulation layer is applied to a light-shielding film, so that positive charges existing in a thin insulation film can be attracted toward the light-shielding film. Consequently it becomes possible to reduce a dark current.
Claims18
A solid-state imaging device comprising:
- a photosensor region having a surface,
- a hole accumulation layer on said surface of said photosensor region,
- an insulation film covering said hole accumulation layer,
- a light-shielding film partially covering said insulation film, and
- means for applying voltage to said light-shielding film, said voltage being lower than a voltage at said hole accumulation layer, such that positive charges in said insulation film are attracted toward said light-shielding film.
A solid-state imaging device comprising:
- a semiconductor substrate of one conductivity type,
- a well region of another conductivity type formed on a surface of said semiconductor substrate,
- a photosensor region of said one conductivity type formed in said well region,
- a hole accumulation region of said another conductivity type formed on a surface of said photosensor region,
- a channel region adjacent to said photosensor region,
- a plurality of transfer electrodes formed on said channel region,
- an insulation film formed on said hold accumulation region, on said transfer electrodes and periphery of said transfer electrodes,
- a light-shielding film formed on said transfer electrodes via said insulation film, and
- means for applying voltage to said light-shielding film, said voltage being lower than a voltage at said hole accumulation layer, such that positive charges in said insulation film are attracted toward said light-shielding film.
A solid-state imaging device comprising:
- a semiconductor substrate of one conductivity type,
- a well region of another conductivity type formed on a surface of said semiconductor substrate,
- a photosensor region of said one conductivity type formed in said well region,
- a hole accumulation region of said another conductivity type formed on a surface of said photosensor region,
- a channel region adjacent to said photosensor region,
- a plurality of transfer electrodes formed on said channel region,
- an insulation film formed on said hole accumulation region, on said transfer electrodes and periphery of said transfer electrodes,
- a light-shielding film formed on said insulation film,
- a polysilicon film formed at least on said hole accumulation layer and electrically connected to said light-shielding film, and
- means for applying voltage to said light-shielding film, said voltage being lower than a voltage at said hole accumulation layer.
A solid-state imaging device comprising:
- an n-type semiconductor substrate,
- a p-type well region formed on the surface of said n-type substrate,
- an n-type diffusion region formed in said p-type well and defining a photosensor region,
- a p+-type hole accumulation layer formed on a surface of said n-type diffusion region,
- an n-type channel region adjacent to said photosensor region,
- a first plurality of transfer electrodes formed on said channel region,
- a second plurality of transfer electrodes formed on said channel region,
- an insulation film formed on said hole accumulation layer, on said transfer electrodes and said periphery of said transfer electrodes,
- a polysilicon film having thickness less than about 1500 angstroms formed on said hole accumulation layer,
- a conductive light-shielding film formed on said insulation film and electrically connected to said polysilicon film, and
- means for applying voltage to said light-shielding film of between -3 and -7 volts lower than a voltage applied to said hole accumulation layer.
A method of operating a solid-state imaging device including a semiconductor substrate, a well region formed on a surface of said semiconductor substrate, a photosensor region formed in said well region, a hole accumulation region formed on a surface of said photosensor region, a channel region adjacent to said photosensor region, a plurality of transfer electrodes on said transfer electrodes, comprising the steps of,
- applying a voltage lower than that of said hold accumulation layer to said light-shielding film, such that positive charges in said insulation film are attracted toward said light-shielding film, and
- applying a positive voltage to one of said transfer electrodes.
Dependencies are inferred from the claim text.