KR100858923B1 - Single-crystalline Substrate for manufacturing GaN based epilayer, the Method of manufacturing the epilayer, LED and LD comprising the GaN based epilayer - Google Patents

Abstract

Provided are a light emitting diode and a laser diode comprising a gallium nitride thin film made of a single crystal substrate for producing a gallium nitride thin film, a gallium nitride thin film manufacturing method, and a single crystal substrate for producing a gallium nitride thin film. Single crystal substrate for producing a gallium nitride thin film according to the present invention is made of sapphire, silicon carbide, zinc oxide, silicon or gallium arsenide (GaAs), nitrogen ion implantation pattern portion including a plurality of regularly repeated patterns on the same plane ; And it is characterized in that it comprises a nitrogen ion non-injection compartment for partitioning the pattern, it is possible to quickly grow the growth of gallium nitride thin film in a manner different from the conventional, and consequently to improve the crystallinity and optical properties of the gallium nitride thin film Can be. In addition, the gallium nitride thin film manufacturing method using the single crystal substrate is easy to manufacture and can improve the crystallinity and optical properties of the gallium nitride thin film, the light emission including the gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film Diodes and laser diodes have the advantage of excellent optical properties.

Description

Single-crystalline substrate for manufacturing GaN based epilayer, the method of manufacturing the epilayer , LED and LD comprising the GaN based epilayer}

1 is a view showing an embodiment of a gallium nitride thin film manufacturing method according to the present invention.

FIG. 2 is an SEM photograph of the surface of the sapphire substrate on which the pattern portions partitioned by the dielectric layers and the photoresist of Examples 1 and 2 are formed.

3 is a SEM photograph of a cross section of a sapphire substrate on which a pattern portion partitioned by the dielectric layer and photoresist of Example 1 is formed.

4 is a graph showing the half width of the X-ray diffraction analysis of the gallium nitride epitaxial layer of Example 1 and Comparative Example 1.

FIG. 5 is a graph showing photoluminescence spectra of gallium nitride epitaxial layers of Example 1 and Comparative Example 1. FIG.

FIG. 6 is a graph showing the full width at half maximum of X-ray diffraction analysis for the N-type doped gallium nitride epi layer grown on the undoped gallium nitride epi layer of Example 1 and Comparative Example 1. FIG.

7 is a graph showing photometric results of UV LEDs prepared in Example 1 and Comparative Example 1. FIG.

8 is a graph showing photometric results of UV LEDs prepared in Example 2 and Comparative Example 1. FIG.

<Description of the symbols for the main parts of the drawings>

11: single crystal substrate 13: dielectric layer

15: compartment portion protective film 17: pattern portion

19: nitrogen ion injection pattern portion 21: nitrogen ion non-injection compartment

23: gallium nitride thin film

The present invention relates to a substrate for manufacturing a gallium nitride thin film, and more particularly, to a gallium nitride thin film manufacturing substrate, gallium nitride thin film manufacturing method and a single crystal substrate for gallium nitride thin film production to improve the crystallinity and optical properties of the gallium nitride thin film A light emitting diode and a laser diode including a gallium nitride thin film.

Gallium nitride with a Wurtzite structure has a direct transition bandgap of 3.4 eV at room temperature and is useful for light emitting diodes (LEDs) and laser diode (LD) devices in the blue and ultraviolet regions. The material used. In particular, it has the same woolitez structure and can form a continuous solid solution with indium nitride (InN) and aluminum nitride (AlN) having a band gap of 1.9 eV and 6.2 eV, respectively, so that the wavelength is adjusted according to the active energy and doping concentration of the impurity. Since it is possible to manufacture a ternary nitride according to the composition it is possible to manufacture a visible light emitting diode having a wide selection range of wavelengths. The gallium nitride used herein is a concept including an alloy of aluminum gallium nitride (Aluminum Gallium Nitride), indium gallium nitride (Indium Gallium Nitride) and aluminum indium gallium nitride (Aluminum Indium Gallium Nitride).

