That much I know is that along with the device models there is a paramater called multiplier. By default it is 1. And by default it gives the maximum current etc. according to its model. You can change the multiplier to 1.2 etc; which a numeric value just will be multiplied to the default emitter area.
And in general the are are in sq. um. But be confirmed it. You can check the values etc. when you run the icfb and messages coming in the icfb command window.