Method for manufacturing a separable semiconductor substrate, and separable semiconductor substrate, thin film device, and composite device manufactured by the method

Abstract

To develop a technique capable of manufacturing a substrate having a large area at low expense in a compound semiconductor substrate.SOLUTION: A method for manufacturing a separable semiconductor substrate, and a thin film element and composite element manufactured thereby are provided. The method for manufacturing a separable semiconductor substrate comprises steps of providing a substrate and forming a buffer layer containing carbon and aluminium nitride.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a separable semiconductor substrate, and a thin film device and composite device manufactured by the same, and more particularly to a method for manufacturing a separable semiconductor substrate for growing and separating compound semiconductor crystals, and a thin film device and composite device manufactured by the same. [Background technology]

[0002] Compound semiconductors are a general term for semiconductors made up of two or more elements, and their use is essential for improving the performance of semiconductor elements and solving heat generation problems.

[0003] Among the various compound semiconductors, the core materials that are expected to show rapid growth include gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), silicon carbide (SiC), and gallium oxide (Ga2O3).

[0004] Gallium nitride (GaN), aluminum nitride (AlN), and aluminum gallium nitride (AlGaN) are III-V compound semiconductors that are being researched and applied as wafer materials to improve the power efficiency of photoelectron devices, emitters, sensors, and advanced high-performance semiconductors operating over a wide wavelength range.

[0005] The compound semiconductors described above are generally manufactured by inducing epitaxial growth on a substrate such as sapphire (Al2O3), silicon (Si) or silicon carbide (SiC), followed by separation.

[0006] The self-separation method is one of the separation methods, and the self-separation method has been reported to include a method of forming a pattern to separate the material and a method of inserting a buffer layer.

[0007] The method of forming the pattern uses a photo process, which is a common semiconductor process, and has the disadvantages of being expensive and complicated.

[0008] The method of inserting a buffer layer utilizes stress due to the difference in thermal expansion coefficients during cooling, but has problems such as poor separation or reduced crystallinity, making it difficult to manufacture a large-area substrate.

[0009] Therefore, there is a demand for the development of a technology that is inexpensive and capable of manufacturing large-area substrates.

[0010] On the other hand, the above-mentioned background art cannot necessarily be said to be publicly known art that was disclosed to the general public before the filing of the present invention. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Registration No. 5307975 B2 "Nitride-based semiconductor substrate, its manufacturing method, and epitaxial substrate for nitride-based semiconductor light-emitting device" (July 5, 2013) Summary of the Invention [Problem to be solved by the invention]

[0012] An object of one embodiment of the present invention is to provide a method for manufacturing a detachable semiconductor substrate, which allows for the manufacture of a large-area compound semiconductor substrate at low cost, and a detachable semiconductor substrate manufactured by the method.

[0013] One embodiment of the present invention aims to provide thin film devices and composite devices fabricated by a method for fabricating separable semiconductor substrates. [Means for solving the problem]

[0014] As a technical means for achieving the above technical object, according to one aspect of the present invention, a method for manufacturing a detachable semiconductor substrate includes the steps of providing a substrate and forming a buffer layer containing carbon and aluminum nitride.

[0015] According to another aspect of the present invention, the method may further include forming a compound semiconductor layer on the buffer layer, and inducing self-separation of the compound semiconductor layer.

[0016] According to another aspect of the present invention, the compound semiconductor layer may be gallium nitride (GaN), aluminum nitride (AlN), or aluminum gallium nitride (AlGaN).

[0017] According to another aspect of the present invention, the substrate may be a sapphire substrate having a size of 2 inches or more.

[0018] According to another aspect of the present invention, the step of forming the buffer layer may include a carbonization step of forming the carbon, a nitridation step of a top surface of the carbon, and a step of forming aluminum nitride on the top surface of the nitrided carbon.

[0019] As a technical means for achieving the above-mentioned technical object, according to another aspect of the present invention, a separable semiconductor substrate includes a mother substrate and a buffer layer disposed on the mother substrate and including carbon and aluminum nitride.

[0020] According to another aspect of the present invention, the separable semiconductor substrate may be 2 inches or larger in size.

[0021] According to another aspect of the present invention, the average light transmittance for light with a wavelength of 400 nm may be reduced by 20 to 80% compared to the average light transmittance of the mother substrate.

[0022] According to another aspect of the present invention, the buffer layer may include a carbon layer, a nitrided carbon layer, and an aluminum nitride layer.

[0023] According to another aspect of the present invention, the carbon layer may have a three-dimensional structure.

[0024] According to another aspect of the present invention, the carbon layer has a D' band wavelength of 1620 cm in a Raman spectrum. -1 It has a peak around 1000 nm and may be amorphous with an sp3 structure.

[0025] According to another aspect of the present invention, the carbon layer may have a surface roughness Ra of 27 nm and a surface roughness Rt of 310 nm or less.

[0026] According to another aspect of the present invention, the aluminum nitride layer may have a surface roughness Ra of 20 nm and a surface roughness Rt of 170 nm or less.

[0027] As a technical means for achieving the above technical object, according to another aspect of the present invention, a thin film device includes a buffer layer containing carbon and aluminum nitride, and includes an electronic device on the buffer layer.

[0028] According to another aspect of the present invention, the thin film device may further include a mother substrate below the buffer layer.

[0029] According to another aspect of the present invention, the thin film device may further include a stress layer covering the electronic device, and a support layer on the stress layer.

[0030] As a technical means for achieving the above-mentioned technical object, according to another aspect of the present invention, a composite device includes a first electronic device including a buffer layer containing carbon and aluminum nitride and a first element layer on the buffer layer, and a second electronic device including a second element layer that is in contact with a surface of the first element layer of the first electronic device and has a characteristic of being formed into a single structure.

