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US 6,646,318 B1Granted
Bandgap tuned vertical color imager cell
AssigneeNational Semiconductor Corporation
InventorsPeter J. Hopper, Philipp Lindorfer
Life of this patent
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Abstract
A combination of materials is used to form the photodiodes of a vertical color imager cell. The materials used to form the photodiodes have different band gaps that allow the photon absorption rates of the photodiodes to be adjusted. By adjusting the photon absorption rates, the sensitivities of the photodiodes and thereby the characteristics of the imager can be adjusted.
Claims15
An imager cell comprising:
- a first layer of material;
- a second layer of material formed on the first layer of material;
- a third layer of material formed on the second layer of material;
- a fourth layer of material formed on the third layer of material;
- a top layer of material formed over the fourth layer of material, the fifth layer of material being different from the fourth layer of material;
- a first region of a first conductivity type formed in the first layer of material and a lower portion of the second layer of material;
- a first region of a second conductivity type formed in an upper portion of the second layer of material to contact the first region of the first conductivity type;
- a first depletion region formed between the first regions of the first and second conductivity types;
- a second region of the first conductivity type formed in the third layer of material and the lower portion of fourth layer of material to contact the first region of the second conductivity type;
- a second region of the second conductivity type formed in an upper portion of the fourth layer of material to contact the second region of the first conductivity type;
- a second depletion region formed between the second regions of the first and second conductivity types;
- a third region of the first conductivity type that is formed in the top layer of material;
- a third region of the second conductivity type formed in a surface of the top layer of material to contact the third region of the first conductivity type;
- and
- a third depletion region formed between the third regions of the first and second conductivity types.
12 more elements
Dependencies are inferred from the claim text.