Crystal Is, Inc.

Rensselaer Polytechnic Institute

Kenneth E Morgan

Leo J Schowalter

Robert T Bondokov

Glen Alfred Slack

Shailaja P Rao

Joseph A Smart

Juan Carlos Rojo

Sandra B Schujman

Shawn Robert Gibb

Shiwen Liu

Timothy J Bettles

Javier Martinez Lopez

J Carlos Rojo

Glen A Stack

Jan Barani

Carlos J Rojo

Reducing the microvoid (MV) density in AlN ameliorates numerous problems related to cracking during crystal growth, etch pit generation during the polishing, reduction of the optical transparency in an AlN wafer, and, possibly, growth pit formation during epitaxial growth of AlN and/or AlGaN. This facilitates practical crystal production strategies and the formation of large, bulk AlN crystals with low defect densities&#x2014;e.g., a dislocation density below 10cmand an inclusion density below 10cmand/or a MV density below 10cm.

Large aluminum nitride crystals with reduced defects and methods of making 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.

Defect reduction in seeded aluminum nitride crystal growth

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, 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 crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cmor less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Method and apparatus for producing large, single-crystals of aluminum nitride

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.

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.

Growing community of inventors

Castleton, NY, United States of America

Kenneth E Morgan