Iii-nitride structures and methods of making same

Abstract

The application provides a group III nitride structure and a manufacturing method thereof. In the manufacturing method, a first mask layer is used as a mask to etch a first group III nitride epitaxial layer to form a groove; a second mask layer is formed on at least the bottom wall of the groove, and the first group III nitride epitaxial layer is subjected to first epitaxial growth with the second mask layer as a mask to form a second group III nitride epitaxial layer which fills the groove and grows in a horizontal direction; and then the second group III nitride epitaxial layer is subjected to second epitaxial growth to form a third group III nitride epitaxial layer on the second group III nitride epitaxial layer and the first mask layer. Since the dislocations of the first group III nitride epitaxial layer mainly extend in the thickness direction, the first epitaxial growth which grows in a horizontal direction can block the dislocations from extending upwards, thereby significantly reducing the dislocation density of the second group III nitride epitaxial layer and the third group III nitride epitaxial layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a group III nitride structure and a manufacturing method thereof. BACKGROUND

[0002] Group III nitride is the third generation of new semiconductor materials after Si, GaAs and other first and second generation semiconductor materials. GaN as a wide band gap semiconductor material has many advantages, such as high saturation drift speed, large breakdown voltage, excellent carrier transport performance, and the ability to form AlGaN, InGaN ternary alloy and AlInGaN quaternary alloy, etc., and it is easy to make GaN-based PN junction. In view of this, in recent years, GaN-based materials and semiconductor devices have been widely and deeply researched, and MOCVD (Metal-organic Chemical Vapor Deposition) technology for growing GaN-based materials is becoming mature; in the research of semiconductor devices, GaN-based LED, LD and other optoelectronic devices and GaN-based HEMT and other microelectronic devices have made remarkable achievements and great progress.

[0003] With the gradual deepening of the application of GaN-based materials in power devices / display devices, the demand for dislocation density of GaN-based materials of terminal products is further improved, and the dislocation density of GaN-based materials grown on the mainstream GaN-based epitaxial substrate Al2O3 substrate by using the mainstream MOCVD epitaxial equipment in the traditional mode is about 1-3E8 / cm^3. In order to manufacture GaN-based power devices with higher voltage and GaN-based LEDs with longer waveband, it is necessary to further reduce the dislocation density of GaN-based materials.

[0004] Therefore, it is necessary to provide a new group III nitride structure and a manufacturing method thereof to meet the above demand. SUMMARY

[0005] The purpose of the present application is to provide a group III nitride structure and a manufacturing method thereof, which can reduce the dislocation density of group III nitride materials and improve the performance of group III nitride semiconductor devices.

[0006] To achieve the above purpose, the first aspect of the present application provides a manufacturing method of a group III nitride structure, comprising:

[0007] providing a first group III nitride epitaxial layer; forming a patterned first mask layer on the first group III nitride epitaxial layer; etching the first group III nitride epitaxial layer to form a groove by taking the patterned first mask layer as a mask;

[0008] forming a second mask layer on at least a bottom wall of the recess; performing a first epitaxial growth on the first group-III nitride epitaxial layer with the second mask layer as a mask to form a second group-III nitride epitaxial layer by lateral growth, the second group-III nitride epitaxial layer filling the recess;

[0009] performing a second epitaxial growth on the second group-III nitride epitaxial layer to form a third group-III nitride epitaxial layer on the second group-III nitride epitaxial layer and the patterned first mask layer.

[0010] It should be noted that the lateral direction in the present application refers to a direction perpendicular to a thickness direction of the first group-III nitride epitaxial layer.

[0011] Optionally, the first group-III nitride epitaxial layer is on a substrate, and the bottom wall of the recess exposes the substrate, and the substrate serves as the second mask layer.

[0012] Optionally, the second mask layer is also formed on the patterned first mask layer, and the third group-III nitride epitaxial layer is formed on the second mask layer.

[0013] Optionally, a material of the first mask layer comprises at least one of silicon dioxide and silicon nitride; and / or a material of the second mask layer comprises at least one of silicon dioxide and silicon nitride.

[0014] Optionally, materials of the first group-III nitride epitaxial layer, the second group-III nitride epitaxial layer and the third group-III nitride epitaxial layer are the same, and comprise at least one of GaN, AlN, AlGaN, InGaN and AlInGaN.

[0015] Optionally, an epitaxial growth process of the second group-III nitride epitaxial layer and / or the third group-III nitride epitaxial layer comprises at least one of an atomic layer deposition method, a chemical vapor deposition method, a molecular beam epitaxial growth method, a plasma-enhanced chemical vapor deposition method, a low-pressure chemical evaporation deposition method and a metal-organic chemical vapor deposition method.

[0016] Optionally, the epitaxial growth processes of the second group-III nitride epitaxial layer and the third group-III nitride epitaxial layer are both metal-organic chemical vapor deposition methods; the second mask layer is formed, and the second group-III nitride epitaxial layer and the third group-III nitride epitaxial layer are grown in a same metal-organic chemical vapor deposition device.

[0017] Optionally, the recess is etched, the second mask layer is formed, and the second group-III nitride epitaxial layer and the third group-III nitride epitaxial layer are grown in a same metal-organic chemical vapor deposition device.

