ELECTRONIC DEVICES

The course aims to provide students with the basic concepts of semiconductor physics, to provide an overview of integrated circuit manufacturing technologies and to understand the behavior of the main electronic devices (diodes, bipolar transistors and MOS transistors) in order to be able to describe them by means of an adequate circuit modeling. At the end of the course the student must be able to analyze and describe the behavior of the devices under study by means of an appropriate circuit model; he must also be able to discern which constructive characteristics (process or project) will influence their performance. The student will also be able to analyze some simple device manufacturing steps in integrated technology.

The teaching is done through frontal lectures. Approximately one third of the lessons are devoted to numerical exercises in the classroom.

1. The crystal structure of solids and the Planar technology
   Semiconductor materials, space lattices and Miller indices. Atomic bonding. Imperfections and impurities. Crystal growth. Thermal oxidation. Thermal diffusion. Ion implantation. Film formation. Lithography and etching. Bipolar technology. CMOS technology.
2. Introduction to quantum mechanics
   Schrödinger's wave equation. Applications of Schrödinger's wave equation. The one-electron atom.
3. Introduction to the quantum theory of solids
   Allowed and forbidden energy bands. The Kronig-Penney model. The k-space diagram. Electrical conduction in solids. Electron effective mass. Concept of hole. Density of states function. The Fermi-Dirac probability function. The Fermi energy level.
4. The semiconductor in equilibrium
   Charge carriers in semiconductors. Dopant atoms and energy levels. The extrinsic semiconductor. Charge neutrality. Position of the Fermi energy level.
5. Carrier transport phenomena
   Carrier drift. Mobility, resistivity and conductivity. Diffusion current density. Einstein relationship.
6. Nonequilibrium Excess Carriers in Semiconductors
   Direct generation/recombination. Carriers injection. Continuity equations. Ambipolar transport. SHR theory of recombination. Excess-carrier lifetime. Auger theory of recombination. Quasi-Fermi energy levels.
7. The pn and metal-semiconductor junctions
   The pn junction. Zero applied bias. pn junction current. The "long" and the "short" diode. Static models. Small-signal models. Junction and diffusion capacitances. Generation-recombination currents. Junction breakdown. The Schottky barrier diode. I-V relationship. Ohmic contacts. Tunnel barrier.
8. The bipolar transistor
   The bipolar transistor operating regions. The Transistor effect. Ebers-Moll model. Static models. Small-signal models. Capacitive effects. Second order effects.
9. The MOS transistor
   The MOS capacitor operating regions. Flat-band voltage. Threshold voltage. Charge distributions. The MOS transistor operating regions. I-V characteristic. Second-order effects. Static and small-signal models.

1. Donald Neamen, Semiconductor physics and devices: basic principles, McGraw Hill
2. G. Giustolisi, G. Palumbo, Introduzione ai dispositivi elettronici, Franco Angeli
3. S. Dimitrijev, Understanding semiconductor devices, Oxford University Press, 2000
4. R. S. Muller, T. I. Kamins, Device Electronics for Integrated Circuits, John Wiley & Sons, 1986