Engineered growth substrate for group III nitride power devices with high-quality nucleation region formed and method for manufacturing the same

Abstract

The disclosed engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed comprises: a support substrate; a seed region (layer) disposed in bond with the support substrate; and a nucleation region disposed on the seed region (layer); wherein the film quality of the nucleation region is the same as the film quality of epitaxially grown on a seed substrate having a thickness of at least twice the thickness of the seed region (layer).

Description

Technology Field

[0001] The present invention (Disclosure) relates to an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed therein and a method for manufacturing the same. Specifically, it relates to an engineered growth substrate for a group 3 nitride power device having a composite material stacked structure having a nucleation region formed therein having film quality suitable for a growth substrate for a group 3 nitride power device, and a method for manufacturing the same. Background Technology

[0002] This section provides background information related to the present disclosure, which is not necessarily prior art.

[0003] A single material substrate is used for growing group 3 nitride semiconductors.

[0004] It is difficult for single-material growth substrates to simultaneously satisfy crystal defect density, surface polarity, device structure thickness, heat dissipation capability, and cost.

[0005] As an alternative, an engineered growth substrate having a composite stacked structure made of different materials was introduced as a wafer for growing Group 3 nitride semiconductors.

[0006] An engineered growth substrate having a composite material laminated structure has a structure in which a thin seed region (layer), a bonding layer, and a support substrate are laminated.

[0007] The device structure is grown on a seed region (layer).

[0008] The support substrate and the bonding layer are intended to provide physical rigidity and stability to the device structure.

[0009] An engineered growth substrate having a composite material stacked structure has a structure in which a thin seed region (layer) is firmly supported by a supporting substrate and a bonding layer from below. Therefore, while reducing costs by using a thin seed region (layer), it can also have quality characteristics superior to those of a single-material growth substrate because a film is formed on top of a seed region (layer) having equivalent physical properties (lattice constant) similar to those of the device structure.

[0010] However, engineered growth substrates having a composite layered structure have limitations in terms of process when used as growth substrates for high-quality growth of device structures for group 3 nitride power devices.

[0011] Specifically, the quality of a high-quality device structure for a group 3 nitride power device is greatly influenced by the quality of the nucleation region grown on the growth substrate (specifically, the seed region (layer)).

[0012] Before depositing a device structure on top of a seed region (layer), a nucleation region is basically grown, and at this time, the thickness uniformity and crystal defect density of the nucleation region have a significant impact on the performance and quality of the device structure deposited on the seed region (layer), as well as on reliability, lifespan, and yield.

[0013] In particular, in power semiconductors such as HEMTs, MOSFETs, and JFETs to which large currents of several to tens of amperes (A) or high voltages of hundreds to thousands of volts (V) are applied, a single fatal crystal defect can affect lifespan or reliability.

[0014] Furthermore, if the thickness uniformity of the nucleation region is poor, the uniformity of physical properties of the device structure material for power devices deteriorates, significantly affecting the performance and yield of the power device.

[0015] Therefore, the growth of the nucleation region on the seed region (layer) must be managed simultaneously in terms of improving thickness uniformity and minimizing crystal defect density.

[0016] Representative crystal defects that have a fatal impact on group 3 nitride power devices include threading dislocations, inversion domains (ID), and inversion domain boundaries (IDB) of various types and characteristics.

[0017] Minimizing crystal defect density requires raising the growth temperature of the nucleation region to a high temperature. On the other hand, uniformity of the thickness of the nucleation region requires raising the growth temperature of the nucleation region to a low temperature or increasing the thickness of the engineered growth substrate to prevent bowing of the engineered growth substrate.

[0018] Increasing the thickness of the seed region (layer) constituting the engineered growth substrate contradicts the reason for adopting the engineered growth substrate.

[0019] In addition, a relatively thick seed region (layer) is subjected to significant thermo-mechanical stress depending on the physical properties of the bonded support substrate and the growth temperature.

