Semiconductor device and method of making

A method of forming a semiconductor device, comprising:

• forming a first epitaxial layer over a substrate;
• forming a trench isolation structure in the first epitaxial layer;
• forming, in the first epitaxial layer, a first doped region of a photodiode, wherein the first doped region has a first conductivity type;
• forming, in the first epitaxial layer and under the first doped region, a second doped region of the photodiode, wherein the second doped region of the photodiode has a second conductivity type different than the first conductivity type;
• and
• forming, in the first epitaxial layer and over the second doped region, a third doped region of the photodiode, wherein the third doped region of the photodiode has the first conductivity type,
• wherein:
• forming the first doped region comprises forming the first doped region to have a bottom sidewall at a first depth relative to an uppermost surface of the first epitaxial layer;
• forming the trench isolation structure comprises forming the trench isolation structure to have a bottom sidewall at a second depth relative to the uppermost surface of the first epitaxial layer;
• and
• the first depth is between about a hundredth to about a fifth of the second depth.

A semiconductor device, comprising:

• a semiconductor body;
• a first photodiode and a second photodiode in the semiconductor body;
• and
• a trench isolation structure between the first photodiode and the second photodiode, wherein:
• the first photodiode comprises:
• a first doped region having a first conductivity type;
• a second doped region, overlying the first doped region, having a second conductivity type different than the first conductivity type;
• and
• a third doped region, overlying the first doped region, having the second conductivity type;
• a first sidewall of the third doped region is adjacent a first portion of a first sidewall of the trench isolation structure;
• the first sidewall of the third doped region extends from a second sidewall of the third doped region to a third sidewall, of the third doped region, under the second sidewall of the third doped region;
• the first sidewall of the trench isolation structure extends from a second sidewall of the trench isolation structure to a third sidewall, of the trench isolation structure, under the second sidewall of the trench isolation structure;
• and
• a first distance between the third sidewall of the third doped region and a surface of the semiconductor body is between about a hundredth to about a fifth of a second distance between the third sidewall of the trench isolation structure and the surface of the semiconductor body.