[0031] According to another aspect of the present invention, the first electronic component may further include a separable substrate thereon. [Effects of the Invention]

[0032] According to any one of the above-described means for solving the problems, an embodiment of the present invention can provide a method for manufacturing a semiconductor substrate in which a compound semiconductor layer having a large area is formed.

[0033] According to one of the solutions to the problems of the present invention, an embodiment of the present invention can provide a method for manufacturing a semiconductor substrate that facilitates separation of a compound semiconductor layer.

[0034] Furthermore, according to any one of the means for solving the problems of the present invention, an embodiment of the present invention can facilitate separation of a compound semiconductor layer having a small thickness.

[0035] Furthermore, according to any one of the solutions of the present invention, an embodiment of the present invention manufactures a separable semiconductor substrate in-situ, which may simplify the process.

[0036] Furthermore, according to any one of the means for solving the problems of the present invention, an embodiment of the present invention can easily adjust the thickness of the carbon layer of the separable semiconductor substrate.

[0037] According to one of the solutions of the present invention, the separable semiconductor substrate can be applied to fabricate thin film devices.

[0038] According to any one of the above-mentioned means for solving the problem of the present invention, in one embodiment of the present invention, the thin film element includes a thin film substrate including a buffer layer containing carbon and aluminum nitride, an electronic element on the thin film substrate, and a stress layer covering the electronic element, thereby facilitating separation between the thin film element and the mother substrate.

[0039] In addition, according to any one of the solutions of the present invention, an embodiment of the present invention further includes a support layer that guides separation of the thin film elements, thereby enabling separation of the thin film elements without damage. In particular, the buffer layer facilitates separation of the substrate, allowing the thickness of the thin film elements to be further reduced.

[0040] According to any one of the above-mentioned means for solving the problems of the present invention, in one embodiment of the present invention, a composite element includes a buffer layer including carbon and aluminum nitride, a first element on the buffer layer, and a second element layer disposed below the first element and in contact with a surface facing the first element layer, characterized by being formed into a single structure. Therefore, various thin composite elements can be connected to form a single structure to realize a device that can operate.

[0041] Furthermore, according to any one of the means for solving the problems of the present invention, one embodiment of the present invention further includes a detachable substrate on the top (above) of the first electronic component, so that the substrate can be separated while the first electronic component and the second electronic component are combined, thereby enabling quick and easy fabrication of complex composite devices.

[0042] The effects that can be obtained by the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawings]

[0043] [Figure 1] 1 is a flowchart of a method for manufacturing a separable semiconductor substrate according to one embodiment of the present invention. [Figure 2] 1 is a graph showing a temperature change during a buffer layer formation step in a method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. [Figure 3] 10 is a graph showing a change in gas supply flow rate during a buffer layer formation step in a method for manufacturing a separable semiconductor substrate in accordance with an embodiment of the present invention. [Figure 4] 1A to 1C are cross-sectional views illustrating a method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. [Figure 5] 1A to 1C are cross-sectional views illustrating a method for manufacturing a separable semiconductor substrate and a method for manufacturing a compound semiconductor substrate therethrough according to an embodiment of the present invention. [Figure 6] 1 is a cross-sectional view illustrating a thin-film element according to an embodiment of the present invention. [Figure 7] 1 is a flowchart of a method for manufacturing a thin-film device according to an embodiment of the present invention. [Figure 8] 8A to 8C are cross-sectional views for explaining a method for manufacturing the thin-film element of FIG. 7. [Figure 9] 1 is a cross-sectional view illustrating a composite element according to an embodiment of the present invention. [Figure 10] 1 is a flowchart of a method for manufacturing a composite element according to an embodiment of the present invention. [Figure 11] 11A to 11C are schematic diagrams for explaining a method for manufacturing the composite element of FIG. 10. [Figure 12] 1 is a graph of UV-Vis (ultraviolet-visible) spectroscopy transmittance for a semiconductor substrate as a function of carbon thickness for a detachable semiconductor substrate according to one embodiment of the present invention. [Figure 13] 1 is a Raman spectrum of a detachable semiconductor substrate according to one embodiment of the present invention. [Figure 14] 4 is a photograph of the surface shape of a detachable semiconductor substrate according to an embodiment of the present invention, depending on the carbon thickness; [Figure 15] 1 is a photograph of the surface shape of an aluminum nitride layer for a separable semiconductor substrate according to one embodiment of the present invention. [Figure 16]1 is a photograph showing an aluminum nitride layer being separated from a sapphire substrate after the aluminum nitride layer is grown on a separable semiconductor substrate according to an embodiment of the present invention. [Figure 17] 1 is a photograph showing a gallium nitride layer being self-separated from a sapphire substrate after the gallium nitride layer is grown on a detachable semiconductor substrate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will now be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts not relevant to the description are omitted in order to clearly explain the present invention, and similar parts are designated by similar reference numerals throughout the specification.

[0045] Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "indirectly connected" through another member or element therebetween. Furthermore, when a part is said to "include" some component, this does not mean that it excludes other components, but that it may further include other components, unless otherwise specified.

[0046] Fig. 1 is a flowchart of a method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. Fig. 2 is a graph showing temperature changes during a buffer layer formation step in the method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. Fig. 3 is a graph showing gas input flow rates during a buffer layer formation step in the method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. Fig. 4 is a cross-sectional view illustrating a separable semiconductor substrate according to an embodiment of the present invention.

[0047] The present invention will be described with reference to FIGS.

