Patent ID: 7417268

Claim:
An image sensor comprising a pixel assembly, each pixel comprising a photodiode and an insulated gate access transistor connected to a read circuit, wherein: the photodiode and the access transistor are formed in and above a first semiconductor substrate; all or part of the read circuit is formed in a second semiconductor substrate; the second substrate is placed above the first substrate and separated therefrom by an intermediary insulating layer covering the insulated gate access transistor; the photodiode receives incident photons arriving in the first semiconductor substrate on its lower surface side opposite to said intermediary insulating layer and comprises a heavily-doped P-type upper area placed at the surface of the first substrate and an N-type buried layer placed under the P-type upper area, said buried layer extending in a source/drain area of the access transistor, and another source/drain area of the access transistor being placed on the other side of its gate at the surface of the first substrate.