Many websites and courses list the doping profile of a BJT as "emitter heavily doped", "base lightly doped" and "collector moderately doped". However, the more reputable sources and textbooks like "Semiconductor Physics and Devices by Donald A. Neamen" state that the collector is the doped the lightest of all, introducing a lot of confusion. However, I was not able to find a good reason for the collector being lightly doped. How does collector doping impact transistor performance?
Why, is the collector the lightest doped of all 3 regions of the BJT? Please provide any references too.
The mentioned part in "Semiconductor Physics and Devices by Donald A. Neamen" is: