Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a sectional view of a metal mask ring obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask technology according …
FIG. 2 is a sectional view of a GaN single-crystal sacri- ficial layer obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 3 is a sectional view of a self-supporting GaN single-crystal sacrificial layer separated in a method for preparing a GaN single-crystal substrate with an …
FIG. 4 is a sectional view of a GaN single-crystal thick film obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 5 is a sectional view of a self-supporting GaN single-crystal substrate obtained in a method for preparing a GaN single-crystal substrate with an edge …
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 preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology, com-prising the following steps: 1) preparing a metal mask ring including: providing a composite epitaxial substrate, the composite epitaxial substrate sequentially comprising a biaxial stress free nitrogen-lattice polar GaN epitaxial thin film, wrinkle-free multilayer single-crystal graphene, and a metal-lattice polar GaN single-crystal template from top to bottom, wherein the nitrogen-lattice polar GaN epitaxial thin film serves as a front surface of the composite epitaxial substrate; and depositing the metal mask ring at an edge of the front surface of the composite epitaxial substrate, wherein the metal mask ring is circular, located at an edge of the composite epitaxial substrate, and connected to the composite epitaxial substrate; and an outer diameter of the metal mask ring is the same as a diameter of the composite epitaxial substrate; 2) growing a GaN single-crystal sacrificial layer in a confined manner including: epitaxially growing the GaN single-crystal sacrificial layer in the confined manner on the front surface of the composite epitaxial substrate in a hydride vapor phase epitaxy (HVPE) chamber with HVPE, wherein in an epitaxial growth process, a gallium metal atom pro-vided by an III-group source chemically reacts with a nitrogen atom provided by a nitrogen source; the metal mask ring catalyzes decomposition of ammonia, thereby blocking attached growth of nitride on the metal mask ring, and prohibiting anisotropic growth of an edge of epitaxial nitride on the composite epitaxial substrate extending toward the metal mask ring; the GaN single-crystal sacrificial layer is confined in a region surrounded by the metal mask ring for growth; and the GaN single-crystal sacrificial layer is not con-nected to the metal-lattice polar GaN single-crystal template in the composite epitaxial substrate in any direction; and further adjusting a flow of the III-group source and a flow of the nitrogen source, thereby controlling a growth rate of the GaN single-crystal sacrificial layer, and controlling a thickness of the GaN single-crystal sacrificial layer to be smaller than a height of the metal mask ring; 3) performing separation with an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer including: keeping the composite epitaxial substrate with the GaN single-crystal sacrificial layer unchanged spatially in the HVPE chamber; cooling an environmental tem-perature in situ; and introducing a thermal stress in a horizontal direction through a time-domain tempera-ture gradient, such that a binding force between the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a binding force between the metal-lattice polar GaN single-crystal template and the single-crystal graphene are greater than an interlayer binding force of the single-crystal graphene, thereby realizing interlayer decoupling on the single-crystal graphene to obtain a composite structure com-posed of the self-supporting GaN single-crystal sacri-ficial layer that is grown secondarily in situ, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template; 4) performing diameter expanded and epitaxial growth to obtain a GaN single-crystal thick film including: taking out the composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template out of the HVPE chamber, heating the HVPE chamber, and growing the GaN single-crystal thick film in a diameter expanded manner on a front surface of the GaN single-crystal sacrificial layer, wherein when a total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, a confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown transversely in the diameter expanded manner to obtain the GaN single-crystal thick film; and B₂ 5) performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate.
The method according to claim 1, wherein in step 1), the composite epitaxial substrate has the diameter of 25-200 mm, and a thickness of 5-10 um; the GaN epitaxial thin film has a thickness of 5-10 um; the single-crystal graphene has a thickness equivalent to a plurality of atomic layers; the metal-lattice polar GaN single-crystal template has a thick-ness of 300-1,500 um; and the metal mask ring has an inner diameter less than the diameter of the composite epitaxial substrate by 0.5-2 mm, and has the height of 20-50 um.