Although gallium nitride has such good applicability as above, it is very difficult to manufacture bulk single crystal due to the characteristics of the material. Currently commercialized thin films in which epitaxial layers are grown on a substrate by metal organic chemical vapor deposition (MOCVD) Use substance. Therefore, the gallium nitride thin film is more generally heteroepitaxial growth than homo epitaxial growth, the selection of the substrate is an important problem. Various kinds of different substrates used for gallium nitride thin film growth may be considered, but chemically stable and heat resistant sapphire (α-Al ₂ O ₃ ) substrates are typically used. However, when using a heterogeneous substrate such as a sapphire substrate, a problem of lattice mismatch between the substrate and gallium nitride may occur. For example, the difference in lattice mismatch between a sapphire substrate and gallium nitride may be up to 16%, and other heterogeneous substrates have the same problem as described above. Due to the lattice mismatch, defects such as misfit dislocations, threading dislocations, stacking defects, and inversion domain boundaries (IDBs) that occur from the beginning of thin film growth are observed. Since the degree of such defects is a very important factor in increasing the lifetime and luminous efficiency of the device, efforts to improve the defects have been attempted through various methods. The conventionally attempted method in this regard is to use a buffer layer. Aluminium nitride buffer layer (H. Amano, N. Sawaki, I. Akasaki and Y. Toyoda, Appl. Phys. Lett. 48, 353 1986) by Akasaki or gallium nitride buffer layer (S. Nakamura, Jpn.J. Appl. Phys. 30, L1705 1991), which provides many nucleation sites where the amorphous or polycrystalline buffer layer has the same crystallinity as the substrate, thereby facilitating the growth of gallium nitride. It reduces the interfacial energy between the substrate and the substrate to promote lateral growth. However, when the aluminum nitride or gallium nitride buffer layer is first formed by the organometallic chemical vapor deposition method or the molecular beam epitaxy method before the thin film crystal growth of gallium nitride, and the gallium nitride thin film is grown, the buffer layer is grown thereon as described above. It is reported that the quality of thin film crystals is improved as a result of facilitating the two-dimensional growth of gallium thin films, but Hashimoto et al. Reported that low-quality gallium nitride was formed due to the roughness of the surface according to the nitriding treatment time. T. Hashimoto, Y. Terakoshi, M. Ishida, M. Yuri, O. Imafuji, T. Sugino, A. Yoshikawa and K. Itoh, J. Crystal Growth 189/190, 254 (1998), Uchida et al. It has been reported that an amorphous compound is formed on the surface of the sapphire substrate to form a protruding surface (K. Uchida, A. Watanabe, F. Yano, M. Kouguchi, T. Tanaka and S. Minigawa, Solid-State Electronics 41 (2), 135 (1997)), therefore, it can be seen that different results are obtained according to the conventional process method depending on the optimization of the process conditions. Due to the sensitive process, the control process had to be difficult.

In order to solve this problem, Korean Patent No. 10-0472260 discloses a method of reducing defects generated during growth of a gallium nitride thin film by using a nitrogen ion implantation treatment method on an entire surface of a sapphire substrate. The method reduces the elastic strain energy caused by lattice mismatch by injecting nitrogen ions into the entire surface of the sapphire substrate to form an amorphous aluminum nitride layer or aluminum nitride oxide layer. Although optical properties may be improved, the problem of dislocation defects needs to be continuously improved, and growth rate decreases due to growth of the gallium nitride thin film from the amorphous layer also has room for improvement.

In addition, the optical device based on gallium nitride is an essential element for the growth of such a high quality gallium nitride thin film to improve the optical properties as described above, but recently improved optical properties of the optical device by improving the crystallinity of the gallium nitride thin film The method which extracts the quantity of light which generate | occur | produced inside from the inside of an optical element suitably is used. One of the methods introduced for this purpose is a method using a patterned sapphire substrate (PSS), but this method can be easily performed using a conventional reactive ion etching (RIE) method in the case of a strong substrate such as a sapphire substrate. Difficulty in mass production due to problems such as difficult to etch and difficult to adjust the thickness as desired.

Accordingly, the first technical problem to be achieved by the present invention is to provide a single crystal substrate for producing a gallium nitride thin film that can improve the crystallinity and optical properties of the gallium nitride thin film.

The second technical problem to be achieved by the present invention is to provide a single crystal substrate for producing the gallium nitride thin film, which is easy to manufacture, and to provide a gallium nitride thin film manufacturing method using the same.

The third technical problem to be achieved by the present invention is to provide a light emitting diode comprising a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film.

A fourth technical problem to be achieved by the present invention is to provide a laser diode comprising a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film.

The present invention to achieve the first technical problem,

A nitrogen ion implantation pattern portion 19 made of sapphire, silicon carbide, zinc oxide, silicon or gallium arsenide (GaAs) and including a plurality of regularly repeated patterns on the same plane; And it provides a single crystal substrate for producing a gallium nitride thin film comprising a nitrogen ion non-injection partition portion 21 for partitioning the pattern.

