Before revision: At a critical voltage called the THRESHOLD VOLTAGE ( Vth ) the channel will actually be so depleted of holes and rich in electrons that it will INVERT to being n-type silicon, and this is called the inversion region.
After revision: At a critical voltage called the THRESHOLD VOLTAGE ( VTH ) the channel will actually be so depleted of holes and rich in electrons that it will INVERT to being n-type silicon, and this is called the inversion region.