I know slightly less than nothing about this topic, but I remember reading this from a while back: "Notes for reversers Electron holes have more effective mass

I know slightly less than nothing about this topic, but I remember reading this from a while back: "Notes for reversers Electron holes have more effective mass, and therefore less mobility. P-type regions are thus made bigger than N-type regions to compensate. The size disparity often differentiates P-type and N-type silicon." Source: http://siliconzoo.org/tutorial.html http://siliconzoo.org/tutorial.html Maybe that is helpful...?