[0048] A method for fabricating a self-separable semiconductor substrate includes providing a substrate and forming a buffer layer comprising carbon and aluminum nitride.

[0049] The step of providing a substrate (S110) is a step of providing a base material for growing a separable semiconductor substrate. A sapphire substrate having a size of 2 inches or more can be provided, but is not limited to this. For example, a Si or SiC substrate can be provided. Accordingly, a large-area compound semiconductor layer to be manufactured can be formed on the substrate.

[0050] The step of forming the buffer layer (S120) is a step of forming a separation-inducing layer so that the compound semiconductor can be grown with excellent crystallinity and the compound semiconductor layer can be easily separated from the substrate later. The step of forming the buffer layer (S120) is performed at a temperature of 1000°C or more, preferably 1000°C to 1600°C, more preferably 1000°C to 1200°C, and more preferably 1100°C.

[0051] If the temperature is less than 1000° C., the diffusion rate for homogeneous nucleation and growth of carbon can be reduced.

[0052] The step of forming the buffer layer (S120) includes a carbonization step of forming carbon, a nitridation step of the upper surface of the carbon, and a step of forming aluminum nitride on the upper surface of the nitrided carbon.

[0053] The carbonization and nitridation steps are performed in-situ using an HVPE apparatus, preferably a horizontal HVPE apparatus, but not necessarily limited to this. For example, an MOCVD, sputter, PECVD, or ALD apparatus may be used.

[0054] As an example, taking a horizontal HVPE apparatus among multiple growth equipment, the HVPE apparatus may have a structure in which six independently controlled heaters are arranged.

[0055] The horizontal HVPE apparatus can configure a source zone and a growth zone within a quartz reactor.

[0056] At one end of the source region, gas supply lines for methane (CH4), ammonia (NH3), hydrogen chloride (HCl), and nitrogen (N2) can be configured. The gas flow rate for each line is measured in sccm (Standard Cubic Centimeter per Minute).

[0057] Meanwhile, referring to FIGS. 2 and 3, the carbonization and nitridation steps specifically include a substrate loading step (S121), a carbonization step (S122), and a nitridation step (S123).

[0058] In the substrate loading step (S121), a substrate is loaded into the growth region, where the temperature is increased from 25° C. to 1100° C. and then maintained at 1100° C., as shown in FIG.

[0059] The carbonization step (S122) is a step of forming carbon on the substrate, where CH gas can be supplied at a flow rate of 500 sccm or less for 20 minutes or less, preferably at a flow rate of 10 sccm to 300 sccm for 2 minutes to 20 minutes.

[0060] At this time, the temperature may be maintained at 1100°C as shown in Figure 2, and CH gas may be injected at 100 sccm as shown in Figure 3. The carbonization step (S122) may be performed for 2 to 10 minutes.

[0061] The nitriding step (S123) is a step of nitriding the upper surface of the carbon. Here, NH gas can be supplied at a flow rate of 4000 sccm or less for 5 minutes or less, and preferably at a flow rate of 2000 sccm to 3000 sccm for 3 seconds to 3 minutes.

[0062] At this time, the temperature is maintained at 1100° C. as shown in FIG. 2, and NH gas is injected at 4000 sccm as shown in FIG. 3. The nitridation step (S123) may be performed for 6 seconds.

[0063] If the upper surface of the carbon is not nitrided in the nitriding step (S123), the surface of the carbon may have few unsaturated bonds or functional groups, making it difficult to grow inorganic materials such as aluminum nitride.

[0064] The aluminum nitride formation step (S124) is a step of growing aluminum nitride. Here, activated gases including NH3 gas and HCl gas may be supplied at a flow rate of 1000 sccm or less for 5 minutes or less, and preferably, NH3 gas may be supplied at a flow rate of 10 to 100 sccm and HCl gas may be supplied at a flow rate of 100 to 1000 sccm for 1 to 5 minutes.

[0065] At this time, the temperature is maintained at 1100°C as shown in Figure 2, and NH3 gas is injected at 40 sccm and HCl gas at 200 sccm as shown in Figure 3. The aluminum nitride formation step (S124) may be performed for 2 to 3 minutes.

[0066] Here, a boat containing aluminum (Al) metal, which is used as a raw material, is placed in the source region, and the temperature of the region where the boat is placed is maintained at 550°C to 650°C. Then, the molten Al metal reacts with HCl gas to produce aluminum chloride (AlCl3) gas.

[0067] The generated AlCl3 gas can be transported to the growth region by a carrier gas.

[0068] Argon (Ar) and nitrogen gas can be used as the carrier gas, and specifically, nitrogen gas can be used.

[0069] In the growth region, AlCl3 gas and NH3 gas can react to grow aluminum nitride (AlN).

[0070] In the unloading step (S125), the substrate is removed after all the processes are completed, and then cooled to 25° C. as shown in FIG.

[0071] A separable semiconductor substrate is obtained through the above-described method.

[0072] 4(b), the buffer layer 20 is composed of a first sub-buffer layer 20A, a second sub-buffer layer 20B, and a third sub-buffer layer 20C. Here, the buffer layer 20 is defined as AWC (AlN with carbon buffer on sapphire).

[0073] Here, the first sub-buffer layer 20A may be a carbon-containing layer.

[0074] The second sub-buffer layer 20B may also be a nitrided carbon layer.

[0075] The third sub-buffer layer 20C may also be an aluminum nitride-containing layer.

[0076] Here, if the thickness of the first sub-buffer layer 20A increases, the average light transmittance may decrease.

[0077] The carbon in the first sub-buffer layer 20A may have a three-dimensional structure.

[0078] In addition, the surface of the first sub-buffer layer 20A can be very smooth.