According to one embodiment of the present invention, the shape of the pattern may be circular, elliptical, striped (striped) or polygonal.

According to another embodiment of the present invention, the material of the substrate may be sapphire and the aluminum nitride film is formed on the surface of the nitrogen ion injection pattern portion.

According to another embodiment of the present invention, the dose of nitrogen ions to the nitrogen ion injection pattern portion is 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² , and the injection energy is in the range of 10 to 100 keV. Can be.

The present invention to achieve the second technical problem,

(a) preparing a single crystal substrate 11;

(b) forming a nitrogen ion implantation pattern portion 19 including a regularly repeated pattern on the same plane of the single crystal substrate 11 and a nitrogen ion non-injection partition portion 21 partitioning the pattern; And

(c) providing a gallium nitride thin film manufacturing method comprising growing a gallium nitride thin film 23 on the surfaces of the nitrogen ion injection pattern portion 19 and the nitrogen ion non-injection partition portion 21.

According to one embodiment of the present invention, the single crystal substrate may be made of sapphire, silicon carbide, zinc oxide, silicon or gallium arsenide.

According to another embodiment of the present invention, the shape of the pattern of step (b) may be circular, elliptical, striped (striped) or polygonal.

According to another embodiment of the present invention, the nitrogen ion implantation treatment of step (b) may be performed in the range of ion dose 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² and implantation energy 10 to 100 keV. have.

According to another embodiment of the present invention, the step (b) comprises the steps of (b1) growing a dielectric layer on the surface of the single crystal substrate; (b2) forming a compartmental protective film that partitions a plurality of regularly repeated patterns on the surface of the dielectric layer; (b3) forming a pattern portion by removing the dielectric layer of the pattern; (b4) forming a nitrogen ion injection pattern part by injecting nitrogen ions into the pattern part; (b5) removing the compartment protection film; And (b6) forming a nitrogen ion non-injection partition that partitions the pattern by removing the exposed dielectric layer after the partition protection film is removed.

According to another embodiment of the present invention, the dielectric layer may be a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), or a silicon oxynitride film (SiON).

According to another embodiment of the present invention, the method of forming the compartmental protective film of step (b2) may be a photolithography process, an inkjet method or an imprinting method.

According to another embodiment of the present invention, the dielectric layer of step (b3) may be removed by RIE.

According to another embodiment of the present invention, the removal of the dielectric layer of step (b6) can be removed with hydrofluoric acid.

According to another embodiment of the present invention, the gallium nitride thin film growth of step (c) may first form a buffer layer on the substrate, and then form an epi layer thereon.

According to another embodiment of the present invention, the gallium nitride thin film growth of the step (c) may be by an organic metal chemical vapor deposition method, molecular beam epitaxy method, atomic layer unit deposition method or plasma chemical vapor deposition method.

The third technical problem to be achieved by the present invention is to provide a light emitting diode comprising a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film.

The fourth technical problem to be achieved by the present invention is to provide a laser diode comprising a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film.

Hereinafter, with reference to the accompanying drawings will be described the present invention in more detail.

The term 'gallium nitride' as used herein is a concept including an alloy of aluminum gallium nitride (Aluminum Gallium Nitride), indium gallium nitride (Aluminum Gallium Nitride) and aluminum indium gallium nitride (Aluminum Indium Gallium Nitride), _a Al _b Ga _{1 -a- b} N (where 0 ≦ a, 0 _{≦ b} , a + b ≦ 1).

