Deep trench isolation (dti) bounded single photon avalanche diode (spad) on a silicon on insulator (soi) substrate

A circuit, comprising:

• a semiconductor on insulator substrate including a semiconductor support layer, a buried insulating layer over the semiconductor support layer and an epitaxial semiconductor layer over the buried insulating layer, wherein the epitaxial semiconductor layer is doped with a first dopant conductivity type;
• a deep trench isolation penetrating completely through the epitaxial semiconductor layer to the buried insulating layer, said deep trench isolation electrically insulating a first region of the epitaxial semiconductor layer from a second region of the epitaxial semiconductor layer;
• a single photon avalanche diode (SPAD) comprising an anode formed by the first region of the epitaxial semiconductor layer and a cathode formed by a well located within the first region of the epitaxial semiconductor layer, said well doped with a second dopant conductivity type opposite the first dopant conductivity type;
• and
• an ancillary circuit for said SPAD located in the second region of the epitaxial semiconductor layer and electrically coupled to said SPAD.