Method of fabricating a low, dark-current germanium-on-silicon pin photo detector

摘要

A method of fabricating a low, dark-current germanium-on-silicon PIN photo detector includes preparing a P-type silicon wafer; implanting the P-type silicon wafer with boron ions; activating the boron ions to form a P+ region on the silicon wafer; forming a boron-doped germanium layer on the P+ silicon surface; depositing an intrinsic germanium layer on the born-doped germanium layer; cyclic annealing, including a relatively high temperature first anneal step and a relatively low temperature second anneal step; repeating the first and second anneal steps for about twenty cycles, thereby forcing crystal defects to the P+ germanium layer; implanting ions in the surface of germanium layer to form an N+ germanium surface layer and a PIN diode; activating the N+ germanium surface layer by thermal anneal; and completing device according to known techniques to form a low dark-current germanium-on-silicon PIN photodetector.