Patent
US 11,767,609 B2LOW-DISLOCATION BULK GAN CRYSTAL AND METHOD OF FABRICATING SAME
Tadao Hashimoto
SixPoint Materials, Inc., Buellton, CA (US)·Sep. 26, 2023·US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 11,767,609 B2Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a schematic drawing of the bulk crystal. In the figure each number represents the followings: 1. A first region (a seed crystal), 1a. A dislocation in …
FIG. 2 is a schematic drawing of the fabrication process of the bulk crystal depicted at steps A-E during fabrication of the bulk crystal. As described below,
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of fabricating a GaN crystal in supercritical ammonia comprising (a) etching a nitrogen polar c-plane surface of a GaN seed crystal to selectively form pits at surface termination points of dislocations, (b) forming metal masks upon surfaces of the pits, wherein the step of forming the metal masks comprises (1) depositing metal powder particles on the nitrogen polar c-plane surface of the GaN seed crystal having pits, (2) removing an excess amount of the metal powder particles from the surface, thereby leaving a quantity of the metal powder particles in the pits, and (3) annealing the GaN seed with the metal powder particles to form metal masks in the pits, and (c) growing a GaN crystal on the GaN seed crystal and above the metal masks in supercritical ammonia.
A method of fabricating a GaN crystal according to claim 1, wherein at least some of the pits formed on the nitrogen polar c-plane surface of the GaN seed crystal have a cone shape.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in an electrolyte and flowing electric current from the GaN seed crystal to the electrolyte.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in molten KOH, NaOH or a eutectic solution of KOH and NaOH.
A method according to claim 1, wherein the metal powder particles comprise silver particles. 11 12
A method according to claim 1, wherein the seed crystal was formed from a bulk crystal formed by ammono-thermal deposition directly upon a crystal formed by HVPE.
A method according to claim 1, wherein the seed has a dislocation density of less than 106 cm⁻².
A method according to claim 1, wherein each of the pits at the surface termination points of dislocations is greater than 10 microns from other of the pits at the surface termination points of dislocations.
A method according to claim 1, wherein the pits are formed by electromechanically etching the seed crystal, and the etchant and the light incident upon the GaN seed crystal are selected to avoid forming excess pits at locations on the surface of the GaN seed crystal that are not associated with the dislocations.
A method according to claim 1, wherein the GaN seed crystal is not planarized between the step of forming the metal masks and the step of growing the GaN crystal on the GaN seed crystal. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
low-dislocation bulk GaN crystal
Materials described outside the worked examples.
GaN seed crystal
GaN
metal powder particles
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
seed crystal dislocation density (HVPE-derived) | ~1e6 cm⁻² | GaN |
ammonothermally grown GaN dislocation density without masks | ~1e5 cm⁻² |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 19
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 11,767,609 B2Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a schematic drawing of the bulk crystal. In the figure each number represents the followings: 1. A first region (a seed crystal), 1a. A dislocation in …
FIG. 2 is a schematic drawing of the fabrication process of the bulk crystal depicted at steps A-E during fabrication of the bulk crystal. As described below,
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of fabricating a GaN crystal in supercritical ammonia comprising (a) etching a nitrogen polar c-plane surface of a GaN seed crystal to selectively form pits at surface termination points of dislocations, (b) forming metal masks upon surfaces of the pits, wherein the step of forming the metal masks comprises (1) depositing metal powder particles on the nitrogen polar c-plane surface of the GaN seed crystal having pits, (2) removing an excess amount of the metal powder particles from the surface, thereby leaving a quantity of the metal powder particles in the pits, and (3) annealing the GaN seed with the metal powder particles to form metal masks in the pits, and (c) growing a GaN crystal on the GaN seed crystal and above the metal masks in supercritical ammonia.
A method of fabricating a GaN crystal according to claim 1, wherein at least some of the pits formed on the nitrogen polar c-plane surface of the GaN seed crystal have a cone shape.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in an electrolyte and flowing electric current from the GaN seed crystal to the electrolyte.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in molten KOH, NaOH or a eutectic solution of KOH and NaOH.
A method according to claim 1, wherein the metal powder particles comprise silver particles. 11 12
A method according to claim 1, wherein the seed crystal was formed from a bulk crystal formed by ammono-thermal deposition directly upon a crystal formed by HVPE.
A method according to claim 1, wherein the seed has a dislocation density of less than 106 cm⁻².
A method according to claim 1, wherein each of the pits at the surface termination points of dislocations is greater than 10 microns from other of the pits at the surface termination points of dislocations.
A method according to claim 1, wherein the pits are formed by electromechanically etching the seed crystal, and the etchant and the light incident upon the GaN seed crystal are selected to avoid forming excess pits at locations on the surface of the GaN seed crystal that are not associated with the dislocations.
