Rubicon develops new sapphire window technique

15 Aug 2012

Novel growth platform will enable manufacture of large optical-grade windows for military, industrial applications.

Rubicon Technology, Inc., a developer of sapphire substrates and products for the LED, semiconductor, and optical industries, has announced a “ground-breaking project”, called Large-Area Net-shape Crystal Extraction (LANCE), to produce large-area sapphire windows of optical quality for military sensing applications.

The project is supported by a grant from the US Air Force Research Laboratory (AFRL), with a total value of $4.7 million over three years.

Rubicon Technology says it is drawing on its experience and expertise with the medium to develop this “unique new crystal growth platform”. The company says that conventional methods used to produce sapphire windows do not meet all the demands of military applications.

Production will be scaled to meet the current and future requirements of the Air Force, beginning with intermediate sizes and progressing to windows as large as 900 x 450 x 20 mm (36 x 18 x 0.8 in). Such sapphire windows will meet a variety of needs in both government and private sector applications.

Sapphire is an optimal material for military and other high-performance applications due to its hardness and strength, transparency in the visible and infrared spectrum, thermal conductivity, thermal shock resistance, abrasion resistance, high melting point and chemical inertness consequently, it is ideally suited for infrared windows in extreme environments where material durability is just as important as optical clarity.

“Sapphire’s exceptional physical and optical qualities offer many benefits in applications such as military IR windows,” noted Raja M. Parvez, President and CEO of Rubicon Technology.

“However, producing high-quality sapphire large enough for such applications has proven difficult. So Rubicon drew on more than a decade of experience and our culture of innovation in crystal growth technology to develop an entirely new platform to address this need. This research sets the stage for many defense and industrial applications for large sapphire windows of exceptional optical quality.

Existing growth technologies that produce large-area sapphire crystals are incapable of generating the thickness required for demanding defense applications. Rubicon’s new technological platform will grow panels approximately two inches thick, which can be cut into multiple windows of varying thickness to meet the needs of the industry.

The platform developed through the LANCE project is distinct from Rubicon’s highly regarded ES2 crystal growth technology, which will remain the platform for Rubicon’s C-plane sapphire used in the LED industry and R-plane sapphire for Silicon-on-Sapphire RFIC applications.

About Rubicon Technology

Rubicon Technology, Inc. develops monocrystalline sapphire and other crystalline products for applications in LEDs, radio frequency integrated circuits (RFICs), blue laser diodes, optoelectronics and other optical applications.

The company applies its proprietary crystal growth technology to produce high-quality sapphire in a form that allows for volume production of various sizes and orientations of substrates and windows.

Rubicon is a vertically-integrated manufacturer with capabilities in crystal growth, high precision core drilling, wafer slicing, surface lapping, large-diameter polishing and wafer cleaning processes, which it employs to convert the bulk crystal into products with the quality and precision specified by its customers.

About the Author

Matthew Peach is a contributing editor to optics.org.