Patent
US 9,978,589Title: NITROGEN-POLAR SEMIPOLAR GAN LAYERS AND DEVICES ON SAPPHIRE SUBSTRATES 100 130 140 110 115 105 FIG. 1
HAN, Jung, LEUNG, Benjamin
YALE UNIVERSITY·US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 9,978,589Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is an elevation view depicting a portion of a substrate comprising III- nitride material epitaxially grown on a patterned sapphire substrate, according …
FIGS. 2C-2F depict structures associated with a process for masking selected surfaces of a patterned sapphire substrate, according to some embodiments;
FIG. 3B is a scanning-electron micrograph showing, in elevation view, coalesced 20 semi-gallium- polar G aN formed on a patterned sapphire substrate, according …
FIG. 4F is a scanning-electron micrograph showing, in plan view, a portion of a semi-nitrogen- polar G aN stripe formed on a patterned sapphire substrate that …
FIG. 5 is a plot of high- resolution x-ray rocking curve measurements taken over a wide range of on-axis and off-axis diffractions for semi-nitrogen-polar G aN …
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 for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer by performing a shadow evaporation to deposit an evaporant; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; and growing semipolar gallium-nitride from the crystal-growth surfaces. Currently amended
The method of claim 1, wherein forming the conformal masking layer comprises depositing a material by a vapor deposition process. Original
The method of claim 1, wherein a thickness of the conformal masking layer is between approximately 10 nm and approximately 50 nm. Previously presented
The method of claim 1, wherein etching regions of the masking layer comprises performing a wet etch. Currently amended
The method of claim 1, wherein growing semipolar gallium-nitride comprises epitaxially growing semi-gallium-polar GaN from the crystal-growth surfaces. Previously presented
The method of claim 1, further comprising: nitridizing the crystal-growth surfaces; and growing a gallium-nitride buffer layer at a temperature below approximately 600 ° C prior to growing the semi-nitrogen-polar GaN. Currently amended
Canceled
The method of claim [[6]] 1, wherein the evaporant comprises a metal. Currently amended
The method of claim [[6]] 1, wherein the evaporant comprises chromium. Currently amended
The method of claim [[6]] 1, wherein the resist does not form over surfaces of the patterned sapphire substrate that are parallel to a c-plane facet of the sapphire. Currently amended
A method for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; epitaxially growing semi-nitrogen-polar gallium-nitride from the crystal-growth surfaces; nitridizing the crystal-growth surfaces; growing a gallium-nitride buffer layer at a temperature below approximately 600 °C prior to growing the semi-nitrogen-polar GaN, wherein growing a gallium-nitride buffer layer comprises: heating the substrate to between approximately 450 ° C and approximately 600 °C; pressurizing a growth chamber to between approximately 100 mbar and approximately 250 mbar; flowing NH 3 into the growth chamber at a rate between approximately 1 slm and approximately 4 slm; flowing trimethylgallium (TMGa) into the growth chamber at a rate between approximately 30 seem and approximately 50 se e m; and growing the gallium-nitride buffer layer to a thickness between approximately 20 nm and approximately 100 nm. Currently amended
The method of claim 18, wherein the semi-nitrogen-polar GaN has a (20 2) facet parallel to a process surface of the substrate. New
The method of claim 18, wherein depositing the resist comprises performing a shadow evaporation to deposit an evaporant. New
The method of claim [[14]] 15, wherein the semi-nitrogen-polar GaN has a (2021) facet parallel to a process surface of the substrate. Currently amended
A substrate comprising: a patterned sapphire substrate having a plurality of surfaces at different orientations and a masking layer formed over some of the surfaces; crystal-growth surfaces that are a portion of the plurality of surfaces and that are not covered by the masking layer; and epitaxial gallium-nitride formed adjacent the crystal-growth surfaces, wherein the patterned sapphire substrate has a (22 4 3) facet approximately parallel to a process surface of the substrate and a c-plane facet approximately parallel to the crystal-growth surfaces. Currently amended
The substrate of claim 20, wherein the patterned sapphire substrate comprises an array of trenches with the crystal-growth surfaces forming walls of the trenches. Previously presented
The substrate of claim 20, further comprising a buffer layer between the crystal-growth surfaces and the epitaxial gallium-nitride. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized. Previously presented
The substrate of claim 20, wherein the epitaxial gallium-nitride has a (2021) or (202 1) facet parallel to an initial unetched surface of the sapphire substrate. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized and include a gallium-nitride buffer layer. Currently amended
Canceled
Layer stacks claimed or described, ordered top of device to substrate.