[0018] Optionally, when the third III-nitride epitaxial layer on the patterned first mask layer is not healed, a fourth III-nitride epitaxial layer is grown on the patterned first mask layer and the third III-nitride epitaxial layer.

[0019] Optionally, the method further comprises growing an LED structure on the fourth III-nitride epitaxial layer.

[0020] Optionally, the method further comprises growing an LED structure on the third III-nitride epitaxial layer.

[0021] Optionally, the method of forming the first III-nitride epitaxial layer comprises epitaxially growing the first III-nitride epitaxial layer on a substrate.

[0022] Optionally, the substrate comprises at least one of sapphire, silicon carbide, and silicon.

[0023] A second aspect of the present application provides a III-nitride structure, comprising:

[0024] a first III-nitride epitaxial layer having a patterned first mask layer on the first III-nitride epitaxial layer;

[0025] a second III-nitride epitaxial layer extending into the first III-nitride epitaxial layer from an opening of the patterned first mask layer, a bottom wall of the second III-nitride epitaxial layer and the first III-nitride epitaxial layer having a second mask layer therebetween, and a side wall of the second III-nitride epitaxial layer being connected to the first III-nitride epitaxial layer;

[0026] a third III-nitride epitaxial layer on the second III-nitride epitaxial layer and the patterned first mask layer, the

[0001] direction of the first III-nitride epitaxial layer, the second III-nitride epitaxial layer, and the third III-nitride epitaxial layer being parallel to a thickness direction.

[0027] Optionally, the first III-nitride epitaxial layer, the second III-nitride epitaxial layer, and the third III-nitride epitaxial layer are of the same material, comprising at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN.

[0028] Optionally, the method further comprises a substrate, and the first III-nitride epitaxial layer is on the substrate.

[0029] Optionally, the substrate serves as the second mask layer.

[0030] Optionally, the substrate comprises at least one of sapphire, silicon carbide, and silicon.

[0031] Optionally, the patterned first mask layer further has the second mask layer thereon, and the third group-III nitride epitaxial layer is on the second mask layer.

[0032] Optionally, the material of the first mask layer comprises at least one of silicon dioxide and silicon nitride; and / or the material of the second mask layer comprises at least one of silicon dioxide and silicon nitride.

[0033] Optionally, the second group-III nitride epitaxial layer is an in-situ second group-III nitride epitaxial layer; and / or the second mask layer is an in-situ second mask layer.

[0034] Optionally, the third group-III nitride epitaxial layer on the patterned first mask layer is not healed, and the patterned first mask layer and the third group-III nitride epitaxial layer have a fourth group-III nitride epitaxial layer thereon.

[0035] Optionally, further comprising: an LED structure on the fourth group-III nitride epitaxial layer.

[0036] Optionally, further comprising: an LED structure on the third group-III nitride epitaxial layer.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] 1) In the method for manufacturing the group-III nitride structure, the patterned first mask layer is used as a mask to etch the first group-III nitride epitaxial layer to form a groove; a second mask layer is formed at least on the bottom wall of the groove, and the second mask layer is used as a mask to perform a first epitaxial growth on the first group-III nitride epitaxial layer to form a second group-III nitride epitaxial layer which fills the groove by lateral growth; and then a second epitaxial growth is performed on the second group-III nitride epitaxial layer to grow a third group-III nitride epitaxial layer on the second group-III nitride epitaxial layer and the patterned first mask layer. Since the dislocations of the first group-III nitride epitaxial layer are mainly linear dislocations of

[0001] direction, i.e. the dislocations extend in the thickness direction of the first group-III nitride epitaxial layer, the first epitaxial growth with a lateral growth direction can block the dislocations from extending upward, thereby significantly reducing the dislocation density of the second group-III nitride epitaxial layer and the third group-III nitride epitaxial layer.

[0039] 2) In an optional solution, the first group-III nitride epitaxial layer is on a substrate, a) a part of the thickness of the first group-III nitride epitaxial layer is etched to form a groove; or b) the entire thickness of the first group-III nitride epitaxial layer is etched to form a groove. In the solution b), since the bottom wall of the groove exposes the substrate, the manufacturing process of the second mask layer can be omitted, and the substrate serves as the second mask layer.

[0040] 3) In an optional solution, the second mask layer is further formed on the patterned first mask layer, and the third III-V nitride epitaxial layer is grown on the second mask layer. The advantage of this solution over the solution of forming the second mask layer only on the bottom wall of the groove is that the patterning process of the second mask layer can be omitted, thus simplifying the process. This is because, in the process of etching the first III-V nitride epitaxial layer to form the groove with the patterned first mask layer as a mask, not only part of the material is removed in the thickness direction, but also part of the material is removed in the lateral direction, in other words, the patterned first mask layer has a suspended section at the opening of the groove; when the second mask layer is deposited, the suspended section will block the second mask layer, so that the second mask layer is deposited only on the patterned first mask layer outside the groove and on the bottom wall of the groove, avoiding the formation of the second mask layer on the side wall of the groove.

