the current gain (beta) of an NPN

[zeldazzz]

what is the commonly used equation for npn current gain(base to collector) if I know the followings.

doe(doping of emitter), dob(base), doc(collector), width_base(the base width between the emitter and collector) and the area_ec(the area of the emitter facing collector).

---------- Post added at 21:42 ---------- Previous post was at 21:36 ----------

I am trying to figure out if there is a simple way to estimate the beta of the parasitic npn or pnp. usually, the beta is 1 or less

 

[dgnani]

Hi zeklazzz,
I am not sure it's that simple after all
- beta depends on the operating point
- many SPICE models for BJTs define beta through calibration parameters rather than geometry and physical constants
- you can have a look here (**broken link removed**) to see what parameters are involved