The method according to claim 1, wherein in step 1), the metal mask ring is made of tungsten or zirconium.
The method according to claim 1, wherein in step 2), the flow of the Ill-group source and the flow of the nitrogen source are adjusted, such that the GaN single-crystal sacri-ficial layer on the composite epitaxial substrate has a transverse growth rate of 0 µm/h to block the attached growth of the nitride on the metal mask ring, and a longitudinal growth rate of 10-200 µm/h; and finally, the GaN single-crystal sacrificial layer has the thickness smaller than the height of the metal mask ring by 5-20 µm, and a diameter smaller than an inner diameter of the metal mask ring by 0.04-0.2 mm.
The method according to claim 1, wherein in step 2), the epitaxial growth is performed at 1,000-1,100° C.
The method according to claim 1, wherein in step 4), the GaN single-crystal thick film is grown in the diameter expanded manner on the front surface of the GaN single-crystal sacrificial layer at 1,000-1,100° C.: when the total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner, and has a longitudinal growth rate of 10-200 µm/h and a transverse growth rate of 0 µm/h; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, the confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown in the diameter expanded manner and has a longitudinal growth rate of 10-200 µm/h, a transverse growth rate being 1/50-1/5 of the longitudinal growth rate, a longitudinal grown thickness of 1-10 mm, and a transverse expanded size being 1.05-1.5 times a difference between the inner diameter and the outer diameter of the metal mask ring.
The method according to claim 1, wherein in step 5), the chemico-mechanical trimming comprises two steps: performing mechanical cutting to remove a composite struc-ture composed of the GaN single-crystal sacrificial layer, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene under the GaN single-crystal thick film, as well as an irregular region caused by anisotropic growth at an edge of the GaN single-crystal thick film, thereby obtain-ing a cylindrical GaN single-crystal thick film with a diam-eter same as the diameter of the composite epitaxial substrate; and thermally treating the cylindrical GaN single-crystal thick film for 30-60 min at 500-700° C. in a hydrogen atmosphere having a vacuum degree of less than 1 Pa, to remove surface impurities of the GaN single-crystal thick film and surface damage caused by the mechanical cutting, and release a biaxial stress caused by the epitaxial growth and the mechanical cutting in the GaN single-crystal thick film, thereby obtaining the stress-free self-supporting GaN single-crystal substrate without diameter reduction and with a thickness of 1-10 mm. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
composite epitaxial substrate
stress-free self-supporting GaN single-crystal substrate
Materials described outside the worked examples.
nitrogen-lattice polar GaN epitaxial thin film
GaN
wrinkle-free multilayer single-crystal graphene
C
tungsten
W
zirconium
Zr
ammonia
NH₃
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | ≥ 10 µm | — |
Thickness | 25–200 mm | — |
Thickness | 5–10 um | — |
Thickness | 300–1500 um | — |
Thickness | 0.5–2 mm | — |
Thickness | 20–50 um | — |
Thickness | 10–200 µm | — |
Thickness | 5–20 µm | — |
Thickness | 0.04–0.2 mm | — |
Temperature | 1000–1100 °C | — |
Thickness | 1–10 mm | — |
Duration | 30–60 min | — |
Temperature | 500–700 °C | — |
Pressure | ≤ 1 Pa | — |
Thickness | 5–10 µm | — |
Thickness | 300–1500 µm | — |
Thickness | 20–50 µm | — |
Temperature | 400–600 °C | — |
Temperature | ≥ 20 °C | — |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 2
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Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a sectional view of a metal mask ring obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask technology according …
FIG. 2 is a sectional view of a GaN single-crystal sacri- ficial layer obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 3 is a sectional view of a self-supporting GaN single-crystal sacrificial layer separated in a method for preparing a GaN single-crystal substrate with an …
FIG. 4 is a sectional view of a GaN single-crystal thick film obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 5 is a sectional view of a self-supporting GaN single-crystal substrate obtained in a method for preparing a GaN single-crystal substrate with an edge …