[0041] 4) In an optional solution, a) the materials of the first III-V nitride epitaxial layer, the second III-V nitride epitaxial layer, and the third III-V nitride epitaxial layer are the same, or b) the materials of at least two of the first III-V nitride epitaxial layer, the second III-V nitride epitaxial layer, and the third III-V nitride epitaxial layer are different. The materials of the first III-V nitride epitaxial layer, and / or the second III-V nitride epitaxial layer, and / or the third III-V nitride epitaxial layer can include at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN. The specific materials of the first III-V nitride epitaxial layer, the second III-V nitride epitaxial layer, and the third III-V nitride epitaxial layer can be determined according to the functions, and the specific functions can include substrate, buffer layer, barrier layer, or channel layer in a device, etc.

[0042] 5) In an optional solution, the epitaxial growth processes of the second III-V nitride epitaxial layer and the third III-V nitride epitaxial layer are both metal organic chemical vapor deposition (MOCVD); the formation of the second mask layer and the growth of the second III-V nitride epitaxial layer and the third III-V nitride epitaxial layer are performed in the same MOCVD equipment. In other words, the second III-V nitride epitaxial layer is an in-situ second III-V nitride epitaxial layer, and the third III-V nitride epitaxial layer is an in-situ third III-V nitride epitaxial layer. The advantage of in-situ is that the process complexity can be reduced, the transfer process of multiple processes between different equipment can be reduced, and the interference of the pollution source in the process with the quality of the second III-V nitride epitaxial layer and the third III-V nitride epitaxial layer can be avoided.

[0043] Further, the etching of the groove, the formation of the second mask layer, and the growth of the second III-V nitride epitaxial layer and the third III-V nitride epitaxial layer are performed in the same MOCVD equipment. In other words, the second mask layer is an in-situ second mask layer. In the groove etching process, the reaction gas in the MOCVD equipment can include Cl2 and BCl3. The above mixed gas can chemically react with the first III-V nitride epitaxial layer to form the groove.

[0044] 6) In an optional solution, when the third III-nitride epitaxial layer on the patterned first mask layer is not healed, a fourth III-nitride epitaxial layer is grown on the patterned first mask layer and the third III-nitride epitaxial layer. The material of the fourth III-nitride epitaxial layer is different from that of the third III-nitride epitaxial layer. This solution can effectively release the stress in the fourth III-nitride epitaxial layer and reduce the dislocations and V-pits in the fourth III-nitride epitaxial layer.

[0045] 7) In an optional solution, an LED structure is grown on the third III-nitride epitaxial layer / the fourth III-nitride epitaxial layer. The LED structure can include an N-type semiconductor layer, a P-type semiconductor layer, and a quantum well layer between the N-type semiconductor layer and the P-type semiconductor layer. In other words, the first III-nitride epitaxial layer, the second III-nitride epitaxial layer, and the third III-nitride epitaxial layer serve as a substrate of the LED structure, or the first III-nitride epitaxial layer, the second III-nitride epitaxial layer, the third III-nitride epitaxial layer, and the fourth III-nitride epitaxial layer serve as a substrate of the LED structure, which can be used to make green LEDs, yellow LEDs, red LEDs, or even infrared LEDs. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a flowchart of a method for manufacturing a III-nitride structure according to a first embodiment of the present application;

[0047] Figures 2 to 4 is a schematic diagram of an intermediate structure corresponding to the flow in Figure 1

[0048] Figure 5 is a schematic diagram of a cross-sectional structure of a III-nitride structure according to the first embodiment of the present application;

[0049] Figure 6 is a schematic diagram of an intermediate structure corresponding to a method for manufacturing a III-nitride structure according to a second embodiment of the present application;

[0050] Figure 7 is a schematic diagram of a cross-sectional structure of a III-nitride structure according to the second embodiment of the present application;

[0051] Figure 8 is a schematic diagram of a cross-sectional structure of a III-nitride structure according to a third embodiment of the present application;

[0052] Figure 9 is a schematic diagram of an intermediate structure corresponding to a method for manufacturing a III-nitride structure according to a fourth embodiment of the present application;

[0053] Figure 10 is a schematic diagram of a cross-sectional structure of a III-nitride structure according to the fourth embodiment of the present application;

[0054] Figure 11 ​This is a schematic cross-sectional view of the group III nitride structure according to the fifth embodiment of the present invention;

[0055] Figure 12 This is a schematic cross-sectional view of the group III nitride structure according to the sixth embodiment of the present invention;

[0056] Figure 13 This is a cross-sectional schematic diagram of the group III nitride structure according to the seventh embodiment of the present invention.

[0057] To facilitate understanding of this invention, all reference numerals appearing in the accompanying drawings are listed below:

[0058] First group III nitride epitaxial layer 11 Patterned first mask layer 12

[0059] Groove 11a Substrate 10

[0060] Second mask layer 13 In-situ second mask layer 13'

[0061] Group III nitride epitaxial layer 14, in-situ Group III nitride epitaxial layer 14'

[0062] Group III nitride epitaxial layer 15, in-situ Group III nitride epitaxial layer 15'

[0063] Group III nitride epitaxial layer 16 LED structure 17

[0064] Structures of Group III nitrides 1, 2, 3, 4, 5, 6, 7 Detailed Implementation

[0065] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0066] Figure 1 This is a flowchart of a method for fabricating a group III nitride structure according to the first embodiment of the present invention. Figures 2 to 4 yes Figure 1 The diagram shows the intermediate structure corresponding to the process flow. Figure 5 This is a cross-sectional schematic diagram of the group III nitride structure of the first embodiment of the present invention.