semipolar GaN on patterned sapphire substrate
Materials described outside the worked examples.
patterned sapphire substrate
Al₂O₃
conformal masking layer
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Duration | 2–4 minutes | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,978,589Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is an elevation view depicting a portion of a substrate comprising III- nitride material epitaxially grown on a patterned sapphire substrate, according …
FIGS. 2C-2F depict structures associated with a process for masking selected surfaces of a patterned sapphire substrate, according to some embodiments;
FIG. 3B is a scanning-electron micrograph showing, in elevation view, coalesced 20 semi-gallium- polar G aN formed on a patterned sapphire substrate, according …
FIG. 4F is a scanning-electron micrograph showing, in plan view, a portion of a semi-nitrogen- polar G aN stripe formed on a patterned sapphire substrate that …
FIG. 5 is a plot of high- resolution x-ray rocking curve measurements taken over a wide range of on-axis and off-axis diffractions for semi-nitrogen-polar G aN …
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 for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer by performing a shadow evaporation to deposit an evaporant; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; and growing semipolar gallium-nitride from the crystal-growth surfaces. Currently amended
The method of claim 1, wherein forming the conformal masking layer comprises depositing a material by a vapor deposition process. Original
The method of claim 1, wherein a thickness of the conformal masking layer is between approximately 10 nm and approximately 50 nm. Previously presented
The method of claim 1, wherein etching regions of the masking layer comprises performing a wet etch. Currently amended
The method of claim 1, wherein growing semipolar gallium-nitride comprises epitaxially growing semi-gallium-polar GaN from the crystal-growth surfaces. Previously presented
The method of claim 1, further comprising: nitridizing the crystal-growth surfaces; and growing a gallium-nitride buffer layer at a temperature below approximately 600 ° C prior to growing the semi-nitrogen-polar GaN. Currently amended
Canceled
The method of claim [[6]] 1, wherein the evaporant comprises a metal. Currently amended
The method of claim [[6]] 1, wherein the evaporant comprises chromium. Currently amended
The method of claim [[6]] 1, wherein the resist does not form over surfaces of the patterned sapphire substrate that are parallel to a c-plane facet of the sapphire. Currently amended
A method for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; epitaxially growing semi-nitrogen-polar gallium-nitride from the crystal-growth surfaces; nitridizing the crystal-growth surfaces; growing a gallium-nitride buffer layer at a temperature below approximately 600 °C prior to growing the semi-nitrogen-polar GaN, wherein growing a gallium-nitride buffer layer comprises: heating the substrate to between approximately 450 ° C and approximately 600 °C; pressurizing a growth chamber to between approximately 100 mbar and approximately 250 mbar; flowing NH 3 into the growth chamber at a rate between approximately 1 slm and approximately 4 slm; flowing trimethylgallium (TMGa) into the growth chamber at a rate between approximately 30 seem and approximately 50 se e m; and growing the gallium-nitride buffer layer to a thickness between approximately 20 nm and approximately 100 nm. Currently amended
The method of claim 18, wherein the semi-nitrogen-polar GaN has a (20 2) facet parallel to a process surface of the substrate. New
The method of claim 18, wherein depositing the resist comprises performing a shadow evaporation to deposit an evaporant. New
The method of claim [[14]] 15, wherein the semi-nitrogen-polar GaN has a (2021) facet parallel to a process surface of the substrate. Currently amended
A substrate comprising: a patterned sapphire substrate having a plurality of surfaces at different orientations and a masking layer formed over some of the surfaces; crystal-growth surfaces that are a portion of the plurality of surfaces and that are not covered by the masking layer; and epitaxial gallium-nitride formed adjacent the crystal-growth surfaces, wherein the patterned sapphire substrate has a (22 4 3) facet approximately parallel to a process surface of the substrate and a c-plane facet approximately parallel to the crystal-growth surfaces. Currently amended
The substrate of claim 20, wherein the patterned sapphire substrate comprises an array of trenches with the crystal-growth surfaces forming walls of the trenches. Previously presented
The substrate of claim 20, further comprising a buffer layer between the crystal-growth surfaces and the epitaxial gallium-nitride. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized. Previously presented
The substrate of claim 20, wherein the epitaxial gallium-nitride has a (2021) or (202 1) facet parallel to an initial unetched surface of the sapphire substrate. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized and include a gallium-nitride buffer layer. Currently amended
Canceled
Layer stacks claimed or described, ordered top of device to substrate.
