Image sensor based on charge carrier avalanche

Abstract

Disclosed herein is an apparatus suitable for radiation detection. The apparatus may comprise a radiation absorption layer and a first electrode on the radiation absorption layer. The radiation absorption layer may be configured to generate charge carriers therein from a radiation particle absorbed by the radiation absorption layer. The first electrode may be configured to generate an electric field in the radiation absorption layer. The first electrode may have a geometry shaping the electric field so that the electric field in an amplification region of the radiation absorption layer has a field strength sufficient to cause an avalanche of the charge carriers in the amplification region.

What is claimed is: 
     
         1 . An apparatus comprising:
 a radiation absorption layer configured to generate charge carriers therein from a radiation particle absorbed by the radiation absorption layer;   a first electrode on the radiation absorption layer;   an outer electrode surrounding the first electrode, and electrically insulated from the first electrode;   wherein the outer electrode is configured to shape the electric field in the amplification region;   wherein a geometry of the first electrode is configured to generate an electric field in an amplification region of the radiation absorption layer, the electric field having a field strength sufficient to cause an avalanche of the charge carriers in the amplification region.   
     
     
         2 . The apparatus of  claim 1 , further comprising a second electrode on the radiation absorption layer, the second electrode being opposite from the first electrode. 
     
     
         3 . The apparatus of  claim 2 , wherein the second electrode is configured to collect charge carriers in the radiation absorption layer. 
     
     
         4 . The apparatus of  claim 2 , wherein the second electrode comprises discrete regions;
 wherein the discrete regions of the second electrode extend into the radiation absorption layer.   
     
     
         5 . The apparatus of  claim 1 , wherein the first electrode extends into the radiation absorption layer. 
     
     
         6 . The apparatus of  claim 1 , wherein the outer electrode is configured not to collect charge carriers. 
     
     
         7 . The apparatus of  claim 1 , wherein the outer electrode comprises discrete regions. 
     
     
         8 . The apparatus of  claim 1 , wherein the amplification region comprises a doped semiconductor; wherein the doped semiconductor is in electrical contact with the first electrode; wherein the doped semiconductor has a non-zero concentration gradient of a dopant. 
     
     
         9 . The apparatus of  claim 1 , wherein the radiation absorption layer comprises an intrinsic semiconductor region. 
     
     
         10 . An apparatus comprising:
 a radiation absorption layer configured to generate charge carriers therein from a radiation particle absorbed by the radiation absorption layer;   a first electrode on the radiation absorption layer;   wherein a geometry of the first electrode is configured to generate an electric field in an amplification region of the radiation absorption layer, the electric field having a field strength sufficient to cause an avalanche of the charge carriers in the amplification region;   wherein the first electrode extends into the radiation absorption layer.   
     
     
         11 . The apparatus of  claim 10 , further comprising a second electrode on the radiation absorption layer, the second electrode being opposite from the first electrode. 
     
     
         12 . The apparatus of  claim 11 , wherein the second electrode is configured to collect charge carriers in the radiation absorption layer. 
     
     
         13 . The apparatus of  claim 11 , wherein the second electrode comprises discrete regions; wherein the discrete regions of the second electrode extend into the radiation absorption layer. 
     
     
         14 . The apparatus of  claim 10 , wherein the amplification region comprises a doped semiconductor; wherein the doped semiconductor is in electrical contact with the first electrode; wherein the doped semiconductor has a non-zero concentration gradient of a dopant. 
     
     
         15 . The apparatus of  claim 10 , wherein the radiation absorption layer comprises an intrinsic semiconductor region. 
     
     
         16 . An apparatus comprising:
 a radiation absorption layer configured to generate charge carriers therein from a radiation particle absorbed by the radiation absorption layer;   a first electrode on the radiation absorption layer;   wherein a geometry of the first electrode is configured to generate an electric field in an amplification region of the radiation absorption layer, the electric field having a field strength sufficient to cause an avalanche of the charge carriers in the amplification region;   wherein the second electrode comprises discrete regions and the discrete regions of the second electrode extend into the radiation absorption layer.   
     
     
         17 . The apparatus of  claim 16 , further comprising a second electrode on the radiation absorption layer, the second electrode being opposite from the first electrode. 
     
     
         18 . The apparatus of  claim 17 , wherein the second electrode is configured to collect charge carriers in the radiation absorption layer. 
     
     
         19 . The apparatus of  claim 16 , wherein the amplification region comprises a doped semiconductor; wherein the doped semiconductor is in electrical contact with the first electrode; wherein the doped semiconductor has a non-zero concentration gradient of a dopant. 
     
     
         20 . The apparatus of  claim 16 , wherein the radiation absorption layer comprises an intrinsic semiconductor region.