Basic of Soler energy (Part-1)

Silicon: Silicon is a gray, tetravalent, nonmetallic element occurring abundantly in nature. Next to Oxygen it is the chief elementary constituent of the earth's crust. The symbol for Silicon is Si its atomic number is 14 and its atomic mass is 28.086. This element is almost always found in various compounds both in nature and in industry, in nature you find it in quartz, jasper, agate, flint, common beach sand, sandstone and many other common rocks and materials. In industry we find it as the main component in the most common building materials such as cement, bricks, glass and others.

Silicon as a Semiconductor: One of the most important uses for Silicon in the second half of the twentieth century and beyond is its ability to conduct electricity in a very controlled manner. Relative to how many impurities or dopants (Boron, Phosphorus, Arsenic, Antimony, etc.) are placed into its crystal structure. Simply put the more dopant in the crystal lattice of Silicon the more it will conduct electricity. In theory pure mono-crystalline Silicon will not conduct electricity very well at all, the beauty of Silicon is that it can be made to take on dopants precisely and after this doping it will normally remain stable under many adverse conditions. Thus making the Silicon wafers an ideal Palette or surface for the construction of today and tomorrow most advanced semiconductor devices.

The making of a Silicon Ingot: With all this talk of sand and glass it may begin to over simplify a very complex process. The process of growing Ingots of mono-crystalline Silicon with a uniform and controlled dopant and oxygen content, and then to take these Ingots and grind, slice and polish them into the final Prime wafers mostly free of defects that major Fab's will use to build advanced semiconductor devices on, is nothing short of a monumental task.

Raw Material: Silicon is the raw material of course; the crucible is filled with pure Polysilicon chips. These chunks of Poly have been made from sand by means of a complex reduction and purification process using Trichlorosilane and Hydrogen. Then the Polysilicon is further distilled and reduced and finally deposited on heated Titanium or Tantalum tubes. After further processing it becomes the material you see it may be in a granular form. The Poly is in a quartz container called a crucible and this material is now ready to go on to the next processing step in the manufacturing of a high quality Silicon ingot.

                                                                    Polysilicon chips