Semiconductor photomultiplier and a process of manufacturing a photomultiplier microcell

A process of manufacturing a photomultiplier microcell;

• the process comprising;
• forming an insulating layer over an active region, wherein the insulating layer facilitates transmission of light through the insulating layer into the active region;
• implanting a dopant through the insulating layer to form a photosensitive diode in the active region, wherein the photosensitive diode comprises an avalanche photo diode (APD) formed on a semiconductor substrate;
• forming an etch stop layer over the insulating layer and creating electrical connections to the photosensitive diode through the insulation layer;
• and
• etching an optical pathway to the etch stop layer, wherein the insulating layer once formed is retained directly over the photosensitive diode throughout the manufacturing process such that the photosensitive diode receives light at least through the insulating layer via the optical pathway, wherein a first refractive index of the insulating layer is mathematically related to a second refractive index associated with the optical pathway.