The single crystal substrate for producing a gallium nitride thin film according to the present invention is made of sapphire, silicon carbide, zinc oxide, silicon or gallium arsenide (GaAs), and includes a plurality of regularly repeated patterns on the same plane as shown in FIG. 2. Nitrogen ion injection pattern portion; And it is characterized in that it comprises a nitrogen ion non-injection compartment for partitioning the pattern. The single crystal substrate for producing a gallium nitride thin film may be made of sapphire, silicon carbide, zinc oxide, silicon, or gallium arsenide (GaAs). Even though the substrates are different from gallium nitride, the gallium nitride crystals can be grown on the substrate, and according to the present invention, lattice mismatch between gallium nitride and heterocrystals can be reduced, thereby making a single crystal substrate for producing a gallium nitride thin film. Can be used as As shown in FIG. 2, the nitrogen ion implantation pattern portion is formed by regularly repeating a pattern of a certain shape such as a triangle or a hexagon, and is subjected to nitrogen ion implantation treatment (N ⁺ -ion implantation) with respect to the pattern portion. do. The pattern is characterized in that each pattern is partitioned by a partition, and the partition is a surface of a single crystal substrate in a state where nitrogen ion implantation is not performed. That is, by repeatedly repeating the pattern portion subjected to the nitrogen ion implantation treatment and the partition portion not subjected to the nitrogen ion implantation treatment on the same plane, the amorphous portion and the crystal portion, that is, the two portions of the single plane of the gallium nitride thin film It can form two phases. By forming two different phases on the same plane as described above, when the epi layer is formed on two upper layers, the epi layer is formed at different growth rates and growth modes. In the case of nitrogen ion injection treatment, AlN or AlON film is formed on the surface to mitigate lattice mismatch, but the growth rate of the epi layer may be slow because it is amorphous. In addition, the lattice mismatch is not alleviated in the partition portion not subjected to the nitrogen ion implantation treatment, but the growth rate of the epi layer is faster than that of the pattern portion, and as a result, the growth is horizontal toward the pattern portion in addition to the growth in the vertical direction (side growth). It will be in a state capable of doing. When horizontal growth occurs from one compartment, horizontal growth can occur simultaneously from adjacent compartments, and as a result, the horizontally grown portions between the compartments meet on the surface of the epitaxial layer grown vertically in the pattern portion, and the portions that meet each other. Since the material having the same crystal structure can be said to have an advantageous effect in terms of lattice mismatch. In addition, a mode in which the relaxed lattice mismatch of the pattern portion subjected to the nitrogen ion implantation propagates by the growth of the crystal may be considered. That is, according to the present invention, the surface treated with nitrogen ion implantation is made of AlN or AlON film to mitigate lattice mismatch, and the epitaxial layer grown on the surface not treated with nitrogen ion implantation grows horizontally due to the difference in growth rate (side growth). It is judged that lattice mismatch is alleviated by doing this.

According to the present invention, by forming a pattern portion and a partition portion composed of a plurality of regularly repeated patterns, the above-described complex action can be made to occur uniformly on the surface of the entire single crystal substrate.

According to one embodiment of the present invention, the shape of the pattern is not limited to the shape and size of a circle, oval, stripe (striped) or polygonal. The polygons may be triangular to 36-angular, and in the case where the shape of the pattern is hexagonal or when the triangles are gathered to take a hexagonal shape as a whole, gallium nitride may be advantageous in terms of crystal growth. In particular, in the present invention, since the gallium nitride crystals grow on the same plane with respect to the pattern portion and the partition portion, it is expected that crystal growth may advantageously occur when both the pattern portion and the partition portion have a hexagonal shape.

According to another embodiment of the present invention, the material of the substrate may be sapphire and the aluminum nitride film may be formed on the surface of the nitrogen ion injection pattern portion.

According to another embodiment of the present invention, the dose of nitrogen ions to the nitrogen ion injection pattern portion is 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² And the injection energy may range from 10 to 100 keV. Since the nitrogen ion implantation treatment method according to the present invention can control the dose of nitrogen ion irradiated to the substrate according to the ion dose amount, it is possible to expect a uniform distribution of nitrogen atoms on the surface of the substrate, and thus Since stress energy is expected to prevent relatively little or non-uniform concentration due to the regularity of nitrogen ion distribution, there is an advantage that it can induce uniform nucleation. If the ion dose is less than 1 × 10 ¹⁵ / cm ^{2, the} aluminum nitride phase may not be sufficiently formed, and 1 × 10 ¹⁷ / cm ² This is because when the excess is exceeded, the surface of the substrate is much damaged due to excessive nitrogen ion implantation treatment, and the surface is so rough that crystallinity may deteriorate during the growth of the gallium nitride epi layer. Similarly, when the implantation energy is less than 10 keV, there is a concern that the aluminum nitride phase may not be formed sufficiently, and when the implantation energy is more than 100 keV, the surface of the substrate may be damaged and the crystallinity of the gallium nitride epi layer may deteriorate.

The gallium nitride thin film manufacturing method according to the present invention comprises the steps of (a) preparing a single crystal substrate (11); (b) forming a nitrogen ion implantation pattern portion 19 including a regularly repeated pattern on the same plane of the single crystal substrate 11 and a nitrogen ion non-injection partition portion 21 partitioning the pattern; And (c) growing a gallium nitride thin film 23 on the surfaces of the nitrogen ion injection pattern portion 19 and the nitrogen ion non-injection partition portion 21.

