Electronic devices - (5 cfu)

Prof. Roberto Menozzi Tel. +39 0521 905832 - Fax. +39 0521 905822
  E-mail. roberto.menozzi@unipr.it
  Home page. http://www2.unipr.it/~menrob10/


Finalità

The course deals with the fundamental physical phenomena that underlie the operation of the most important semiconductor electron devices. As a complement to class lectures, a few hours will be spent in the lab working on device characterization and model extraction.

Programma

Basics of semiconductor physics. Semiconductors under equilibrium conditions. Mass action law. Fermi-Dirac and Maxwell-Boltzmann distributions.

Metal-semiconductor junctions. Metal-semiconductor junction under equilibrium conditions. Image-force barrier lowering. I-V characteristics. Ohmic contacts.

PN junctions. Non-uniform doping distributions. The PN junction at equilibrium. Debye length. Reverse bias. Capacitance of a reverse-biased diode. Avalanche and Zener breakdown. Continuity equations. Shockley-Hall-Read recombination. Auger and surface recombination. I-V characteristics of the PN diode. Long-base and short-base diodes. Validity of the low-injection and quasi-equilibrium approximations. Currents in the space-charge region. G-R currents in forward and reverse bias. Switching transients. Diffusion capacitance.

Bipolar Junction Transistors (BJTs). Forward-active region. Base transport factor. Emitter efficiency. BJT switching behavior. Ebers-Moll model. Early effect. Integrated BJTs. Low-current effects. High-injection effects: Kirk effect, base resistance. Base transit time. Charge-control model. Small-signal model. Frequency limitations: fT and fMAX. Substrate and lateral pnp transistors.

MOS Transistor (MOSFET). Ideal MOS systems. Band structure. Accumulation, depletion, inversion, strong inversion. Threshold voltage and body effect. C-V characteristics of the ideal MOS system. Non-ideal MOS systems: cahrges in the oxide and at the interface. MOS transistors. Body effect. Bulk charge effect. Threshold voltage adjustment. Sub-threshold current. Short-channel and narrow-channel effects. Source/drain charge sharing. Drain-induced barrier lowering. Sub-surface punch-through. Mobility reduction. Velocity saturation. Drain current in short-channel MOSFETs. Effects of scaling on short-channel MOSFETs. Electric field in the saturated velocity region: quasi-2D model. Hot carrier effects: substrate and gate currents.

Modalità d'esame

The test is based on an oral discussion. Lab reports may be evaluated and contribute to the final marks.

Testi consigliati

R. S. Muller, T. I. Kamins, P. K. Ko, “Device Electronics for Integrated Circuits,” 3rd Edition, John Wiley & Sons, 2003. ISBN: 0-471-42877-9


Ultimo aggiornamento: 22-06-2005


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