Sensor device and method for forming the same

Abstract

Various embodiments of the present disclosure are directed towards a sensor device comprising a photodetector with a simplified manufacturing process. A semiconductor substrate comprises an avalanche region at which a p-type region and an n-type region form a PN junction. An inner absorption layer is recessed into the semiconductor substrate, wherein the inner absorption layer has a bottom protrusion protruding towards the avalanche region. A peripheral absorption layer is on a sidewall of the inner absorption layer and a bottom of the inner absorption layer and further extends from the sidewall to the bottom protrusion. The inner absorption layer and the peripheral absorption layer share a common semiconductor material and have a smaller bandgap than the semiconductor substrate. Further, the peripheral absorption layer has a doping concentration that is elevated relative to a doping concentration of the inner absorption layer.