Side-use of a Ge p-i-n photo diode for electrical application in a photonic BiCMOS technology

In this paper we demonstrate the potential use of a germanium p-i-n diode, available without additional processing effort in a photonic BiCMOS technology, for electronic applications. A cut-off frequency above 400 GHz was obtained by S-parameter measurements without any certain design optimization of the diode. The device construction on SOI yields in the isolation of the diode from the substrate. Moreover, the lateral current flow enables low series resistance for the diode. Potential applications are antenna-switching or mixers.