[0067] First, refer to Figure 1 Step S1 and Figure 2 As shown, a first group III nitride epitaxial layer 11 is provided; a patterned first mask layer 12 is formed on the first group III nitride epitaxial layer 11; and a groove 11a is formed by etching the first group III nitride epitaxial layer 11 using the patterned first mask layer 12 as a mask.

[0068] Reference Figure 2As shown, in the embodiment, the first group-III nitride epitaxial layer 11 can be formed on the substrate 10. The substrate 10 can be at least one of sapphire, silicon carbide, and silicon, which is not limited in the embodiment.

[0069] The group-III nitride material of the first group-III nitride epitaxial layer 11 can be AlN, or at least one of GaN, AlGaN, InGaN, and AlInGaN, which is not limited in the embodiment. The AlN can be used as a nucleation layer. The first group-III nitride epitaxial layer 11 has dislocations, which are mainly linear dislocations of

[0001] direction, i.e. dislocations extending in the thickness direction of the first group-III nitride epitaxial layer 11.

[0070] In step S1, the first group-III nitride epitaxial layer 11 formed on the substrate 10 can be an existing structure, or step S1 can include: epitaxially growing the first group-III nitride epitaxial layer 11 on the substrate 10.

[0071] The forming process of the first group-III nitride epitaxial layer 11 can include: an atomic layer deposition (ALD) method, or a chemical vapor deposition (CVD) method, or a molecular beam epitaxy (MBE) method, or a plasma enhanced chemical vapor deposition (PECVD) method, or a low pressure chemical vapor deposition (LPCVD) method, or a metal organic chemical vapor deposition (MOCVD) method, or a combination thereof.

[0072] In some embodiments, the first group-III nitride epitaxial layer 11 after the substrate 10 is peeled off can be the first group-III nitride epitaxial layer 11 in step S1.

[0073] The material of the first mask layer 12 can include at least one of silicon dioxide and silicon nitride.

[0074] In the embodiment, the etching of the first group-III nitride epitaxial layer 11 can adopt a dry etching method, or a wet etching method.

[0075] Dry etching can be inductively coupled plasma etching (ICP). Etching gases can include Cl2 and BCl3. In dry etching, because the plasma of the etching gas reacts chemically not only with the Group III nitride material to be etched in the thickness direction, but also with the Group III nitride material to be etched in the transverse direction perpendicular to the thickness, after etching, a suspended section will be formed at the opening of the groove 11a in the patterned first mask layer 12.

[0076] The etching solution used in wet etching can be H3PO4 solution or KOH solution, which is corrosive to the N-plane. The GaN crystal has a wurtzite structure, where Ga and N atomic layers are stacked in an ABABAB hexagonal layer structure, and each Ga(N) atom is bonded to four surrounding N(Ga) atoms in a diamond-like tetrahedral structure. Using the Ga-N bond parallel to the C-axis (

[0001] crystal direction) as a reference, if the Ga atom in each Ga-N bond is further away from the lower surface, the upper surface is the Ga plane; if the N atom in each Ga-N bond is further away from the lower surface, the upper surface is the N plane. In this embodiment, the upper surface of the first group III nitride epitaxial layer 11 can be controlled to be the N plane.

[0077] In wet etching, since the etching solution reacts chemically not only with the group III nitride material to be etched in the thickness direction, but also with the group III nitride material to be etched in the transverse direction, after etching is completed, the patterned first mask layer 12 also forms a suspended section at the opening of the groove 11a.

[0078] In this embodiment, as Figure 2 As shown, the groove 11a is formed by etching a portion of the thickness of the first group III nitride epitaxial layer 11.

[0079] Next, still referring to Figure 1 Step S2 and Figure 3 As shown, a second mask layer 13 is formed on the bottom wall of the groove 11a; refer to Figure 4 As shown, using the second mask layer 13 as a mask, the first group III nitride epitaxial layer 11 is epitaxially grown for the first time, and the second group III nitride epitaxial layer 14 is formed by lateral growth. The second group III nitride epitaxial layer 14 fills the groove 11a.

[0080] The material of the second mask layer 13 may include at least one of silicon dioxide and silicon nitride, and the formation method may include physical vapor deposition or chemical vapor deposition. Since the patterned first mask layer 12 has a suspended section at the opening of the groove 11a, when the second mask layer 13 is deposited, the suspended section will isolate the second mask layer 13, so that the second mask layer 13 is deposited only on the patterned first mask layer 12 outside the groove 11a and on the bottom wall of the groove 11a, avoiding deposition on the sidewall of the groove 11a.

[0081] Referring to Figure 3 In the embodiment shown, only the second mask layer 13 of the bottom wall of the groove 11a is reserved. The second mask layer 13 outside the groove 11a can be removed by dry etching. For example, photoresist is arranged on the second mask layer 13, and the patterned photoresist after exposure and development exposes the second mask layer 13 outside the groove 11a.

