alok_ky
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Hi,
When the capacitance of a MOS is measured at high frequencies (assuming it is biased), then no inversion layer is generated, as there are no minority carriers (Assume that gate is biased positive and semiconductor is p-type). Then to compensate for the +ve voltage on the gate of the cap., there has to -ve voltage in the semiconductor.
Books say that the holes move away from the depletion region edge, thus extending it.
But, still, the capacitance that the books write, is based upon maximum depletion width, for surface potential = 2* (intrnsic potential - fermi potential).
I want to know, when the depletion region has widened, to create moe negative charge, to compensate for the positive charge on the gate, why this increase in depletion width does not contribute to the reduction of the moscap.
The books say that the depletion layer width cannot be more than ...some Wmax...
Why is it so ?
When the capacitance of a MOS is measured at high frequencies (assuming it is biased), then no inversion layer is generated, as there are no minority carriers (Assume that gate is biased positive and semiconductor is p-type). Then to compensate for the +ve voltage on the gate of the cap., there has to -ve voltage in the semiconductor.
Books say that the holes move away from the depletion region edge, thus extending it.
But, still, the capacitance that the books write, is based upon maximum depletion width, for surface potential = 2* (intrnsic potential - fermi potential).
I want to know, when the depletion region has widened, to create moe negative charge, to compensate for the positive charge on the gate, why this increase in depletion width does not contribute to the reduction of the moscap.
The books say that the depletion layer width cannot be more than ...some Wmax...
Why is it so ?