[0079] Separation of the obtained semiconductor substrate can be induced at the interface between the substrate and the first sub-buffer layer 20A during the cooling process.

[0080] Here, due to the difference in thermal expansion coefficient between the substrate and the first sub-buffer layer 20A, tensile stress may act on the surface of the substrate and compressive stress may act on the surface of the first sub-buffer layer 20A, with the interface as the base.

[0081] The crystallinity of the buffer layer 20 can be inherited through the third sub-buffer layer 20C.

[0082] Here, the surface of the third sub-buffer layer 20C can be very smooth.

[0083] The buffer layer 20 can be removed by a CMP (Chemical Mechanical Polishing) method.

[0084] Meanwhile, a compound semiconductor substrate having high-quality crystallinity can be obtained by utilizing a separable semiconductor substrate according to an embodiment of the present invention, which will be described in detail with reference to FIG.

[0085] FIG. 5 is a cross-sectional view illustrating a method for manufacturing a self-separable semiconductor substrate according to another embodiment of the present invention, and a method for manufacturing a compound semiconductor substrate therethrough.

[0086] 5(a) and 5(b), a buffer layer 20 is formed on a substrate 10. The process of forming the buffer layer 20 is the same as that described with reference to FIGS. 1 to 4, and therefore, a redundant description thereof will be omitted.

[0087] Referring to FIG. 5(c), the method may further include forming a compound semiconductor layer on the buffer layer 20 and inducing separation of the compound semiconductor layer.

[0088] Here, the compound semiconductor may include a nitride or oxide semiconductor, such as gallium nitride (GaN), but is not limited to this. Exemplary materials include aluminum nitride (AlN), aluminum gallium nitride (AlGaN), gallium oxide (GaO), and aluminum gallium oxide (AlGa)O.

[0089] In some embodiments, a device layer may be formed on a compound semiconductor.

[0090] Meanwhile, the gallium nitride layer 30 can be grown using an HVPE apparatus, preferably a vertical HVPE apparatus, and can be grown to a thickness of 700 μm or more.

[0091] Referring to FIG. 5(d), after furnace cooling, separation can be induced at the interface between the substrate 10 and the first sub-buffer layer 20A.

[0092] As described above, since the detachable semiconductor substrate according to one embodiment of the present invention includes a gallium nitride layer or an aluminum gallium nitride layer, the compound semiconductor layer on the gallium nitride layer or the aluminum gallium nitride layer maintains the crystallinity of the underlying gallium nitride layer or the aluminum gallium nitride layer, thereby providing an effect of improving the crystallinity of the compound semiconductor layer.

[0093] In particular, since the buffer layer 20 has a stacked structure of the first sub-buffer layer 20A, the second sub-buffer layer 20B, and the third sub-buffer layer 20C, peeling can be induced by the difference in thermal expansion coefficients between the first sub-buffer layer 20A and the second sub-buffer layer 20B during furnace cooling, and the van der Waals bonding of the first sub-buffer layer 20A can provide the effect of facilitating self-separation of the first sub-buffer layer 20A.

[0094] Furthermore, the method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention is characterized by being an in-situ method, which has the effect of making the process economical and easy.

[0095] Furthermore, the detachable semiconductor substrate according to an embodiment of the present invention has a smooth surface, thereby improving the quality.

[0096] FIG. 6 is a cross-sectional view illustrating a thin-film device according to an embodiment of the present invention.

[0097] As described above, the separable semiconductor substrate according to an embodiment of the present invention can be used as a template or substrate for manufacturing thin film devices, and is particularly suitable as a substrate for forming thin film devices for flexible devices. A thin film device using the separable semiconductor substrate of the present invention will now be described with reference to FIG.

[0098] 6, a thin-film device 300 according to an embodiment of the present invention includes a buffer layer 20, a device layer 332, a stress layer, and a support layer. In some embodiments, a mother substrate 10 may further be included.

[0099] The buffer layer 20 is an intermediate layer that allows the compound semiconductor to be grown with excellent crystallinity and allows the compound semiconductor layer 331 to be easily separated from the mother substrate 10 later.

[0100] As described above, the buffer layer 20 is composed of the first sub-buffer layer 20A, the second sub-buffer layer 20B, and the third sub-buffer layer 20C. The description of each component has been given with reference to FIGS. 1 to 5, so a duplicate description thereof will be omitted.

[0101] In some embodiments, the buffer layer 20 may be formed on the mother substrate 10 .

[0102] The mother substrate 10 can be used to form the first sub-buffer layer 20A on the mother substrate 10. The mother substrate 10 can be made of sapphire, silicon, silicon carbide, or the like.

[0103] The device layer 332 is a layer including elements, which are the core components of the thin-film device 300, and the functions of the thin-film device 300 can be realized by the elements formed in the device layer 332.

[0104] The device layer 332 may be stacked on the buffer layer 20 .

[0105] The element layer 332 includes elements, which may include, for example, at least one of a diode, an LED, a transistor, an amplifier, a series circuit, an inductor, and a capacitor.

[0106] In some embodiments, device layer 332 may be formed on semiconductor layer 331 .

[0107] As described above, the semiconductor layer 331 can include a nitride semiconductor or an oxide semiconductor.

[0108] The semiconductor layer 331 may be formed to an appropriate thickness so that the device in the device layer 332 can maintain its electrical characteristics. For example, the semiconductor layer 331 may be formed to a thickness of 400 nm to 10 μm. If the thickness of the semiconductor layer 331 is less than 400 nm, the semiconductor layer 331 may be damaged by breaking or cracking, which may later cause a deterioration in performance of the thin-film device 300. If the thickness of the semiconductor layer 331 exceeds 10 μm, problems may arise such as a deterioration in electrical characteristics and difficulty in heat management.

