You can simulate the ft frequency of the transistors. Bias the transistor in strong saturation(mos) or active region(bjt) then apply a small signal sinusoid to the gate or base. Sweep the frequency of the sinusoid, and check for the current gain. The frequency at which the small signal current gain is "1", is your ft.
Ft of the bjts are much higher than that of mosfets.
I don't think this is a good question,
bicmos support mos and bipolar,
so the mos part may be still slow,
and the fast part is similar to bipolar
process