BiCMOS takes advantage of CMOS and bipolar transistors. You can use it for either digital or analog. Typically you use bipolar transistors for speed or drive capacity and CMOS for low power and gate density. Typically you can just look at gate design already in use for CMOS or Bipolar - same stuff but with BiCMOS you can mix them on the same chip.
Right now most of the practical experience and knowledge about BiCMOS design is in academic (IEEE) papers, companies that manufacture BiCMOS parts or graduate school level text books like