Growth of bulk single crystals of aluminum nitride
OwnerCharles Eric Hunterinventor
Life of this patent
Estimating the term…
Abstract
Bulk, low impurity aluminum nitride (AlN) single crystals are grown by sublimation or similar deposition techniques at growth rates greater than 0.5 mm/hr.
Claims21
An apparatus for the growth of bulk single crystals of AlN at enhanced growth rates by depositing vapor species of Al and N on the crystal growth interface of a seed crystal, said apparatus comprising:
- a furnace chamber, a heater, a thermal sink, a seed holder thermally linked to said thermal sink, a source material supply and a temperature control system for maintaining a sufficiently low temperature at the growth surface of the seed crystal to create a sufficient thermal gradient along which the vapor species move to the crystal growth interface;
- and
- an effusion system for sweeping away impurity atoms/molecules and non-stoichiometric vapor constituents at the crystal growth interface.
An apparatus for the growth of bulk single crystals of AlN at enhanced growth rates by depositing vapor species of Al and N on the growth surface of a crystal growth interface through the recondensation of sublimed Al-and N-containing source material, said apparatus comprising:
- a furnace chamber;
- a heater within said furnace chamber;
- a crucible having a diameter, D, located within said furnace chamber and holding at least a portion of the source material in solid or liquid form, said source material having a purity defined by less than about 0.08% excess Al content, less than about 0.05% non-dopant/non-alloying electrically active impurities content, and less than about 400 ppm oxygen content by weight;
- a seed holder holding a seed crystal within said crucible at a height, H, above the source material;
- and
- the H:D aspect ratio being less than about 2.5:1.
The system of claim 14 wherein said H:D aspect ratio is less than about 1:3.
An apparatus for the growth of large diameter bulk single crystals of AlN by depositing vapor species of Al and N on the growth surface of a crystal growth interface through the recondensation of sublimed Al-and N-containing source material, said apparatus comprising:
- a furnace chamber;
- a crucible having a substantially flat bottom surface and a diameter, D, said crucible being located within said furnace chamber and holding at least a portion of the source material in solid or liquid form;
- a horizontally disposed flat plate heater located below the flat bottom of said crucible in close spaced relation thereto for supplying heat to the system with a uniform horizontal thermal profile;
- a seed holder holding a seed crystal within said crucible at a height, H, above the source material;
- and
- the H:D aspect ratio being less than about 1:3.
An apparatus for the growth of bulk single crystals of AlN at enhanced growth rates by depositing species of Al from a liquid Al source and N from an N.sub.2 gas source on the growth surface of a seed crystal, said apparatus comprising:
- a furnace chamber;
- a first crucible area within the furnace chamber, said first crucible area containing a thermal sink and a seed holder holding a seed crystal with the seed crystal in heat transfer relationship to the thermal sink;
- a heater for maintaining a desired thermal gradient within the first crucible area;
- means for introducing N.sub.2 gas into the first crucible area;
- means for introducing Al vapor into the first crucible area, said means for introducing Al vapor comprising a second crucible area in fluid communication with the first crucible area and containing liquid Al;
- and
- a heater associated with the second crucible area for maintaining the temperature of the liquid Al.
Dependencies are inferred from the claim text.