Semiconductor sensor and methods thereof

A method, comprising:

• providing a substrate;
• forming a germanium layer over the substrate;
• after forming the germanium layer, forming a doped layer along a bottom portion of the germanium layer, wherein the forming the doped layer includes performing an ion implantation process into the germanium layer;
• and
• after forming the doped layer, forming an optical sensor within the germanium layer.

A semiconductor device, comprising:

• a silicon (Si) substrate including a pixel region and a logic region adjacent to the pixel region;
• a germanium (Ge) layer formed in a trench within the Si substrate disposed within the pixel region, wherein a Ge—Si interface is defined along sidewalls and along a bottom surface of the trench, and wherein a sensor is disposed within the Ge layer;
• and
• a doped region disposed proximate to the Ge—Si interface, wherein the doped region substantially blocks electrons within the Si substrate from entering the Ge layer.