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 preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology, com-prising the following steps: 1) preparing a metal mask ring including: providing a composite epitaxial substrate, the composite epitaxial substrate sequentially comprising a biaxial stress free nitrogen-lattice polar GaN epitaxial thin film, wrinkle-free multilayer single-crystal graphene, and a metal-lattice polar GaN single-crystal template from top to bottom, wherein the nitrogen-lattice polar GaN epitaxial thin film serves as a front surface of the composite epitaxial substrate; and depositing the metal mask ring at an edge of the front surface of the composite epitaxial substrate, wherein the metal mask ring is circular, located at an edge of the composite epitaxial substrate, and connected to the composite epitaxial substrate; and an outer diameter of the metal mask ring is the same as a diameter of the composite epitaxial substrate; 2) growing a GaN single-crystal sacrificial layer in a confined manner including: epitaxially growing the GaN single-crystal sacrificial layer in the confined manner on the front surface of the composite epitaxial substrate in a hydride vapor phase epitaxy (HVPE) chamber with HVPE, wherein in an epitaxial growth process, a gallium metal atom pro-vided by an III-group source chemically reacts with a nitrogen atom provided by a nitrogen source; the metal mask ring catalyzes decomposition of ammonia, thereby blocking attached growth of nitride on the metal mask ring, and prohibiting anisotropic growth of an edge of epitaxial nitride on the composite epitaxial substrate extending toward the metal mask ring; the GaN single-crystal sacrificial layer is confined in a region surrounded by the metal mask ring for growth; and the GaN single-crystal sacrificial layer is not con-nected to the metal-lattice polar GaN single-crystal template in the composite epitaxial substrate in any direction; and further adjusting a flow of the III-group source and a flow of the nitrogen source, thereby controlling a growth rate of the GaN single-crystal sacrificial layer, and controlling a thickness of the GaN single-crystal sacrificial layer to be smaller than a height of the metal mask ring; 3) performing separation with an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer including: keeping the composite epitaxial substrate with the GaN single-crystal sacrificial layer unchanged spatially in the HVPE chamber; cooling an environmental tem-perature in situ; and introducing a thermal stress in a horizontal direction through a time-domain tempera-ture gradient, such that a binding force between the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a binding force between the metal-lattice polar GaN single-crystal template and the single-crystal graphene are greater than an interlayer binding force of the single-crystal graphene, thereby realizing interlayer decoupling on the single-crystal graphene to obtain a composite structure com-posed of the self-supporting GaN single-crystal sacri-ficial layer that is grown secondarily in situ, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template; 4) performing diameter expanded and epitaxial growth to obtain a GaN single-crystal thick film including: taking out the composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template out of the HVPE chamber, heating the HVPE chamber, and growing the GaN single-crystal thick film in a diameter expanded manner on a front surface of the GaN single-crystal sacrificial layer, wherein when a total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, a confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown transversely in the diameter expanded manner to obtain the GaN single-crystal thick film; and B₂ 5) performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate.
The method according to claim 1, wherein in step 1), the composite epitaxial substrate has the diameter of 25-200 mm, and a thickness of 5-10 um; the GaN epitaxial thin film has a thickness of 5-10 um; the single-crystal graphene has a thickness equivalent to a plurality of atomic layers; the metal-lattice polar GaN single-crystal template has a thick-ness of 300-1,500 um; and the metal mask ring has an inner diameter less than the diameter of the composite epitaxial substrate by 0.5-2 mm, and has the height of 20-50 um.
The method according to claim 1, wherein in step 1), the metal mask ring is made of tungsten or zirconium.
The method according to claim 1, wherein in step 2), the flow of the Ill-group source and the flow of the nitrogen source are adjusted, such that the GaN single-crystal sacri-ficial layer on the composite epitaxial substrate has a transverse growth rate of 0 µm/h to block the attached growth of the nitride on the metal mask ring, and a longitudinal growth rate of 10-200 µm/h; and finally, the GaN single-crystal sacrificial layer has the thickness smaller than the height of the metal mask ring by 5-20 µm, and a diameter smaller than an inner diameter of the metal mask ring by 0.04-0.2 mm.