[0020] Therefore, the process technology to grow at high temperatures to minimize the crystal defect density of the nucleation region on a relatively thick seed region (layer) while simultaneously maximizing the thickness uniformity of the nucleation region has been an issue facing significant difficulties. Prior art literature

[0021] 1. Korean Registered Patent Publication No. 10-1154916 The problem to be solved

[0022] The present invention (Disclosure) aims to provide an engineered growth substrate for a group 3 nitride power device and a method for manufacturing the same, wherein crystal defects such as threading dislocations of various types and characteristics, inversion domains (ID), and inversion domain boundaries (IDB) are minimized and a nucleation region with improved thickness uniformity is formed.

[0023] The present invention (Disclosure) aims to provide an engineered growth substrate for a group 3 nitride power device and a method for manufacturing the same, wherein a nucleation region is already formed having a film quality that is further improved compared to the film quality that can be expected in a nucleation region grown directly in a seed region (layer) of a composite material stacked structure (seed region (layer) - bonding layer - support substrate). means of solving the problem

[0024] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0025] To solve the above-mentioned problem, an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to one aspect of the various aspects describing the present invention comprises: a support substrate; a seed region (layer) disposed in bond with the support substrate; and a nucleation region disposed on the seed region (layer); wherein the film quality of the nucleation region is the same as the film quality of epitaxially grown on a seed substrate having a thickness of at least twice the thickness of the seed region (layer).

[0026] According to one aspect of the various aspects describing the present invention, in an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed therein, the seed region (layer) and the seed substrate are of the same material and crystal structure and are single-crystal SiC, and the nucleation region is epitaxial AlN.

[0027] In an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to one aspect of the various aspects describing the present invention, the seed region (layer) is characterized by being formed by slicing the seed substrate on which the nucleation region is grown.

[0028] According to one aspect of the various aspects describing the present invention, in an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed therein, the thickness of the seed region (layer) is characterized as being 50 to 200 μm.

[0029] In an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to any one aspect of the various aspects describing the present invention, the film-forming quality is characterized by including thickness uniformity or crystal defect density.

[0030] In an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to one aspect of the various aspects describing the present invention, the crystal defect density is characterized by including an ID (Inversion Domain) and an IDB (Inversion Domain Boundary) in addition to threading dislocations.

[0031] In an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to one aspect of the various aspects describing the present invention, the support substrate is characterized as being one of single-crystal Si, single-crystal SiC, polycrystalline AlN ceramic, and polycrystalline SiC ceramic materials.

[0032] Here, in order to minimize the effects of thermomechanical stress, it is desirable to prioritize the selection of a support substrate in which the difference in the coefficient of thermal expansion between the seed region (layer) material and the substrate is zero or minimized.

[0033] According to one aspect of the various aspects describing the present invention, in an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed therein, the seed region (layer) or one surface of the seed substrate is characterized by having a raised or recessed pattern formed on the surface where the nucleation region is grown.

[0034] A method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to another aspect among the various aspects describing the present invention comprises: a seed substrate preparation step (S100) of preparing a seed substrate provided with a single crystal SiC having a set thickness; a nucleation region formation step (S200) of forming a nucleation region on the upper surface of the seed substrate; a seed substrate modification step (S300) of forming a reforming layer parallel to the nucleation region inside the seed substrate by irradiating the seed substrate with a stealth laser; and a seed region separation step (S500) of separating the seed region (layer) in which the nucleation region is formed from the seed substrate at the boundary of the reforming layer.

[0035] A method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to another aspect among the various aspects describing the present invention comprises: a temporary substrate bonding step (S400) in which a temporary substrate is bonded to the upper surface of the nucleation region via a predetermined adhesive layer before or after the seed substrate modification step (S300); a wafer bonding step (S700) in which a support substrate is wafer-bonded via a predetermined wafer bonding layer to the opposite side of the surface where the nucleation region is formed among the two sides of the seed region (layer) separated by the seed region separation step (S500); and a temporary substrate removal step (S800) in which the temporary substrate is separated from the nucleation region.

