Question

When the voltage across the drain and the source (VDS) is increased from a small amount (assuming that the gate voltage, VG with respect to the source is higher than the threshold voltage, Vt), then the width of the induced channel in NMOS (assume that VDS is always small when compared to the Vov)

(a) Will remain as was before

(b) Will become non uniform and will take a tapered shape with deepest width at the drain

(c) Will become non uniform and will take a tapered shape with deepest width at the source

(d) Will remain uniform but the width of the channel will increase

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I would like to ask this question from MOSFETs Device Strucuture and Physical Operation topic in portion MOS Field Effect Transistors (MOSFETs) of Electronic Devices & Circuits

Answer 1

Correct answer is (c) Will become non uniform and will take a tapered shape with deepest width at the source

Explanation: The voltage across the source will be VOV and the voltage will decrease linearly to VOV – VDS as we reach the drain end. The width of the induced channel is proportional to the voltage.