Avalanche Photo-Transistor

Abstract

Methods and devices for an avalanche photo-transistor. In one aspect, an avalanche photo-transistor includes a detection region configured to absorb light incident on a first surface of the detection region and generate one or more charge carriers in response, a first terminal in electrical contact with the detection region and configured to bias the detection region, an interim doping region, a second terminal in electrical contact with the interim doping region and configured to bias the interim doping region, a multiplication region configured to receive the one or more charge carriers flowing from the interim doping region and generate one or more additional charge carriers in response, a third terminal in electrical contact with the multiplication region and configured to bias the multiplication region, wherein the interim doping region is located in between the detection region and the multiplication region.

1 . (canceled) 
     
     
         2 . A system comprising:
 a light source configured to transmit an optical signal; and   a photo-detection device comprising:
 a germanium detection region configured to:
 absorb a portion of the optical signal transmitted by the light source; and 
 generate one or more charge carriers in response to absorbing the portion of the optical signal; 
 
 an interim doping region having a doping concentration that is greater than a threshold doping concentration; 
 a silicon multiplication region in contact with the interim doping region, the silicon multiplication region configured to:
 receive a portion of the one or more charge carriers flowing from the germanium detection region through the interim doping region; and 
 generate additional charge carriers in response to receiving the portion of the one or more charge carriers, 
 
 wherein the interim doping region is formed between the germanium detection region and the silicon multiplication region, and 
   wherein a voltage bias across the germanium detection region and a voltage bias across the silicon multiplication region are separately biased.   
     
     
         3 . The system of  claim 2 , wherein the interim doping region comprises silicon. 
     
     
         4 . The system of  claim 2 , wherein the germanium detection region comprised a p-doped region. 
     
     
         5 . The system of  claim 4 , wherein the interim doping region is p-doped. 
     
     
         6 . The system of  claim 5 , further comprising an n-doped region in contact with the silicon multiplication region, and wherein the n-doped region is configured to collect the additional charge carriers generated by the silicon multiplication region. 
     
     
         7 . The system of  claim 2 , wherein the threshold doping concentration is at least 10 16  cm −3 . 
     
     
         8 . The system of  claim 2 , wherein the interim doping region surrounds the germanium detection region. 
     
     
         9 . The system of  claim 2 , wherein the interim doping region is laterally adjacent to the germanium detection region with respect to a surface of the germanium detection region that receives the portion of the optical signal. 
     
     
         10 . The system of  claim 2 , wherein a bias voltage difference across the germanium detection region is less than 3 volts. 
     
     
         11 . The system of  claim 2 , further comprising a measurement device configured to measure, based on the additional charge carriers, at least one of a direct time-of-flight information, an indirect time-of-flight information, or an indirect frequency delay representing a distance between the system and an object. 
     
     
         12 . A system comprising:
 a light source configured to transmit an optical signal; and   a photo-detection device comprising:
 a germanium detection region configured to:
 absorb a portion of the optical signal transmitted by the light source; and 
 generate one or more charge carriers in response to absorbing the portion of the optical signal; 
 
 an interim doping region having a doping concentration that is greater than a threshold doping concentration; 
 a silicon multiplication region in contact with the interim doping region, the silicon multiplication region configured to:
 receive a portion of the one or more charge carriers flowing from the germanium detection region through the interim doping region; and 
 generate additional charge carriers in response to receiving the portion of the one or more charge carriers, 
 
 wherein the interim doping region is formed between the germanium detection region and the silicon multiplication region, 
 wherein, during an operation of the photo-detection device, a bias voltage difference across the germanium detection region is less than 3 volts, and 
 wherein, during the operation of the photo-detection, a bias voltage difference across the silicon multiplication region is less than 7 volts. 
   
     
     
         13 . The system of  claim 12 , wherein the interim doping region comprises silicon. 
     
     
         14 . The system of  claim 12 , wherein the germanium detection region comprised a p-doped region. 
     
     
         15 . The system of  claim 14 , wherein the interim doping region is p-doped. 
     
     
         16 . The system of  claim 15 , further comprising an n-doped region in contact with the silicon multiplication region, and wherein the n-doped region is configured to collect the additional charge carriers generated by the silicon multiplication region. 
     
     
         17 . The system of  claim 12 , wherein the threshold doping concentration is at least 10 16  cm 3 . 
     
     
         18 . The system of  claim 12 , wherein the interim doping region surrounds the germanium detection region. 
     
     
         19 . The system of  claim 12 , wherein the interim doping region is laterally adjacent to the germanium detection region with respect to a surface of the germanium detection region that receives the portion of the optical signal. 
     
     
         20 . The system of  claim 12 , further comprising a measurement device configured to measure, based on the additional charge carriers, at least one of a direct time-of-flight information, an indirect time-of-flight information, or an indirect frequency delay representing a distance between the system and an object. 
     
     
         21 . A photo-detection device comprising:
 a germanium detection region configured to:
 absorb a portion of an optical signal transmitted from a light source; and 
 generate one or more charge carriers in response to absorbing the portion of the optical signal; 
   an interim doping region having a doping concentration that is greater than a threshold doping concentration;   a silicon multiplication region in contact with the interim doping region, the silicon multiplication region configured to:
 receive a portion of the one or more charge carriers flowing from the germanium detection region through the interim doping region; and 
 generate additional charge carriers in response to receiving the portion of the one or more charge carriers, 
   wherein the interim doping region is formed between the germanium detection region and the silicon multiplication region, and   wherein a voltage bias across the germanium detection region and a voltage bias across the silicon multiplication region are separately biased.