SiGe APDs in a BiCMOS Process
This work investigated the implementation of an APD using a BiCMOS Process (ams S35).
The layout and cross-sectional views of the BiCMOS APDs as well as a comparison between Si and SiGe APDs are seen below.
The idea is that using the Ge layer we could extend the responsivity of the APD to greater than 1,000 nm.
However, the fact that the Ge is graded and, perhaps more importantly highly doped and thin (so the E field doesn't extend much into the layer) limits performance.
The improvement in using the thin, graded, SiGe epitaxial base layer in a BiCMOS process over a simple Si APD is minimal.
Last Updated Sunday, May 20, 2018