Systems and methods for imaging using single photon avalanche diodes

Abstract

Single-photon avalanche diode includes a central junction having a central p+ area and a deep-n well in contact with the central p+ area, a p-type guard ring disposed between the central junction and the deep-n well, and a shallow trench isolation separated from the central p+ area. Imaging apparatus includes a plurality of pixels, each pixel comprising a complementary metal-oxide-semiconductor-implemented single photon avalanche device and one or more signal converters electrically coupled thereto and configured to detect changes in output therefrom.

What is claimed is: 
     
         1 . A single-photon avalanche diode comprising:
 a central junction including a central p+ area and a deep-n well in contact with the central p+ area;   a p-type guard ring disposed between the central junction and the deep-n well; and   a shallow trench isolation separated from the central p+ area.   
     
     
         2 . The single-photon avalanche diode of  claim 1 , further comprising a photosensitive area disposed proximate to the surface of the diode. 
     
     
         3 . The single-photon avalanche diode of  claim 2 , wherein the photosensitive area has an octagonal shape. 
     
     
         4 . The single-photon avalanche diode of  claim 1  wherein the guard ring is configured to substantially surround the p+ area. 
     
     
         5 . The single-photon avalanche diode of  claim 1  wherein the guard ring is disposed between the p+ area and the shallow trench isolation. 
     
     
         6 . An imaging apparatus, comprising:
 a plurality of pixels, each pixel comprising a complementary metal-oxide-semiconductor-implemented single photon avalanche device and one or more signal converters electrically coupled thereto and configured to detect changes in output therefrom.   
     
     
         7 . The apparatus of  claim 6 , wherein the one or more signal converters comprise delay-locked loop-based time-to-digital converters. 
     
     
         8 . The apparatus of  claim 6 , each single photon avalanche diode further comprising a quenching circuit and a resetting circuit connected in series with the single photon avalanche diode. 
     
     
         9 . The apparatus of  claim 8 , wherein the quenching circuit further comprises a resistive component. 
     
     
         10 . The apparatus of  claim 9 , wherein the resistive component further comprises a variable resistor. 
     
     
         11 . The apparatus of  claim 9 , wherein the resistive component further comprises a resistor. 
     
     
         12 . The apparatus of  claim 6 , wherein the resetting circuit further comprises an active resetting circuit. 
     
     
         13 . The apparatus of  claim 8 , wherein the single photon avalanche diodes are arranged in an array. 
     
     
         14 . The apparatus of  claim 13 , wherein the array further comprises a two-dimensional 64×64 array. 
     
     
         15 . The apparatus of  claim 13 , wherein the array further comprises a two-dimensional 128×128 array. 
     
     
         16 . The apparatus of  claim 8 , wherein the signal converters are further coupled to a processor configured to compress data. 
     
     
         17 . The apparatus of  claim 8 , wherein the apparatus is configured to detect a signal categorized as a non-homogeneous Poisson process 
     
     
         18 . The apparatus of  claim 8 , further comprising a C-mount adapter disposed proximate to the surface of the apparatus, enabling it to connect to a microscope. 
     
     
         19 . A laser scanning microscopy system comprising the imaging apparatus of  claim 6 . 
     
     
         20 . A two-photon microscopy system comprising the imaging apparatus of  claim 6 . 
     
     
         21 . An endoscopic imaging system comprising the imaging apparatus of  claim 6 .