Identify the correct statement about MOS capacitor-

For an N-type substrate, a negative voltage is applied and accumulation occurs

For a P-type substrate, a negative voltage is applied and accumulation occurs

For an N-type substrate, a positive voltage is applied and accumulation occurs

For a P-type substrate, a positive voltage is applied and an N-type inversion layer is formed

Answer

Answer: Option D

Solution

Answer: Option D

Solution:

A MOS capacitor consists of a metal gate, oxide layer, and semiconductor substrate. The behavior of the surface region depends on the type of substrate and the polarity of the applied gate voltage.

For a P-type substrate with positive gate voltage: The applied positive potential repels holes (majority carriers) away from the surface and attracts electrons (minority carriers) towards the oxide–semiconductor interface. This leads to the formation of an N-type inversion layer. Hence, Option D is correct.

Option A: Incorrect, because in an N-type substrate under negative voltage, holes move towards the surface causing accumulation, not inversion.

Option B: Incorrect, because in a P-type substrate with negative voltage, holes are attracted to the surface, again causing accumulation, not inversion.

Option C: Incorrect, because in an N-type substrate with positive voltage, electrons accumulate at the surface, leading to accumulation only, not inversion.

Therefore, the correct statement is Option D.