Method for manufacturing separable semiconductor substrate, separable semiconductor substrate manufactured thereby, thin film element and composite element

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 in which a compound semiconductor crystal is grown and separated, and a thin film device and composite device manufactured by the same. [Background technology]

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

[0003] Among 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 (Ga 2 O 3 ) is available.

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

[0005] The aforementioned compound semiconductors are generally made of sapphire (Al 2 O 3 ), they are manufactured by inducing epitaxial growth on a silicon (Si) or silicon carbide (SiC) substrate and then separating it.

[0006] One of the separation methods is the self-separation method, and as the self-separation method, a method of forming a pattern and separating the layers, and a method of inserting a buffer layer have been reported.

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

[0008] The method of inserting a buffer layer utilizes stress caused by a difference in thermal expansion coefficient during cooling, but has problems in that separation is not good or crystallinity is reduced, making it difficult to manufacture a large-area substrate.

[0009] Therefore, there is a demand for 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 prior to the filing of the present invention. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japan Patent No. 5307975 B2 "Nitride-based semiconductor substrate and 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 enables 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 using a method for fabricating a separable semiconductor substrate. [Means for solving the problem]

[0014] As a technical means for achieving the above-mentioned 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 including 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 an upper surface of the carbon, and a step of forming aluminum nitride on the upper surface of the nitridation-treated 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, the buffer layer including carbon and aluminum nitride.

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

[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 at a wavelength of 1620 cm in a Raman spectrum. -1 It has a peak near the center 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-mentioned 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 element includes a first electronic element including a buffer layer containing carbon and aluminum nitride and a first element layer on the buffer layer, and a second electronic element including a second element layer that is in contact with a surface of the first element layer of the first electronic element and has a characteristic of being formed of a single structure.

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

[0032] According to any one of the above-mentioned 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 is enlarged.

[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] According to one embodiment of the present invention, the compound semiconductor layer having a small thickness can be easily separated.

[0035] According to one embodiment of the present invention, the detachable semiconductor substrate is manufactured in situ, which may simplify the process.

[0036] According to one of the solutions 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 embodiment 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, a thin-film element includes a thin-film substrate including a buffer layer including 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] According to one embodiment of the present invention, the thin film element can be separated without damage since the support layer for inducing separation of the thin film element is further included. In particular, the thickness of the thin film element can be further reduced since the buffer layer facilitates separation of the substrate.

[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 electronic element on the buffer layer, and a second electronic element including a second element layer disposed below the first electronic element and in contact with a surface facing the first element layer and having a feature of being formed into a single structure, so that various thin composite elements are connected to realize a device that can operate as a single structure.

[0041] In addition, according to any one of the means for solving the problems of the present invention, one embodiment of the present invention further includes a separable substrate on the top (above) of the first electronic device, so that the substrate can be separated in a state in which the first electronic device and the second electronic device are combined, thereby making it possible to quickly and easily manufacture a complex composite device.

[0042] The effects that can be obtained by the present invention are not limited to those 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 description 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. [Diagram 2] 4 is a graph showing a temperature change during a buffer layer formation step in a method for manufacturing a separable semiconductor substrate in accordance with an embodiment of the present invention. [Diagram 3] 4 is a graph showing a change in gas input 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. [Diagram 5] 1A to 1C are cross-sectional views illustrating a method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention, and a method for manufacturing a compound semiconductor substrate through the method. [Figure 6] 1 is a cross-sectional view illustrating a thin-film element according to an embodiment of the present invention. [Figure 7] 2 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] 2 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] 4 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 a surface profile according to a carbon thickness of a separable semiconductor substrate according to an embodiment of the present invention. [Figure 15] 1 is a photograph of the surface profile of an aluminum nitride layer for a separable semiconductor substrate according to one embodiment of the present invention. [Figure 16]4 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] 4 is a photograph showing a gallium nitride layer being self-separated from a sapphire substrate after the gallium nitride layer is grown on a separable semiconductor substrate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Hereinafter, the embodiments of the present invention will 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 that are not related 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 described as being "connected" to another part, this includes not only the case where the part is "directly connected" to another part, but also the case where the part is "indirectly connected" to another part through another member or element therebetween. Furthermore, when a part is described as "comprising" some component, this does not mean that the part excludes other components, but that the part may further include other components, unless otherwise specified.

[0046] Fig. 1 is a flow chart of a method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. Fig. 2 is a graph showing a temperature change at a buffer layer forming step in the method for manufacturing a separable semiconductor substrate according to an embodiment of the present invention. Fig. 3 is a graph showing a gas input flow rate at a buffer layer forming 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 for explaining 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 manufacturing 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 may be provided, but is not limited thereto. For example, a substrate of Si or SiC may be provided. Accordingly, a large area compound semiconductor layer to be manufactured can be formed.

