Reusable nitride wafer, method of making, and use thereof
First Claim
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1. A gallium-containing nitride wafer, comprising:
- a crystalline substrate member having at least a diameter greater than about 25 millimeters and a thickness between about 100 micrometers and about 10 millimeters, a substantially wurtzite structure;
a first, epi-ready, large-area surface, characterized by a root-mean-square surface roughness less than about 0.5 nanometer measured over an area of 20 micrometers by 20 micrometers, 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,a second large-area surface, characterized by a root-mean-square surface roughness less than about 10 micrometers measured over an area of at least 20 micrometers by 20 micrometers;
an edge perimeter that is substantially round, with at least one orientation flat; and
at least one regrowth interface, wherein,the at least one regrowth interface is substantially parallel to the first, epi-ready surface and is separated from the first surface by a distance of at least 10 micrometers;
an average concentration of at least one impurity selected from oxygen, hydrogen, silicon, carbon, fluorine, chlorine, lithium, sodium, and potassium, in a five-micrometer-thick layer on one side of the at least one regrowth interface is higher than an average concentration of the impurity in a five-micrometer-thick layer on an opposite side of the at least one regrowth interface by at least five percent and by less than a factor of five; and
an average concentration of at the at least one impurity within a 5 micrometer-thick layer centered at the at least one regrowth interface is greater than an average concentration of the impurity in a five-micrometer-thick layer on opposite sides of the at least one regrowth interface by at least 10 percent and by less than a factor of 103.
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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.
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Citations
21 Claims
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1. A gallium-containing nitride wafer, comprising:
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a crystalline substrate member having at least a diameter greater than about 25 millimeters and a thickness between about 100 micrometers and about 10 millimeters, a substantially wurtzite structure; a first, epi-ready, large-area surface, characterized by a root-mean-square surface roughness less than about 0.5 nanometer measured over an area of 20 micrometers by 20 micrometers, 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,a second large-area surface, characterized by a root-mean-square surface roughness less than about 10 micrometers measured over an area of at least 20 micrometers by 20 micrometers; an edge perimeter that is substantially round, with at least one orientation flat; and at least one regrowth interface, wherein, the at least one regrowth interface is substantially parallel to the first, epi-ready surface and is separated from the first surface by a distance of at least 10 micrometers; an average concentration of at least one impurity selected from oxygen, hydrogen, silicon, carbon, fluorine, chlorine, lithium, sodium, and potassium, in a five-micrometer-thick layer on one side of the at least one regrowth interface is higher than an average concentration of the impurity in a five-micrometer-thick layer on an opposite side of the at least one regrowth interface by at least five percent and by less than a factor of five; and an average concentration of at the at least one impurity within a 5 micrometer-thick layer centered at the at least one regrowth interface is greater than an average concentration of the impurity in a five-micrometer-thick layer on opposite sides of the at least one regrowth interface by at least 10 percent and by less than a factor of 103. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A bulk single-crystal semiconductor wafer, comprising:
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a crystalline substrate member having a thickness between about 100 micrometers and about 10 millimeters, a first surface being epi-ready, and first, second and third layers having first, second and third average impurity concentrations, respectively, wherein said second average impurity concentration is less than said third average impurity concentration, and said first average impurity concentration is greater than both said second and third average impurity concentrations; at least one regrowth interface within said first layer, said regrowth interface being substantially parallel to said first surface and separated from said first surface by a distance of at least 10 micrometers, said regrowth interface having a secondary electron yield higher than that of the material immediately above and below said regrowth interface; and said wafer being heatable to at least 950°
C. for six hours in an atmosphere consisting essentially of ammonia at a pressure of about 760 Torr without undergoing visible degradation. - View Dependent Claims (16, 17)
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18. A reusable bulk GaN single-crystal semiconductor wafer, comprising:
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a first layer having a first average impurity concentration; a regrowth interface within the first layer, wherein the regrowth interface has a higher secondary electron yield than that of the material immediately above and below the interface; a second layer having a second average impurity concentration; and a third layer having a third average impurity concentration, the first layer lying between the second layer and the third layer; wherein the second average impurity concentration is less than the third average impurity concentration and the first average impurity concentration is greater than both the second and third average impurity concentrations. - View Dependent Claims (19, 20, 21)
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Specification