The gallium nitride thin film manufacturing method according to the present invention includes a nitrogen ion injection pattern portion 19 including a plurality of regularly repeated patterns on the same plane according to the present invention; And a gallium nitride thin film in the same manner without a pattern portion or a non-pattern portion for a single crystal substrate for producing a gallium nitride thin film including a nitrogen ion non-implantation partition portion 21 partitioning the pattern.

As described above, the single crystal substrate for producing a gallium nitride thin film may be formed of sapphire, silicon carbide, zinc oxide, silicon, or gallium arsenide, and the pattern of step (b) may be circular, elliptical, or striped. It may be a shape (stripe) or polygonal, and the like, but is not limited so long as the shape is regularly repeated, the polygon may be a triangular to 36 square. In addition, the nitrogen ion implantation treatment in step (b) may be performed in the range of ion dose 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² and injection energy of 10 to 100 keV.

In the step (b), the nitrogen ion implantation pattern portion 19 including a pattern regularly repeated on the same plane of the single crystal substrate 11 and the nitrogen ion non-injection partition portion 21 partitioning the pattern are formed. Although not limited to one possible method, according to an embodiment of the present invention, the step (b) includes the steps of (b1) growing the dielectric layer 13 on the surface of the single crystal substrate 11; (b2) forming a compartmental protective film 15 partitioning a plurality of regularly repeated patterns on the surface of the dielectric layer 13; (b3) forming the pattern portion 17 by removing the dielectric layer of the pattern; (b4) injecting nitrogen ions into the pattern portion 17 to form a nitrogen ion injection pattern portion 19; (b5) removing the compartmental protective film 15; And (b6) forming a nitrogen ion non-injection partition 21 for partitioning the pattern by removing the exposed dielectric layer after the partition protection film 15 is removed.

According to another embodiment of the present invention, the dielectric layer 13 may use a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), a silicon oxynitride film (SiON), or the like, which is a general ion implantation protection layer. Can be. The dielectric layer 13 is not particularly limited as long as it can be deposited on a substrate for manufacturing a gallium nitride thin film by vapor deposition or the like. However, the dielectric layer 13 has a strength that can protect the compartment from nitrogen ion injection during nitrogen ion injection treatment. Should have

According to another embodiment of the present invention, the method for forming the partition protective film 15 of the step (b2) may be a photolithography process, an inkjet method or an imprinting method, etc., may represent the shape of the pattern portion As long as it can serve as a mask, any known method can be used to form the compartmental protective film.

According to another embodiment of the present invention, a method of removing the dielectric layer 13 of step (b3) may be used, but a known depth may be removed when the dielectric layer is removed by reactive ion etching (RIE). As a result, a precise pattern portion can be formed, and damage to the compartment protective film can be prevented so that the nitrogen ion implantation treatment can be performed only on the pattern portion in a subsequent step.

The nitrogen ion implantation treatment of step (b4) may be performed in an ion dose of 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² and an injection energy of 10 to 100 keV, and the partition of step (b5). The removal of the protective film 15 is different depending on the formation method of the compartmental protective film, and when a photoresist is used as the compartmental protective film by the photolithography method, an appropriate solvent, for example, AZ1512 is used as the photoresist. In this case, n-methyl pyrrolidone can be removed.

According to another embodiment of the present invention, the removal of the dielectric layer in step (b6) may be performed by a known method, but when removing with hydrofluoric acid, the dielectric layer remaining on the substrate may be removed by a simple process.

According to another embodiment of the present invention, the gallium nitride thin film growth of step (c) may first form a buffer layer on the substrate, and then form an epi layer thereon. By forming a nitride compound semiconductor buffer layer such as aluminum nitride or gallium nitride at a relatively low temperature, lattice deformation of the nitride compound semiconductor crystal is alleviated, thereby improving the physical and optical properties of the epi layer.

According to another embodiment of the present invention, the gallium nitride thin film growth of step (c) may be by a known thin film growth method, in particular organometallic chemical vapor deposition method, molecular beam epitaxy method, atomic layer unit deposition method or Plasma chemical vapor deposition, or the like.

The light emitting diode according to the present invention may include a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film, and the improvement of gallium nitride of the gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film according to the present invention. Due to the crystallinity and the optical properties, the light emitting diode can also improve the optical properties.