[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 at a temperature of 1000°C to 1600°C, more preferably at a temperature of 1000°C to 1200°C, and more preferably at a temperature of 1100°C.

[0051] If the process is carried out at a temperature below 1000° C., the diffusion rate for homogeneous nucleation and growth of carbon can be decreased.

[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 a HVPE apparatus, preferably a horizontal HVPE apparatus, but is not limited thereto. Exemplarily, 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, methane (CH 4 ), ammonia (NH 3 ), hydrogen chloride (HCl), nitrogen (N 2 ) gas supply lines can be configured. The unit of gas flow rate supplied by each line is 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. Here, the gas is CH 4 The gas can be supplied at a flow rate of 500 sccm or less for 20 minutes or less, and preferably at a flow rate of 10 to 300 sccm for 2 to 20 minutes.

[0060] At this time, the temperature was maintained at 1100°C as shown in FIG. 2, and the gas was CH 4 The gas may be injected at 100 sccm. The carbonization step (S122) may be carried out for 2 to 10 minutes.

[0061] The nitriding step (S123) is a step of nitriding the upper surface of the carbon. Here, the gas is NH 3 The 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 to 3000 sccm for 3 seconds to 3 minutes.

[0062] At this time, the temperature was maintained at 1100°C as shown in FIG. 2, and the gas was NH 4 The gas may be injected at 4000 sccm. The nitridation step (S123) may be performed for 6 seconds.

[0063] If the upper surface of the carbon is not nitrided in the nitridation step (S123), the surface of the carbon has few unsaturated bonds or functional groups, so that it may be difficult to grow inorganic substances such as aluminum nitride.

[0064] The aluminum nitride formation step (S124) is a step of growing aluminum nitride. 3 The active gas containing HCl gas and NH gas can be supplied at a flow rate of 1000 sccm or less within 5 minutes. 3 The gas may be supplied at a flow rate of 10 sccm to 100 sccm, and HCl at a flow rate of 100 sccm to 1000 sccm, for 1 minute to 5 minutes.

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

[0066] Here, a boat containing aluminum (Al) metal 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. The molten Al metal reacts with HCl gas to produce aluminum chloride (AlCl 3 ) gas can be produced.

[0067] The generated AlCl 3 The gas may be transported to the growth region by a carrier gas.

[0068] The carrier gas may be argon (Ar) or nitrogen gas, and more specifically, nitrogen gas may be used.

[0069] In the growth area, AlCl 3 Gas and NH 3 It can react with gases to grow aluminum nitride (AlN).

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

[0071] Through the above-described method, a separable semiconductor substrate is obtained.

[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] Also, the second sub-buffer layer 20B may be a nitrided carbon layer.

[0075] Also, the third sub-buffer layer 20C may be an aluminum nitride-containing layer.

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

[0077] Furthermore, the carbon of 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 may be induced at the interface between the substrate and the first sub-buffer layer 20A during a cooling process.

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

[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 using a separable semiconductor substrate according to an embodiment of the present invention, for a detailed description of which, please also refer to FIG.

[0085] FIG. 5 is a cross-sectional view for explaining 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 through the method.

[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 duplicated 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. It may be gallium nitride (GaN), but is not necessarily limited thereto. Exemplary compounds include aluminum nitride (AlN), aluminum gallium nitride (AlGaN), gallium oxide (Ga 2 O 3 ), Aluminum Gallium Oxide (AlGa) 2 O 3 And so on.

[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 may be induced at the interface between the substrate 10 and the first sub-buffer layer 20A.

[0092] As described above, since the separable 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 aluminum gallium nitride layer maintains the crystallinity of the lower (lower) 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 layered 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 coefficient between the first sub-buffer layer 20A and the second sub-buffer layer 20B during furnace cooling, and the van der Waals bonds 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] In addition, the detachable semiconductor substrate according to an embodiment of the present invention exhibits 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 elements, and is particularly suitable as a substrate for forming thin film elements of flexible devices. A thin film element using the separable semiconductor substrate of the present invention will now be described with reference to FIG. 6.

[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 that 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. Since the description of each component has been given with reference to FIGS. 1 to 5, the duplicated description thereof will not be repeated.

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

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

[0103] The device layer 332 is a layer including elements that 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 deposited 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, a device layer 332 may be formed on the 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 elements of the element layer 332 can maintain their 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 being broken or cracked, and such damage may later cause a decrease in performance of the thin film element 300. If the thickness of the semiconductor layer 331 exceeds 10 μm, problems may occur such that the electrical characteristics are decreased and heat management is difficult.

