Semiconductor sensor and methods thereof

A method, comprising:

• forming a first doped passivation layer over a substrate, wherein the first doped passivation layer includes a doped silicon (Si) layer or a doped germanium (Ge) layer;
• forming an intrinsic Ge layer over the first doped passivation layer;
• after forming the intrinsic Ge layer, performing a first ion implantation process to form a doped cathode region of an optical sensor embedded within the intrinsic Ge layer and performing a second ion implantation process to form a doped anode region of the optical sensor embedded within the intrinsic Ge layer, wherein the doped cathode region and the doped anode region are separated by a portion of the intrinsic Ge layer;
• and
• bonding the substrate to a separate substrate including one or more logic devices.

A semiconductor device, comprising:

• an intrinsic germanium (Ge) layer interfacing a silicon (Si) substrate at least along a bottom surface of the Ge layer;
• an optoelectronic device formed within the intrinsic Ge layer, wherein the optoelectronic device includes an anode region and a cathode region that are both embedded within the intrinsic Ge layer;
• and
• a doped layer embedded within the intrinsic Ge layer beneath the optoelectronic device, wherein respective first and second portions of the intrinsic Ge layer are disposed above and below the doped layer.