PHOTODIODES AND METHODS FOR FABRICATING PHOTODIODES

1 . A photodiode, comprising:

a first semiconductor type surface region;

a second semiconductor type surface layer formed in a portion of said first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of said first semiconductor type surface region and said second semiconductor type surface layer;

a passivation coating on said second semiconductor surface layer;

an etch stop coating on a portion of said passivation coating;

an opening over at least a portion of said active photodiode region, said opening extending through said etch stop coating down to said passivation coating;

a dielectric reflective optical coating filter, comprising a plurality of dielectric layers, that fills at least a portion of said opening and thereby covers the at least a portion of said active photodiode region;

wherein said opening allows a portion of light incident on the photodiode to be received by said active photodiode region; and

wherein said dielectric reflective optical coating filter reflects a portion of light incident on the photodiode and thereby shapes a spectral response of the photodiode.

2 . The photodiode of claim 1 , wherein said dielectric reflective optical coating filter fills the entire said opening.

3 . The photodiode of claim 1 , wherein:

said dielectric reflective optical coating filter includes a top surface that is generally parallel to a top surface of said passivation coating and sidewalls that extend from said top surface of said dielectric reflective optical coating filter towards said passivation coating; and

further comprising a dark mirror covering said top surface and said sidewalls of said dielectric reflective optical coating filter.

4 . The photodiode of claim 1 , wherein:

said first semiconductor type is one of P type and N type; and

said second semiconductor type is the other one of P type and N type.

5 . The photodiode of claim 1 , wherein:

said passivation coating comprises an oxide layer on said second semiconductor type surface layer and a second dielectric layer different from said oxide layer on said oxide layer; and

said second dielectric layer, of said passivation coating, extends beyond said second semiconductor type surface layer.

6 . The photodiode of claim 1 , wherein said etch stop coating, on the portion of said passivation coating, comprises a layer resistant to oxide etch on an oxide layer.

7 . The photodiode of claim 1 , wherein the portion of said passivation coating, on which is said etch stop coating, comprises a peripheral portion of said passivation coating.

8 . The photodiode of claim 1 , wherein said etch stop coating comprises at least one of silicon nitride and polysilicon, and overlies and extends beyond a peripheral portion of said second semiconductor surface layer.

9 . A photodiode, comprising:

a first semiconductor type surface region;

a second semiconductor type surface layer formed in a portion of said first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of said first semiconductor type surface region and said second semiconductor type surface layer;

an etch stop coating formed on a portion of said first semiconductor type surface region that surrounds said second semiconductor type surface layer;

an opening over at least a portion of said active photodiode region, said opening extending through said etch stop coating down to said second semiconductor type surface layer or down to a thin oxide layer on said second semiconductor type surface layer;

a dielectric reflective optical coating filter, comprising a plurality of dielectric layers, that covers said opening;

wherein said opening allows a portion of light incident on the photodiode to be received by said active photodiode region; and

wherein said dielectric reflective optical coating filter reflects a portion of light incident on the photodiode and thereby shapes a spectral response of the photodiode.

10 . The photodiode of claim 9 , wherein:

said dielectric reflective optical coating filter fills at least a portion of said opening;

said dielectric reflective optical coating filter includes a top surface that is generally parallel to a top surface of said passivation coating and sidewalls that extend from said top surface of said dielectric reflective optical coating filter towards said second semiconductor type surface layer; and

further comprising a dark mirror covering said top surface and said sidewalls of said dielectric reflective optical coating filter.

11 . A photodiode, comprising:

a first semiconductor type surface region;

a second semiconductor type surface layer formed in a portion of said first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of said first semiconductor type surface region and said second semiconductor type surface layer;

a dielectric reflective optical coating filter, comprising a plurality of dielectric layers, above said second semiconductor type surface layer;

an etch stop coating on a portion of said dielectric reflective optical coating filter;

an opening over at least a portion of said active photodiode region, said opening extending through said etch stop coating down to said dielectric reflective optical coating filter;

wherein said opening allows a portion of light incident on the photodiode to be received by said active photodiode region; and

wherein said dielectric reflective optical coating filter reflects a portion of light incident on the photodiode and thereby shapes a spectral response of the photodiode.

12 . The photodiode of claim 11 , wherein said dielectric reflective optical coating filter is on said second semiconductor type surface layer.

13 . The photodiode of claim 11 , further comprising:

a passivation coating between said second semiconductor surface layer and said dielectric reflective optical coating filter.

14 . The photodiode of claim 13 , wherein:

said passivation coating comprises an oxide layer on said second semiconductor type surface layer and a second dielectric layer different from said oxide layer on said oxide layer; and

said second dielectric layer, of said passivation coating, extends beyond said second semiconductor type surface layer.