The method according to claim 1, wherein in step 2), the epitaxial growth is performed at 1,000-1,100° C.
The method according to claim 1, wherein in step 4), the GaN single-crystal thick film is grown in the diameter expanded manner on the front surface of the GaN single-crystal sacrificial layer at 1,000-1,100° C.: when the total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner, and has a longitudinal growth rate of 10-200 µm/h and a transverse growth rate of 0 µm/h; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, the confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown in the diameter expanded manner and has a longitudinal growth rate of 10-200 µm/h, a transverse growth rate being 1/50-1/5 of the longitudinal growth rate, a longitudinal grown thickness of 1-10 mm, and a transverse expanded size being 1.05-1.5 times a difference between the inner diameter and the outer diameter of the metal mask ring.
The method according to claim 1, wherein in step 5), the chemico-mechanical trimming comprises two steps: performing mechanical cutting to remove a composite struc-ture composed of the GaN single-crystal sacrificial layer, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene under the GaN single-crystal thick film, as well as an irregular region caused by anisotropic growth at an edge of the GaN single-crystal thick film, thereby obtain-ing a cylindrical GaN single-crystal thick film with a diam-eter same as the diameter of the composite epitaxial substrate; and thermally treating the cylindrical GaN single-crystal thick film for 30-60 min at 500-700° C. in a hydrogen atmosphere having a vacuum degree of less than 1 Pa, to remove surface impurities of the GaN single-crystal thick film and surface damage caused by the mechanical cutting, and release a biaxial stress caused by the epitaxial growth and the mechanical cutting in the GaN single-crystal thick film, thereby obtaining the stress-free self-supporting GaN single-crystal substrate without diameter reduction and with a thickness of 1-10 mm. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
composite epitaxial substrate
stress-free self-supporting GaN single-crystal substrate
Materials described outside the worked examples.
nitrogen-lattice polar GaN epitaxial thin film
GaN
wrinkle-free multilayer single-crystal graphene
C
tungsten
W
zirconium
Zr
ammonia
NH₃
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | ≥ 10 µm | — |
Thickness | 25–200 mm | — |
Thickness | 5–10 um | — |
Thickness | 300–1500 um | — |
Thickness | 0.5–2 mm | — |
Thickness | 20–50 um | — |
Thickness | 10–200 µm | — |
Thickness | 5–20 µm | — |
Thickness | 0.04–0.2 mm | — |
Temperature | 1000–1100 °C | — |
Thickness | 1–10 mm | — |
Duration | 30–60 min | — |
Temperature | 500–700 °C | — |
Pressure | ≤ 1 Pa | — |
Thickness | 5–10 µm | — |
Thickness | 300–1500 µm | — |
Thickness | 20–50 µm | — |
Temperature | 400–600 °C | — |
Temperature | ≥ 20 °C | — |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 2
Related documents with shared materials, methods, properties, or citations.
