High performance GeSi avalanche photodiode operating beyond Ge bandgap limits

An avalanche photodiode, comprising:

• a substrate;
• and
• a multi-layer structure disposed on a first surface of the substrate, comprising:
• at least one top stressor layer including an amorphous silicon layer, the at least one top stressor layer coupled to at least one metal contact of a first electrical polarity;
• a germanium (Ge) absorption layer on which the at least one top stressor layer is disposed;
• a charge layer on which the Ge absorption layer is disposed;
• a multiplication layer on which the charge layer is disposed;
• and
• a contact layer on which the multiplication layer is disposed, the contact layer coupled to at least one metal contact of a second electrical polarity opposite to the first electrical polarity,
• wherein the at least one top stressor layer is configured to increase a tensile strain in the Ge absorption layer such that absorption of the Ge absorption layer between 1550 nm and 1650 nm is increased.

An avalanche photodiode, comprising:

• a substrate;
• a multi-layer structure disposed on the substrate, comprising:
• at least one top stressor layer including an amorphous silicon layer, the at least one top stressor layer coupled to at least one metal contact of a first electrical polarity;
• a germanium (Ge)-containing absorption layer doped with p-type dopants on which the at least one top stressor layer is disposed, a doping concentration of the p-type dopants is controlled such that a graded doping profile of the p-type dopants is formed within the Ge-containing absorption layer;
• a charge layer on which the Ge-containing absorption layer is disposed;
• a multiplication layer on which the charge layer is disposed;
• and
• a contact layer on which the multiplication layer is disposed, the contact layer coupled to at least one metal contact of a second electrical polarity opposite to the first electrical polarity,
• wherein the at least one top stressor layer is configured to increase a tensile strain in the Ge-containing absorption layer such that absorption of the Ge-containing absorption layer between 1550 nm and 1650 nm is increased.