Solid state image pick-up device for imaging an object placed thereon
View Patent ↗The solid state image pick-up device comprises a chip wherein an object to be photographed is put directly on the back surface of the chip, a light incident on the object enters the inner portion of the chip, signal electric charges generated in the inner portion of the chip by the light, the signal electric charges are collected in a photo detective region and the photo detective region has a barrier diffusion layer adjacent thereto so as to collect the signal electric charges effectively. The above-mentioned structure of the solid state image pick-up device can provide superior features that the chip of the solid state image pick-up device is protected from the deterioration of elements included in the chip and the destruction of the elements by Electro Static Discharge, resulting in the reliability improvement of the chip.
1. A solid-state image pickup device comprising:
a semiconductor substrate having a front surface and a rear surface;
a photo detective layer formed in said semiconductor substrate at a side of said front surface and detecting a light entering through said rear surface, said photo detective layer having:
a first region having a first conductive type;
a plurality of second regions having a second conductive type opposite to said first conductive type, each of said second regions constituting a photo diode and being separated from each other by said first region;
said plurality of second regions having a top surface that is positioned at a side of said front surface and a bottom surface that is positioned at a side of said rear surface; and
a third region contacting said bottom surface of one of said second regions and having said first conductive type, said third region being lower in impurity density than said first region.
2. The solid-state image pickup device according to claim 1 , wherein said first region is deeper than said second regions.
3. The solid-state image pickup device according to claim 1 , further comprising a MOSFET formed in said first region, said MOSFET dumps a charge accumulated in one of said second regions.
4. The solid-state image pickup device according to claim 3 , wherein
said MOSFET has source and drain regions of said second conductive type, one of said source and drain regions contacting with one of said second regions.
5. The solid-state image pickup device according to claim 1 , wherein said semiconductor substrate comprises a silicon substrate.