Method for making cleaved facets for lasers fabricated with gallium nitride and other noncubic materials
First Claim
1. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate comprising:
- epitaxially growing a noncubic layer on said noncubic substrate;
fusing said epitaxially grown noncubic layer to a second substrate having said vertical plane as a cleavage plane; and
cleaving said second substrate along said vertical plane,whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate.
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Accused Products
Abstract
Optically flat cleaved facet mirrors are fabricated in GaN epitaxial films grown on sapphire by wafer fusing a GaN film with a sapphire substrate to a cubic substrate such as an InP or GaAs substrate. The sapphire substrate may then partially or entirely removed by lapping, dry etching, or wet etching away a sacrificial layer disposed in the interface between the sapphire substrate and the GaN layer. Thereafter, the cubic InP or GaN substrate is cleaved to produce the cubic crystal facet parallel to the GaN layer in which active devices are fabricated for use in lasers, photodetectors, light emitting diodes and other optoelectronic devices.
187 Citations
31 Claims
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1. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate comprising:
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epitaxially growing a noncubic layer on said noncubic substrate; fusing said epitaxially grown noncubic layer to a second substrate having said vertical plane as a cleavage plane; and cleaving said second substrate along said vertical plane, whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate. - View Dependent Claims (2, 3, 4, 5, 8, 9)
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6. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate, comprising:
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epitaxially growing a noncubic layer on said noncubic substrate; fusing said epitaxially grown noncubic layer to a second substrate which has said vertical plane as a cleavage plane; and cleaving said second substrate along said vertical plane, removing at least part of said noncubic substrate by etching away said noncubic substrate, whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate.
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7. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate, comprising;
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epitaxially growing a noncubic layer on said noncubic substrate; fusing said epitaxially grown noncubic layer to a second substrate which has said vertical plane as a cleavage plane; and cleaving said second substrate along said vertical plane, disposing a sacrificial layer on said noncubic substrate prior to epitaxially growing said layer thereon and further comprising removing at least part of said noncubic substrate by wet etching away said sacrificial layer, whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate.
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10. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate, comprising:
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epitaxially growing a noncubic layer on said noncubic substrate; fusing said epitaxially grown noncubic layer to a second substrate which has said vertical lane as a cleavage lane; and cleaving said second substrate along a vertical plane; and wherein Expitaxially growing said layer on said noncubic substrate comprises first epitaxially growing a buffer layer on said noncubic substrate and then epitaxially growing a device layer on said noncubic substrate, epitaxially growing a fusion layer on said device layer, whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate. - View Dependent Claims (11)
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12. A method for fabricating a cleaved facet along a vertical plane in a noncubic material epitaxially grown on a surface of a noncubic substrate, said vertical plane being perpendicular to said surface of said noncubic substrate, comprising:
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epitaxially growing a noncubic layer on said noncubic substrate; fusing said epitaxially grown noncubic layer to a second substrate which has said vertical plane as a cleavage plane; and cleaving said second substrate along said vertical plane; and wherein Expitaxially growing said layer on said noncubic substrate comprises first epitaxially growing a buffer layer on said noncubic substrate and then epitaxially growing a device layer on said noncubic substrate, where epitaxially growing said buffer device layer comprises epitaxially growing a GaN buffer and device layers on a sapphire substrate and further comprises epitaxially growing a fusion layer on said device layer, whereby an optically flat vertical reflecting plane is fabricated in said layer epitaxially grown on said noncubic substrate. - View Dependent Claims (13)
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14. An improvement in a method for fabricating mirror facets in a photonic device comprising:
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epitaxially growing an active device layer on a surface of a noncubic substrate; wafer fusing said epitaxially grown active device layer to an oriented substrate to provide a fused structure, said oriented substrate having a vertical cleavage plane perpendicular to said surface of said noncubic substrate; and cleaving said fused structure to obtain a cleaved vertical plane through said fused structure, whereby an optically flat mirror surface for said photonic device is obtained. - View Dependent Claims (15, 16, 17, 19)
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18. An improvement in a method for fabricating mirror facets in a photonic device comprising:
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epitaxially growing an active device layer on a surface of a noncubic substrate; wafer fusing said epitaxially grown active device layer to an oriented substrate to provide a fused structure, said oriented substrate having a vertical cleavage plane perpendicular to said surface of said noncubic substrate; and cleaving said fused structure to obtain a cleaved vertical plane through said fused structure, where epitaxially growing said active device layer on said noncubic substrate comprises epitaxially growing a Inx Ga1-x N/Iny Ga1-y N multiple quantum well layer on said substrate, where x and y are each numbers between 0 and 1 inclusive, whereby an optically flat mirror surface for said photonic device is obtained.
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20. An improvement in a method for fabricating mirror facets in a photonic device comprising:
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epitaxially growing an active device layer on a surface of a noncubic substrate; wafer fusing said epitaxially grown active device layer to an oriented substrate to provide a fused structure, said oriented substrate having a cleavage plane perpendicular to said surface of said noncubic substrate; and cleaving said fused structure to obtain a vertical cleaved plane through said fused structure, where epitaxially growing said active device layer on said sapphire substrate comprises first epitaxially growing a nucleation layer at a first temperature and thereafter growing a thicker active device layer at a second higher temperature, whereby an optically flat mirror surface for said photonic device is obtained.
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21. An improvement in a method for fabricating mirror facets in a photonic device comprising:
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epitaxially growing an active device layer on a surface of a noncubic substrate; wafer fusing said epitaxially grown active device layer to an oriented substrate to provide a fused structure, said oriented substrate having a vertical cleavage plane perpendicular to said surface of said noncubic substrate; and cleaving said fused structure to obtain a a vertical cleaved plane through said fused structure, defining a plurality of channels in said oriented substrate prior to fusing to permit fluid escape from an interface defined in said fused structure between said active device layer and said oriented substrate during fusing of said active device layer and oriented substrate, whereby an optically flat mirror surface for said photonic device is obtained.
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22. A method for fabricating a p-type electrical contact on a layer of metallic nitride comprising:
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disposing said metallic nitride layer on a first substrate; disposing a p-type fusion layer on a second substrate; fusing said metallic nitride to said p-type fusion layer on said second substrate; removing at least part of said second substrate to form an opening for an electrical contact to said metallic nitride layer; and forming an electrical contact in said opening, whereby a reduced resistance contact is provided to said metallic nitride layer. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method for activating a p-type dopant in a metallic nitride layer comprising:
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disposing a p-type doped metallic nitride layer on a first substrate; disposing a fusion layer on a second substrate; fusing said p-type doped metallic nitride layer to said fusion layer on said second substrate; and simultaneously annealing said p-type doped metallic nitride layer while fusing said p-type doped metallic nitride layer to said fusion on said second substrate to inhibit loss of nitrogen from said p-type doped metallic nitride layer while activating a p-type dopant in said p-type doped metallic nitride layer, whereby an increase in p-type dopant activation is provided to said metallic nitride layer. - View Dependent Claims (29, 30, 31)
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Specification