Hey guys I'm reading Vlsi basics.I got one doubt.In nMos FET If Vgs>Vt then why channel length has been created.Because of Vgs the depletion region will increase deeper which will obstruct the Ids current.
Explain??
In an NMOS the channel is p-type an source/drain is n-type.
When you apply a positive voltage to the gate relative to the bulk the electric field attracts electrons under the gate, inside the p-type bulk. When you have a strong enough electric field there is enough electrons there to make a conductive n-type path between source and drain through the channel.
You inverted the channel from p-type to n-type essentially.