Multi-pixel detector and associated method for increasing angular sensitivity

1. An image sensor with a multi-pixel detector, comprising:

a first pixel formed in a substrate and having a first photodiode region;

a second pixel formed in the substrate adjacent to the first pixel and having a second photodiode region; and

a microlens above both the first pixel and the second pixel and having

(a) in a first cross-sectional plane perpendicular to a top surface of the substrate and including both the first and the second photodiode regions, a first height profile having N 1 local maxima, N 1 ≥1, and

(b) in a second cross-sectional plane perpendicular to the first cross-sectional plane and the top surface and including only one of the first and the second photodiode regions, a second height profile having N 2 >N 1 local maxima.

2. The image sensor of claim 1 ,

the first height profile having N 1 =1 local maxima and being characterized by first radius of curvature R 1 ; and

the second height profile including a first local maxima and a second local maxima corresponding to respective radii of curvature R 21 <R 1 and R 22 <R 1 .

3. The image sensor of claim 2 , the radius of curvature R 1 =730±70 nanometers.

4. The image sensor of claim 2 , the radii of curvature R 21 and R 22 being equal to within ten percent of (R 21 +R 22 )/2.

5. The image sensor of claim 2 , the radii of curvature R 21 and R 22 being equal to 580±60 nm.

6. The image sensor of claim 1 , the microlens having a maximum thickness of 730±70 nanometers.