The conduction and valence bands in semiconductors and the equations governing the flow of charges in various semiconductors, mainly Silicon. The formation of p-n junctions and the operation of transistors, their current voltage characteristics and their equivalent circuit models will be presented in detail. The course will also discuss the operation mechanisms and fundamental properties/parameters of the metal-oxide-semiconductor Field Effect Transistor (MOSFET).

2 lectures per week

None.

None.

80% Examination

20% Laboratory Report

The course intends to:

■ establish the links between the crystal structure, the chemical composition and the electronic and transport properties of semiconductors like Si, Ge and GaAs, which are extremely important for the working of all the electronic devices (diodes, bipolar transistors, and field effect transistors)

■ establish the links between the electronic properties of bulk semiconductors and the electrical behaviour of p-n junctions, MOS structures, Schottky and Ohmic contacts as basic building blocks of all semiconductor devices including diodes, bipolar and MOS transistors, photodiodes and lasers;

■ establish the links between the physical properties of p-n junctions and MOS structure used as building blocks of a MOS transistor and the electrical behaviour and the current voltage characteristics of the MOS transistors;

■ introduce the basic processes used in the fabrication of semiconductor devices and integrated circuits;

By the end of this course students will be able to:

■ Calculate majority and minority carrier concentrations, conductivity, mobility, diffusion coefficient, and current density from fundamental material properties of bulk semiconductors;

■ Sketch band diagrams for intrinsic and doped semiconductors, p-n junctions, Schottky barriers, Ohmic contacts, and MOS structures, considering how they are formed and adopting typical semiconductor terminology (including bands, effective density of states, Fermi levels, generation/recombination, carrier lifetime, majority/minority carriers);

■ explain how the current flow in semiconductors through drift and diffusion of electrons and holes determines the physical properties of semiconductor junctions and how those properties give rise to device I-V and C-V characteristics;

■ calculate the depletion depths, fields, built-in potentials, I-V and C-V characteristics of p-n junctions, MOS structures, Schottky barriers and Ohmic contacts (where appropriate);

■ compare simple analytical models of p-n junctions, diodes, MOS structures and MOSFETs with accurate simulations of their physical behaviour;

■ design MOS transistors to a specification of desired properties, considering the scaling principles of MOSFETs;

■ describe the sequence of fundamental fabrication steps for silicon MOS transistors and CMOS circuits, considering the physics and chemistry involved as well as the typical equipment used for lithography, diffusion, implantation oxidation and deposition of metals, dielectric layers and semiconductor layers;

■ calculate layer thicknesses from oxidation processes (both dry and wet), diffused and implanted dopant distributions, junction depths and effective layer thicknesses resulting from diffusion, pre-deposition and drive-in processes;

Students must attend the degree examination and submit at least 75% by weight of the other components of the course's summative assessment.

Students must attend the timetabled laboratory classes.

Students should attend at least 75% of the timetabled classes of the course.

Note that these are minimum requirements: good students will achieve far higher participation/submission rates.  Any student who misses an assessment or a significant number of classes because of illness or other good cause should report this by completing a MyCampus absence report.