Internal Heating for Ammonothermal Growth of Group-III Nitride Crystals

Tech ID: 27641 / UC Case 2009-283-0

Brief Description

A new process for heating vessels used in the ammonothermal growth of group-III nitrides.


The current technique for ammonothermal growth of group-III nitrides includes externally heating the vessel holding the group-III nitride source material. The heating process involves heating the outside of the vessel causing the heat to transfer from the outer walls to the inner walls resulting in heating the fluid surrounded by the walls of the vessel. Current vessels, or reactors, are long and cylindrical creating two zones of liquid: the lower zone, that holds the source or seed materials, and the higher zone. The two zones are often separated by a baffle plate, restricting fluid flow and allowing each zone the ability to have different temperatures. Improving the heating process and baffle designs for these reactors will make them more efficient and effective allowing for increased growth rates and improvements in crystal quality. 


Researchers at the University of California, Santa Barbara have created a new process for heating vessels used in the ammonothermal growth of group-III nitrides. This new technique uses internal heaters in replace of or in conjunction with, external heaters. The use of internal heaters offers many advantages over external heaters. First, any number of heaters can be used and can be placed in any location inside the vessel. Additionally, heaters can be integrated to other parts of the vessel, such as the baffle plates which will allow more efficient and more effective designs. Each individual internal heater can have its own temperature and be adapted into any shape, form, size or material.  Using internal heaters will assist in establishing a temperature gradient, throughout spatial zones inside the vessel, and solubility gradients resulting in increased growth rates and improved crystal quality of group-III nitride crystals. 


  • Increased efficiency
  • Improved design
  • Each heater can have unique characteristics (temperature, size, shape, form, materials, etc.)


  •  Ammonothermal growth of group-III nitride crystals

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 8,641,823 02/04/2014 2009-283


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Other Information


ammonothermal growth, nitride, group-III nitride, crystal, bulk growth, indbulk

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