semipolar GaN on patterned sapphire substrate
Materials described outside the worked examples.
patterned sapphire substrate
Al₂O₃
conformal masking layer
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Duration | 2–4 minutes | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,978,589Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is an elevation view depicting a portion of a substrate comprising III- nitride material epitaxially grown on a patterned sapphire substrate, according …
FIGS. 2C-2F depict structures associated with a process for masking selected surfaces of a patterned sapphire substrate, according to some embodiments;
FIG. 3B is a scanning-electron micrograph showing, in elevation view, coalesced 20 semi-gallium- polar G aN formed on a patterned sapphire substrate, according …
FIG. 4F is a scanning-electron micrograph showing, in plan view, a portion of a semi-nitrogen- polar G aN stripe formed on a patterned sapphire substrate that …
FIG. 5 is a plot of high- resolution x-ray rocking curve measurements taken over a wide range of on-axis and off-axis diffractions for semi-nitrogen-polar G aN …
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 for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer by performing a shadow evaporation to deposit an evaporant; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; and growing semipolar gallium-nitride from the crystal-growth surfaces. Currently amended
The method of claim 1, wherein forming the conformal masking layer comprises depositing a material by a vapor deposition process. Original
The method of claim 1, wherein a thickness of the conformal masking layer is between approximately 10 nm and approximately 50 nm. Previously presented
The method of claim 1, wherein etching regions of the masking layer comprises performing a wet etch. Currently amended
The method of claim 1, wherein growing semipolar gallium-nitride comprises epitaxially growing semi-gallium-polar GaN from the crystal-growth surfaces. Previously presented
The method of claim 1, further comprising: nitridizing the crystal-growth surfaces; and growing a gallium-nitride buffer layer at a temperature below approximately 600 ° C prior to growing the semi-nitrogen-polar GaN. Currently amended
Canceled
The method of claim [[6]] 1, wherein the evaporant comprises a metal. Currently amended
The method of claim [[6]] 1, wherein the evaporant comprises chromium. Currently amended
The method of claim [[6]] 1, wherein the resist does not form over surfaces of the patterned sapphire substrate that are parallel to a c-plane facet of the sapphire. Currently amended
A method for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; epitaxially growing semi-nitrogen-polar gallium-nitride from the crystal-growth surfaces; nitridizing the crystal-growth surfaces; growing a gallium-nitride buffer layer at a temperature below approximately 600 °C prior to growing the semi-nitrogen-polar GaN, wherein growing a gallium-nitride buffer layer comprises: heating the substrate to between approximately 450 ° C and approximately 600 °C; pressurizing a growth chamber to between approximately 100 mbar and approximately 250 mbar; flowing NH 3 into the growth chamber at a rate between approximately 1 slm and approximately 4 slm; flowing trimethylgallium (TMGa) into the growth chamber at a rate between approximately 30 seem and approximately 50 se e m; and growing the gallium-nitride buffer layer to a thickness between approximately 20 nm and approximately 100 nm. Currently amended
The method of claim 18, wherein the semi-nitrogen-polar GaN has a (20 2) facet parallel to a process surface of the substrate. New
The method of claim 18, wherein depositing the resist comprises performing a shadow evaporation to deposit an evaporant. New
The method of claim [[14]] 15, wherein the semi-nitrogen-polar GaN has a (2021) facet parallel to a process surface of the substrate. Currently amended
A substrate comprising: a patterned sapphire substrate having a plurality of surfaces at different orientations and a masking layer formed over some of the surfaces; crystal-growth surfaces that are a portion of the plurality of surfaces and that are not covered by the masking layer; and epitaxial gallium-nitride formed adjacent the crystal-growth surfaces, wherein the patterned sapphire substrate has a (22 4 3) facet approximately parallel to a process surface of the substrate and a c-plane facet approximately parallel to the crystal-growth surfaces. Currently amended
The substrate of claim 20, wherein the patterned sapphire substrate comprises an array of trenches with the crystal-growth surfaces forming walls of the trenches. Previously presented
The substrate of claim 20, further comprising a buffer layer between the crystal-growth surfaces and the epitaxial gallium-nitride. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized. Previously presented
The substrate of claim 20, wherein the epitaxial gallium-nitride has a (2021) or (202 1) facet parallel to an initial unetched surface of the sapphire substrate. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized and include a gallium-nitride buffer layer. Currently amended
Canceled
Layer stacks claimed or described, ordered top of device to substrate.
