Reusable nitride wafer, method of making, and use thereof
AssigneeSLT Technologies, Inc.
InventorsMark P. D'Evelyn, Michael Ragan Krames
Life of this patent
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Abstract
Techniques for processing materials for manufacture of gallium-containing nitride substrates are disclosed. More specifically, techniques for fabricating and reusing large area substrates using a combination of processing techniques are disclosed. The methods can be applied to fabricating substrates of GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, and others. Such substrates can be used for a variety of applications including optoelectronic devices, lasers, light emitting diodes, solar cells, photo electrochemical water splitting and hydrogen generation, photo detectors, integrated circuits, transistors, and others.
Claims24
A method for re-using of preparing a used crystalline nitride wafer from which a layer has been removed for a regrowth process, said used crystalline nitride wafer having a diameter greater than about 25 millimeters and a thickness between about 100 micrometers and about 10 millimeters, a substantially wurtzite structure, a first surface from which said layer was removed, said a first surface having a root-mean-square surface roughness greater than about 10 nanometers measured over an area of 20 micrometers by 20 micrometers;, and a second surface opposite said first surface and having a root-mean-square surface roughness less than about 10 micrometers measured over an area of at least 20 micrometers by 20 micrometers, said method comprising:
- preparing at least one of said first surface and said second surface for re-growth to form a planarized substrate;
- performing bulk crystal growth on said planarized substrate to form a regrown wafer;
- and
- preparing a regrowth surfaceon said regrown wafer to an epi-ready state, said regrowth surface having a surface threading dislocation density less than about 107 cm−2, a stacking-fault concentration below about 102 cm−1, and a symmetric x-ray rocking curve full width at half maximum (FWHM) less than about 100 arcsec, and a root-mean-square surface roughness less than about 0.5 nanometers measured over an area of 20 micrometers by 20 micrometers.
A method for re-using a used crystalline nitride wafer from which a layer has been removed, the used crystalline nitride wafer having a thickness between about 100 micrometers and about 10 millimeters, a substantially wurtzite structure, a first surface from which the layer was removed, the first surface having a root-mean-square surface roughness greater than about 10 nanometers measured over an area of 20 micrometers by 20 micrometers;
- and a second surface opposite the first surface and having a root-mean-square surface roughness less than about 10 micrometers measured over an area of at least 20 micrometers by 20 micrometers, the method comprising:
- preparing at least one of the first surface and the second surface for re-growth to form a planarized substrate;
- performing bulk crystal growth on the planarized substrate to form a regrown wafer;
- and
- preparing a regrowth surface on the regrown wafer to an epi-ready state, the regrowth surface having a surface threading dislocation density less than about 107 cm −2, a stacking-fault concentration below about 102 cm−1, and a symmetric x-ray rocking curve full width at half maximum (FWHM) less than about 100 arcsec, and a root-mean-square surface roughness less than about 0.5 nanometers measured over an area of 20 micrometers by 20 micrometers.
Dependencies are inferred from the claim text.