Instructor: Engr. Penmyrn I. Sabanal
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Electronics Circuits: Devices and Analysis ECE220a
Semiconductor Fundamentals
I. Introduction to Semiconductor
Diodes, transistors, integrated circuits, and other so-called "solid state"
devices are made from crystals of a semiconductor material, usually Silicon or
Germanium. At room temperature, the crystals of pure silicon and germanium are
neither good insulators nor good conductors. This is why they are called
semiconductors.
Semiconductor
- materials whose electrical conductivity lies between conductor and an
insulator
- have a medium energy gap that results in small amount of current flow
- have 4 electrons in its outer most orbit and which forms crystalline
structure
- pure semiconductor materials are Germanium, Silicon, and Carbon
- as the temperature increases in a semiconductor material, electrons drift
from one atom to another
- current flow in semiconductor materials consists of both electron flow and
hole movement
- has negative temperature coefficient of resistance, i.e. the resistance of
semiconductor decreases with increase in temperature and vice versa
- the resistivity lies between insulator and conductor
- doping increases conductivity of semiconductor
