Back-surface-incident type light-receiving device and optical module

A back-surface-incident type light-receiving device comprising:

• a substrate having a front surface and a back surface opposite from the front surface;
• an n-type layer, a multiplication layer, a p-type electric field control layer, a light absorption layer, and a window layer which are layered in order on the front surface;
• a p-type region provided in part of the window layer;
• an anode electrode provided on the p-type region and connected to the p-type region;
• and
• an anode pad and a cathode pad which are provided on the back surface,
• wherein first and second connecting holes penetrate the substrate,
• a third connecting hole penetrates from the window layer to the n-type layer,
• the cathode pad is electrically connected to the n-type layer via the first connecting hole,
• the anode pad is electrically connected to the anode electrode via the second and third connecting holes, and
• a light-receiving region is provided on the back surface.