The laser diode according to the present invention may also include a gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film, and the improvement of gallium nitride in the gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film according to the present invention. Due to the crystallinity and the optical properties, the laser diode can also improve the optical properties.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

<Example 1>

A low pressure chemical vapor deposition machine (Sungjin Semitech; SJF-1000LP-T4) was used to deposit a silicon nitride film (Si ₃ N ₄ ) with a thickness of 1,300Å on a sapphire substrate (Sinko, Japan) with a diameter of 2 inches using SiH ₄ and NH ₃ . Grown. Using a mask in which a triangular pattern was formed on the surface of the silicon nitride film, a protective layer for partitioning a pattern in which a triangle having a length of 30 μm on one side and a 5 μm interval between adjacent triangles was regularly formed was formed. The photoresist used in the photolithography process was AZ1512, and the thickness of the formed photoresist layer was 1.6 μm. Thereafter, the silicon nitride film not protected by the compartmental protective film was removed by RIE (Plasma 100MPS-C, Oxford, UK) to form a pattern. In order to inject nitrogen ions only into the pattern portion on the sapphire substrate, with nitrogen nitride and photoresist as a protective film, nitrogen ions are implanted with an energy of 60 keV and an ion dose of 1 × 10 ¹⁶ / cm ² (N ⁺ -implantation). Then, after removing the photoresist with n-methyl pyrrolidone, the silicon nitride film was removed by RIE (Plasma 100MPS-C, Oxford (UK)). As a result, a single crystal substrate for gallium nitride growth was prepared, in which the triangular nitrogen ion implantation area was 60% of the total surface area of the sapphire single crystal substrate.

The sapphire substrate from which the photoresist and the silicon nitride film was removed was washed with organic matter, and then etched in H ₂ SO ₄ : H ₃ PO ₄ = 3: 1 solution and 10% HF solution for 10 minutes, respectively, followed by organometallic chemical vapor phase. It was mounted in a deposition reactor (D-180 (Spectra Blue); Emcore, USA). After heat washing at 1,100 ° C. for 10 minutes in a hydrogen atmosphere, the mixture was cooled to 550 ° C. to grow a gallium nitride buffer layer having a thickness of about 30 nm, and the reactor pressure was 500 Torr. After growing the buffer layer, the temperature was further raised to 1,040 ° C. to grow a gallium nitride epi layer having a thickness of about 2 μm, and the reactor pressure was 500 Torr. Subsequently, an N-type doped gallium nitride epitaxial layer was formed at the same temperature, and then the UV LED chip was grown. Multi-quantum wells of UV LEDs were fabricated by growing InGaN, GaN, and AlGaN at 1,000 ℃ for 5 cycles with 10 ~ 20nm thickness.

<Example 2>

The pattern shape was replaced with a hexagon with a diagonal length of 70 μm and an interval of 35 μm between adjacent hexagons.As a result, a single crystal substrate for gallium nitride growth with a hexagonal nitrogen ion implantation area of 33% of the total sapphire single crystal substrate surface area was prepared. Except that except for the first embodiment.

Comparative Example 1

After sapphire substrate (Shinkosa, Japan) having a diameter of 2 inches, the organic material was washed, and then etched in H ₂ SO ₄ : H ₃ PO ₄ = 3: 1 solution and 10% HF solution for 10 minutes, respectively. It was mounted in a reactor for chemical vapor deposition (D-180 (Spectra Blue); Emcore, USA). After heat washing at 1,100 ° C. for 10 minutes in a hydrogen atmosphere, the mixture was cooled to 550 ° C. to grow a gallium nitride buffer layer having a thickness of about 30 nm, and the reactor pressure was 500 Torr. After growing the buffer layer, the temperature was further raised to 1,040 ° C. to grow a gallium nitride epi layer having a thickness of about 2 μm, and the reactor pressure was 500 Torr. Subsequently, an N-type doped gallium nitride epi layer was formed at the same temperature, and then the UV LED structure was grown. Multi-quantum wells of UV LEDs were fabricated by growing InGaN, GaN, and AlGaN at 1,000 ℃ for 5 cycles with 10 ~ 20nm thickness.

<Test Example 1>

Gallium nitride  Surface shape confirmation test of thin film growth substrate

SEM image of the surface of the sapphire substrate on which the pattern portion was formed, in order to confirm that the pattern portion partitioned by the dielectric layer and the photoresist was formed on the surface of the sapphire substrate in the previous step of nitrogen ion injection into the pattern portion of Example 1 or Example Photographed. The results are shown in FIG.