[0082] Referring to Figure 4 As shown, the second mask layer 13 shields the first group-III nitride epitaxial layer 11 of the bottom wall of the groove 11a, so that when the first group-III nitride epitaxial layer 11 is subjected to the first epitaxial growth, it cannot grow in the thickness direction and only grows in the lateral direction. The dislocations of the first group-III nitride epitaxial layer 11 are mainly dislocations extending in the thickness direction, so that the lateral growth can block the dislocations in the thickness direction from continuing to extend upward, thereby significantly reducing the dislocation density of the second group-III nitride epitaxial layer 14.

[0083] The material of the second group-III nitride epitaxial layer 14 can be the same as or different from that of the first group-III nitride epitaxial layer 11. The material of the second group-III nitride epitaxial layer 14 can be at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN, which is not limited in the embodiment.

[0084] The forming process of the second group-III nitride epitaxial layer 14 can refer to the forming process of the first group-III nitride epitaxial layer 11.

[0085] Next, still referring to steps S3 and S4 in Figure 1 and Figure 5 , the second group-III nitride epitaxial layer 14 is subjected to the second epitaxial growth to grow and form a third group-III nitride epitaxial layer 15 on the second group-III nitride epitaxial layer 14 and the patterned first mask layer 12.

[0086] The second epitaxial growth includes growth in the lateral direction and the thickness direction.

[0087] The material of the third group-III nitride epitaxial layer 15 can be the same as or different from that of the second group-III nitride epitaxial layer 14. The material of the third group-III nitride epitaxial layer 15 can be at least one of GaN, AlGaN, InGaN, and AlInGaN, which is not limited in the embodiment.

[0088] The function of the third group III nitride epitaxial layer 15 can be the same as or different from that of the second group III nitride epitaxial layer 14 / first group III nitride epitaxial layer 11. For example, the first group III nitride epitaxial layer 11 and the second group III nitride epitaxial layer 14 can be substrates in a device, and the third group III nitride epitaxial layer 15 can be a buffer layer, barrier layer, or channel layer in a device. The buffer layer can reduce the screw dislocation (TD) density in the upper semiconductor layer and the TD bending caused by the lateral growth mechanism. For another example, the first group III nitride epitaxial layer 11 and the second group III nitride epitaxial layer 14 can be buffer layers in a device, and the third group III nitride epitaxial layer 15 can be a barrier layer or channel layer in a device; or the first group III nitride epitaxial layer 11, the second group III nitride epitaxial layer 14, and the third group III nitride epitaxial layer 15 can all be substrates, buffer layers, barrier layers, or channel layers in a device.

[0089] Figure 5 This is a cross-sectional schematic diagram of the group III nitride structure of the first embodiment of the present invention.

[0090] Reference Figure 5 As shown, the group III nitride structure 1 of this embodiment includes:

[0091] A first group III nitride epitaxial layer 11 has a patterned first mask layer 12 on it;

[0092] A second group III nitride epitaxial layer 14 extends from the opening of the patterned first mask layer 12 into the first group III nitride epitaxial layer 11. A second mask layer 13 is provided between the bottom wall of the second group III nitride epitaxial layer 14 and the first group III nitride epitaxial layer 11. The sidewalls of the second group III nitride epitaxial layer 14 are connected to the first group III nitride epitaxial layer 11.

[0093] The third group III nitride epitaxial layer 15 is located on the second group III nitride epitaxial layer 14 and the patterned first mask layer 12. The

[0001] crystal orientation of the first group III nitride epitaxial layer 11, the second group III nitride epitaxial layer 14 and the third group III nitride epitaxial layer 15 is parallel to the thickness direction.

[0094] As can be seen, because the second mask layer 13 blocks the first group III nitride epitaxial layer 11 on the bottom wall of the groove 11a, the first group III nitride epitaxial layer 11 cannot grow in the thickness direction during the first epitaxial growth, and only grows in the lateral direction. The dislocations in the first group III nitride epitaxial layer 11 are mainly dislocations extending in the thickness direction. Therefore, lateral growth can block the dislocations in the thickness direction from continuing to extend upward, thereby significantly reducing the dislocation density of the second group III nitride epitaxial layer 14 and the third group III nitride epitaxial layer 15.

[0095] The materials of the first group III nitride epitaxial layer 11, the second group III nitride epitaxial layer 14, and the third group III nitride epitaxial layer 15 can be the same or different. The materials of the first group III nitride epitaxial layer 11, and / or the second group III nitride epitaxial layer 14, and / or the third group III nitride epitaxial layer 15 can be at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN, and this embodiment does not limit this.

[0096] The functions of the Group III nitride epitaxial layer 11, and / or the Group III nitride epitaxial layer 14, and / or the Group III nitride epitaxial layer 15 may be the same or different. The Group III nitride epitaxial layer 11, and / or the Group III nitride epitaxial layer 14, and / or the Group III nitride epitaxial layer 15 may be a substrate, buffer layer, barrier layer, or channel layer in the device.

[0097] The material of the second mask layer 13 can be selected from materials that can inhibit the growth of the first group III nitride epitaxial layer 11, such as at least one of silicon dioxide and silicon nitride. The material of the first mask layer 12 can be selected from materials on which the second group III nitride epitaxial layer 14 can be attached, such as at least one of silicon dioxide and silicon nitride.

