Image sensor and method for fabricating the same

1. A method for fabricating an image sensor comprising:

forming a photodiode over a semiconductor substrate;

forming an interlayer dielectric layer over the semiconductor substrate including the photodiode;

forming a wave guide in the interlayer dielectric layer by performing an ion implantation process;

forming a color filter over the interlayer dielectric layer including the wave guide;

forming a planarization layer over the color filter; and

forming a micro lens over the planarization layer,

wherein forming the wave guide comprises:

forming a photoresist pattern over the interlayer dielectric layer exposing the uppermost surface of the interlayer dielectric layer;

performing the ion implantation process to implant ions of a wave guide material into the interlayer dielectric layer;

removing the photoresist pattern after performing the ion implantation process; and,

performing an annealing process with respect to the semiconductor substrate to thereby diffuse the implanted wave guide material after removing the photoresist pattern,

wherein performing the ion implantation process comprises:

implanting ions of the wave guide material at a first implantation dosage;

implanting ions of the wave guide material at a second implantation dosage smaller than the first implantation dosage; and

implanting ions of the wave guide material at a third implantation dosage smaller than the second implantation dosage.

2. The method of claim 1 , wherein the wave guide material is different than a material of the interlayer dielectric layer.

3. The method of claim 1 , wherein the first implantation dosage is a quantity of the wave guide material which extends from the uppermost surface of the interlayer dielectric layer to a region above the uppermost surface of the photodiode.

4. The method of claim 1 , wherein the second implantation dosage is at least one-third of the first implantation dosage and the third implantation dosage is at least one-third of the second ion implantation dosage.

5. The method of claim 1 , wherein the photoresist pattern is formed such that the width of the exposed uppermost surface of the interlayer dielectric layer is 20 to 40% of the overall width of the photodiode.

6. The method of claim 1 , wherein the wave guide material comprises a material having a greater atomic weight than the material of the interlayer dielectric layer.

7. The method of claim 1 , wherein the wave guide material comprises arsenic.

8. The method of claim 1 , wherein the wave guide is formed of a material having greater refractivity than the interlayer dielectric layer.

9. A method comprising:

forming a photodiode; and then

forming a dielectric layer over the photodiode; and then

forming a wave guide in the dielectric layer by performing a plurality of ion implantation processes; and then

forming a color filter over the dielectric layer including the wave guide; and then

forming a micro lens over the color filter,

wherein the wave guide comprises a first ion implantation layer, a second ion implantation layer and a third ion implantation layer,

wherein the first ion implantation layer extends from the uppermost surface of the dielectric layer to a region above the uppermost surface of the photodiode and the color filter is formed over and contacts the first ion implantation layer.

10. A method comprising:

forming a photodiode;

forming a dielectric layer over the photodiode;

forming a wave guide in the dielectric layer by performing a plurality of ion implantation processes;

forming a color filter over the dielectric layer including the wave guide; and

forming a micro lens over the color filter,

wherein the wave guide comprises a first ion implantation layer, a second ion implantation layer and a third ion implantation layer,

wherein the second ion implantation layer is formed in the first ion implantation layer and the third ion implantation layer is formed in the second ion implantation layer.