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p-channel Enhancement Mode MOSFET :

The cross-sectional view of the p-channel enhancement mode MOSFET fabricated on n-type substrate is as shown in Figure. Figure also shows the corresponding electrical symbol of the device.

The basic idea behind the operation of p-channel enhancement mode MOSFET is to connect the majority carriers present in the p-type drain and p-type source diffusions which are holes by a channel of carriers of the same type as the source and drain (i.e. holes) and opposite to that of the substrate (which is n type).

If a negative voltage is applied to the gate terminal it induces the hole inversion layer which connects the p-type source and the p-type drain regions.

Now, the existence of potential difference between source and drain causes the movement of holes in the inversion channel and hence the drain current.