[0098] In addition, refer to Figure 5 As shown, in this embodiment, the first group III nitride epitaxial layer 11 can be located on the substrate 10. The substrate 10 can be at least one of sapphire, silicon carbide, and silicon, and this embodiment is not limited thereto.

[0099] In some embodiments, the first group III nitride epitaxial layer 11 can be the first group III nitride epitaxial layer 11 after the substrate 10 has been stripped.

[0100] Figure 6 This is a schematic diagram of the intermediate structure corresponding to the method for fabricating the group III nitride structure of the second embodiment of the present invention. Figure 7 This is a cross-sectional schematic diagram of the group III nitride structure according to the second embodiment of the present invention. (Refer to...) Figure 6 and Figure 7 As shown, the group III nitride structure 2 and its fabrication method in this embodiment are similar to... Figures 1 to 5 The group III nitride structure 1 and its fabrication method are largely the same as those in the embodiments, except that: the second mask layer 13 is also formed on the patterned first mask layer 12, and the third group III nitride epitaxial layer 15 is grown and formed on the second mask layer 13.

[0101] The advantage of this embodiment over the scheme that forms the second mask layer 13 only on the bottom wall of the groove 11a is that the patterning process of the second mask layer 13 can be omitted, simplifying the process.

[0102] Figure 8This is a cross-sectional schematic diagram of the group III nitride structure according to the third embodiment of the present invention. (Refer to...) Figure 8 As shown, the group III nitride structure 3 in this embodiment... Figure 1 and Figure 7 The group III nitride structures 1 and 2 in the embodiments are largely the same, with the only difference being that: the second mask layer 13 is an in-situ second mask layer 13', the second group III nitride epitaxial layer is an in-situ second group III nitride epitaxial layer 14', and the third group III nitride epitaxial layer 15 is an in-situ third group III nitride epitaxial layer 15'.

[0103] Correspondingly, the method for fabricating the group III nitride structure 3 in this embodiment is the same as... Figures 1 to 5 Implementation examples Figure 6 and Figure 7 The fabrication methods of the group III nitride structures 1 and 2 in the embodiments are largely the same, with the only difference being that the etching of the groove 11a in step S1, the formation of the second mask layer 13 and the growth of the second group III nitride epitaxial layer 14 in step S2, and the growth of the third group III nitride epitaxial layer 15 in step S3 are all performed in the same MOCVD equipment.

[0104] In the etching process of groove 11a, the reaction gas in the MOCVD equipment may include Cl2 and BCl3. The above-mentioned mixed gas can chemically react with the first group III nitride epitaxial layer 11 to form groove 11a.

[0105] The advantages of performing the process in the same MOCVD equipment, i.e., in situ, are: it can reduce process complexity, reduce the transfer process between multiple processes in different equipment, and avoid contamination sources interfering with the quality of the second group III nitride epitaxial layer 14 and the third group III nitride epitaxial layer 15.

[0106] In some embodiments, the etching of the groove 11a can also be performed using the dry etching or wet etching methods described in the foregoing embodiments. After the groove 11a is formed, it is transferred to an MOCVD equipment to sequentially form a second mask layer 13, a second group III nitride epitaxial layer 14, and a third group III nitride epitaxial layer 15.

[0107] Figure 9 This is a schematic diagram of the intermediate structure corresponding to the method for fabricating the group III nitride structure of the fourth embodiment of the present invention. Figure 10 This is a cross-sectional schematic diagram of the group III nitride structure according to the fourth embodiment of the present invention. (Refer to...) Figure 9 and Figure 10 As shown, the group III nitride structure 4 and its fabrication method in this embodiment are similar to... Figures 1 to 5 The group III nitride structure 1 and its fabrication method are largely the same as those in the embodiments, except that: in step S1, the entire thickness of the first group III nitride epitaxial layer 11 is etched to form a groove 11a.

[0108] In the embodiment, since the bottom wall of the groove 11a exposes the substrate 10, the manufacturing process of the second mask layer 13 can be omitted, and the substrate 10 can be used as the second mask layer 13.

[0109] The scheme of the embodiment can also be combined with the scheme of the embodiment Figure 8 The scheme of the embodiment is combined with the scheme of the embodiment, that is, the second group-III nitride epitaxial layer is an in-situ second group-III nitride epitaxial layer 14', and the third group-III nitride epitaxial layer 15 is an in-situ third group-III nitride epitaxial layer 15'.

[0110] Figure 11 is a schematic diagram of a cross-sectional structure of a group-III nitride structure of a fifth embodiment of the present application. As shown in Figure 11 , the group-III nitride structure 5 of the embodiment and the manufacturing method thereof are substantially the same as the group-III nitride structures 1, 2, 3, 4 and the manufacturing methods thereof of the embodiments Figures 1 to 10 , and the difference is that an LED structure 17 is further grown on the third group-III nitride epitaxial layer 15.

[0111] The LED structure 17 can include an N-type semiconductor layer, a P-type semiconductor layer, and a quantum well layer between the N-type semiconductor layer and the P-type semiconductor layer.