Mapping and Evaluating GaN Wafers for Vertical Device Applications
GALLIUM NITRIDE POWER DEVICE AND MANUFACTURING METHOD THEREOF
PROCESS FOR LARGE-SCALE AMMONOTHERMAL MANUFACTURING OF SEMIPOLAR GALLIUM NITRIDE BOULES
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LATERAL GAN JFET WITH VERTICAL DRIFT REGION
GAN SINGLE-CRYSTAL MASS AND METHOD OF ITS MANUFACTURE, AND SEMICONDUCTOR DEVICE AND METHOD OF ITS MANUFACTURE
GALLIUM NITRIDE SUBSTRATE AND OPTICAL DEVICE USING THE SAME
METHOD FOR DIRECTLY DEPOSITING PALLADIUM ONTO A NON-ACTIVATED SURFACE OF A GALLIUM NITRIDE SEMICONDUCTOR
GAN-CRYSTAL FREE-STANDING SUBSTRATE AND METHOD FOR PRODUCING THE SAME
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GaN SUBSTRATE
GALLIUM NITRIDE CRYSTAL, GALLIUM NITRIDE SUBSTRATE, AND METHOD FOR PRODUCING GALLIUM NITRIDE SUBSTRATE
Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a sectional view of a metal mask ring obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask technology according …
FIG. 2 is a sectional view of a GaN single-crystal sacri- ficial layer obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 3 is a sectional view of a self-supporting GaN single-crystal sacrificial layer separated in a method for preparing a GaN single-crystal substrate with an …
FIG. 4 is a sectional view of a GaN single-crystal thick film obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 5 is a sectional view of a self-supporting GaN single-crystal substrate obtained in a method for preparing a GaN single-crystal substrate with an edge …
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 preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology, com-prising the following steps: 1) preparing a metal mask ring including: providing a composite epitaxial substrate, the composite epitaxial substrate sequentially comprising a biaxial stress free nitrogen-lattice polar GaN epitaxial thin film, wrinkle-free multilayer single-crystal graphene, and a metal-lattice polar GaN single-crystal template from top to bottom, wherein the nitrogen-lattice polar GaN epitaxial thin film serves as a front surface of the composite epitaxial substrate; and depositing the metal mask ring at an edge of the front surface of the composite epitaxial substrate, wherein the metal mask ring is circular, located at an edge of the composite epitaxial substrate, and connected to the composite epitaxial substrate; and an outer diameter of the metal mask ring is the same as a diameter of the composite epitaxial substrate; 2) growing a GaN single-crystal sacrificial layer in a confined manner including: epitaxially growing the GaN single-crystal sacrificial layer in the confined manner on the front surface of the composite epitaxial substrate in a hydride vapor phase epitaxy (HVPE) chamber with HVPE, wherein in an epitaxial growth process, a gallium metal atom pro-vided by an III-group source chemically reacts with a nitrogen atom provided by a nitrogen source; the metal mask ring catalyzes decomposition of ammonia, thereby blocking attached growth of nitride on the metal mask ring, and prohibiting anisotropic growth of an edge of epitaxial nitride on the composite epitaxial substrate extending toward the metal mask ring; the GaN single-crystal sacrificial layer is confined in a region surrounded by the metal mask ring for growth; and the GaN single-crystal sacrificial layer is not con-nected to the metal-lattice polar GaN single-crystal template in the composite epitaxial substrate in any direction; and further adjusting a flow of the III-group source and a flow of the nitrogen source, thereby controlling a growth rate of the GaN single-crystal sacrificial layer, and controlling a thickness of the GaN single-crystal sacrificial layer to be smaller than a height of the metal mask ring; 3) performing separation with an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer including: keeping the composite epitaxial substrate with the GaN single-crystal sacrificial layer unchanged spatially in the HVPE chamber; cooling an environmental tem-perature in situ; and introducing a thermal stress in a horizontal direction through a time-domain tempera-ture gradient, such that a binding force between the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a binding force between the metal-lattice polar GaN single-crystal template and the single-crystal graphene are greater than an interlayer binding force of the single-crystal graphene, thereby realizing interlayer decoupling on the single-crystal graphene to obtain a composite structure com-posed of the self-supporting GaN single-crystal sacri-ficial layer that is grown secondarily in situ, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template; 4) performing diameter expanded and epitaxial growth to obtain a GaN single-crystal thick film including: taking out the composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template out of the HVPE chamber, heating the HVPE chamber, and growing the GaN single-crystal thick film in a diameter expanded manner on a front surface of the GaN single-crystal sacrificial layer, wherein when a total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, a confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown transversely in the diameter expanded manner to obtain the GaN single-crystal thick film; and B₂ 5) performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate.
The method according to claim 1, wherein in step 1), the composite epitaxial substrate has the diameter of 25-200 mm, and a thickness of 5-10 um; the GaN epitaxial thin film has a thickness of 5-10 um; the single-crystal graphene has a thickness equivalent to a plurality of atomic layers; the metal-lattice polar GaN single-crystal template has a thick-ness of 300-1,500 um; and the metal mask ring has an inner diameter less than the diameter of the composite epitaxial substrate by 0.5-2 mm, and has the height of 20-50 um.