[0109] If the thickness of the semiconductor layer 331 is 400 nm to 10 μm, the device layer 332 may be damaged during the process of separating the mother substrate 10. In this case, a stress layer covering the device layer 332 may be further disposed.

[0110] The stress layer is a layer that protects the thin-film element 300 when the thin-film element 300 is separated, and is disposed on the element layer 332 of the thin-film element 300 .

[0111] The stress layer may be formed of a material that has internal tensile deformation so as to relieve stress during mechanical substrate separation. For example, the stress layer may be made of nickel (Ni), copper (Cu), chromium (Cr), gold (Au), titanium (Ti), palladium (Pd), tin (Sn), etc. More preferably, the stress layer may include nickel.

[0112] In some embodiments, a support layer may further be disposed on the stress layer.

[0113] The support layer is a layer that serves to facilitate separation of the thin film element 300 .

[0114] The support layer can support the thin film element 300 together with the stress layer when separating the thin film element 300. Furthermore, the support layer is configured so that it can be easily removed by heat treatment after separation.

[0115] For example, a thermal release tape may be used as the support layer. The thermal release tape is attached in contact with the stress layer and, together with the stress layer, may induce mechanical separation while minimizing damage to the thin film device 300. After separation, the stress layer and the support layer may be additionally removed by heat treating them.

[0116] FIG. 7 is a flowchart of a method for manufacturing a thin-film device according to an embodiment of the present invention.

[0117] 8A to 8C are cross-sectional views for explaining a method for manufacturing the thin-film element shown in FIG.

[0118] Referring to FIG. 7, the method for manufacturing a thin film device according to the present invention forms a buffer layer on a mother substrate (S710).

[0119] Referring to (a) and (b) of Figures 8, the buffer layer 20 can be manufactured through a carbonization step to form carbon, a nitridation step on the top surface of the carbon, and a step of forming aluminum nitride on the top surface of the nitrided carbon.

[0120] The method for forming the buffer layer 20 has been described in detail with reference to FIG. 5, so the same description will be omitted.

[0121] Referring to FIG. 8( c ), the semiconductor layer 331 may be manufactured by forming a compound semiconductor layer on the buffer layer 20 .

[0122] The method for forming the semiconductor layer 331 has been described in detail with reference to FIG. 5, so the same description will be omitted.

[0123] Referring again to FIG. 7, the method for manufacturing a thin film device continues by forming a device layer (S720).

[0124] 8(c), the device layer 332 may be formed by various known methods, preferably CVD, HVPE, MBE, sputtering, PECVD, ALD, or the like.

[0125] In some embodiments, device layer 332 can include a plurality of micro-elements, which can be fabricated through a patterning process.

[0126] Thereafter, the thin film device manufacturing method may further include forming a separation assisting portion 340 on the device layer 332 .

[0127] The separation aid 340 may include a stress layer 341 and a support layer 342 .

[0128] The stress layer 341 can be formed by various known manufacturing methods such as plasma sputtering, electroplating, etc. Preferably, it can be formed by electroplating.

[0129] When the stress layer 341 is formed by electroplating, the stress layer 341 can be manufactured through a first cleaning step, a plating step, a second cleaning step, and a drying step. Specifically, in the cleaning step, distilled water can be used to clean the sample including the buffer layer 20 and the device layer 332. Then, in the plating step, the sample is immersed in an electroplating solution, a jig is connected, and electroplating can be performed by adjusting the current and voltage using a power supply. In this case, electroplating can be performed at a temperature range of 50 to 60°C, the distance between the sample and the electrode can be adjusted to 15 to 25 cm, and the current density can be 60 to 80 mA / cm. 2 Then, in the second cleaning and drying step, the sample including the stress layer 341 may be cleaned with distilled water and dried using nitrogen gas.

[0130] In some embodiments, the method for manufacturing the thin-film device 300 of the present invention can then additionally separate the mother substrate 10 below the buffer layer 20 .

[0131] Referring to FIG. 8(d), separation of the mother substrate 10 can be accomplished by self-separation or mechanical separation.

[0132] For example, if the semiconductor layer 331 and the device layer 332 are sufficiently thick, the mother substrate 10 may be capable of self-separation. For example, self-separation of the interface between the buffer layer 20 and the mother substrate 10 can be induced by cooling the thin-film device 300 at an appropriate temperature so that stress acts on the buffer layer 20. In this case, the separation assistance portion 340 for self-separation may be omitted.

[0133] Furthermore, if the semiconductor layer 331 and the device layer 332 are thin, the mother substrate 10 may be mechanically separable.

[0134] When the mother substrate 10 is separated by mechanical separation, a stress layer 341 is formed on the element layer 332, and a support layer 342 is attached on the stress layer 341, and the thin film element 300 can be separated from the mother substrate 10 by removing the support layer 342.

[0135] As described above, the method for manufacturing the thin-film device 300 of the present invention includes a device formation step and a device isolation step.

[0136] That is, the device is formed on the thin film substrate through the device formation step, and the mother substrate 10 is separated from the thin film device 300 through the device separation step.

[0137] When the thick mother substrate 10 is separated, the device can be provided supported on a thin buffer layer 20, thereby enabling the production of thin film devices 300 with small thicknesses.

[0138] Furthermore, the method for manufacturing the thin film device 300 according to the embodiment of the present invention may include a step of forming a separation assisting portion 340 on the device layer 332 and a mechanical separation step.

