Pinned photodiode integrated with trench isolation and fabrication method

A method for fabricating a photo sensor, comprising:

• forming at least one trench in a substrate of a first conductivity type;
• forming at least one doped region of the first conductivity type underneath the bottom of a corresponding trench;
• and
• forming at least one doped region of a second conductivity type sandwiched between the corresponding doped region of the first conductivity type and the substrate;
• wherein both edges of each doped region of the first and second conductivity types are separated from the bottom corners of the trench;
• wherein the distance from either edge of each doped region of the first conductivity type and the second conductivity type to the trench corner is in the range of 0.1 to 0.3 μm.

A method for fabricating a photo sensor, comprising:

• forming at least one trench in a substrate of a first conductivity type;
• forming at least one doped region of the first conductivity type underneath the bottom of a corresponding trench;
• forming at least one doped region of a second conductivity type sandwiched between the corresponding doped region of the first conductivity type and the substrate;
• forming a well of the first conductivity type, the well of the first conductivity type coupled to the doped region of the first conductivity type;
• and
• forming a well of the second conductivity type, the well of the second conductivity type coupled to the doped region of the second conductivity type;
• wherein both edges of each doped region of the first and second conductivity types are separated from the bottom corners of the trench.