Semiconductor photodetector device

Abstract

A transmitted light absorption/recombination layer, a barrier layer, a wavelength selection/absorption layer, and an InP window layer having a p-type region are supported by an n-type substrate and arranged in that order. Light with a wavelength of 1.3 μm reaches the wavelength selection/absorption layer through the InP window layer. Then, the light is absorbed by the wavelength selection/absorption layer and drawn from the device as an electric current signal. Light with a wavelength of 1.55 μm reaches the transmitted light absorption/recombination layer through the barrier layer. Then, the light is absorbed by the transmitted light absorption/recombination layer, generating electrons and holes. These electrons and holes recombine with each other and hence disappear.

1 . A semiconductor photodetector device comprising: 
 a first semiconductor layer of a first conductivity type;    a first absorption layer;    a second semiconductor layer having a bandgap larger than the bandgap of said first absorption layer; and    a second absorption layer between said first semiconductor layer and said first absorption layer, said second absorption layer having a bandgap smaller than the bandgap of said first absorption layer, wherein    said first semiconductor layer, said first absorption layer, and said second semiconductor layer are arranged from bottom to top, in that order in a laminated structural    said semiconductor photodetector device detects light incident on a second semiconductor layer side, and    said second semiconductor layer includes a doped region of a second conductivity type.    
   
   
       2 . The semiconductor photodetector device according to  claim 1 , further comprising a barrier layer between said first absorption layer and said second absorption layer, said barrier layer having a larger bandgap than said second absorption layer.  
   
   
       3 . The semiconductor photodetector device according to  claim 1 , further comprising a multilayer reflective layer on said second semiconductor layer, reflecting light at wavelengths longer than the bandgap wavelength of said first absorption layer.  
   
   
       4 . The semiconductor photodetector device according to  claim 1 , wherein said second semiconductor layer further includes a multilayer reflective layer reflecting light at wavelengths longer than the bandgap wavelength of said first absorption layer.  
   
   
       5 . The semiconductor photodetector device according to  claim 1 , further comprising a multiplication layer between said first absorption layer and said barrier layer, said multiplication layer including an AlInAs layer.  
   
   
       6 . A semiconductor photodetector device comprising: 
 a first semiconductor layer of a first conductivity type;    a first absorption layer;    a second semiconductor layer having a bandgap larger than the bandgap of said first absorption layer; and    a second absorption layer between said second semiconductor layer and said first absorption layer or on said second semiconductor layer, said second absorption layer having a bandgap smaller than the bandgap of said first absorption layer, wherein    said first semiconductor layer, said first absorption layer, said second absorption layer, and said second semiconductor layer are arranged from bottom to top, in that order, in a laminated structure,    said semiconductor photodetector device detects light incident on a first semiconductor layer side, and    said second semiconductor layer includes a doped region of a second conductivity type.    
   
   
       7 . The semiconductor photodetector device according to  claim 6 , further comprising a multiplication layer between said first absorption layer and said first semiconductor layer, said multiplication layer including an AlInAs layer.  
   
   
       8 . The semiconductor photodetector device according to  claim 6 , further comprising a multilayer reflective layer between said first semiconductor layer and said first absorption layer, reflecting light at wavelengths longer than the bandgap wavelength of said first absorption layer.  
   
   
       9 . The semiconductor photodetector device according to  claim 8 , further comprising a multiplication layer between said first absorption layer and said multilayer reflective layer, said multiplication layer including an AlInAs layer.  
   
   
       10 . A semiconductor photodetector device comprising: 
 a first semiconductor layer of a first conductivity type;    a first absorption layer;    a second semiconductor layer having a bandgap larger than the bandgap of said first absorption layer;    a second absorption layer on said second semiconductor layer, said second absorption layer having a bandgap larger than the bandgap of said first absorption layer but smaller than the bandgap of said second semiconductor layer; and    a third absorption layer between said first semiconductor layer and said first absorption layer, said third absorption layer having a bandgap smaller than the bandgap of the bandgap of said first absorption layer, wherein    said first semiconductor layer, said third absorption layer, said first absorption layer, said second semiconductor layer, and said second semiconductor absorption layer are arranged from bottom to top, in that order, in a laminated structure,    said semiconductor photodetector device detects light incident on a second semiconductor layer side, and    said second semiconductor layer includes a doped region of a second conductivity type.    
   
   
       11 . The semiconductor photodetector device according to  claim 10 , further comprising a barrier layer between said first absorption layer and said third absorption layer, said barrier layer having a larger bandgap than said third absorption layer.  
   
   
       12 . The semiconductor photodetector device according to  claim 10 , further comprising a multilayer reflective layer between said first absorption layer and said second semiconductor layer or between said second semiconductor layer and said second absorption layer or on said second absorption layer, reflecting light at wavelengths longer than the bandgap wavelength of said first absorption layer.  
   
   
       13 . The semiconductor photodetector device according to  claim 10 , further comprising a multiplication layer between said first absorption layer and said barrier layer, said multiplication layer including an AlInAs layer.  
   
   
       14 . A semiconductor photodetector device comprising: 
 a first semiconductor layer of a first conductivity type;    a first absorption layer;    a second semiconductor layer having a bandgap larger than the bandgap of said first absorption layer;    a second absorption layer on said second semiconductor layer, said second absorption layer having a bandgap smaller than bandgap of said first absorption layer; and    a third absorption layer between said first semiconductor layer and said first absorption layer, said third absorption layer having a bandgap larger than the bandgap of said first absorption layer, wherein    said first semiconductor layer, said third absorption layer, said first absorption layer, said second semiconductor layer, and said second absorption layer are arranged from bottom to top, in that order, in a laminated structure, and    said semiconductor photodetector device detects light incident on a first semiconductor layer side,    said second semiconductor layer includes a doped region of a second conductivity type.    
   
   
       15 . The semiconductor photodetector device according to  claim 14 , further comprising a barrier layer between said first absorption layer and said third absorption layer, said barrier layer having a larger bandgap than said third absorption layer.  
   
   
       16 . The semiconductor photodetector device according to  claim 14 , further comprising a multiplication layer between said first absorption layer and said barrier layer, said multiplication layer including an AlInAs layer.  
   
   
       17 . The semiconductor photodetector device according to  claim 14 , further comprising a multilayer reflective layer between said first semiconductor layer and said third absorption layer and/or between said third absorption layer and said barrier layer and/or between said barrier layer and said first absorption layer, reflecting light at wavelengths longer than the bandgap wavelength of said first absorption layer.