Semiconductor Device Modeling and Characterization EE5342, Lecture 7-Spring 2002. Professor Ronald L. Carter [email protected] http://www.uta.edu/ronc/. Ideal Junction Theory. Assumptions E x = 0 in the chg neutral reg. (CNR) MB statistics are applicable Neglect gen/rec in depl reg (DR)
Ideal JunctionTheory (cont.)
Apply the Continuity Eqn in CNR
Forward Bias Energy Bands
Evaluating thediode current
Special cases forthe diode current
Js,p = qni2Dp coth(Wn/Lp)/(NdLp) = qni2Dp/(NdWn), Wn << Lp, “short” = qni2Dp/(NdLp), Wn >> Lp, “long”
Js,n = qni2Dn coth(Wp/Ln)/(NaLn) = qni2Dn/(NaWp), Wp << Ln, “short” = qni2Dn/(NaLn), Wp >> Ln, “long”
Js,n << Js,p when Na >> Nd
Diffnt’l, one-sided diode conductance
Static (steady-state) diode I-V characteristic
Charge distr in a (1-sided) short diode
Wn = xnc- xn
Charge distr in a 1-sided short diode
* Semiconductor Physics and Devices, 2nd ed., by Neamen, Irwin, Boston, 1997.
**Device Electronics for Integrated Circuits, 2nd ed., by Muller and Kamins, John Wiley, New York, 1986.
***Physics of Semiconductor Devices, Shur, Prentice-Hall, 1990.