The method according to claim 1, wherein in step 1), the metal mask ring is made of tungsten or zirconium.
The method according to claim 1, wherein in step 2), the flow of the Ill-group source and the flow of the nitrogen source are adjusted, such that the GaN single-crystal sacri-ficial layer on the composite epitaxial substrate has a transverse growth rate of 0 µm/h to block the attached growth of the nitride on the metal mask ring, and a longitudinal growth rate of 10-200 µm/h; and finally, the GaN single-crystal sacrificial layer has the thickness smaller than the height of the metal mask ring by 5-20 µm, and a diameter smaller than an inner diameter of the metal mask ring by 0.04-0.2 mm.
The method according to claim 1, wherein in step 2), the epitaxial growth is performed at 1,000-1,100° C.
The method according to claim 1, wherein in step 4), the GaN single-crystal thick film is grown in the diameter expanded manner on the front surface of the GaN single-crystal sacrificial layer at 1,000-1,100° C.: when the total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner, and has a longitudinal growth rate of 10-200 µm/h and a transverse growth rate of 0 µm/h; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, the confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown in the diameter expanded manner and has a longitudinal growth rate of 10-200 µm/h, a transverse growth rate being 1/50-1/5 of the longitudinal growth rate, a longitudinal grown thickness of 1-10 mm, and a transverse expanded size being 1.05-1.5 times a difference between the inner diameter and the outer diameter of the metal mask ring.
The method according to claim 1, wherein in step 5), the chemico-mechanical trimming comprises two steps: performing mechanical cutting to remove a composite struc-ture composed of the GaN single-crystal sacrificial layer, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene under the GaN single-crystal thick film, as well as an irregular region caused by anisotropic growth at an edge of the GaN single-crystal thick film, thereby obtain-ing a cylindrical GaN single-crystal thick film with a diam-eter same as the diameter of the composite epitaxial substrate; and thermally treating the cylindrical GaN single-crystal thick film for 30-60 min at 500-700° C. in a hydrogen atmosphere having a vacuum degree of less than 1 Pa, to remove surface impurities of the GaN single-crystal thick film and surface damage caused by the mechanical cutting, and release a biaxial stress caused by the epitaxial growth and the mechanical cutting in the GaN single-crystal thick film, thereby obtaining the stress-free self-supporting GaN single-crystal substrate without diameter reduction and with a thickness of 1-10 mm. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
composite epitaxial substrate
stress-free self-supporting GaN single-crystal substrate
Materials described outside the worked examples.
nitrogen-lattice polar GaN epitaxial thin film
GaN
wrinkle-free multilayer single-crystal graphene
C
tungsten
W
zirconium
Zr
ammonia
NH₃
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | ≥ 10 µm | — |
Thickness | 25–200 mm | — |
Thickness | 5–10 um | — |
Thickness | 300–1500 um | — |
Thickness | 0.5–2 mm | — |
Thickness | 20–50 um | — |
Thickness | 10–200 µm | — |
Thickness | 5–20 µm | — |
Thickness | 0.04–0.2 mm | — |
Temperature | 1000–1100 °C | — |
Thickness | 1–10 mm | — |
Duration | 30–60 min | — |
Temperature | 500–700 °C | — |
Pressure | ≤ 1 Pa | — |
Thickness | 5–10 µm | — |
Thickness | 300–1500 µm | — |
Thickness | 20–50 µm | — |
Temperature | 400–600 °C | — |
Temperature | ≥ 20 °C | — |
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Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1 is a sectional view of a metal mask ring obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask technology according …
FIG. 2 is a sectional view of a GaN single-crystal sacri- ficial layer obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 3 is a sectional view of a self-supporting GaN single-crystal sacrificial layer separated in a method for preparing a GaN single-crystal substrate with an …
FIG. 4 is a sectional view of a GaN single-crystal thick film obtained in a method for preparing a GaN single-crystal substrate with an edge metal mask …
FIG. 5 is a sectional view of a self-supporting GaN single-crystal substrate obtained in a method for preparing a GaN single-crystal substrate with an edge …
