Microfabrication Principles
LearningSpace will help you study
Microfabrication processes used for VLSI and other technologies. Starting with
the basic understanding of semiconductor properties and wafer preparation, the
fundamentals of microfabrication processes, including solid state diffusion,
ion implantation, thermal oxidation, and material etching are presented. The
learningSpace is organized in the following section:
Learning
Unit One: Semiconductor Properties & Wafer Preparation
Learning
Unit One covers fundamental issues relating to crystalline material properties
including the three major types of crystalline materials and common cubic
structures. You will learn to evaluate crystal structures in terms of crystal
planes and directions as well the various types of defects and impurities that
can exist within these structures during fabrication. Finally, you will also
learn the process by which the raw material for creating single-crystal silicon
wafers is first purified and then with many subsequent steps transformed into
high-purity, polished, single crystal wafers.
Learning
Unit Two covers issues relating to thermal diffusion and includes both theory
and the practical applications of the fabrication process step. You will gain
an understanding of how dopants/impurities are introduced into the silicon
substrate and how these dopants in turn affect the electrical properties of the
silicon. It also covers how these dopants move within the material and how this
leads to the formation of p-n junctions. Calculations of junction depth and
surface impurity concentration are shown.
Learning Unit Three: Ion Implantation
Learning
Unit Three addresses the ideas and theories related to Ion-Implantation. You
will be given the mathematical foundation of the theories behind this modern
process so that you may be able to design depth profiles and calculate device
junctions as well as calculate impurity concentration levels. The advantages
and disadvantages of ion-implantation, channeling, lattice damage and annealing
are also described.
Learning Unit Four: Thermal Oxidation
Learning
Unit Four covers both the theory behind the oxidation of silicon (i.e. surface
reaction rate, diffusion of dopants through an oxide layer, how steam oxidation
and dry oxidation differ in term of diffusion coefficients) and the calculation
of the projected thickness of oxide layers grown under various conditions. You
will learn the uses for oxide layer and factors, which influence oxidation, and
formation of thin oxides, and their uses.
Learning
Unit Five covers the difference between wet and dry etching, the equipment that
is used for each type of etching process and the theory behind both wet and dry
etching.