Pixel isolation elements, devices and associated methods
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. An imager device, comprising:
at least two adjacent light sensitive image sensor pixels each having a light incident surface, and a backside surface opposite the light incident surface, and each of said pixels having at least one doped region disposed on at least one of the light incident surface and the backside surface and a textured region comprising silicon and exhibiting a thickness in a range of about 50 nm and about 2 microns;
a conformal textured film layer associated with the textured region and forming a heterojunction, wherein the conformal textured film layer comprises a different material from the textured region; and
a peripheral isolation element at least partially separating said at least two adjacent pixels, wherein the peripheral isolation element provides at least one of optical isolation, light trapping, and electrical isolation, and wherein the peripheral isolation element comprises at least two materials having different indices of refraction.
2. The imager device of claim 1 , wherein the textured region is located on the light incident surface.
3. The imager device of claim 1 , wherein the textured region is located on the backside surface.
4. The imager device of claim 3 , further comprising an additional textured region located on the light incident surface.
5. The imager device of claim 1 , wherein the textured region comprises one of ones, pillars, pyramids, and inverted features.
6. The imager device of claim 1 , wherein the textured region exhibits a thickness in a range between about 500 nm and about 2 microns.
7. The imager device of claim 1 , wherein the textured region exhibits a thickness in a range between about 500 nm and about 1 micron.
8. The imager device of claim 1 , wherein the conformal textured layer is formed via deposition on said textured region.
9. The imager device of claim 8 , wherein the conformal textured film layer comprises one of germanium and silicon germanium.
10. The imager device of claim 1 , wherein said adjacent pixels are formed monolithically on a semiconductor substrate.
11. The imager device of claim 1 , wherein the peripheral isolation element comprises silicon oxide and hafnium oxide.