"The term epitaxial comes from the Greek word meaning 'arranged upon.' In semiconductor technology, it refers to the single crystalline structure of the film. The structure comes about when silicon atoms are deposited on a bare silicon wafer in a CVD reactor. When the chemical reactants are controlled and the system parameters are set correctly, the depositing atoms arrive at the wafer surface with sufficient energy to move around on the surface and orient themselves to the crystal arrangement of the wafer atoms. Thus an epitaxial film deposited on a <111>-oriented wafer will take on a <111> orientation.

If, on the other hand, the wafer surface has a thin layer of silicon dioxide, an amorphous surface layer, or contamination the depositing atoms have no structure to align to. The resulting film structure is poly silicon. This condition is useful for some applications, such as MOS gates and is unwanted if the goal is to grow a single-crystal film structure."

Microchip Fabrication fourth edition by Peter Van Zant, © 2000

SVM has a wide variety of epitaxial wafers in our multi-million dollar inventory. We can also supply wafers with a customized epi layer to meet your exact specifications. If you would like to learn more about epi wafers, please contact SVM for more information.