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Sapphire boules grown by Rubicon Technology. Crystal sizes depicted include 3 kg, 31 kg, 83 kg, and 200 kg. A 12‐inch ruler is included for scale.
Source publication
As sensor technology and applications have advanced over the years, the
size of sensor windows has grown substantially to satisfy current and
future demands. Rubicon Technology, with their strong history in scaling
sapphire crystal growth and large scale production processes, has
successfully produced large sapphire blanks using a highly modified
h...
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Citations
... Commercially grown Kyropoulos (KY) and heat exchanger method (HEM) sapphire boules have reached 300 kg and over 450 mm diameter in the last half-decade, driven by economies of scale and demand for sapphire substrates for the LED (light emitting diode) industry. 1,2 Additionally, edge-defined film-fed growth (EFG) sapphire is commercially available in plates up to 304 mm x 508 mm. 3 However, larger sapphire windows are desirable for military applications (e.g. 1 meter by 1 meter). Both boule-growth techniques (like KY and HEM) and EFG face substantial challenges scaling up to those dimensions. ...
... We have previously grown HDSM crystals up to 350 x 940 x 38 mm in vacuum with a tungsten heating element. 1 These crystals could yield a panel with usable dimensions of up to 350 x 508 x 29 mm. To increase the size of the crystals it was necessary to add afterheating (outside the melt-heating zone) to minimize thermal gradients which can crack the crystals as they are being grown. ...
The article reviews current state of the art in growing large sapphire crystals used for epitaxial substrates of GaN light-emitting diodes and optical windows. Results of crystal growth with the Czochralski, Kyropoulos, heat-exchanger methods, horizontal directional crystallization, and edge-defined film-fed growth are demonstrated and discussed, along with recommendations of useful tools to increase crystal size.
The main techniques of bulk sapphire crystal growth (i.e., Verneuil, Czochralski, Kyropoulos, HEM – heat exchange method, GSM – gradient solidification method, and horizontal directed crystallization method are described shortly. Melt growth techniques for production of sapphire crystals with predetermined or variable cross-section (i.e., Stepanov, EFG – edge-defined film-fed growth, GES – growth from an element of shape, VST – variable shaping technique, and NCS – noncapillary shaping technique) are shown. After that typical growth techniques for production of sapphire fiber crystals (i.e., EFG, micro zone floating, micro pulling down, ICM – internal crystallization method, and µ-PD – micro pulling down technique) also are presented.