semipolar GaN on patterned sapphire substrate
Materials described outside the worked examples.
patterned sapphire substrate
Al₂O₃
conformal masking layer
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Duration | 2–4 minutes | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 9,978,589Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is an elevation view depicting a portion of a substrate comprising III- nitride material epitaxially grown on a patterned sapphire substrate, according …
FIGS. 2C-2F depict structures associated with a process for masking selected surfaces of a patterned sapphire substrate, according to some embodiments;
FIG. 3B is a scanning-electron micrograph showing, in elevation view, coalesced 20 semi-gallium- polar G aN formed on a patterned sapphire substrate, according …
FIG. 4F is a scanning-electron micrograph showing, in plan view, a portion of a semi-nitrogen- polar G aN stripe formed on a patterned sapphire substrate that …
FIG. 5 is a plot of high- resolution x-ray rocking curve measurements taken over a wide range of on-axis and off-axis diffractions for semi-nitrogen-polar G aN …
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 for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer by performing a shadow evaporation to deposit an evaporant; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; and growing semipolar gallium-nitride from the crystal-growth surfaces. Currently amended
The method of claim 1, wherein forming the conformal masking layer comprises depositing a material by a vapor deposition process. Original
The method of claim 1, wherein a thickness of the conformal masking layer is between approximately 10 nm and approximately 50 nm. Previously presented
The method of claim 1, wherein etching regions of the masking layer comprises performing a wet etch. Currently amended
The method of claim 1, wherein growing semipolar gallium-nitride comprises epitaxially growing semi-gallium-polar GaN from the crystal-growth surfaces. Previously presented
The method of claim 1, further comprising: nitridizing the crystal-growth surfaces; and growing a gallium-nitride buffer layer at a temperature below approximately 600 ° C prior to growing the semi-nitrogen-polar GaN. Currently amended
Canceled
The method of claim [[6]] 1, wherein the evaporant comprises a metal. Currently amended
The method of claim [[6]] 1, wherein the evaporant comprises chromium. Currently amended
The method of claim [[6]] 1, wherein the resist does not form over surfaces of the patterned sapphire substrate that are parallel to a c-plane facet of the sapphire. Currently amended
A method for forming an epitaxial layer of semipolar gallium-nitride on a substrate, the method comprising: forming a conformal masking layer over a patterned surface of a patterned sapphire substrate; depositing a resist over a portion of the masking layer; etching regions of the masking layer that are not covered by the resist to expose crystal- growth surfaces on the patterned sapphire substrate; epitaxially growing semi-nitrogen-polar gallium-nitride from the crystal-growth surfaces; nitridizing the crystal-growth surfaces; growing a gallium-nitride buffer layer at a temperature below approximately 600 °C prior to growing the semi-nitrogen-polar GaN, wherein growing a gallium-nitride buffer layer comprises: heating the substrate to between approximately 450 ° C and approximately 600 °C; pressurizing a growth chamber to between approximately 100 mbar and approximately 250 mbar; flowing NH 3 into the growth chamber at a rate between approximately 1 slm and approximately 4 slm; flowing trimethylgallium (TMGa) into the growth chamber at a rate between approximately 30 seem and approximately 50 se e m; and growing the gallium-nitride buffer layer to a thickness between approximately 20 nm and approximately 100 nm. Currently amended