[0036] In a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to another aspect among the various aspects describing the present invention, the wafer bonding step (S700) includes a step (S600) of flattening the side of the two sides of the seed region (layer) to which the support substrate is bonded.

[0037] In a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to another aspect among the various aspects describing the present invention, the seed region separation step (S500) is characterized in that each of the seed substrates on both sides centered on the modified layer is separated without external force due to a structural asymmetry including a quantitative difference in thermal properties including a thermal expansion coefficient or a difference in thickness.

[0038] In a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to another aspect among the various aspects describing the present invention, the support substrate is characterized in that its thermal characteristics, including the effective thermal expansion coefficient and effective thermal conductivity, are similar to or identical to those of the seed region (layer). Effects of the invention

[0039] According to the present invention, high-quality growth of a device structure for a group 3 nitride power device is possible using an engineered growth substrate having a nucleation region having excellent film-forming quality in terms of thickness uniformity and minimization of crystal defect density.

[0040] According to the present invention, an engineered growth substrate having a nucleation region having excellent film formation quality in terms of thickness uniformity and minimization of crystal defect density can be obtained.

[0041] According to the present invention, the thickness non-uniformity and crystal defect density of the nucleation region grown on an engineered growth substrate of a composite layered structure can be significantly improved.

[0042] According to the present invention, by growing a high-quality nucleation region on a thick seed substrate and manufacturing an engineered growth substrate by separating the seed region (layer), which is part of the seed substrate, and the nucleation region together, the thick seed substrate can be separated into multiple seed regions (layers) for use. Accordingly, excellent film deposition quality of the nucleation region is secured, and at the same time, significant cost reduction is possible.

[0043] According to the present invention, a seed region (layer) in which a nucleation region is formed is separated from a thick seed substrate by utilizing a quantitative difference in thermal properties, including the thermal expansion coefficient between the seed region (layer) and the seed substrate, or structural asymmetry, including a difference in thickness, thereby allowing separation with minimal external force. Brief explanation of the drawing

[0044] FIG. 1 is a drawing showing one embodiment of an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed thereon. FIGS. 2 to 9 are drawings showing an embodiment of a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to the present invention. Specific details for implementing the invention

[0045] Hereinafter, an embodiment implementing an engineered growth substrate for a Group 3 nitride power device having a high-quality nucleation region formed according to the present invention and a method for manufacturing the same will be described in detail with reference to the drawings.

[0046] However, it should be noted that the intrinsic technical concept of the present invention is not limited to the embodiments described below, and encompasses a scope in which the embodiments described below can be easily proposed by a person skilled in the art based on the intrinsic technical concept of the present invention through substitution or modification.

[0047] Furthermore, the terms used below are selected for the convenience of explanation; therefore, in grasping the intrinsic technical concept of the present invention, they should not be limited to their dictionary meanings but should be appropriately interpreted in a sense consistent with the technical concept of the present invention.

[0048] FIG. 1 is a drawing showing one embodiment of an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed thereon.

[0049] Referring to FIG. 1, an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to the present embodiment includes a support substrate (210), a seed region (layer) (120), and a nucleation region (101).

[0050] The support substrate (210) is configured to structurally support the seed region (layer) (120) and the nucleation region (101).

[0051] When the seed region (layer) (120) is provided with a single-crystal SiC material and the nucleation region (101) is provided with an epitaxial AlN, the support substrate (210) is preferably provided with any one of single-crystal Si, single-crystal SiC, polycrystalline AlN ceramic, and polycrystalline SiC ceramic material.

[0052] Furthermore, in order to minimize the effects of thermomechanical stress during the growth process of the subsequent device structure, it is preferable that the support substrate (210) be selected from a material in which the difference in the coefficient of thermal expansion with the seed region (layer) material is zero or minimized.

[0053] It is preferable that the support substrate (210) be formed with a thickness of 500 to 1,000 μm for structural support.

[0054] The seed region (layer) (120) is bonded to the support substrate (210) and is formed with a thickness of 50 to 200 μm.

