Semiconductor sensor and methods thereof

A method, comprising:

• forming a germanium layer within a trench defined in a silicon substrate;
• forming an implant region along a bottom portion of the germanium layer within the trench, the implant region including a doped layer extending from a first lateral end of the trench to a second lateral end of the trench and spaced a distance from an interface between the germanium layer and a bottom surface of the trench defined by a portion of the silicon substrate, wherein the doped layer interposes respective first and second portions of the germanium layer disposed above and below the doped layer;
• and
• after forming the implant region, forming an optical device within the germanium layer.

A semiconductor device, comprising:

• an undoped germanium (Ge) layer formed over a substrate and defining a Ge-substrate interface, wherein an optical sensor is disposed within the undoped Ge layer;
• and
• an ion-implanted Ge region spaced a distance from the Ge-substrate interface, wherein the ion-implanted Ge region includes a doped layer that interposes respective first and second portions of the undoped Ge layer disposed above and below the doped layer;
• wherein an anode and a cathode of the optical sensor are embedded within the first portion of the undoped Ge layer disposed above the doped layer.