Silicon is the raw material most often used in integrated circuit (IC)
             fabrication. It is the second most abundant substance on the earth. It is
             extracted from rocks and common beach sand and put through an exhaustive
             purification process. In this form, silicon is the purist industrial
             substance that man produces, with impurities comprising less than one part
             in a billion. That is the equivalent of one tennis ball in a string of
             golf balls stretching from the earth to the moon.
             Semiconductors are usually materials which have energy-band gaps
             smaller than 2eV. An important property of semiconductors is the ability
             to change their resistivity over several orders of magnitude by doping.
             Semiconductors have electrical resistivities between 10-5 and 107 ohms.
             Semiconductors can be crystalline or amorphous. Elemental semiconductors
             are simple-element semiconductor materials such as silicon or germanium.
             Silicon is the most common semiconductor material used today. It is
             used for diodes, transistors, integrated circuits, memories, infrared
             detection and lenses, light-emitting diodes (LED), photosensors, strain
             gages, solar cells, charge transfer devices, radiation detectors and a
             variety of other devices. Silicon belongs to the group IV in the periodic
             table. It is a grey brittle material with a diamond cubic structure.
             Silicon is conventionally doped with Phosphorus, Arsenic and Antimony and
             Boron, Aluminum, and Gallium acceptors. The energy gap of silicon is 1.1
             eV. This value permits the operation of silicon semiconductors devices at
             Now I will give you some brief history of the evolution of electronics
             which will help you understand more about semiconductors and the silicon
             chip. In the early 1900's before integrated circuits and silicon chips
             were invented, computers and radios were made with vacuum tubes. The
             vacuum tube was invented in 1906 by Dr.Lee DeFore...