US Patent 7687837 Image sensor and fabrication method thereof

An image sensor includes a substrate having an active pixel sensor region defined therein, a plurality of first conductivity type photodiodes formed in the active pixel sensor region and a first conductivity-type first deep well formed in the active pixel sensor region in a location which does not include the plurality of the first conductivity-type photodiodes. Moreover, the first deep well is electrically connected to a positive voltage.