An avalanche breakdown photodiode having a mixed composite charge layer, comprising
- a P-type ohmic contact layer, said P-type ohmic contact layer being a first semiconductor p+-doped;
- an N-type ohmic contact layer, said N-type contact layer being a second semiconductor n+-doped;
- a P-type window layer, said P-type window layer being a third semiconductor p−-doped and deposed between said P-type ohmic contact layer and said N-type ohmic contact layer;
- a first graded bandgap layer, said first graded bandgap layer being a fourth semiconductor p+-doped and deposed between said P-type window layer and said N-type ohmic contact layer;
- a first absorption layer, said first absorption layer being a fifth semiconductor p−-doped and deposed between said first graded bandgap layer and said N-type ohmic contact layer;
- a second absorption layer, said second absorption layer being a sixth semiconductor undoped and deposed between said first absorption layer and said N-type ohmic contact layer;
- a second graded bandgap layer, said second graded bandgap layer being a seventh semiconductor undoped and deposed between said second absorption layer and said N-type ohmic contact layer;
- a first P-type field control layer, said first P-type field control layer being an eighth semiconductor p−-doped and deposed between said second graded bandgap layer and said N-type ohmic contact layer;
- a second P-type field control layer, said second P-type field control layer being a ninth semiconductor p−-doped and deposed between said first P-type field control layer and said N-type ohmic contact layer;
- a third P-type field control layer, said third P-type field control layer being a tenth semiconductor p−-doped and deposed between said second P-type field control layer and said N-type ohmic contact layer;
- a multiplication layer (M-layer), said M-layer being an eleventh semiconductor undoped and deposed between said third P-type field control layer and said N-type ohmic contact layer;
- an N-type charge layer, said N-type charge layer being a twelfth semiconductor n+-doped and deposed between said M-layer and said N-type ohmic contact layer;
- and
- a transport layer, said transport layer being a thirteenth semiconductor undoped and deposed between said N-type charge layer and said N-type ohmic contact layer,
- wherein, from top to bottom, the photodiode comprises said P-type ohmic contact layer, said P-type window layer, said first graded bandgap layer, said first absorption layer, said second absorption layer, said second graded bandgap layer, said first P-type field control layer, said second P-type field control layer, said third P-type field control layer, said M-layer, said N-type charge layer, said transport layer, and said N-type ohmic contact layer;
- an epitaxial-layers structure is obtained with an electrode of said M-layer being n-side down;
- a mixed composite charge layer comprising said first, said second, and said third P-type field control layers is obtained;
- and
- a heterojunction structure comprising said first, said second, and said third P-type field control layers is obtained with a mesa shape between said first and said second P-type field control layers obtained through chemical selective etching to confine the field of said M-layer at center of the photodiode with said mesa shape,
- wherein said P-type ohmic contact layer is of p+-type indium gallium arsenic phosphide (InGaAsP);
- said P-type window layer is of p+-type indium phosphide (InP);
- said first graded bandgap layer is of p+-type indium gallium arsenide (InGaAs);
- said first absorption layer is of graded p−-doped InGaAs;
- said second absorption layer is of undoped InGaAs;
- said second graded bandgap layer is of undoped InGaAs;
- said first P-type field control layer is of p−-doped indium aluminum arsenide (InAlAs);
- said second P-type field control layer is of p−-doped InP;
- said third P-type field control layer is of p−-doped InAlAs;
- said M-layer is of undoped InAlAs;
- said N-type charge layer is of n+-doped InAlAs;
- said transport layer is of undoped InP;
- and
- said N-type ohmic contact layer is of n+-doped InP.