CMOS Image Sensor Having improved signal eficiency and method for manufacturing the same

Abstract

A CMOS image sensor and a method for manufacturing the same improves signal efficiency by reducing a dark signal, and includes a substrate having a first conductive type comprising an image area and a circuit area, a STI isolation layer in the substrate for electrical isolation within the circuit area, and a field oxide in the substrate for electrical isolation within the image area.

1 - 18 . (canceled) 
   
   
       19 . A CMOS image sensor comprising:
 a substrate having a first conductive type and comprising an image area and a circuit area;   a LOCOS field oxide in the substrate for electrical isolation within the image area;   a channel stop ion area below the LOCOS field oxide; and   a gate electrode on the circuit area of the substrate, the gate electrode having a gate oxide on the circuit area and a polysilicon gate on the gate oxide, the gate oxide being formed in such a way that both sides of the gate oxide and the polysilicon gate overlap with the LOCOS field oxide.   
   
   
       20 . The CMOS image sensor of  claim 19 , wherein the field oxide comprises a thermal oxide, and the CMOS image sensor further comprises a CVD oxide formed on an edge portion of the field oxide. 
   
   
       21 . The CMOS image sensor of  claim 19 , wherein the gate oxide comprises a CVD oxide and has side portions formed on the field oxide. 
   
   
       22 . The CMOS image sensor of  claim 19 , further comprising a well having the first conductive type in the substrate. 
   
   
       23 . The CMOS image sensor of  claim 19 , further comprising a photodiode having a second conductive type in the image area of the substrate. 
   
   
       24 . The CMOS image sensor of  claim 23 , wherein the first conductive type is P-type and the second conductive type is N-type. 
   
   
       25 . The CMOS image sensor of  claim 19 , wherein the channel stop ion has the first conductive type. 
   
   
       26 . A CMOS image sensor comprising:
 a substrate having a first conductive type and comprising an image area and a circuit area;   a LOCOS field oxide in the substrate for electrical isolation within the image area;   a channel stop ion area directly below the LOCOS field oxide, in the substrate; and   a gate electrode on the circuit area of the substrate, the gate electrode having a gate oxide on the circuit area and a polysilicon gate on the gate oxide, the gate oxide being formed in such a way that both sides of the gate oxide and the polysilicon gate overlap with the LOCOS field oxide.