Solid state imaging 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 pick-up device comprising:
a semiconductor substrate having a front surface and a rear surface;
a MOSFET formed over said semiconductor substrate at a side of the front surface; and
a photo detective layer formed in said semiconductor substrate at a side of the front surface and detecting a near infrared light entering through the rear surface, wherein said photo detective layer comprises:
a first region having a first conductive type;
a plurality of second regions having a second conductive type opposite to the 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 the rear surface; and
a third region contacting the bottom surface of one of said second regions and having the first conductive type, said third region being lower in impurity density than said first region, and
wherein an impurity concentration of the semiconductor substrate is less than 1×10 17 /cm 3 .
2. The solid state image pick-up device according to claim 1 , wherein said first region is deeper than said second regions.
3. The solid state image pick-up device according to claim 1 , 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.
4. The solid state image pick-up device according to claim 1 , wherein said semiconductor substrate comprises a silicon substrate.