Pixel isolation elements, devices and methods of making the same
Light trapping pixels, devices incorporating such pixels, and various associated methods are provided. In one aspect, for example, a light trapping pixel device can include a light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall disposed into at least a portion of the pixel and extending at least substantially around the pixel periphery. The pixel can also include a backside light trapping material substantially covering the backside surface and a peripheral light trapping material substantially covering the peripheral sidewall. The light contacting the backside light trapping material or the peripheral light trapping material is thus reflected back toward the pixel.
1 . A substantially light trapping device, comprising:
at least one light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall disposed into at least a portion of the pixel and extending around the pixel sidewall periphery;
an internally reflective frontside light trapping material covering at least a portion of the light incident surface;
a backside light trapping material at least partially covering the backside surface; and
a peripheral light trapping material at least partially covering the peripheral sidewall;
wherein the backside light trapping material and the peripheral light trapping material reflect and trap incident light from passing out of the pixel, and
wherein the backside light trapping material includes a high refractive index material sandwiched between two low refractive index materials.
2 . The device of claim 1 , wherein the internally reflective frontside light trapping material is operable to allow entrance of light into the pixel and operable to reflect light impinging thereupon from inside the pixel back into the pixel.
3 . The device of claim 2 , wherein the internally reflective frontside light trapping material includes an aperture to allow entry of light into the pixel.
4 . The device of claim 3 , further comprising a lens functionally coupled to the aperture and operable to focus incident light through the aperture and into the pixel.
5 . The device of claim 1 , wherein the peripheral sidewall extends completely from the light incident surface to the backside surface.
6 . The device of claim 1 , wherein the peripheral light trapping material extends to the backside surface.
7 . The device of claim 6 , wherein the peripheral light trapping material is in contact with the backside light trapping material.
8 . The device of claim 4 , wherein the peripheral light trapping material extends to the light incident surface.
9 . A substantially light trapping device, comprising:
at least one light sensitive pixel having a light incident surface, a backside surface opposite the light incident surface, and a peripheral sidewall disposed into at least a portion of the pixel and extending around the pixel sidewall periphery;
a backside light trapping material at least partially covering and directly on the backside surface; and
a peripheral light trapping material at least partially covering and directly on the peripheral sidewall; and
an internally reflective frontside light trapping material covering at least a portion of the light incident surface operable to allow entrance of light into the pixel and operable to reflect light impinging thereupon from inside the pixel back into the pixel,
wherein,
the backside light trapping material includes a high refractive index material sandwiched between two low refractive index materials,
the backside light trapping material and the peripheral light trapping material reflect and trap incident light from passing out of the pixel, and
the peripheral light trapping material extends to the light incident surface and is in contact with the internally reflective frontside light trapping material.
10 . The device of claim 1 , wherein the two low refractive index materials are the same materials.
11 . The device of claim 1 , wherein the two low refractive index materials are different materials.
12 . The device of claim 9 , wherein the two low refractive index materials are the same materials.
13 . The device of claim 9 , wherein the two low refractive index materials are different materials.
14 . The device of claim 1 , wherein the peripheral light trapping material extends to and is in contact with the internally reflective frontside light trapping material.