A method according to claim 1, wherein the GaN seed crystal is not planarized between the step of forming the metal masks and the step of growing the GaN crystal on the GaN seed crystal. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
low-dislocation bulk GaN crystal
Materials described outside the worked examples.
GaN seed crystal
GaN
metal powder particles
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
seed crystal dislocation density (HVPE-derived) | ~1e6 cm⁻² | GaN |
ammonothermally grown GaN dislocation density without masks | ~1e5 cm⁻² |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 19
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 11,767,609 B2Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a schematic drawing of the bulk crystal. In the figure each number represents the followings: 1. A first region (a seed crystal), 1a. A dislocation in …
FIG. 2 is a schematic drawing of the fabrication process of the bulk crystal depicted at steps A-E during fabrication of the bulk crystal. As described below,
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of fabricating a GaN crystal in supercritical ammonia comprising (a) etching a nitrogen polar c-plane surface of a GaN seed crystal to selectively form pits at surface termination points of dislocations, (b) forming metal masks upon surfaces of the pits, wherein the step of forming the metal masks comprises (1) depositing metal powder particles on the nitrogen polar c-plane surface of the GaN seed crystal having pits, (2) removing an excess amount of the metal powder particles from the surface, thereby leaving a quantity of the metal powder particles in the pits, and (3) annealing the GaN seed with the metal powder particles to form metal masks in the pits, and (c) growing a GaN crystal on the GaN seed crystal and above the metal masks in supercritical ammonia.
A method of fabricating a GaN crystal according to claim 1, wherein at least some of the pits formed on the nitrogen polar c-plane surface of the GaN seed crystal have a cone shape.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in an electrolyte and flowing electric current from the GaN seed crystal to the electrolyte.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in molten KOH, NaOH or a eutectic solution of KOH and NaOH.
A method according to claim 1, wherein the metal powder particles comprise silver particles. 11 12
A method according to claim 1, wherein the seed crystal was formed from a bulk crystal formed by ammono-thermal deposition directly upon a crystal formed by HVPE.
A method according to claim 1, wherein the seed has a dislocation density of less than 106 cm⁻².
A method according to claim 1, wherein each of the pits at the surface termination points of dislocations is greater than 10 microns from other of the pits at the surface termination points of dislocations.
A method according to claim 1, wherein the pits are formed by electromechanically etching the seed crystal, and the etchant and the light incident upon the GaN seed crystal are selected to avoid forming excess pits at locations on the surface of the GaN seed crystal that are not associated with the dislocations.
A method according to claim 1, wherein the GaN seed crystal is not planarized between the step of forming the metal masks and the step of growing the GaN crystal on the GaN seed crystal. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
low-dislocation bulk GaN crystal
Materials described outside the worked examples.
GaN seed crystal
GaN
metal powder particles
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
seed crystal dislocation density (HVPE-derived) | ~1e6 cm⁻² | GaN |
ammonothermally grown GaN dislocation density without masks | ~1e5 cm⁻² |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 19
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 11,767,609 B2Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a schematic drawing of the bulk crystal. In the figure each number represents the followings: 1. A first region (a seed crystal), 1a. A dislocation in …
FIG. 2 is a schematic drawing of the fabrication process of the bulk crystal depicted at steps A-E during fabrication of the bulk crystal. As described below,
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of fabricating a GaN crystal in supercritical ammonia comprising (a) etching a nitrogen polar c-plane surface of a GaN seed crystal to selectively form pits at surface termination points of dislocations, (b) forming metal masks upon surfaces of the pits, wherein the step of forming the metal masks comprises (1) depositing metal powder particles on the nitrogen polar c-plane surface of the GaN seed crystal having pits, (2) removing an excess amount of the metal powder particles from the surface, thereby leaving a quantity of the metal powder particles in the pits, and (3) annealing the GaN seed with the metal powder particles to form metal masks in the pits, and (c) growing a GaN crystal on the GaN seed crystal and above the metal masks in supercritical ammonia.
A method of fabricating a GaN crystal according to claim 1, wherein at least some of the pits formed on the nitrogen polar c-plane surface of the GaN seed crystal have a cone shape.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in an electrolyte and flowing electric current from the GaN seed crystal to the electrolyte.
A method of fabricating a GaN crystal according to claim 1, wherein the pits are formed by immersing the GaN seed crystal in molten KOH, NaOH or a eutectic solution of KOH and NaOH.
A method according to claim 1, wherein the metal powder particles comprise silver particles. 11 12
A method according to claim 1, wherein the seed crystal was formed from a bulk crystal formed by ammono-thermal deposition directly upon a crystal formed by HVPE.
A method according to claim 1, wherein the seed has a dislocation density of less than 106 cm⁻².
A method according to claim 1, wherein each of the pits at the surface termination points of dislocations is greater than 10 microns from other of the pits at the surface termination points of dislocations.
