Patent ID: 7288825

Claim:
A low noise photodetector comprising: a body of semiconductor material having a surface substantially surrounded by dielectric material, the surface comprising a first portion that is passivated and a second portion that is unpassivated, the body comprising a first region doped to a first type of conductivity (p or n), a second region peripherally around the first region doped to the second type of conductivity (n or p) forming a first p-n junction with the first region and a third region doped to the first type of conductivity (p or n) peripherally around the second region forming a second p-n junction with the second region; the first and second p-n junctions intersecting the surface of the body in intersection regions that are within the first portion of the surface that is passivated, respective ohmic contacts to the first region, the second region and the third region for collecting photogenerated current and biasing the first and second p-n junctions, whereby carriers generated at the unpassivated portion of the semiconductor surface are prevented from reaching the first region by junctions of opposite polarity.