[0109] If the thickness of the semiconductor layer 331 is between 400 nm and 10 μm, the element layer 332 may be damaged in the process of separating the mother substrate 10. In this case, a stress layer covering the element 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 an 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 during separation of the thin-film element 300. Furthermore, the support layer is configured so as to be easily removable by heat treatment after separation.

[0115] For example, a thermal release tape may be used as the support layer. The thermal release tape may be 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 the stress layer and the support layer.

[0116] FIG. 7 is a flow chart of a method for manufacturing a thin-film device according to one 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 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.

[0120] The method of 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 of 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 fabricating 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 by CVD, HVPE, MBE, Sputter, PECVD, ALD, or the like.

[0125] In some embodiments, device layer 332 can include a plurality of microelements, and the microelements can be fabricated through a patterning process.

[0126] Thereafter, the thin film device manufacturing method may further include forming a separation assistant 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 may be formed by various known manufacturing methods such as plasma sputtering, electroplating, etc. Preferably, the stress layer 341 is formed by electroplating.

[0129] When the stress layer 341 is formed through electroplating, the stress layer 341 may 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 may be used to clean the sample including the buffer layer 20 and the device layer 332. Thereafter, in the plating step, the sample may be immersed in an electrolytic plating solution, a jig may be connected, and electroplating may be performed by adjusting the current and voltage using a power supply. In this case, electroplating may be performed at a temperature range of 50 to 60°C, the distance between the sample and the electrode may be adjusted to 15 to 25 cm, and the current density may 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 element 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 element 300 at an appropriate temperature so that stress acts on the buffer layer 20. In this case, the separation assistant portion 340 for self-separation may be omitted.

[0133] Also, 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, elements are formed on the thin film substrate through an element formation step, and the mother substrate 10 is separated from the thin film elements 300 through an element 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 assistant portion 340 on the device layer 332 and a mechanical separation step.

[0139] In this case, since the stress layer 341 and the support layer 342 on the device layer 332 are configured to cover the thin device layer 332, damage to the thin thin-film device 300 can be minimized during the mechanical separation step. In particular, since the buffer layer 20 facilitates separation of the substrate, the thickness of the thin-film device 300 can be further reduced. This can 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.

[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 element 500 and the second electronic element 400 may be composed of the same or different elements.

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

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

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

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

[0149] In some embodiments, the first electronic element 500 and the second electronic element 400 may be composed of different types of elements and may operate as separate devices. For example, when the first electronic element 500 and the second electronic element 400 are composed of display elements, the first electronic element 500 may include a TFT (Thin Film Transistor) element for driving the display element, and the second electronic element 400 may include a light-emitting element constituting a pixel of the display. In this case, the substrate of the first electronic element 500 and the substrate of the second electronic element 400 may be stacked on each other to realize 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, so a duplicated description of each component will be omitted.

[0153] The second electronic device 400 may include a mother substrate 10 and a second device layer 422. The mother substrate 10 may include a substrate used in various known device stacking methods. Examples of such substrates include silicon, SiC, GaN, GaAs, and Al. 2 O 3 , ZnO, and the like can be used.

[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 flow chart 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 a method for manufacturing the composite element of FIG.

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

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

[0159] Referring to (b) of FIG. 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 step of the first electronic device 500 and the second electronic device 400 may be performed by contacting the first device layer 332 of the first electronic device 500 with the upper part of the second device layer 422 of the second electronic device 400 and performing a heat treatment at 300 to 500° C. A composite device may be manufactured by inducing bonding between the first device layer 332 and the second device layer 422 by performing a heat treatment at preferably 400° C. or more. However, the present invention is not limited thereto, and the first electronic device 500 and the second electronic device 400 may be bonded to each other through 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 a difference in thermal expansion coefficient 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 can cause the mother substrate 10 of the first electronic element 500 to be self-isolated.

[0165] In some embodiments, the mother substrate 10 can be mechanically separated. For example, a support layer can be attached 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 composite element with a thin thickness can be easily provided.

[0168] Hereinafter, 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 be described with reference to the following experimental example.