15 . The photodiode of claim 11 , wherein said etch stop coating, on the portion of said passivation coating, comprises a layer resistant to oxide etch on an oxide layer.

16 . The photodiode of claim 11 , wherein:

said first semiconductor type is one of P type and N type; and

said second semiconductor type is the other one of P type and N type.

17 . A method of a fabricating a photodiode, comprising:

(a) implanting and thereby forming a second semiconductor type shallow surface layer into a portion of a first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of the first semiconductor type surface region and the second semiconductor type shall surface layer;

(b) forming a passivation coating on said shallow surface layer, wherein said passivation coating comprises a thin oxide layer on said shallow surface layer and a second dielectric layer different from said thin oxide layer on said thin oxide layer;

(c) forming an etch stop coating on said second dielectric layer, wherein said etch stop coating comprises at least one layer resistant to oxide etch;

(d) performing at least some of interlayer dielectric (ILD) processing, metal processing, contact processing, via processing and passivation processing, which results in multiple layers being formed above said etch stop coating;

(e) removing at least a portion of said multiple layers formed at step (d) and at least a portion of said etch stop coating to produce an opening that extends down to said passivation coating over at least a portion of said active photodiode region; and

(f) filling at least a portion of said opening with a dielectric reflective optical coating filter so that said dielectric reflective optical coating filter covers said at least a portion of said active photodiode region.

18 . The method of claim 17 , wherein step (f) comprising filling the entire said opening with said dielectric reflective optical coating filter.

19 . The method of claim 17 , wherein after step (f) said dielectric reflective optical coating filter includes a top surface that is generally parallel to a top surface of said passivation coating and sidewalls that extend from said top surface towards said passivation coating, and further comprising:

(g) covering said top surface and said sidewalls of said dielectric reflective optical coating filter with a dark mirror.

20 . A method of a fabricating a photodiode, comprising:

(a) implanting and thereby forming a second semiconductor type shallow surface layer into a portion of a first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of the first semiconductor type surface region and the second semiconductor type shallow surface layer;

(b) forming an etch stop coating over said second semiconductor type shallow surface layer, wherein said etch stop coating comprises at least one layer ( 316 ) resistant to oxide etch;

(c) performing at least some of interlayer dielectric (ILD) processing, metal processing, contact processing, via processing and passivation processing, which results in multiple layers being formed above said etch stop coating;

(d) removing at least a portion of said multiple layers formed at step (c) and at least a portion of said etch stop coating to produce an opening, over at least a portion of said active photodiode region, that extends down to said second semiconductor type shallow surface layer or down to a thin oxide that covers said second semiconductor type shallow surface layer; and

(e) filling at least a portion of said opening with a dielectric reflective optical coating filter so that said dielectric reflective optical coating filter covers said at least a portion of said active photodiode region.

21 . The method of claim 20 , wherein step (e) comprising filling the entire said opening with said dielectric reflective optical coating filter.

22 . The method of claim 20 , wherein after step (e) said dielectric reflective optical coating filter includes a top surface that is generally parallel to a top surface of said passivation coating and sidewalls that extend from said top surface towards said passivation coating, and further comprising:

(f) covering said top surface and said sidewalls of said dielectric reflective optical coating filter with a dark mirror.

23 . A method of a fabricating a photodiode, comprising:

(a) implanting and thereby forming a second semiconductor type shallow surface layer into a portion of a first semiconductor type surface region, wherein an active photodiode region is formed by a PN junction of the first semiconductor type surface region and the second semiconductor type shall surface layer;

(b) forming a dielectric reflective optical coating filter over at least a portion of said active photodiode region;

(c) forming an etch stop coating over said dielectric reflective optical coating filter, wherein said etch stop coating comprises at least one layer resistant to oxide etch;

(d) performing at least some of interlayer dielectric (ILD) processing, metal processing, contact processing, via processing and passivation processing, which results in multiple layers being formed above said etch stop coating; and

(e) removing at least a portion of said multiple layers formed at step (d) and at least a portion of said etch stop coating to produce an opening that extends down to said dielectric reflective optical coating filter over at least a portion of said active photodiode region.

24 . The method of claim 23 , further comprising:

between steps (a) and (b), forming a passivation coating on said shallow surface layer, wherein said passivation coating comprises a thin oxide layer on said shallow surface layer and a second dielectric layer different from said thin oxide layer on said thin oxide layer; and

wherein step (b) comprises forming said dielectric reflective optical coating filter on said passivation coating.