The answer to your question is given on the following page:
http://ecee.colorado.edu/~bart/book/flatband.htm
Dear Dr. Behnam Farid,
Thank you very much. But the answer to my question is not there in this article.
Dear Rajeev, I thought the page gave the full answer to your question in which you refer to "a MOS capacitor with oxide charges and interface charges". Section 6.3.2 deals with the case of both having a capacitor and interface charges. Once you have the voltage, you can immediately calculate the sought-after intercept, by equating the work functions. For clarity, please consider pp. 592-600 of the book Solid State Physics, by Ashcroft & Mermin, where only the influence of capacitance is left out (Eq. (29.10) takes account of the space charge). Incidentally, the capacitance can also be rigorously calculated by the knowledge of the polarizability of the oxide layer.
Thank you Dr.Bhnam Farid, I shall read the book that you have mentioned.
You are welcome Rajeev. The only thing that the book does not consider is capacitive effects, which is considered on the page (Sec. 6.3.2) I referred to earlier.
Flat band is dependent on Na or Nd concentration in a semiconductor. so its the difference of the fermi and either VB or CB depending on the nature of the semiconductor.
With the presence of oxide charges, a shift in flat band (threshold voltage) is observed. This shift can be found by the difference in Phi MS and the Vfb required to compensate the oxide charge+ semiconductor. Trap sites usually do not respond when the usually carried at high frequency. But its influence is observed when carrying CV at low frequency. Trap sites will respond by exchanging the charge (charging and discharging at Low freq). When Comparing both High and low frequency measurement, a difference (Del Vfb) will be reflected in the MS plot.
Either passivation of these traps or measuring the Vfb using electrochemical method will reduce the complexity.
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