[amp_mcq option1=”A single diode” option2=”Two diodes” option3=”Three diodes” option4=”Four diodes” correct=”option1″]
The correct answer is: A single diode.
A diode is a semiconductor device that allows current to flow in one direction only. In an nMOS device, the source and drain are isolated by a p-n junction diode. This diode is formed when the p-type substrate is brought into contact with the n-type drain. The p-n junction diode acts as a barrier to current flow, preventing current from flowing from the source to the drain when the device is turned off.
Option B is incorrect because two diodes would not be enough to isolate the source and drain. A single diode is sufficient to create a barrier to current flow.
Option C is incorrect because three diodes would be too many. A single diode is sufficient to create a barrier to current flow.
Option D is incorrect because four diodes would be even more than necessary. A single diode is sufficient to create a barrier to current flow.