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 preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology, com-prising the following steps: 1) preparing a metal mask ring including: providing a composite epitaxial substrate, the composite epitaxial substrate sequentially comprising a biaxial stress free nitrogen-lattice polar GaN epitaxial thin film, wrinkle-free multilayer single-crystal graphene, and a metal-lattice polar GaN single-crystal template from top to bottom, wherein the nitrogen-lattice polar GaN epitaxial thin film serves as a front surface of the composite epitaxial substrate; and depositing the metal mask ring at an edge of the front surface of the composite epitaxial substrate, wherein the metal mask ring is circular, located at an edge of the composite epitaxial substrate, and connected to the composite epitaxial substrate; and an outer diameter of the metal mask ring is the same as a diameter of the composite epitaxial substrate; 2) growing a GaN single-crystal sacrificial layer in a confined manner including: epitaxially growing the GaN single-crystal sacrificial layer in the confined manner on the front surface of the composite epitaxial substrate in a hydride vapor phase epitaxy (HVPE) chamber with HVPE, wherein in an epitaxial growth process, a gallium metal atom pro-vided by an III-group source chemically reacts with a nitrogen atom provided by a nitrogen source; the metal mask ring catalyzes decomposition of ammonia, thereby blocking attached growth of nitride on the metal mask ring, and prohibiting anisotropic growth of an edge of epitaxial nitride on the composite epitaxial substrate extending toward the metal mask ring; the GaN single-crystal sacrificial layer is confined in a region surrounded by the metal mask ring for growth; and the GaN single-crystal sacrificial layer is not con-nected to the metal-lattice polar GaN single-crystal template in the composite epitaxial substrate in any direction; and further adjusting a flow of the III-group source and a flow of the nitrogen source, thereby controlling a growth rate of the GaN single-crystal sacrificial layer, and controlling a thickness of the GaN single-crystal sacrificial layer to be smaller than a height of the metal mask ring; 3) performing separation with an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer including: keeping the composite epitaxial substrate with the GaN single-crystal sacrificial layer unchanged spatially in the HVPE chamber; cooling an environmental tem-perature in situ; and introducing a thermal stress in a horizontal direction through a time-domain tempera-ture gradient, such that a binding force between the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a binding force between the metal-lattice polar GaN single-crystal template and the single-crystal graphene are greater than an interlayer binding force of the single-crystal graphene, thereby realizing interlayer decoupling on the single-crystal graphene to obtain a composite structure com-posed of the self-supporting GaN single-crystal sacri-ficial layer that is grown secondarily in situ, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene, and a composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template; 4) performing diameter expanded and epitaxial growth to obtain a GaN single-crystal thick film including: taking out the composite structure composed of the single-crystal graphene and the metal-lattice polar GaN single-crystal template out of the HVPE chamber, heating the HVPE chamber, and growing the GaN single-crystal thick film in a diameter expanded manner on a front surface of the GaN single-crystal sacrificial layer, wherein when a total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, a confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown transversely in the diameter expanded manner to obtain the GaN single-crystal thick film; and B₂ 5) performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate.
The method according to claim 1, wherein in step 1), the composite epitaxial substrate has the diameter of 25-200 mm, and a thickness of 5-10 um; the GaN epitaxial thin film has a thickness of 5-10 um; the single-crystal graphene has a thickness equivalent to a plurality of atomic layers; the metal-lattice polar GaN single-crystal template has a thick-ness of 300-1,500 um; and the metal mask ring has an inner diameter less than the diameter of the composite epitaxial substrate by 0.5-2 mm, and has the height of 20-50 um.
The method according to claim 1, wherein in step 1), the metal mask ring is made of tungsten or zirconium.
