Defect-free semiconductor templates for epitaxial growth
AssigneeNL-Nanosemiconductor GmbH
InventorsVitaly Shchukin, Nikolai Ledentsov
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Abstract
A semiconductor device includes at least one defect-free epitaxial layer. At least a part of the device is manufactured by a method of fabrication of defect-free epitaxial layers on top of a surface of a first solid state material having a first thermal evaporation rate and a plurality of defects, where the surface comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects, the method including the steps of selective deposition of a second material, having a high temperature stability, on defect-free regions of the first solid state material, followed by subsequent evaporation of the regions in the vicinity of the defects, and subsequent overgrowth by a third material forming a defect-free layer.
Claims42
A semiconductor device comprising a substrate, a plastically relaxed layer grown on top of the substrate wherein a thickness of the plastically relaxed layer exceeds a critical thickness for plastic strain relaxation, and a defect-free layer grown on top of the plastically relaxed layer;
- wherein at least a part of the device is manufactured by a method of fabrication of defect-free epitaxial layers on top of a surface of the plastically relaxed layer having a first thermal evaporation rate and a plurality of defects, wherein the surface comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects, the method comprising the steps of:
- a) depositing a cap layer comprising a second material having a second thermal evaporation rate different from the first thermal evaporation rate, wherein the cap layer is selectively deposited on the defect-free surface region, such that at least one of the regions of the surface in the vicinity of the defects remains uncovered;
- b) annealing a structure created in step a) at a temperature and duration such that at least one of the surface regions in the vicinity of the defects that is uncovered evaporates, while defect-free surface regions covered by the cap layer remain unaffected, and at least one annealed region is formed;
- and
- c) depositing a third material, latticematched or nearly lattice matched to the plastically relaxed layer, such that the third material overgrows both the cap layer and annealed regions of the plastically relaxed layer forming the defect-free-layer.
A semiconductor device comprising a substrate, a plastically relaxed layer grown on top of the substrate wherein a thickness of the plastically relaxed layer exceeds a critical thickness for plastic strain relaxation, and a defect-free layer grown on top of the plastically relaxed layer;
- wherein at least a part of the device is manufactured by a method of fabrication of defect-free epitaxial layers on a surface of the plastically relaxed layer, the method comprising the steps of:
- a) depositing the plastically relaxed layer having a first thermal evaporation rate, wherein the plastically relaxed layer is lattice-mismatched to a substrate, wherein a thickness of the plastically relaxed layer exceeds a critical thickness required for a formation of defects, such that a plurality of defects are formed in the plastically relaxed layer, wherein the surface of the plastically relaxed layer comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects;
- b) depositing a cap layer of a second material having a second thermal evaporation rate different from the first thermal evaporation rate, such that the cap layer is selectively deposited on the defect-free surface regions, and at least one of the surface regions in the vicinity of the defects remains uncovered;
- c) annealing a structure formed in step b) at a temperature and duration such that at least one of the surface regions in the vicinity of the defects that is uncovered evaporates, while defect-free surface regions covered by the cap layer remain unaffected, and at least one annealed region is formed;
- and
- d) depositing a third material, latticematched or nearly lattice matched to the first epitaxial layer, such that the third material overgrows both the cap layer and annealed regions of the first epitaxial layer, forming the defect-free layer suitable as a template for further epitaxial growth.
A GaN-based vertical cavity surface emitting laser comprising a cavity comprising a substrate, a plastically relaxed layer grown on top of the substrate wherein a thickness of the plastically relaxed layer exceeds a critical thickness for plastic strain relaxation, and a defect-free layer grown on top of the plastically relaxed layer, wherein at least a part of the cavity is made by a method comprising the steps of:
- a) depositing the plastically relaxed layer having a first thermal evaporation rate on the substrate, wherein the plastically relaxed layer is lattice-mismatched to the substrate, wherein a thickness of the plastically relaxed layer exceeds a critical thickness required for a formation of defects, such that a plurality of defects are formed in the plastically relaxed layer, such that a surface of said plastically relaxed layer comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects;
- b) depositing a cap layer of a second material having a second thermal evaporation rate different from the first thermal evaporation rate, such that the cap layer is selectively deposited on the defect-free surface regions, and at least one of the surface regions in the vicinity of the defects remains uncovered;
- c) annealing a structure formed in step b) at a temperature and duration such that at least one of the surface regions in the vicinity of the defects that is uncovered evaporates, while defect-free surface regions covered by the cap layer remain unaffected, and at least one annealed region is formed;
- and
- d) depositing a third material, latticematched or nearly lattice matched to the first epitaxial layer, such that the third material overgrows both the cap layer and annealed regions of the first epitaxial layer, forming the defect-free layer suitable as a template for further epitaxial growth.
A GaN-based edge-emitting laser comprising a waveguide comprising a substrate, a plastically relaxed layer grown on top of the substrate wherein a thickness of the plastically relaxed layer exceeds a critical thickness for plastic strain relaxation, and a defect-free layer grown on top of the plastically relaxed layer, wherein at least a part of the waveguide is made by a method comprising the steps of:
- a) depositing the plastically relaxed layer having a first thermal evaporation rate on the substrate, wherein the plastically relaxed layer is lattice-mismatched to the substrate, wherein a thickness of the plastically relaxed layer exceeds a critical thickness required for a formation of defects, such that a plurality of defects are formed in the plastically relaxed layer, such that a surface of said plastically relaxed layer comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects;
- b) depositing a cap layer of a second material having a second thermal evaporation rate different from the first thermal evaporation rate, such that the cap layer is selectively deposited on the defect-free surface regions, and at least one of the surface regions in the vicinity of the defects remains uncovered;
- c) annealing a structure formed in step b) at a temperature and duration such that at least one of the surface regions in the vicinity of the defects that is uncovered evaporates, while defect-free surface regions covered by the cap layer remain unaffected, and at least one annealed region is formed;
- and
- d) depositing a third material, latticematched or nearly lattice matched to the plastically relaxed layer, such that the third material overgrows both the cap layer and annealed regions of the plastically relaxed layer, forming the defect-free layer suitable as a template for further epitaxial growth.
A GaN-based tilted cavity laser comprising a cavity comprising a substrate, a plastically relaxed layer grown on top of the substrate wherein a thickness of the plastically relaxed layer exceeds a critical thickness for plastic strain relaxation, and a defect-free layer grown on top of the plastically relaxed layer, wherein at least a part of the cavity is made by a method comprising the steps of:
- a) depositing the plastically relaxed layer having a first thermal evaporation rate on the substrate, wherein the plastically relaxed layer is lattice-mismatched to the substrate, wherein a thickness of the plastically relaxed layer exceeds a critical thickness required for a formation of defects, such that a plurality of defects are formed in the plastically relaxed layer, such that a surface of said plastically relaxed layer comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects;
- b) depositing a cap layer of a second material having a second thermal evaporation rate different from the first thermal evaporation rate, such that the cap layer is selectively deposited on the defect-free surface regions, and at least one of the surface regions in the vicinity of the defects remains uncovered;
- c) annealing a structure formed in step b) at a temperature and duration such that at least one of the surface regions in the vicinity of the defects that is uncovered evaporates, while defect-free surface regions covered by the cap layer remain unaffected, and at least one annealed region is formed;
- and
- d) depositing a third material, latticematched or nearly lattice matched to the plastically relaxed layer, such that the third material overgrows both the cap layer and annealed regions of the plastically relaxed layer, forming the defect-free layer suitable as a template for further epitaxial growth.
Dependencies are inferred from the claim text.