A method according to claim 1, wherein the pits are formed by electromechanically etching the seed crystal, and the etchant and the light incident upon the GaN seed crystal are selected to avoid forming excess pits at locations on the surface of the GaN seed crystal that are not associated with the dislocations.
A method according to claim 1, wherein the GaN seed crystal is not planarized between the step of forming the metal masks and the step of growing the GaN crystal on the GaN seed crystal. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
low-dislocation bulk GaN crystal
Materials described outside the worked examples.
GaN seed crystal
GaN
metal powder particles
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
seed crystal dislocation density (HVPE-derived) | ~1e6 cm⁻² | GaN |
ammonothermally grown GaN dislocation density without masks | ~1e5 cm⁻² |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 19
Related documents with shared materials, methods, properties, or citations.
organic acid electrolyte
oxalic acid
C₂H₂O₄
KOH or NaOH or eutectic KOH/NaOH
eutectic solution of KOH and NaOH
silver particles
Ag
nickel
Ni
vanadium
V
platinum
Pt
supercritical ammonia
NH₃
seed dislocation density (claimed upper limit) | ≤ 1000000 cm⁻² | GaN |
grown GaN dislocation density with metal masks | ~1/10 or less of seed relative | GaN |
Temperature | 150–450 °C | — |
Temperature | 200–400 °C | — |
Duration | 1–300 second | — |
Thickness | 0.5–1 µm | — |
Thickness | ≤ 1 µm | — |
Thickness | ≤ 100000 cm | — |
Thickness | 0.01–10 µm | — |
Thickness | ≤ 1000000 cm | — |
Thickness | ≥ 10 µm | — |
Cited non-patent literature · 2
INDIUM GALLIUM NITRIDE-BASED OHMIC CONTACT LAYERS FOR GALLIUM NITRIDE-BASED DEVICES
organic acid electrolyte
oxalic acid
C₂H₂O₄
KOH or NaOH or eutectic KOH/NaOH
eutectic solution of KOH and NaOH
silver particles
Ag
nickel
Ni
vanadium
V
platinum
Pt
supercritical ammonia
NH₃
seed dislocation density (claimed upper limit) | ≤ 1000000 cm⁻² | GaN |
grown GaN dislocation density with metal masks | ~1/10 or less of seed relative | GaN |
Temperature | 150–450 °C | — |
Temperature | 200–400 °C | — |
Duration | 1–300 second | — |
Thickness | 0.5–1 µm | — |
Thickness | ≤ 1 µm | — |
Thickness | ≤ 100000 cm | — |
Thickness | 0.01–10 µm | — |
Thickness | ≤ 1000000 cm | — |
Thickness | ≥ 10 µm | — |
Cited non-patent literature · 2
INDIUM GALLIUM NITRIDE-BASED OHMIC CONTACT LAYERS FOR GALLIUM NITRIDE-BASED DEVICES
organic acid electrolyte
oxalic acid
C₂H₂O₄
KOH or NaOH or eutectic KOH/NaOH
eutectic solution of KOH and NaOH
silver particles
Ag
nickel
Ni
vanadium
V
platinum
Pt
supercritical ammonia
NH₃
seed dislocation density (claimed upper limit) | ≤ 1000000 cm⁻² | GaN |
grown GaN dislocation density with metal masks | ~1/10 or less of seed relative | GaN |
Temperature | 150–450 °C | — |
Temperature | 200–400 °C | — |
Duration | 1–300 second | — |
Thickness | 0.5–1 µm | — |
Thickness | ≤ 1 µm | — |
Thickness | ≤ 100000 cm | — |
Thickness | 0.01–10 µm | — |
Thickness | ≤ 1000000 cm | — |
Thickness | ≥ 10 µm | — |
Cited non-patent literature · 2
INDIUM GALLIUM NITRIDE-BASED OHMIC CONTACT LAYERS FOR GALLIUM NITRIDE-BASED DEVICES
organic acid electrolyte
oxalic acid
C₂H₂O₄
KOH or NaOH or eutectic KOH/NaOH
eutectic solution of KOH and NaOH
silver particles
Ag
nickel
Ni
vanadium
V
platinum
Pt
supercritical ammonia
NH₃
seed dislocation density (claimed upper limit) | ≤ 1000000 cm⁻² | GaN |
grown GaN dislocation density with metal masks | ~1/10 or less of seed relative | GaN |
Temperature | 150–450 °C | — |
Temperature | 200–400 °C | — |
Duration | 1–300 second | — |
Thickness | 0.5–1 µm | — |
Thickness | ≤ 1 µm | — |
Thickness | ≤ 100000 cm | — |
Thickness | 0.01–10 µm | — |
Thickness | ≤ 1000000 cm | — |
Thickness | ≥ 10 µm | — |
Cited non-patent literature · 2
INDIUM GALLIUM NITRIDE-BASED OHMIC CONTACT LAYERS FOR GALLIUM NITRIDE-BASED DEVICES