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

[0170] First, a 4-inch sapphire substrate was loaded into a horizontal HVPE apparatus. 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] The carbonization process was carried out by using CH 4 The gas was supplied at a flow rate of 100 sccm for 0, 2.5, 5.4, 10, and 15 minutes. 3 The gas was supplied at a flow rate of 4000 sccm for 0.1 minutes (6 seconds). Then, aluminum nitride was treated with NH 3 Then, HCl gas was supplied at a flow rate of 400 sccm for 2.3 minutes (138 seconds) for growth. After this, the substrate on which growth was completed was cooled to room temperature of 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, CH 4When the gas supply time was 0, 2.5, 5.4, 10, and 15 minutes, the average light transmittance was 85, 73, 60, 30, and 18%, respectively, for light with a wavelength of 400 nm. Compared to Production Example 1, the average light transmittance of Production Example 3 was reduced by 30%.

[0177] The decrease in optical transmittance suggests that there is a carbon layer on top of the buffer layer. 4 It was confirmed that the thickness of the carbon layer could be controlled by the 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 at a wavelength of 1620 cm in the Raman spectrum. -1 It was analyzed that it was an amorphous form with an sp3 structure having a peak near

[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 of Preparation Examples 1 to 5 were analyzed using a Dektak 150 surface inspection device. 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 showing the surface profile of a carbon layer of a detachable semiconductor substrate according to an embodiment of the present invention according to a variation in thickness.

[0184] FIG. 15 is a photograph of the surface profile 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 including the carbon layer and the 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 it was confirmed whether self-separation was possible.

[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 is inserted into a vertical HVPE apparatus, and HCl gas is injected using metal gallium as a source to generate gallium chloride (GaCl) gas. NH 3 The gases were injected together to grow gallium nitride. Then, the furnace was cooled to room temperature of 25° C. to obtain a 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 of 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 sapphire substrate was removed from the substrate of Production Example 6 that had been furnace-cooled to room temperature of 25° C., and the possibility of self-separation was confirmed. The results are shown in FIG.

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

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

[0199] The scope of the present invention is defined by the claims set forth below rather than the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalent concepts 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 idea or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative and not limiting in all respects. For example, each component described as a single form may be implemented in a distributed form, and similarly, each component described as a distributed form may be implemented in a combined form. [Explanation of symbols]

[0201] 10: Substrate 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. Providing a substrate; and A method for manufacturing a detachable semiconductor substrate, comprising forming a buffer layer comprising carbon and aluminum nitride.

2. forming a compound semiconductor layer on the buffer layer; and 2. The method of claim 1, further comprising the step of inducing self-separation of the compound semiconductor layer.

3. 3. The method for producing a separable semiconductor substrate according to claim 2, wherein the compound semiconductor layers are gallium nitride (GaN), aluminum nitride (AlN) and aluminum gallium nitride (AlGaN).

4. 2. The method of claim 1, wherein the substrate is a sapphire substrate having a size of 2 inches or more.

5. The step of forming the buffer layer comprises: a carbonization step for forming the carbon; nitriding the upper surface of the carbon; and 2. The method of claim 1, further comprising forming aluminum nitride on an upper surface of said nitrided carbon.

6. A motherboard; and disposed on the mother substrate, A detachable semiconductor substrate comprising a buffer layer comprising carbon and aluminum nitride.

7. 7. The self-separable semiconductor substrate according to claim 6, wherein the self-separable semiconductor substrate is 2 inches or larger in size.

8. 7. The separable semiconductor substrate according to claim 6, 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.

9. 7. The separable semiconductor substrate of claim 6, wherein the buffer layer includes a carbon layer, a nitride layer, and an aluminum nitride layer.

10. The separable semiconductor substrate of claim 9, wherein the carbon layer is a three-dimensional structure.

11. The carbon layer has a D′ band at a wavelength of 1620 cm in the Raman spectrum. －１ 10. The separable semiconductor substrate according to claim 9, characterized in that it is amorphous and has an sp3 structure, and has a peak near the peak.

12. The separable semiconductor substrate according to claim 9, wherein the carbon layer has a surface roughness Ra of 27 nm and a surface roughness Rt of 310 nm or less.

13. 10. The separable semiconductor substrate according to claim 9, wherein the aluminum nitride layer has a surface roughness Ra of 20 nm and a surface roughness Rt of 170 nm or less.

14. A buffer layer comprising carbon and aluminum nitride; and A thin film device comprising an electronic device on the buffer layer.

15. The thin-film device of claim 14 further comprising a mother substrate below the buffer layer.

16. a stress layer covering the electronic element; and The thin-film element of claim 15 further comprising a support layer on the stress layer.

17. a first electronic device comprising a buffer layer comprising carbon and aluminum nitride, and a first device layer on the buffer layer; and A composite device comprising a second electronic element, the second electronic element comprising a second device layer contiguous with a surface of the first device layer of the first electronic element and having a feature of a structure.

18. The first electronic element 20. The composite device of claim 17, further comprising an upper detachable substrate.

Images