[0055] When the seed region (layer) (120) is provided for the growth of a group 3 nitride power device, the seed region (layer) (120) is preferably formed with a thickness of 100 to 200 μm.

[0056] The bonding of the seed region (layer) (120) and the support substrate (210) is preferably a permanent bond and is formed by a predetermined wafer bonding material. The wafer bonding layer can be formed with a thickness of 1 to 10 μm.

[0057] The nucleation region (101) is epitaxially grown and placed on the seed region (layer) (120), and is composed of epitaxial AlN material.

[0058] The thickness of the nucleation region (101) is less than 3㎛, preferably 0.1㎛ or less.

[0059] In this embodiment, the nucleation region (101) is not directly epitaxially grown on the seed region (layer) (120), but rather the nucleation region (101) is epitaxially grown on a seed substrate (100) having a thickness of at least twice the thickness of the seed region (layer) (120), and then the seed region (layer) (120) on which the nucleation region (101) is formed is separated from the seed substrate (100).

[0060] According to this, the film quality of the nucleation region (101) is the same as the film quality of the nucleation region (101) that is epitaxially grown on a seed substrate (100) having a thickness of more than twice the thickness of the seed region (layer) (120).

[0061] The quality of this membrane is significantly improved compared to the quality of the membrane of the nucleation region (101) grown directly in the seed region (layer) (120).

[0062] Film quality refers to thickness uniformity and / or crystal defect density, and crystal defect density includes ID (Inversion Domain) and IDB (Inversion Domain Boundary).

[0063] ID refers to the region where the arrangement of grown atoms is inverted (i.e., the N polar face region existing on the Al polar face or vice versa), and IDB refers to the boundary between the inverted portion and the normal portion.

[0064] Therefore, a higher density of threading dislocations, IDs, and IDBs indicates larger crystal defects.

[0065] In this embodiment, the AlN material used as the nucleation region material can be deposited at a growth temperature of 1,200°C or higher to ensure much better quality. However, as the growth temperature increases, the bowing of the growth substrate increases, making it difficult to ensure thickness uniformity.

[0066] To solve this, the inventor devised a method of growing AlN, which is the material of the nucleation region (101), using a thick seed substrate (100), and separating the seed region (layer) (120) and the nucleation region (101) from the seed substrate (100) on which the nucleation region (101) has been grown.

[0067] Specifically, the seed region (layer) (120) in which the nucleation region (101) is grown is formed by slicing from the seed substrate (100) by the method described below. In addition, the seed substrate (100) from which the seed region (layer) (120) has been separated is reused by repeating the growth and slicing of the nucleation region.

[0068] As a result, the consumption of the relatively expensive seed substrate is minimized, and the excellent film quality of the nucleation region (101) is secured.

[0069] Meanwhile, in this embodiment, in order to achieve excellent film formation quality of the nucleation region (101), it is preferable that a raised or recessed pattern be formed on the surface of the seed substrate (100) where the nucleation region (101) is grown. Accordingly, the ELOG growth of the nucleation region (101) can be easily guided.

[0071] FIGS. 2 to 9 are drawings showing an embodiment of a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed according to the present invention.

[0072] Referring to FIGS. 2 to 9, a method for manufacturing an engineered growth substrate for a group 3 nitride power device having a nucleation region formed according to the present embodiment includes a seed substrate preparation step (S100), a nucleation region formation step (S200), a seed substrate modification step (S300), and a seed region separation step (S500).

[0073] The seed substrate preparation step (S100) is a step of preparing a seed substrate (100) provided with single-crystal SiC of a set thickness.

[0074] The nucleation region formation step (S200) is a step of forming a nucleation region (101) on the upper surface of a seed substrate (100). The nucleation region (101) is composed of an epitaxial AlN material.

[0075] The seed substrate modification step (S300) is a step of forming a reforming layer parallel to the nucleation region (101) inside the seed substrate (100) by irradiating the seed substrate (100) with a stealth laser.

[0076] The seed region separation step (S500) is a step of separating the seed region (layer) in which the nucleation region is formed from the seed substrate (100) at the boundary of the modified layer.

