Synthetic sapphire is a single crystal form of corundum, AI₂O₃. Sapphire is aluminum oxide in purest form with no porosity or grain boundaries, making it theoretically dense. The combination of favorable chemical, electrical, 
mechanical, optical, surface, thermal, and durability properties make sapphire the preferred material for high 
performance system and component designs. For various semiconductor applications sapphire is the best 
choice in the comparison with other synthetic single crystals.