Energy Band Diagram of MOSFET
Energy band diagram: Equilibrium : In ideal conditions there is no external supply to the device so the energy gap between conduction and valence band is high. The gap between Evac and Efm is called the work function qΦ m is the energy required by an electron to move from Fermi energy to vacuum energy level. Electron affinity (χ): It is the energy required to move an electron from the conduction band of a semiconductor to vacuum energy. Ionization energy: The energy required to move an electron from the valence band of semiconductor to vacuum energy. Fig: Equilibrium condition of MOSFET Accumulation: Accumulation of charges at the channel takes place when we apply V GS <0. As we apply external supply V GS <0 the holes get accumulated at the surface this is called accumulation. The electrons in metal increases so the E FM increases but it is known that the work function of a material doesn’t change so E VAC is increased with equal rise of E FM thus tilting th...