As shown in FIG. 2, it can be seen that a pattern portion in which a triangular or hexagonal pattern partitioned by a dielectric layer and a photoresist is regularly formed on the sapphire substrate surface is formed. Therefore, it can be seen that the single crystal substrate for producing a gallium nitride thin film according to the present invention can be produced while satisfying reproducibility and precision.

<Test Example 2>

Pattern part  Formation confirmation test

In order to confirm that the pattern portion partitioned by the dielectric layer and the photoresist was formed on the surface of the sapphire substrate before the nitrogen ion injection to the pattern portion of Example 1, SEM photographs were taken of the cross section of the patterned sapphire substrate. The results are shown in FIG.

As shown in FIG. 3, a silicon nitride film (Si ₃ N ₄ ) having a thickness of 1300 μs and a photoresist having a thickness of 1.6 μm are formed on the surface of the sapphire substrate, and the pattern portion of the sapphire substrate is completely removed. It can be seen that the surface is exposed. The silicon nitride film and the photoresist may protect the surface partition of the substrate from nitrogen ion implantation, and may allow nitrogen ion implantation only for the pattern portion.

<Test Example 3>

Epilayer  Crystallinity test

Double crystal X-ray diffraction (DCXRD) with a double crystal X-ray diffractometer (Xpert PRO, PAnalitical) to analyze the crystallinity of the epi layer at the end of growth of the gallium nitride epi layer of Example 1 and Comparative Example 1; Double crystal X-ray diffraction was performed, and an X-ray rocking curve is shown in FIG. 4. As a result, looking at the full width at half maximum (FWHM) of the X-ray rocking curve in gallium nitride peak (0002), the comparative example 1 shows 0.096 while the comparative example 1 shows 0.085. Since the smaller the half-value width, the more uniform crystals were formed, it can be confirmed from the above results that the crystallinity of the gallium nitride thin film epilayer according to the present invention is superior to the prior art.

<Test Example 4>

Epilayer  Optical property test

In order to analyze the optical properties of the epitaxial layer after the growth of the gallium nitride epitaxial layer of Example 1 and Comparative Example 1, photoluminescence spectra of gallium nitride at room temperature were obtained by using a PL device (RPM2000, Accent optical technologies (UK)). Measured. The results are shown in FIG. As shown in FIG. 5, it can be seen that the case of Example 1 has a higher intensity than that of Comparative Example 1 at 365 nm, which is a light emission wavelength of gallium nitride. In addition, it can be seen that yellow luminescence near 550 nm wavelength due to nitrogen voids or various defects shows a significantly lower value in Example 1 than in Comparative Example 1. It can be seen that the gallium nitride epi layer according to the present invention is superior to the gallium nitride epi layer according to the prior art as in the result of Experimental Example 3, the optical properties.

<Test Example 5>

N-type Doped Gallium nitride Epilayer  Crystallinity test

N-type doped gallium nitride epitaxial layers were grown on the undoped gallium nitride epitaxial layers of Example 1 and Comparative Example 1 with a double crystal X-ray diffractometer (Xpert PRO, PAnalitical) to confirm their crystallinity. Double crystal X-ray diffraction (DCXRD) was performed to show an X-ray rocking curve (X-ray rocking curve) in FIG. 6. As a result, looking at the full width at half maximum (FWHM) of the X-ray rocking curve in gallium nitride peak (0002), the comparative example 1 shows 0.070 while the comparative example 1 shows 0.063. Since the smaller the half-value width, the more uniform the crystal was formed, it can be seen that the crystallinity of the N-doped gallium nitride epitaxial layer according to the present invention is superior to the prior art.

<Test Example 6>

UV LED Optical properties test

In order to test the optical properties of the UV LEDs prepared in Examples 1, 2 and Comparative Example 1, an electrode was placed on the wafer, and a current of 100 mA was applied to the LED chip tester. (ELT-1000, Ecopia21). The results are shown in FIGS. 7 and 8, and from the results, it can be seen that Examples 1 and 2 both exhibit 79 to 80% improved brightness compared to Comparative Example 1. Although the surface area of the nitrogen injection treatment pattern part of Example 1 is 60% of the total surface area and 33% of Example 2, the degree of brightness enhancement effect is similar. That is, the reason that the result of the excellent brightness enhancement effect is shown regardless of the surface area of the nitrogen injection treatment pattern portion is considered to be due to the repeated uniform pattern of the present invention. In addition, the luminosity of Example 2 is slightly higher than that of Example 1, in which the pattern portion and the partition portion of the surface of the single crystal substrate of Example 2 are hexagonal, indicating that the crystal growth side of gallium nitride, which is hexagonal, has a hexagonal shape. It is considered to be one of the factors that have a favorable effect on.

