Unit pixel of image sensor and image sensor including the same

Abstract

A unit pixel of an image sensor includes a photoelectric conversion region, an isolation region, a floating diffusion region and a transfer gate. The photoelectric conversion region is formed in a semiconductor substrate. The isolation region surrounds the photoelectric conversion region, extends substantially vertically with respect to a first surface of the semiconductor substrate, and crosses the incident side of the photoelectric conversion region so as to block leakage light and diffusion carriers. The floating diffusion region is disposed in the semiconductor substrate above the photoelectric conversion region. The transfer gate is disposed adjacent to the photoelectric conversion region and the floating diffusion region, extends substantially vertically with respect to the first surface of the semiconductor substrate, and transmits the photo-charges from the photoelectric conversion region to the floating diffusion region.

What is claimed is: 
     
         1 . A pixel unit comprising:
 a semiconductor substrate having a first surface and a second surface;   a photoelectric conversion region within the semiconductor substrate;   an isolation region surrounding the photoelectric conversion region, and comprising dielectric material extending substantially vertically from the first surface of the semiconductor substrate to the second surface of the semiconductor substrate;   a floating diffusion region within the semiconductor substrate and disposed above the photoelectric conversion region;   a transfer gate disposed adjacent to the photoelectric conversion region and the floating diffusion region and extending substantially vertically from the first surface of the semiconductor substrate to the photoelectric conversion region; and   a polysilicon region within the isolation region and surrounded by the isolation region.   
     
     
         2 . The pixel unit of  claim 1 , wherein the isolation region has an end surface coplanar with the second surface of the semiconductor substrate. 
     
     
         3 . The pixel unit of  claim 1 , wherein a portion of the transfer gate extends into the photoelectric conversion region. 
     
     
         4 . The pixel unit of  claim 1 , further comprising:
 at least one transistor disposed above the photoelectric conversion region.   
     
     
         5 . The pixel unit of  claim 1 , further comprising:
 a color filter disposed on the second surface of the semiconductor substrate.   
     
     
         6 . The pixel unit of  claim 5 , further comprising:
 a micro lens disposed on the color filter.   
     
     
         7 . The pixel unit of  claim 5 , further comprising:
 a dielectric layer interposed between the second surface of the semiconductor substrate and the color filter.   
     
     
         8 . The pixel unit of  claim 1 , wherein the photoelectric conversion region collects photo-charges in response to incident light, and configured such that a leakage component of the incident light is reflected internally at a sidewall surface of the isolation region, and a reflection component of the incident light reaches the photoelectric conversion region.