Crystal Is, Inc.

Shailaja P Rao

Leo J Schowalter

Robert T Bondokov

Glen Alfred Slack

Kenneth E Morgan

Jianfeng Chen

Shawn Robert Gibb

Shichao Wang

Takashi Suzuki

Keisuke Yamaoka

Sandra B Schujman

In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.

Thermal control for formation and processing of aluminum nitride

In various embodiments, single-crystal aluminum nitride boules and substrates having high transparency to ultraviolet light and low defect density are formed. The single-crystal aluminum nitride may function as a platform for the fabrication of light-emitting devices such as light-emitting diodes and lasers.

Large, UV-transparent aluminum nitride single crystals

Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density&#x2264;100 cm. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

Defect reduction in seeded aluminum nitride crystal growth

UV-transparent aluminum nitride single crystal having a diameter of 35 mm to 150 mm and a predefined UV transparency metric at a wavelength of 265 nm

In various embodiments, methods of forming single-crystal AlN include providing a substantially undoped polycrystalline AlN ceramic having an oxygen concentration less than approximately 100 ppm, forming a single-crystal bulk AlN crystal by a sublimation-recondensation process at a temperature greater than approximately 2000&#xb0; C., and cooling the bulk AlN crystal to a first temperature between approximately 1500&#xb0; C. and approximately 1800&#xb0; C. at a first rate less than approximately 250&#xb0; C./hour.

Aluminum nitride bulk crystals having high transparency to ultraviolet light and methods of forming them

Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density &#x2264;100 cm. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

In various embodiments, non-zero thermal gradients are formed within a growth chamber both substantially parallel and substantially perpendicular to the growth direction during formation of semiconductor crystals, where the ratio of the two thermal gradients (parallel to perpendicular) is less than 10, by, e.g., arrangement of thermal shields outside of the growth chamber.

System for growth of large aluminum nitride single crystals with thermal-gradient control

Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density&#x2266;100 cm. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

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Albany, NY, United States of America

Shailaja P Rao