[0077] In this embodiment, the process proceeds in the order of growing a nucleation region (101) on a seed substrate (100), then modifying the seed substrate (100) to separate the seed region (layer) (120) on which the nucleation region (101) has grown from the seed substrate (100).

[0078] That is, the nucleation region (101) is not formed on a thin seed region (layer) (120) separated from the seed substrate (100), but is formed on a relatively thick seed substrate (100).

[0079] It is preferable that the set thickness of the seed substrate (100) be at least twice the thickness of the seed region (layer) (120). For example, the thickness of the seed substrate (100) may be at least 500 μm for 4-inch and 6-inch wafers and at least 750 μm for 8-inch wafers, based on the wafer diameter.

[0080] According to this, the thickness uniformity of the nucleation region (101) and the quality of the high-quality film formation can be secured.

[0081] Specifically, AlN material used as the nucleation region material can achieve much better quality (minimization of crystal defects) when deposited at a growth temperature of 1,200°C or higher. However, as the growth temperature increases, wafer bowing becomes greater, making it difficult to ensure thickness uniformity.

[0082] To solve this, the AlN material of the nucleation region (101) is used with a thick seed substrate (100) to prevent bowing of the wafer and ensure thickness uniformity, and at the same time, the growth temperature is 1,200°C or higher to obtain high-quality film deposition quality.

[0083] Meanwhile, the device structure (e.g., in a GaN HEMT, a buffer layer, a channel layer, a barrier layer, a cap layer) grown in the nucleation region (101) is carried out at a temperature lower than the growth temperature of the nucleation region (101) (around 1,000°C), so the low crystal defects and thickness uniformity of the nucleation region (101) can ensure high quality of the subsequently grown device structure.

[0084] Meanwhile, in the present embodiment, the seed substrate preparation step (S100) may allow the nucleation region (101) to grow in an ELOG (epitaxial lateral overgrowth) manner by forming a raised or recessed pattern to a predetermined depth on the surface of the seed substrate (100).

[0086] Next, the seed substrate modification step (S300) is described in detail.

[0087] The seed substrate modification step (S300) is a step of forming a reforming layer parallel to the nucleation region inside the seed substrate (100) by irradiating the seed substrate (100) with a stealth laser.

[0088] The stealth laser (L) is a laser (Light Amplification by Stimulated Emission of Radiation) of a wavelength capable of penetrating the seed substrate (100) or the nucleation region (101), and is an optical system configured to form a focal point at a specific point inside the seed substrate (100) using a separate optical system.

[0089] At the focused point of the laser, photons are locally concentrated in a microscopic space, resulting in a nonlinear energy absorption phenomenon.

[0090] Accordingly, at the focal point where the photons of the stealth laser (L) are concentrated, the bonds between the constituent atoms are destroyed. At this time, if the focal point where the photons of the stealth laser (L) are concentrated is moved along a specific plane to form a scanning plane, a modified layer (110) is formed along the scanning plane.

[0091] It is preferable that the modified layer (110) be formed at a depth corresponding to the thickness of the seed region (layer) (120) on the upper surface of the seed substrate (100) on which the nucleation region (101) is formed.

[0092] It is preferable that the stealth laser (L) be irradiated to have a short path to the modified layer (110) on both sides of the seed substrate (100), but it may also be irradiated along a relatively long path.

[0093] Meanwhile, in the present embodiment, the seed region separation step (S500) is a step of separating the seed region (layer) (120) in which the nucleation region (101) is formed from the seed substrate (100) with respect to the modified layer (110).

[0094] In this embodiment, there are no restrictions on the method of separating the seed region. Therefore, any example in which a separation method is applied should be included within the scope of the present invention.

[0096] Hereinafter, a process for manufacturing an engineered growth substrate for a group 3 nitride power device having a high-quality nucleation region formed thereon according to the present embodiment is described by separating the seed region (layer) (120) in which the nucleation region (101) is formed from the seed substrate (100).