[0139] In this case, the stress layer 341 and the support layer 342 on the device layer 332 are configured to cover the thin device layer 332, thereby minimizing damage to the thin thin-film device 300 during the mechanical separation step. In particular, the buffer layer 20 facilitates separation of the substrate, so the thickness of the thin-film device 300 can be further reduced. This may enable the realization of flexible devices such as nano LEDs.

[0140] 8(e), the auxiliary isolation portion 340 on the device layer 332 may be additionally removed. The auxiliary isolation portion 340 may be removed by various methods such as mechanical or chemical removal.

[0141] 8(f), the buffer layer 20 may then be additionally removed from the semiconductor layer 331. For example, the buffer layer 20 may be removed by a polishing method such as CMP. FIG. 9 is a cross-sectional view illustrating a composite device according to an embodiment of the present invention.

[0142] Referring to FIG. 9, the composite device is composed of a first electronic element 500 and a second electronic element 400 .

[0143] The composite device of the present invention includes two electronic device substrates stacked on top of each other.

[0144] The first electronic component 500 and the second electronic component 400 may be the same or different components.

[0145] One surface of the device layer 332 of the first component 500 may be stacked in a contiguous structure with one surface of the device layer 332 of the second component 400 .

[0146] 9, the device layer 332 of the first device 500 may be disposed on top, and the device layer 422 of the second device 400 may be disposed on the bottom so as to be in contact with the device layer 332 of the first device 500. In this case, the substrate layer 410, device layer 422, and device substrate layer 421 of the second device 400 may be stacked from the bottom, and the device layer 332, semiconductor layer 331, and buffer layer 20 of the first device may be stacked in this order.

[0147] The elements of the element layer 332 of the first electronic component 500 and the elements of the element layer 422 of the second electronic component 400 may be in direct contact with each other. However, this is not limited thereto, and the first electronic component 500 and the second electronic component 400 may be stacked with an intermediate insulating layer sandwiched therebetween. In this case, the intermediate insulating layer may be provided with a connecting wire for connecting the first electronic component 500 and the second electronic component 400 to each other.

[0148] The first electronic component 500 and the second electronic component 400 connected to each other can be connected and operate as a single device. For example, two stacked LED elements can operate as a device that operates as one pixel.

[0149] In some embodiments, the first electronic component 500 and the second electronic component 400 may be configured as different types of components and may operate as separate devices. For example, if the first electronic component 500 and the second electronic component 400 are configured as display components, the first electronic component 500 may include a thin film transistor (TFT) component for driving the display component, and the second electronic component 400 may include a light-emitting element that constitutes a pixel of the display. In this case, the substrate of the first electronic component 500 and the substrate of the second electronic component 400 may be stacked on each other to implement a display device.

[0150] The first electronic element 500 may include a buffer layer 20 and a first element layer 332. The buffer layer 20 of the first electronic element 500 may be composed of a first sub-buffer layer 20A, a second sub-buffer layer 20B, and a third sub-buffer layer 20C.

[0151] The buffer layer 20 has the same features as those of the buffer layer 20 described with reference to FIG. 4 of the present invention, so a duplicated description of each component will be omitted.

[0152] The first device layer 332 has the same features as the device layer 332 described with reference to FIG. 6, and therefore, a duplicated description of each component will be omitted.

[0153] The second electronic component 400 may include a mother substrate 10 and a second component layer 422. The mother substrate 10 may include a substrate used in various known component stacking methods, such as at least one of silicon, SiC, GaN, GaAs, Al2O3, and ZnO.

[0154] The second element layer 422 may include at least one of a diode, an LED, a transistor, an amplifier, a series circuit, an inductor, and a capacitor.

[0155] FIG. 10 is a flowchart of a method for manufacturing a composite element according to an embodiment of the present invention.

[0156] FIG. 11 is a schematic diagram for explaining the method for manufacturing the composite element of FIG.

[0157] Referring to FIG. 10, in the composite device manufacturing method of the present invention, a first electronic device and a second electronic device are prepared (S1010).

[0158] 11(a), the preparation of the first electronic component 500 may be a step of preparing the first electronic component 500 including the buffer layer 20 and the first device layer 332, and the preparation step of the first electronic component 500 may be the same as the method of manufacturing the thin-film device 300 described with reference to FIG. 8. Therefore, a duplicated description will be omitted.

[0159] Referring to (b) of Figure 11, the preparation of the second electronic element 400 may be a step of preparing the second electronic element 400 including a substrate layer 410, a second element layer 422 and an element substrate layer 421, and the second electronic element 400 may be prepared by manufacturing the second electronic element 400 in a manner of forming the element substrate layer 421 and the second element layer 422 on the substrate layer 410.

[0160] Referring again to FIG. 10, the composite device manufacturing method of the present invention includes bonding the first electronic device and the second electronic device together (S1020).

[0161] 11(c), the bonding of the first electronic component 500 and the second electronic component 400 may be performed by bringing the first device layer 332 of the first electronic component 500 into contact with the upper part of the second device layer 422 of the second electronic component 400 and performing a heat treatment at 300 to 500°C. Preferably, a composite device may be manufactured by performing a heat treatment at 400°C or higher to induce bonding between the first device layer 332 and the second device layer 422. However, the bonding is not limited thereto, and the first electronic component 500 and the second electronic component 400 may be bonded to each other using various bonding methods, such as bonding different types of devices to each other.

[0162] Referring again to FIG. 10, the composite device manufacturing method of the present invention separates the mother substrate of the first electronic device (S1030).

