CMOS-compatible active pixel image array using vertical pnp cell
AssigneeNational Semiconductor Corporation
InventorRichard Billings Merrill
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Abstract
A preferred pnp bipolar phototransistor pixel element in accordance with the present invention has a p-type collector region formed in p-type semiconductor material. An n-type base region is formed in the collector region. A p-type emitter region is formed in the base region. An annular n-type capacitor region is formed in the base region surrounding and spaced-apart from the emitter region. Conductive material is disposed over the capacitor region and separated therefrom by underlying dielectric material to define the pixel element's coupling capacitor.
Claims4
A vertical pnp bipolar phototransistor pixel element comprising:
- a collector region formed of semiconductor material of p-type conductivity;
- a base region of n-type conductivity formed in the collector region the base region having a first conductivity;
- an emitter region of p-type conductivity formed in the base region;
- a capacitor region of n-type conductivity formed in the base region in spaced-apart relationship to the emitter region the capacitor region having a second conductivity that is greater than the first conductivity;
- dielectric material formed on a surface of the capacitor region;
- and
- conductive material formed on the dielectric material above the capacitor region to be capacitively coupled to the capacitor region.
Dependencies are inferred from the claim text.