The method of claim 18, wherein the semi-nitrogen-polar GaN has a (20 2) facet parallel to a process surface of the substrate. New
The method of claim 18, wherein depositing the resist comprises performing a shadow evaporation to deposit an evaporant. New
The method of claim [[14]] 15, wherein the semi-nitrogen-polar GaN has a (2021) facet parallel to a process surface of the substrate. Currently amended
A substrate comprising: a patterned sapphire substrate having a plurality of surfaces at different orientations and a masking layer formed over some of the surfaces; crystal-growth surfaces that are a portion of the plurality of surfaces and that are not covered by the masking layer; and epitaxial gallium-nitride formed adjacent the crystal-growth surfaces, wherein the patterned sapphire substrate has a (22 4 3) facet approximately parallel to a process surface of the substrate and a c-plane facet approximately parallel to the crystal-growth surfaces. Currently amended
The substrate of claim 20, wherein the patterned sapphire substrate comprises an array of trenches with the crystal-growth surfaces forming walls of the trenches. Previously presented
The substrate of claim 20, further comprising a buffer layer between the crystal-growth surfaces and the epitaxial gallium-nitride. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized. Previously presented
The substrate of claim 20, wherein the epitaxial gallium-nitride has a (2021) or (202 1) facet parallel to an initial unetched surface of the sapphire substrate. Previously presented
The substrate of claim 20, wherein the crystal-growth surfaces are nitridized and include a gallium-nitride buffer layer. Currently amended
Canceled
Layer stacks claimed or described, ordered top of device to substrate.
semipolar GaN on patterned sapphire substrate
Materials described outside the worked examples.
patterned sapphire substrate
Al₂O₃
conformal masking layer
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Duration | 2–4 minutes | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
epitaxial gallium-nitride
GaN
chromium evaporant
Cr
ammonia
NH₃
trimethylgallium
Ga(CH₃)3
| — |
Thickness | 10–40 nm | — |
Temperature | 900–1100 °C | — |
Duration | 1–10 minutes | — |
Temperature | 900–1000 °C | — |
Duration | 0.5–5 minutes | — |
Temperature | 450–600 °C | — |
Thickness | 20–100 nm | — |
Duration | 0.5–3 minutes | — |
Thickness | ≥ 50 nm | — |
Thickness | 0.25–10 µm | — |
Thickness | 50–2000 nm | — |
Temperature | ≤ 600 °C | — |
epitaxial gallium-nitride
GaN
chromium evaporant
Cr
ammonia
NH₃
trimethylgallium
Ga(CH₃)3
| — |
Thickness | 10–40 nm | — |
Temperature | 900–1100 °C | — |
Duration | 1–10 minutes | — |
Temperature | 900–1000 °C | — |
Duration | 0.5–5 minutes | — |
Temperature | 450–600 °C | — |
Thickness | 20–100 nm | — |
Duration | 0.5–3 minutes | — |
Thickness | ≥ 50 nm | — |
Thickness | 0.25–10 µm | — |
Thickness | 50–2000 nm | — |
Temperature | ≤ 600 °C | — |
epitaxial gallium-nitride
GaN
chromium evaporant
Cr
ammonia
NH₃
trimethylgallium
Ga(CH₃)3
| — |
Thickness | 10–40 nm | — |
Temperature | 900–1100 °C | — |
Duration | 1–10 minutes | — |
Temperature | 900–1000 °C | — |
Duration | 0.5–5 minutes | — |
Temperature | 450–600 °C | — |
Thickness | 20–100 nm | — |
Duration | 0.5–3 minutes | — |
Thickness | ≥ 50 nm | — |
Thickness | 0.25–10 µm | — |
Thickness | 50–2000 nm | — |
Temperature | ≤ 600 °C | — |
epitaxial gallium-nitride
GaN
chromium evaporant
Cr
ammonia
NH₃
trimethylgallium
Ga(CH₃)3
| — |
Thickness | 10–40 nm | — |
Temperature | 900–1100 °C | — |
Duration | 1–10 minutes | — |
Temperature | 900–1000 °C | — |
Duration | 0.5–5 minutes | — |
Temperature | 450–600 °C | — |
Thickness | 20–100 nm | — |
Duration | 0.5–3 minutes | — |
Thickness | ≥ 50 nm | — |
Thickness | 0.25–10 µm | — |
Thickness | 50–2000 nm | — |
Temperature | ≤ 600 °C | — |