[0163] 11(d), for example, a process of inducing self-separation of the mother substrate 10 may be performed by heat-treating the mother substrate 10 of the first electronic component 500 and then cooling it to 25° C. At this time, a tensile stress may act on the surface of the mother substrate 10 and a compressive stress may act on the surface of the first sub-buffer layer 20A based on the interface due to the difference in thermal expansion coefficients between the mother substrate 10 and the first sub-buffer layer 20A.

[0164] The tensile stress of the mother substrate 10 and the compressive stress of the first sub-buffer layer 20A allow the mother substrate 10 of the first electronic component 500 to be self-separated.

[0165] In some embodiments, the mother substrate 10 can be mechanically separated. For example, a support layer can be adhered to the exposed surface of the mother substrate 10, and the mother substrate 10 can be mechanically separated by applying mechanical stress.

[0166] 11(e), in some embodiments, the buffer layer 20 may be additionally removed from the composite element from which the mother substrate 1 has been removed. In this case, the buffer layer 20 may be removed by mechanical separation, and a separation assistant for removing the buffer layer 20 may be disposed on the buffer layer 20.

[0167] When the buffer layer 20 is removed, a composite element can be provided in which the element layer 332 and the semiconductor layer 331 of the first electronic element 500 are bonded onto the second electronic element 400, as shown in (f) of FIG. 11, and a thin composite element can be easily provided.

[0168] The effect of the separable semiconductor substrate according to an embodiment of the present invention in facilitating self-separation of a compound semiconductor layer will now be described with reference to the following experimental example.

[0169] (Production Examples 1 to 5 - Production of Substrates Including Buffer Layers) The substrate according to the manufacturing example was manufactured by the following method.

[0170] First, a 4-inch sapphire substrate was loaded into a horizontal HVPE reactor. Specifically, as shown in Table 1 below, substrates of Production Examples 1 to 5 were manufactured by forming a buffer layer with different carbonization treatment times.

[0171] [Table 1]

[0172] Carbonization was performed by supplying CH4 gas at a flow rate of 100 sccm for 0, 2.5, 5.4, 10, and 15 minutes in a source region maintained at a temperature of 1100°C. Nitridation was performed by supplying NH3 gas at a flow rate of 4000 sccm for 0.1 minutes (6 seconds). Next, aluminum nitride was grown by supplying NH3 and HCl gas at a flow rate of 400 sccm for 2.3 minutes (138 seconds). After this, the substrates on which growth was completed were cooled to room temperature (25°C) and harvested.

[0173] (Experimental Example 1 - UV-Vis analysis) The transmittance of Production Examples 1 to 5 was evaluated using a UV-Vis spectrophotometer, and the results are shown in FIG.

[0174] FIG. 12 is a graph of UV-Vis spectroscopy transmittance through a semiconductor substrate as a function of carbon thickness for a detachable semiconductor substrate according to one embodiment of the present invention.

[0175] Referring to FIG. 12, it can be seen that the average light transmittance for light with a wavelength of 400 nm is reduced by 20 to 80% compared to the average light transmittance of the mother substrate.

[0176] Specifically, when the CH4 gas supply time was 0, 2.5, 5.4, 10, and 15 minutes, the average light transmittance for light with a wavelength of 400 nm was 85, 73, 60, 30, and 18%, respectively, and the average light transmittance of Production Example 3 was reduced by 30% compared to Production Example 1.

[0177] The decrease in light transmittance suggested the presence of a carbon layer on top of the buffer layer, and it was confirmed that the thickness of the carbon layer could be controlled by the CH4 gas supply time.

[0178] (Experimental Example 2 - Raman Analysis) Preparation Example 3 was subjected to Raman analysis at room temperature using a Raman spectrophotometer equipped with a 532 nm laser.

[0179] FIG. 13 is a Raman spectrum of a detachable semiconductor substrate according to one embodiment of the present invention.

[0180] Referring to FIG. 13, the carbon layer has a D′ band wavelength of 1620 cm in the Raman spectrum. -1 It was analyzed to be amorphous with an sp3 structure having a peak around .

[0181] Therefore, it was confirmed that the carbon layer has a three-dimensional structure with van der Waals bonds between atomic layers.

[0182] (Experimental Example 3 - Analysis of Surface Shape and Surface Roughness) The surface shape and surface roughness of the carbon layer and aluminum nitride layer were analyzed using a Dektak 150 surface inspector in Preparation Examples 1 to 5. The results are shown in Table 2 below, and the surface shapes are shown in Figures 14 and 15.

[0183] FIG. 14 is a photograph of the surface shape of a detachable semiconductor substrate according to an embodiment of the present invention, depending on the thickness of the carbon layer.

[0184] FIG. 15 is a photograph of the surface shape of an aluminum nitride layer of a separable semiconductor substrate according to one embodiment of the present invention.

[0185] [Table 2]

[0186] Referring to Table 2 and FIG. 14, it can be seen that the surface roughness Ra of the carbon layer is 27 nm, and Rt is 310 nm or less.

[0187] Referring to Table 2 and FIG. 15, it can be seen that the surface roughness Ra of the aluminum nitride layer is 20 nm, and Rt is 170 nm or less.

[0188] As shown in Table 2, when the carbonization time was 5.4 minutes, the surface roughness Ra of the carbon layer was 22.1 nm and Rt was 307.1 nm, and when the aluminum nitride formation time was 2.3 minutes, the surface roughness Ra of the aluminum nitride layer was 18 nm and Rt was 166.8 nm.

[0189] Therefore, the fabricated buffer layer containing a carbon layer and an aluminum nitride layer is believed to facilitate crystal growth and to be a high-quality self-separable semiconductor substrate with a nano-level surface.

[0190] Meanwhile, in order to confirm the ease of separation of the detachable substrate of the present invention, a gallium nitride substrate was manufactured and checked for its self-separation ability.