The method according to claim 1, wherein in step 2), the flow of the Ill-group source and the flow of the nitrogen source are adjusted, such that the GaN single-crystal sacri-ficial layer on the composite epitaxial substrate has a transverse growth rate of 0 µm/h to block the attached growth of the nitride on the metal mask ring, and a longitudinal growth rate of 10-200 µm/h; and finally, the GaN single-crystal sacrificial layer has the thickness smaller than the height of the metal mask ring by 5-20 µm, and a diameter smaller than an inner diameter of the metal mask ring by 0.04-0.2 mm.
The method according to claim 1, wherein in step 2), the epitaxial growth is performed at 1,000-1,100° C.
The method according to claim 1, wherein in step 4), the GaN single-crystal thick film is grown in the diameter expanded manner on the front surface of the GaN single-crystal sacrificial layer at 1,000-1,100° C.: when the total thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is not greater than the height of the metal mask ring, the GaN single-crystal thick film is grown in the confined manner, and has a longitudinal growth rate of 10-200 µm/h and a transverse growth rate of 0 µm/h; and when the thickness of the GaN single-crystal thick film and the GaN single-crystal sacrificial layer is greater than the height of the metal mask ring, the confinement effect of the metal mask ring is weakened, and the GaN single-crystal thick film is grown in the diameter expanded manner and has a longitudinal growth rate of 10-200 µm/h, a transverse growth rate being 1/50-1/5 of the longitudinal growth rate, a longitudinal grown thickness of 1-10 mm, and a transverse expanded size being 1.05-1.5 times a difference between the inner diameter and the outer diameter of the metal mask ring.
The method according to claim 1, wherein in step 5), the chemico-mechanical trimming comprises two steps: performing mechanical cutting to remove a composite struc-ture composed of the GaN single-crystal sacrificial layer, the nitrogen-lattice polar GaN epitaxial thin film and the single-crystal graphene under the GaN single-crystal thick film, as well as an irregular region caused by anisotropic growth at an edge of the GaN single-crystal thick film, thereby obtain-ing a cylindrical GaN single-crystal thick film with a diam-eter same as the diameter of the composite epitaxial substrate; and thermally treating the cylindrical GaN single-crystal thick film for 30-60 min at 500-700° C. in a hydrogen atmosphere having a vacuum degree of less than 1 Pa, to remove surface impurities of the GaN single-crystal thick film and surface damage caused by the mechanical cutting, and release a biaxial stress caused by the epitaxial growth and the mechanical cutting in the GaN single-crystal thick film, thereby obtaining the stress-free self-supporting GaN single-crystal substrate without diameter reduction and with a thickness of 1-10 mm. ∗ ∗ ∗ ∗ ∗
Layer stacks claimed or described, ordered top of device to substrate.
composite epitaxial substrate
stress-free self-supporting GaN single-crystal substrate
Materials described outside the worked examples.
nitrogen-lattice polar GaN epitaxial thin film
GaN
wrinkle-free multilayer single-crystal graphene
C
tungsten
W
zirconium
Zr
ammonia
NH₃
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | ≥ 10 µm | — |
Thickness | 25–200 mm | — |
Thickness | 5–10 um | — |
Thickness | 300–1500 um | — |
Thickness | 0.5–2 mm | — |
Thickness | 20–50 um | — |
Thickness | 10–200 µm | — |
Thickness | 5–20 µm | — |
Thickness | 0.04–0.2 mm | — |
Temperature | 1000–1100 °C | — |
Thickness | 1–10 mm | — |
Duration | 30–60 min | — |
Temperature | 500–700 °C | — |
Pressure | ≤ 1 Pa | — |
Thickness | 5–10 µm | — |
Thickness | 300–1500 µm | — |
Thickness | 20–50 µm | — |
Temperature | 400–600 °C | — |
Temperature | ≥ 20 °C | — |
Patents and literature cited by this patent (applicant and examiner references).
Cited patents · 2
Related documents with shared materials, methods, properties, or citations.
Mapping and Evaluating GaN Wafers for Vertical Device Applications
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