CMOS Image Sensor and Manufacturing Method Thereof

Abstract

Disclosed are a CMOS image sensor and a manufacturing method thereof. The method includes forming an isolation layer in a semiconductor substrate, defining an active region including a photo diode region and a transistor region; forming a gate insulating layer and a gate electrode on the transistor region; forming a first low-concentration diffusion region in the photo diode region; forming a second low-concentration diffusion region in the transistor region; forming an insulating layer over an entire surface of the substrate; implanting fluorine ions in an upper surface of the photo diode region; etching the insulating layer to form insulating sidewalls on sides of the gate electrode; forming a high-concentration diffusion region in the transistor region partially overlapping with the second low-concentration diffusion region; and forming a third low-concentration diffusion region on the upper surface of the photo diode region, the third low-concentration diffusion region having a conductivity type opposite to the first low-concentration diffusion region.

1 . A CMOS image sensor including a photo diode and a MOS transistor, the photo diode comprising:
 a first low-concentration diffusion region in a semiconductor substrate, having a conductivity type opposite to the substrate; and   a fluorine implant layer in an upper surface of the substrate, at least partially overlapping with the first low-concentration diffusion region.   
   
   
       2 . The sensor of  claim 1 , wherein the photo diode further comprises a second low-concentration diffusion region having a conductivity type opposite to the first low-concentration diffusion region. 
   
   
       3 . The sensor of  claim 2 , wherein the second low-concentration diffusion region has a shallower dopant concentration profile than the first low-concentration diffusion region. 
   
   
       4 . The sensor of  claim 1 , further comprising an isolation layer in the substrate a predetermined distance from the first low-concentration diffusion region. 
   
   
       5 . The sensor of  claim 2 , further comprising an isolation layer in the substrate a predetermined distance from the first low-concentration diffusion region. 
   
   
       6 . The sensor of  claim 1 , wherein the MOS transistor comprises a gate insulating layer and a gate electrode. 
   
   
       7 . The sensor of  claim 6 , wherein the gate electrode comprises polysilicon and fluorine ions. 
   
   
       8 . The sensor of  claim 2 , wherein the MOS transistor comprises a gate insulating layer and a gate electrode. 
   
   
       9 . The sensor of  claim 8 , wherein the gate electrode comprises polysilicon and fluorine ions. 
   
   
       10 . The sensor of  claim 6 , further comprising insulating sidewalls on sides of the gate electrode. 
   
   
       11 . The sensor of  claim 10 , wherein the insulating sidewalls comprise at least one of a nitride and a TEOS oxide. 
   
   
       12 . The sensor of  claim 11 , wherein the insulating sidewalls comprise fluorine ions. 
   
   
       13 . The sensor of  claim 1 , wherein the MOS transistor comprises a third low-concentration diffusion region having a conductivity type opposite to the substrate. 
   
   
       14 . The sensor of  claim 13 , wherein the third low-concentration diffusion region has a shallower dopant concentration profile than the first low-concentration diffusion region. 
   
   
       15 . The sensor of  claim 13 , wherein the MOS transistor comprises a high-concentration diffusion region, at least partially overlapping with the third low-concentration diffusion region. 
   
   
       16 . The sensor of  claim 15 , wherein the third low-concentration diffusion region has a shallower dopant concentration profile than the high-concentration diffusion region. 
   
   
       17 . The sensor of  claim 1 , further comprising a high-concentration diffusion region. 
   
   
       18 . The sensor of  claim 4 , further comprising a complementary low-concentration diffusion region on an upper surface of the photodiode which extends to the isolation layer and partially overlaps with the first low-concentration diffusion region.