[0191] (Manufacturing Example 6 - Gallium nitride substrate manufacturing) Gallium nitride was grown on the substrate of Production Example 3 to produce a gallium nitride substrate.

[0192] Specifically, the substrate of Preparation Example 3 was inserted into a vertical HVPE reactor, and HCl gas was injected using metal gallium as a source to generate gallium chloride (GaCl) gas, and NH3 gas was also injected in a growth region maintained at a temperature of 1000°C to grow gallium nitride. The furnace was then cooled to room temperature, 25°C, to obtain the gallium nitride substrate of Preparation Example 6.

[0193] (Experimental Example 4 - Confirmation of self-separation of aluminum nitride) The sapphire substrate was removed from the substrate of Production Example 3 that had been furnace-cooled to room temperature (25° C.), and the possibility of self-separation was confirmed. The results are shown in FIG.

[0194] FIG. 16 is a photograph showing the aluminum nitride layer being self-separated from the sapphire substrate after the aluminum nitride layer is grown on the self-separable semiconductor substrate according to one embodiment of the present invention.

[0195] Referring to FIG. 16, it was confirmed that the aluminum nitride substrate was self-separated from the sapphire substrate and bulged.

[0196] (Experimental Example 5 - Confirmation of Gallium Nitride Self-Separation) The possibility of self-separation was confirmed by removing the sapphire substrate from the substrate of Production Example 6 that had been furnace-cooled to room temperature of 25° C. The results are shown in FIG.

[0197] FIG. 17 is a photograph showing the gallium nitride layer being self-separated from the sapphire substrate after the gallium nitride layer is grown on the separable semiconductor substrate according to one embodiment of the present invention.

[0198] Referring to FIG. 17, it can be seen that the gallium nitride substrate was easily separated from the sapphire substrate, and it was confirmed that no cracks or breakage occurred in the gallium nitride substrate.

[0199] The scope of the present invention is represented by the claims set forth below rather than by the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

[0200] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting. For example, each component described as a single component may be implemented in a distributed form, and similarly, each component described as a distributed component may be implemented in a combined form. [Explanation of symbols]

[0201] 10: Circuit board 20: Buffer layer 20A: First sub-buffer layer 20B: Second sub-buffer layer 20C: Third sub-buffer layer 30: Semiconductor layer 40: Methane supply line 50: Ammonia supply line 60: Hydrogen chloride supply line 300: Thin film element 331: Semiconductor layer 332: First element layer 340: Auxiliary separation section 341: Stress layer 342:Support layer 400: Second electronic element 410: Substrate layer 421: Element substrate layer 422: Second element layer 500: First electronic element

Claims

1. a motherboard; and disposed on the mother substrate, a buffer layer comprising carbon and aluminum nitride; the buffer layer includes a carbon layer, a nitride layer, and an aluminum nitride layer; The carbon layer has a peak at a wavelength of about 1620 cm −1 of the D′ band in a Raman spectrum, and is amorphous with an sp3 structure.

2. 2. The self-separable semiconductor substrate according to claim 1, wherein the self-separable semiconductor substrate is 2 inches or larger in size.

3. 2. The separable semiconductor substrate according to claim 1, wherein the average light transmittance for light with a wavelength of 400 nm is reduced by 20 to 80% compared to the average light transmittance of the mother substrate.

4. The separable semiconductor substrate of claim 1 , wherein the carbon layer has a three-dimensional structure.

5. 2. The separable semiconductor substrate according to claim 1, wherein the carbon layer has a surface roughness Ra of 27 nm and a surface roughness Rt of 310 nm or less.

6. 2. The separable semiconductor substrate according to claim 1, wherein the aluminum nitride layer has a surface roughness Ra of 20 nm and a surface roughness Rt of 170 nm or less.

7. A method for producing a separable semiconductor substrate according to any one of claims 1 to 6, comprising: providing a substrate; and A method for manufacturing a detachable semiconductor substrate, comprising forming a buffer layer comprising carbon and aluminum nitride.

8. forming a compound semiconductor layer on the buffer layer; and 8. The method of claim 7, further comprising the step of inducing self-separation of the compound semiconductor layer.

9. 9. The method for manufacturing a separable semiconductor substrate according to claim 8, wherein the compound semiconductor layers are gallium nitride (GaN), aluminum nitride (AlN), and aluminum gallium nitride (AlGaN).

10. The step of forming the buffer layer comprises: a carbonization step for forming the carbon; nitriding the upper surface of the carbon; and 8. The method of claim 7, further comprising forming aluminum nitride on the top surface of the nitrided carbon.

11. a buffer layer comprising carbon and aluminum nitride; and an electronic element on the buffer layer; the buffer layer includes a carbon layer, a nitride layer, and an aluminum nitride layer; The thin film element is characterized in that the carbon layer has a peak in the D' band wavelength of about 1620 cm -1 in a Raman spectrum and is amorphous with an sp3 structure.

12. a stress layer covering the electronic element; and The thin film device of claim 11 further comprising a support layer on the stress layer.

13. a first electronic device comprising a buffer layer comprising carbon and aluminum nitride and a first device layer on the buffer layer; and a second electronic component including a second device layer contiguous with a surface of the first device layer of the first electronic component and having a structured characteristic; the buffer layer includes a carbon layer, a nitride layer, and an aluminum nitride layer; The composite element is characterized in that the carbon layer has a peak in the D' band wavelength of about 1620 cm -1 in a Raman spectrum and is amorphous with an sp3 structure.

14. The first electronic element The composite device of claim 13 further comprising an upper detachable substrate.

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