[0097] To this end, a method of sequentially bonding two wafers (temporary substrate and support substrate) is proposed.

[0098] The first wafer bonding includes a temporary substrate bonding step (S400) in which a temporary substrate (300) is bonded to the upper surface of a nucleation region (101) via a predetermined adhesive layer (301) before or after the seed substrate modification step (S300). Although not shown, prior to forming the predetermined adhesive layer (301), a prevention layer made of a predetermined material may be added to protect the nucleation region (101).

[0099] The seed region separation step (S500) is performed after the temporary substrate bonding step (S400) is completed.

[0100] The second wafer bonding step (S700) includes a wafer bonding step (S700) in which a support substrate (210) is wafer bonded to the opposite side of the side on which the nucleation region (101) is formed among the two sides of the seed region (layer) (120) separated by the seed region separation step (S500) via a predetermined wafer bonding layer (130).

[0101] Meanwhile, in the present embodiment, the wafer bonding step (S700) corresponding to the second wafer bonding preferably includes a step (S600) of flattening the side on which the support substrate (210) is bonded among the two sides of the seed region (layer) (120).

[0102] Here, it goes without saying that the surface of the seed substrate (100) generated as a result of the separation of the seed region (layer) (120) can also be flattened for the growth of a new nucleation region.

[0103] Afterwards, the manufacturing of an engineered growth substrate for a group 3 nitride power device having a nucleation region formed according to the present embodiment is completed by a temporary substrate removal step (S800) that separates the temporary substrate (300) from the nucleation region (101).

[0104] Here, it is preferable that the temporary substrate (300) be selected to have thermal characteristics, including the effective thermal expansion coefficient and effective thermal conductivity, similar or identical to those of the support substrate (210).

[0105] In addition, it is more desirable that the crystal structures of the temporary substrate (300) and the support substrate (200) both have a single crystal structure.

[0106] This enables normal and excellent bonding between the support substrate (210) and the seed region (layer) (120) in the wafer bonding step (S700).

[0107] Specifically, when the wafer bonding step (S700) is performed, the temporary substrate (300) and the seed region (layer) (120) on which the nucleation region (101) is formed are already bonded via a predetermined adhesive layer (301), and the wafer bonding process is generally performed after heating the substrate and bonding layer to be bonded to a predetermined temperature.

[0108] Therefore, if there is a large difference between the thermal characteristics of the temporary substrate (300) and the support substrate (210), a difference in the shrinkage characteristics of the interface between the support substrate (210) and the seed region (layer) (120) will occur during the bonding process, which has a negative effect on stable bonding characteristics.

[0109] Meanwhile, the bonding layer (301) between the temporary substrate (300) and the nucleation region (101) is an organic material (polymer) such as resin, epoxy, SU-8, BCB, etc., and a metal such as Sn, In, Zn, Ga, Au, Ni, Ag, Cu, SiO2, SiN, which allows the temporary substrate (300) to be easily removed and separated in the subsequent temporary substrate removal step (S800). x It can be selected from ceramic materials such as ITO, GaN, InGaN, AlGaN, AlGaInN, ZnO, and ZITO.

[0110] Next, wafer bonding between the support substrate (210) and the seed region (layer) (120) is SiO2, SiN x It is formed through dielectric ceramic materials such as SOG (Spin-on-Glass), AlN, Al2O3, ITO, GaN, InGaN, AlGaN, AlGaInN, ZnO, and ZITO.

[0111] For excellent bonding characteristics, it is desirable to form a surface with a surface roughness of less than 1 nm before bonding. Furthermore, surface treatment such as plasma or solution that increases surface energy may be performed.

[0113] Hereinafter, a preferred seed region separation method devised by the inventors will be described.

[0114] In this embodiment, the seed region separation step (S500) is characterized in that both sides (100a, 120) of the seed substrate (100) are separated without external force due to a quantitative difference in thermal properties including the thermal expansion coefficient or a structural asymmetry including a difference in thickness, with respect to the modified layer (110). This implies separation with minimal external force.

