1 / 29

Metal oxide semiconductor capacitor MOS capacitor

Metal oxide semiconductor capacitor MOS capacitor. MOS capacitor before joining. The metallic gate may be replaced with a heavily doped p+ polysilicon gate. The Fermi energy levels are approximately at the same level. Positive electron energy. MOS capacitor before joining.

indra
Download Presentation

Metal oxide semiconductor capacitor MOS capacitor

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Metal oxide semiconductor capacitor MOS capacitor

  2. MOS capacitor before joining The metallic gate may be replaced with a heavily doped p+ polysilicon gate. The Fermi energy levels are approximately at the same level.

  3. Positive electron energy MOS capacitor before joining

  4. MOS capacitor after joiningAssume that there is no charge in the oxide layer

  5. MOS capacitor energy levels

  6. MOS capacitor energy levels

  7. V G MOS capacitor p type semiconductorvoltage bias effects - - - - E + + + +

  8. V G MOS capacitor p type semiconductorvoltage bias effects –battery switched + + + + E - + - + - + - +

  9. V G MOS capacitor n type semiconductorvoltage bias effects + + + + E - - - -

  10. V G MOS capacitor n type semiconductorvoltage bias effects –battery switched - - - - E + - + - + - + -

  11. MOS capacitor after joiningAssume that there is charge in the oxide layer

  12. V G MOS capacitor p type semiconductor gate voltage VG = VFlatband Charge No depletion layer No bending

  13. V G MOS capacitor p type semiconductor gate voltage VG = VT “threshold” Charge Inversion layer

  14. MOS capacitor –charge distribution . . Charge separation yields a capacitance

  15. Problem 6.1 Charge distributions are depicted in an MOS capacitor. 1) Is the semiconductor n or p type? 2) Does the bias make it an accumulation mode, depletion mode or an inversion mode? P type Inversion P type depletion

  16. Problem 6.1 Charge distributions are depicted in an MOS capacitor. 1) Is the semiconductor n or p type? 2) Does the bias make it an accumulation mode, depletion mode or an inversion mode? n type inversion P type accumulation

  17. Electric field due to charges Assume Boundary condition

  18. MOS capacitor – changing charge distribution with changing voltageaccumulation mode . .

  19. MOS capacitor – changing charge distribution with changing voltagedepletion mode . .

  20. MOS capacitor – changing charge distribution with changing voltage

  21. MOS capacitor – changing charge distribution with changing voltage veractor -- vericap

  22. definition Approximate proportion of charge located at x

  23. Problem 6.22 Using superposition, find the dependence of the “flat bad voltage” as the charge density changes. Nonuniform charge density @ x Change of flat band voltage Superimposition applies

  24. Problem 6.23 Using superposition, find the dependence of the “flat bad voltage” for a particular charge density profiles.. Charges located just at the interface

  25. Problem 6.23 Using superposition, find the dependence of the “flat bad voltage” for a particular charge density profiles.. Charge density is nonuniform

  26. Problem 6.28 Consider the high-frequency capacitance-voltage relationship. Locate the inversion; threshold; depletion; flat band, and accumulation points.

More Related