The above results indicate that the optical characteristics of the UV LED according to the present invention are superior to those of the prior art even though the shape of the pattern or the area of the nitrogen ion injection unit is different. The above results indicate that the surface treated with nitrogen ion implantation mitigates lattice mismatch, and the epitaxial layer grown on the surface without nitrogen ion implantation mitigates lattice mismatch by horizontal growth (side growth) due to the growth rate difference. Is generated in a complex manner, and the complex effect is uniformly generated for the entire substrate, and the optical properties of the UV-LED grown from the epitaxial layer are also improved.

As described above, the single crystal substrate for producing a gallium nitride thin film according to the present invention can quickly grow the growth of the gallium nitride thin film in a manner different from the conventional one, and as a result, the crystallinity and optical properties of the gallium nitride thin film can be improved. . In addition, the gallium nitride thin film manufacturing method using the single crystal substrate is easy to manufacture and can improve the crystallinity and optical properties of the gallium nitride thin film, the light emission including the gallium nitride thin film manufactured by the single crystal substrate for producing the gallium nitride thin film Diodes and laser diodes have excellent optical properties.

Claims (17)

A substrate made of an element selected from the group consisting of sapphire, silicon carbide, zinc oxide, silicon and potassium arsenide; And A nitrogen ion implantation pattern portion having a plurality of regularly repeated patterns on the plane of the substrate and having an aluminum nitride film formed thereon; And a gallium nitride non-injection partition which partitions the pattern. 2. The single crystal substrate of claim 1, wherein the pattern is circular, elliptical, striped (striped) or polygonal. delete The method of claim 1, wherein the dose of nitrogen ions to the nitrogen ion injection pattern portion is 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² , the injection energy is in the range of 10 to 100 keV Single crystal substrate for producing gallium nitride thin film. (a) preparing a single crystal substrate; (b1) growing a dielectric layer on the surface of the single crystal substrate; (b2) forming a compartmental protective film that partitions a plurality of regularly repeated patterns on the surface of the dielectric layer; (b3) forming a pattern portion by removing the dielectric layer of the pattern; (b4) forming a nitrogen ion injection pattern part by injecting nitrogen ions into the pattern part; (b5) removing the compartment protection film; And (b6) nitrogen ion implantation including a pattern regularly repeated on the same plane of the single crystal substrate by forming a nitrogen ion non-injection compartment partitioning the pattern by removing the exposed dielectric layer after the partition protection film is removed; Forming a pattern portion and a nitrogen ion non-injection compartment that partitions the pattern; And (C) a gallium nitride thin film manufacturing method comprising the step of growing a gallium nitride thin film on the surface of the nitrogen ion implantation pattern portion and the nitrogen ion non-injection compartment. The method of claim 5, wherein the single crystal substrate is made of an element selected from the group consisting of sapphire, silicon carbide, zinc oxide, silicon, and gallium arsenide. 6. The method of claim 5, wherein the shape of the pattern of step (b2) is circular, elliptical, striped (striped) or polygonal. The nitrogen ion implantation treatment of step (b4) is performed in the range of ion dose 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² and injection energy of 10 to 100 keV. Gallium thin film manufacturing method. delete The method of claim 5, wherein the dielectric layer is a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ), or a silicon oxynitride film (SiON). The method of claim 5, wherein the method of forming the compartmental protective film of step (b2) is a photolithography process, an inkjet method or an imprinting method. The method of claim 5, wherein the dielectric layer of step (b3) is removed by RIE. 6. The method of claim 5, wherein the removing of the dielectric layer of step (b6) is performed with hydrofluoric acid. The method of claim 5, wherein the gallium nitride thin film growth of step (c) comprises first forming a buffer layer on the substrate, and then forming an epitaxial layer thereon. The method of claim 5, wherein the gallium nitride thin film growth of step (c) is performed by an organometallic chemical vapor deposition method, molecular beam epitaxy method, atomic layer unit deposition method or plasma chemical vapor deposition method. A light emitting diode comprising a gallium nitride thin film manufactured by the single crystal substrate for producing a gallium nitride thin film of claim 1. A laser diode comprising a gallium nitride thin film manufactured by a single crystal substrate for producing a gallium nitride thin film according to claim 1 or 2.

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