[0115] Specifically, a nucleation region (101) is formed in the seed region (layer) (120) at the boundary of the modified layer (110), and a temporary substrate (300) is attached via the adhesive layer (301).

[0116] On the other hand, the seed substrate (100a) is thinned by the thickness of the seed region (layer) (120) from the seed substrate (100) at the boundary of the modified layer (110), and there are no other changes in shape.

[0117] Therefore, the seed region (layer) (120) and the seed substrate (100a) have the same constituent material, but their physical properties differ due to structural differences based on the bonding structure.

[0118] First, the thermal expansion coefficient and thermal conductivity resulting from the physical properties of the seed region (layer) (120) and the seed substrate (100a) are the same.

[0119] However, depending on the thickness, the structure bonded with other materials, and the physical properties of the bonded other materials, the effective thermal expansion coefficient and effective thermal conductivity that can be applied to actual physical action are different between the side including the seed region (layer) (120), nucleation region (101), bonding layer (301) and temporary substrate (300) and the side including the seed substrate (100), with the modification layer (110) as the boundary.

[0120] This is a factor that causes the degree of thermal expansion of the upper and lower sides to differ with respect to the modified layer (110), and acts as the first factor that allows the seed region (layer) (120) and the seed substrate (100a) to be 'separated without external force' with respect to the modified layer (110).

[0121] In addition, there is a difference in thickness between the seed region (layer) (120) and the seed substrate (100a), a nucleation region (101) is formed on the seed region (layer) (120), and a temporary substrate (300) is attached via an adhesive layer (301).

[0122] The seed region (layer) (120) and the seed substrate (100a) have the same lattice constant based on the constituent material, but the seed region (layer) (120) in which the nucleation region (101) is formed and the adhesive layer (301) and temporary substrate (300) are attached thereto does not have the same lattice constant based on the intrinsic physical properties of the seed region (layer) (120).

[0123] This creates mechanical stress in the modified layer (110), which is the boundary between the seed region (layer) (120) and the seed substrate (100a), and acts as another factor that allows the seed region (layer) (120) and the seed substrate (100a) to be 'separated without external force' at the boundary of the modified layer (110).

[0124] Accordingly, the quantitative-qualitative identity of the physical properties of the seed region (layer) (120) and the seed substrate (100a), separated by the modified layer (110), is destroyed, thereby generating stress along the modified layer (110), and thus having the characteristic of being separated without external mechanical force applied from the outside.

[0125] The inventor named this separation method 'Hot Self Split'.

[0126] Meanwhile, other methods for separating the seed region (layer) (120) from the seed substrate (100) include using ion implantation and laser lift-off (LLO).

[0127] These are explained in contrast to the 'hot self split' described earlier.

[0128] The method using ion implants is a method of forcibly injecting hydrogen ions into the seed substrate to form a reforming layer and then separating the seed region.

[0129] The method using ion implants may appear similar to the hot self-split method described above in that it forms a modified layer for separation, but it has the problem that the film quality of the seed substrate along the path where hydrogen ions are injected is significantly damaged.

[0130] Ion implant technology is based on a technique that accelerates hydrogen ions so that they can penetrate the surface of a target substrate and be embedded to a specific depth.

[0131] Therefore, the surface and interior of the seed substrate along the path where hydrogen ions pass cannot avoid implant damage caused by hydrogen ions, and in order to recover from this damage, a separate high-temperature heat treatment (annealing) process must be performed.

[0132] When using an impurity-free SiC substrate as a seed substrate, even if changes in impurity concentration due to heat treatment, i.e., annealed damage, are not taken into account, a heat treatment process is required to repair implant damage.

[0133] This presents the problem of increased manufacturing costs as well as longer lead times due to the addition of processes.

[0134] In addition, the depth to which the hydrogen ions injected in this way penetrate varies depending on the magnitude of the applied energy and the energy lost through collisions with the surface.

[0135] Therefore, the seed region securing technology using hydrogen ion-based ion implant technology makes it difficult to secure a seed region of uniform quality, and in particular, subsequent processes such as heat treatment are essential when reusing the remaining seed substrate (100) after the seed region is separated.

