Image sensor with heating effect and related methods

Abstract

An image sensor including a semiconductor layer. A light absorber layer couples with the semiconductor layer at a pixel of the image sensor and absorbs incident light to substantially prevent the incident light from entering the semiconductor layer. The light absorber layer heats a depletion region of the semiconductor layer in response to absorbing the incident light, creating electron/hole pairs. The light absorber layer may include one or more narrow bandgap materials.

What is claimed is: 
     
         1 . An image sensor, comprising:
 a semiconductor layer, and;   a light absorber layer coupled with the semiconductor layer at a pixel of the image sensor, the light absorber layer configured to absorb a predetermined range of wavelengths of incident light and to substantially prevent all of the predetermined range of wavelengths of incident light from entering the semiconductor layer;   wherein the light absorber layer is configured to heat a region of the semiconductor layer.   
     
     
         2 . The image sensor of  claim 1 , further comprising:
 a microlens, the light absorber layer coupled between the microlens and the semiconductor layer, the microlens configured to refract the incident light towards the light absorber layer; and   a guide coupled between the microlens and the light absorber layer and configured to convey the refracted light to the light absorber layer.   
     
     
         3 . The image sensor of  claim 1 , wherein the image sensor comprises a backside integrated (BSI) sensor. 
     
     
         4 . The image sensor of  claim 1 , wherein the light absorber layer is positioned between two shallow trenches in the semiconductor layer, each shallow trench extending only partially through the semiconductor layer from a backside of the semiconductor layer towards a frontside of the semiconductor layer. 
     
     
         5 . The image sensor of  claim 1 , wherein the light absorber layer is positioned between two deep trenches of the semiconductor layer, each deep trench extending fully through the semiconductor layer from a backside of the semiconductor layer through to a frontside of the semiconductor layer. 
     
     
         6 . The image sensor of  claim 1 , further comprising an anti-reflective coating coupled to the light absorption layer. 
     
     
         7 . The image sensor of  claim 2 , wherein a length of the light absorbing layer is at least as long as a length of the microlens at an end of the microlens adjacent to the semiconductor layer. 
     
     
         8 . The image sensor of  claim 1 , wherein the light absorber layer is configured to create electron/hole pairs in the heated region. 
     
     
         9 . An image sensor, comprising:
 a photodiode comprised at least partially within a semiconductor layer;   a light absorber layer coupled with the photodiode, the light absorber layer configured to absorb incident light within predetermined wavelengths to substantially prevent the predetermined wavelengths of incident light from passing from the light absorber layer to the photodiode; and   at least one dielectric layer directly coupled with the semiconductor layer;   wherein the light absorber layer is configured to heat a region of the semiconductor layer.   
     
     
         10 . The image sensor of  claim 9 , wherein the light absorber layer is comprised at a backside of the semiconductor layer, wherein the at least one dielectric layer comprises a frontside dielectric layer and a backside dielectric layer, wherein the backside dielectric layer is located at the backside of the semiconductor layer; wherein a focusing element is comprised proximate the backside dielectric layer and is configured to focus the incident light through the backside dielectric layer towards the light absorber layer; and wherein the frontside dielectric layer is comprised at a frontside of the semiconductor layer opposite the backside of the semiconductor layer. 
     
     
         11 . The image sensor of  claim 9 , wherein the light absorber layer is comprised at a frontside of the semiconductor layer; the at least one dielectric layer comprises a frontside dielectric layer coupled at the frontside of the semiconductor layer; and a focusing element is comprised proximate the frontside dielectric layer and is configured to focus the incident light through the frontside dielectric layer towards the light absorber layer. 
     
     
         12 . The image sensor of  claim 9 , wherein the light absorber layer is configured to create electron/hole pairs in the heated region. 
     
     
         13 . An image sensor, comprising:
 a semiconductor layer, and;   substantially all of a first side of a light absorber layer directly coupled with the semiconductor layer at a pixel of the image sensor, the light absorber layer configured to absorb a predetermined range of wavelengths of incident light and to substantially prevent all of the predetermined range of wavelengths of incident light from entering the semiconductor layer;   wherein the light absorber layer is configured to heat a region of the semiconductor layer.   
     
     
         14 . The image sensor of  claim 13 , further comprising:
 a microlens, the light absorber layer coupled between the microlens and the semiconductor layer, the microlens configured to refract the incident light towards the light absorber layer; and   a guide coupled between the microlens and the light absorber layer and configured to convey the refracted light to the light absorber layer.   
     
     
         15 . The image sensor of  claim 13 , wherein the image sensor comprises a backside integrated (BSI) sensor. 
     
     
         16 . The image sensor of  claim 13 , wherein the light absorber layer is positioned between two shallow trenches in the semiconductor layer, each shallow trench extending only partially through the semiconductor layer from a backside of the semiconductor layer towards a frontside of the semiconductor layer. 
     
     
         17 . The image sensor of  claim 13 , wherein the light absorber layer is positioned between two deep trenches of the semiconductor layer, each deep trench extending fully through the semiconductor layer from a backside of the semiconductor layer through to a frontside of the semiconductor layer. 
     
     
         18 . The image sensor of  claim 13 , further comprising an anti-reflective coating coupled to the light absorption layer. 
     
     
         19 . The image sensor of  claim 14 , wherein a length of the light absorbing layer is at least as long as a length of the microlens at an end of the microlens adjacent to the semiconductor layer. 
     
     
         20 . The image sensor of  claim 14 , wherein the light absorber layer is configured to create electron/hole pairs in the heated region.