Doping

You can change the behavior of silicon and turn it into a conductor by doping it. In doping, you mix a small amount of an impurity into the silicon crystal. 

There are two types of impurities:

• N-type - In N-type doping, phosphorus or arsenic is added to the silicon in small quantities.  This type of element is added because when introduced to the silicon lattice, 1 extra electron will remain. An N-type doped silicon is a good conductor because of these extra electrons.

• P-type - In P-type doping, boron or gallium is the dopant. Boron and gallium each have only three outer electrons. When mixed into the silicon lattice, they form "holes" in the lattice where a silicon electron has nothing to bond to. These holes act as a transport for current which makes P-type silicon also a good conductor.

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