[0136] Next, unlike the aforementioned stealth laser, the seed region securing technology using laser lift-off (LLO) has a problem in that it is very difficult to secure a thin yet large-area seed region because, at the same time, the high-energy short-wavelength laser is absorbed by the 'seed region (GaN, InGaN, AlGaN) / growth substrate (sapphire)' structure formed of heterogeneous materials and the seed region (GaN, InGaN, AlGaN) is separated from the growth substrate (sapphire), and this phenomenon occurs explosively in a very short period of time.

Claims

Claim 1 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, comprising: a support substrate; a seed region (layer) disposed in bonded to the support substrate; and a nucleation region disposed on the seed region (layer); wherein the film quality of the nucleation region is the same as the film quality of epitaxially grown on a seed substrate having a thickness of at least twice the thickness of the seed region (layer). Claim 2 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, characterized in that, in claim 1, the seed region (layer) and the seed substrate have the same material and crystal structure and are single-crystal SiC, and the nucleation region is epitaxial AlN. Claim 3 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed in claim 2, wherein the seed region (layer) is formed by slicing the seed substrate on which the nucleation region is grown. Claim 4 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, characterized in that, in claim 2, the thickness of the seed region (layer) is 50 to 200 μm. Claim 5 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, wherein the film quality of claim 1 includes thickness uniformity or crystal defect density. Claim 6 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed therein, characterized in that, in claim 5, the crystal defect density includes threading dislocations, inversion domains (ID), or inversion domain boundaries (IDB). Claim 7 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, wherein the support substrate is one of single-crystal Si, single-crystal SiC, polycrystalline AlN ceramic, and polycrystalline SiC ceramic material. Claim 8 An engineered growth substrate for a group 3 nitride power device having a nucleation region formed thereon, characterized in that, in claim 1, a raised or recessed pattern is formed on the surface where the nucleation region is grown, as one surface of the seed region (layer) or the seed substrate. Claim 9 A seed substrate preparation step (S100) for preparing a seed substrate made of single-crystal SiC having a set thickness; a nucleation region formation step (S200) for forming a nucleation region on the upper surface of the seed substrate; and a seed substrate modification step (S300) for irradiating the seed substrate with a stealth laser to form a reforming layer parallel to the nucleation region inside the seed substrate. A method for manufacturing an engineered growth substrate for a Group 3 nitride power device having a nucleation region formed thereon, comprising: a seed region separation step (S500) for separating the seed region (layer) in which the nucleation region is formed from the seed substrate at the boundary of the modified layer; a temporary substrate bonding step (S400) for bonding a temporary substrate to the upper surface of the nucleation region via a predetermined adhesive layer before or after the seed substrate modification step (S300); a wafer bonding step (S700) for wafer bonding a support substrate via a predetermined wafer bonding layer to the opposite side of the surface in which the nucleation region is formed among the two sides of the seed region (layer) separated by the seed region separation step (S500); and a temporary substrate removal step (S800) for separating the temporary substrate from the nucleation region. Claim 10 delete Claim 11 A method for manufacturing an engineered growth substrate for a group 3 nitride power device having a nucleation region formed, wherein the wafer bonding step (S700) comprises a step (S600) of flattening the side of the two sides of the seed region (layer) to which the support substrate is bonded. Claim 12 A method for manufacturing an engineered growth substrate for a group 3 nitride power device having a nucleation region formed, wherein, in claim 9, the seed region separation step (S500) is characterized in that each of the seed substrates on both sides centered on the modified layer is separated without external force due to a structural asymmetry including a quantitative difference in thermal properties including a thermal expansion coefficient or a difference in thickness. Claim 13 A method for manufacturing an engineered growth substrate for a group 3 nitride power device having a nucleation region formed therein, wherein, in claim 9, the support substrate is characterized in that its thermal characteristics, including the effective thermal expansion coefficient and effective thermal conductivity, are similar to or identical to those of the seed region (layer).

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