Table of Contents - Glossary - Study Aids

- Introduction
- Semiconductor Fundamentals
- The Metal-Semiconductor Junction
- The p-n diode
- The Bipolar Transistor
- The MOS Capacitor
- The MOSFET
- Comprehensive Questions

- What is the driving force behind the semiconductor industry?
- Why is silicon the material of choice when making integrated circuits?
- Name three advantages of smaller devices.
- What do the following acronyms stand for: MOSFET, CMOS?
- Who invented the MOSFET?

- Draw the (632) plane and justify your answer.
- Name and draw two different directions in the (110) plane.
- Find the maximum filling factor in a body centered cubic lattice (treat the atoms as rigid spheres).
- Name a donor and acceptor for GaAs (zincblende lattice) and justify your answer based on the number of atoms in the outer shell
- How do we know that the energy of an electron in the hydrogen atom is quantized?
- Write an expression relating the two longest wavelengths of the Balmer series to the longest wavelength of the Paschen series
- What is the difference between a
*state*and an energy level? - Why is the density of states in k-space constant for
**all**semiconductors? - Two identical atoms separated by a large distance from each other are measured to have the same lowest energy. Does this statement violate the Pauli exclusion principle?
- Consider an electron with effective mass
*m*which occupies the lowest energy level in an infinite quantum well with^{*}= m_{0}*L*= 10 nm. Derive an expression for the charge density distribution in the well and plot it._{x} - Why do the discreet atomic energy levels form energy bands as they are brought together in a crystal?
- As holes simply correspond to missing electrons why do we even bother to call them holes?
- Why are we so interested in the almost filled and almost empty bands of a semiconductor?
- The Fermi function provides the probability of occupancy of a particular energy level requiring only the Fermi energy and the energy of the energy level, but is independent of the density of available states. How can that be?

- Plot
*1/C*versus^{2}*V*for an MOS capacitor. Find an expression for the slope and the intercept of the straight line which fits this curve in "depletion"._{G}

- Name the four terminals of a MOSFET and describe their function.
- What is an "inversion" layer?
- What is the doping type of the source, drain and substrate of a p-type MOSFET?
- Is the overlap of the gate with the source and drain regions required, beneficial or irrelevant?
- Can you explain why an enhancement-mode MOSFET is also called a normally- off MOSFET?
- How do you explain that the drain current is at first proportional to the drain- source voltage?
- How small must the drain-source voltage be for the linear model to be valid?
- What are the basic assumptions of the quadratic model?
- Can the quadratic model still used to describe an n-type MOSFET biased with a negative drain voltage? Explain your answer.
- Why can we not use the same expression to describe a MOSFET in the
quadratic and saturation regime? Use the quadratic model of an n-type MOSFET
and explain
what happens within the device at
*V*=_{DS}*V*-_{G}*V*._{T} - Why is the current calculated by the variable depletion layer model always larger than that of the quadratic model?

- Why does the p-n diode between the substrate and the drain not block the flow of electrons between the source and the drain?