[0112] The N-type semiconductor layer is used to provide electrons, and the P-type semiconductor layer is used to provide holes, so that the electrons and the holes recombine in the quantum well layer to emit light. The N-type semiconductor layer and / or the P-type semiconductor layer can include a group-III nitride material. The group-III nitride material can be at least one of GaN, AlGaN, InGaN, and AlInGaN. The N-type ions in the N-type semiconductor layer can be at least one of Si ions, Ge ions, Sn ions, Se ions, or Te ions. The P-type doping ions in the P-type semiconductor layer can be at least one of Mg ions, Zn ions, Ca ions, Sr ions, or Ba ions.

[0113] In some embodiments, the N-type semiconductor layer can be close to the third group-III nitride epitaxial layer 15, and the P-type semiconductor layer is far away from the third group-III nitride epitaxial layer 15. In other embodiments, the P-type semiconductor layer can be close to the third group-III nitride epitaxial layer 15, and the N-type semiconductor layer is far away from the third group-III nitride epitaxial layer 15.

[0114] The quantum well layer can be a single quantum well layer or a multi-quantum well layer.

[0115] The forming process of the LED structure 17 can refer to the forming process of the third group-III nitride epitaxial layer 15.

[0116] Figure 12 is a schematic diagram of a cross-sectional structure of a group-III nitride structure of a sixth embodiment of the present application. As shown in Figures 1 to 10 , the group-III nitride structure 6 of the embodiment and the manufacturing method thereof are substantially the same as the group-III nitride structures 1, 2, 3, 4 and the manufacturing methods thereof of the embodimentsFigure 13 The Group III nitride structure 1, 2, 3, 4 and the method for manufacturing the same of the embodiment are substantially the same as those of the embodiment, except that the fourth Group III nitride epitaxial layer 16 is grown on the patterned first mask layer 12 and the third Group III nitride epitaxial layer 15.

[0117] The material of the fourth Group III nitride epitaxial layer 16 is different from that of the third Group III nitride epitaxial layer 15.

[0118] Specifically, the material of the fourth Group III nitride epitaxial layer 16 can include more kinds of elements than the material of the third Group III nitride epitaxial layer 15. For example, when the material of the third Group III nitride epitaxial layer 15 is GaN, the material of the fourth Group III nitride epitaxial layer 16 at least further includes at least one of Al and In. When the material of the third Group III nitride epitaxial layer 15 is AlN, the material of the fourth Group III nitride epitaxial layer 16 at least further includes at least one of Ga and In.

[0119] The material of the fourth Group III nitride epitaxial layer 16 can be at least one of AlGaN, InGaN and AlInGaN.

[0120] The scheme of the embodiment can effectively release the stress in the fourth Group III nitride epitaxial layer 16 and reduce the dislocation and V-pits in the fourth Group III nitride epitaxial layer 16. If the fourth Group III nitride epitaxial layer 16 is grown directly on the patterned first mask layer 12 and the second Group III nitride epitaxial layer 14, V-pits will be formed on the patterned first mask layer 12.

[0121] Figure 13 is a schematic diagram of a cross-sectional structure of a Group III nitride structure of a seventh embodiment of the present application. As shown in Figure 12 , the Group III nitride structure 7 and the method for manufacturing the same of the embodiment are substantially the same as those of the embodiment, except that the LED structure 17 is grown on the fourth Group III nitride epitaxial layer 16. Figure 11 The specific structure and forming method of the LED structure 17 can refer to the specific structure and forming method of the LED structure 17 in the embodiment.

[0122] ​ The specific structure and forming method of the LED structure 17 can refer to the specific structure and forming method of the LED structure 17 in the embodiment.

[0123] Although the present application is disclosed as above, the present application is not limited to the above. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the scope of the claims.​

Claims

1. A method for fabricating a group III nitride structure, characterized in that, include: A first group III nitride epitaxial layer (11) is provided; a patterned first mask layer (12) is formed on the first group III nitride epitaxial layer (11); using the patterned first mask layer (12) as a mask, the first group III nitride epitaxial layer (11) is etched to form a groove (11a); wherein the patterned first mask layer (12) has a suspended section at the groove (11a); A second mask layer (13) is formed at least on the bottom wall of the groove (11a); using the second mask layer (13) as a mask, the first group III nitride epitaxial layer (11) is epitaxially grown for the first time to form a second group III nitride epitaxial layer (14) by transverse epitaxial growth below the suspended section, and the second group III nitride epitaxial layer (14) fills the groove (11a); A second epitaxial growth is performed on the second group III nitride epitaxial layer (14) to grow a third group III nitride epitaxial layer (15) on the second group III nitride epitaxial layer (14) and the patterned first mask layer (12).

2. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The first group III nitride epitaxial layer (11) is located on the substrate (10), the bottom wall of the groove (11a) exposes the substrate (10), and the substrate (10) acts as the second mask layer (13).

3. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The second mask layer (13) is also formed on the patterned first mask layer (12), and the third group III nitride epitaxial layer (15) is grown and formed on the second mask layer (13).

4. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The material of the first mask layer (12) includes at least one of silicon dioxide and silicon nitride; and / or the material of the second mask layer (13) includes at least one of silicon dioxide and silicon nitride.

5. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The first group III nitride epitaxial layer (11), the second group III nitride epitaxial layer (14), and the third group III nitride epitaxial layer (15) are made of the same material, including at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN.

6. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The epitaxial growth process of the second group III nitride epitaxial layer (14) and / or the third group III nitride epitaxial layer (15) includes at least one of atomic layer deposition, chemical vapor deposition, molecular beam epitaxy, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, and organometallic chemical vapor deposition.

7. The method for fabricating a group III nitride structure according to claim 6, characterized in that, The epitaxial growth processes of the second group III nitride epitaxial layer (14) and the third group III nitride epitaxial layer (15) are both metal-organic chemical vapor deposition (MOCVD). The formation of the second mask layer (13) and the growth of the second group III nitride epitaxial layer (14) and the third group III nitride epitaxial layer (15) are carried out in the same MOCVD equipment.

8. The method for fabricating a group III nitride structure according to claim 7, characterized in that, The etching of the groove (11a), the formation of the second mask layer (13), and the growth of the second group III nitride epitaxial layer (14) and the third group III nitride epitaxial layer (15) are performed in the same metal-organic chemical vapor deposition apparatus.

9. The method for preparing a group III nitride structure according to any one of claims 1 to 8, characterized in that, When the third group III nitride epitaxial layer (15) located on the patterned first mask layer (12) is not healed, a fourth group III nitride epitaxial layer (16) is also grown on the patterned first mask layer (12) and the third group III nitride epitaxial layer (15).

10. The method for fabricating a group III nitride structure according to claim 9, characterized in that, Also includes: An LED structure (17) is grown on the fourth group III nitride epitaxial layer (16).

11. The method for preparing a group III nitride structure according to any one of claims 1 to 8, characterized in that, Also includes: An LED structure (17) is grown on the third group III nitride epitaxial layer (15).

12. The method for fabricating a group III nitride structure according to claim 1, characterized in that, The method for forming the first group III nitride epitaxial layer (11) includes: epitaxially growing the first group III nitride epitaxial layer (11) on a substrate (10).

13. The method for fabricating a group III nitride structure according to claim 2 or 12, characterized in that, The substrate (10) includes at least one of sapphire, silicon carbide and silicon.

14. A group III nitride structure, characterized in that, include: A first group III nitride epitaxial layer (11) having a patterned first mask layer (12) on the first group III nitride epitaxial layer (11); A second group III nitride epitaxial layer (14) extends into the first group III nitride epitaxial layer (11) from the opening of the patterned first mask layer (12). A second mask layer (13) is provided between the bottom wall of the second group III nitride epitaxial layer (14) and the first group III nitride epitaxial layer (11). The sidewall of the second group III nitride epitaxial layer (14) is connected to the first group III nitride epitaxial layer (11). The patterned first mask layer (12) has a suspended section at the opening, and the second group III nitride epitaxial layer (14) is formed below the suspended section by lateral epitaxial growth. The third group III nitride epitaxial layer (15) is located on the second group III nitride epitaxial layer (14) and the patterned first mask layer (12), and the [0001] crystal orientation of the first group III nitride epitaxial layer (11), the second group III nitride epitaxial layer (14) and the third group III nitride epitaxial layer (15) are parallel to the thickness direction.

15. The group III nitride structure according to claim 14, characterized in that, The first group III nitride epitaxial layer (11), the second group III nitride epitaxial layer (14), and the third group III nitride epitaxial layer (15) are made of the same material, including at least one of GaN, AlN, AlGaN, InGaN, and AlInGaN.

16. The group III nitride structure according to claim 14, characterized in that, Also includes: Substrate (10), on which the first group III nitride epitaxial layer (11) is located.

17. The group III nitride structure according to claim 16, characterized in that, The substrate (10) serves as the second mask layer (13).

18. The group III nitride structure according to claim 16 or 17, characterized in that, The substrate (10) includes at least one of sapphire, silicon carbide and silicon.

19. The group III nitride structure according to claim 14, characterized in that, The patterned first mask layer (12) also has a second mask layer (13), and the third group III nitride epitaxial layer (15) is located on the second mask layer (13).

20. The group III nitride structure according to claim 14 or 19, characterized in that, The material of the first mask layer (12) includes at least one of silicon dioxide and silicon nitride; and / or the material of the second mask layer (13) includes at least one of silicon dioxide and silicon nitride.

21. The group III nitride structure according to claim 14, characterized in that, The second group III nitride epitaxial layer (14) is an in-situ group III nitride epitaxial layer (14'); and / or the second mask layer (13) is an in-situ second mask layer (13').

22. The group III nitride structure according to claim 14, characterized in that, The third group III nitride epitaxial layer (15) located on the patterned first mask layer (12) is not healed, and the patterned first mask layer (12) and the third group III nitride epitaxial layer (15) have a fourth group III nitride epitaxial layer (16).

23. The group III nitride structure according to claim 22, characterized in that, Also includes: LED structure (17) located on the fourth group III nitride epitaxial layer (16).

24. The group III nitride structure according to claim 14, characterized in that, Also includes: LED structure (17) located on the third group III nitride epitaxial layer (15).

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