Thermal Technology of Santa Rosa, Calif., says it has successfully tested the first commercially available edge-defined, film-fed growth (EFG) crystal grower with the capacity to grow sapphire crystals up to 300 × 500 × 15 mm and will ship the first one to a customer this month. The first sapphire test plate grown was >15 mm thick, with no visible bubbles, cracks, grain boundaries or twins. Thermal Technology President and CEO Matt Mede displays a sapphire crystal produced by the company’s commercially available EFG crystal grower. Large plates such as these are required for applications including transparent armor. (Photo: Thermal Technology) The EFG process, invented in the US more than 40 years ago for the production of sapphire filaments, has since been used to produce sapphire parts in a variety of shapes, including plates, tubes, rods and ribbons. “The market is requiring larger crystals, and up until now, large sapphire crystal producers had to build their own machines,” said Matt Mede, company president and CEO. Equipment for growing smaller EFG sapphire crystals is commercially available in the Ukraine. Sapphire (aluminum oxide) has a unique combination of physical and chemical properties, including hardness, transparency over a wide range of wavelengths from infrared to ultraviolet and a high dielectric strength. It is chemically inert and has a high melting point, making it suitable for applications including supermarket scanner windows, pads for orthodontics, substrates for GaN blue LEDs and silicon devices, wear surfaces, cutting edges, IR windows and transparent armor.