KR19990080779A - Method for manufacturing gallium nitride based blue light emitting diode using gallium nitride semiconductor substrate - Google Patents

Abstract

The present invention provides a multi-layered gallium nitride compound semiconductor thin film layer having excellent crystallinity in a state in which crystal lattice mismatch does not exist. Thus, a gallium nitride compound using a gallium nitride semiconductor substrate having high crystallinity and electrical and optical properties The present invention relates to a method of manufacturing a blue light emitting diode, wherein a multi-layered gallium nitride semiconductor layer is formed on a silicon substrate by a chemical vapor deposition method to form a gallium nitride bulk layer, and is free from stress deformation due to lattice mismatch or thermal expansion. Forming a gallium nitride based thin film, and forming n-type and p-type metal electrodes on the lower part of the gallium nitride semiconductor substrate and on the multi-layered gallium nitride-based thin film layer, respectively. Increase the amount of shadow mask by using silicon oxide film or silicon nitride film And mask etching process and complex combination of masks when forming electrodes can be greatly reduced, and there are advantages that can be applied to existing mass production technology as it is. In addition to mass production, the light emitting area of the device is not reduced, thereby producing a relatively high quality device.

Description

Method for manufacturing gallium nitride-based blue light emitting diode using gallium nitride semiconductor substrate

The present invention relates to a method for growing a crystal of a gallium nitride compound semiconductor on a gallium nitride semiconductor substrate, in particular a state in which a crystal lattice mismatch with a multi-layer gallium nitride compound semiconductor thin film layer having excellent crystal characteristics does not exist The present invention relates to a method for manufacturing a gallium nitride-based blue light emitting diode having high quality crystallinity and electrical and optical characteristics.

Recently, a gallium nitride compound semiconductor is a semiconductor crystal, for example, Ga _1-X Al _X N, Ga _1-X In _X N compound, a blue light emitting diode using a semiconductor crystal in which X is in the range of 0≤X≤1 Heterogeneous sapphire (Al ₂ O ₃ ), MgAl ₂ O ₄ , Si, SiC, GaAs, etc. are used for the fabrication. In particular, sapphire with good thermal properties at a high temperature of 1000 ° C. or higher is used. I use it. As a method of growing a crystal of a gallium nitride compound semiconductor, an organometallic compound vapor deposition method (hereinafter referred to as "MOCVD method") is widely known. In this method, organic metal gases such as trimethyl gallium [Ga (CH ₃ ) ₃ ], trimethyl aluminum [Al (CH ₃ ) ₃ ], trimethyl indium [In (CH ₃ ) ₃ ], and the like are used as a reaction gas. The surface chemical reaction occurs at a high temperature of about 1000 to 1100 ° C. to grow a gallium nitride compound semiconductor thin film on a sapphire substrate.

However, due to the geometric lattice mismatch between the gallium nitride thin film layer and the sapphire substrate to be grown on the dissimilar substrate, a large number of egde-type threading dislocations are caused in the crystal growth direction in the semiconductor thin film so that the hexagonal pyramid phase or Hexagonal plate structure is shown, and the crystal defects lower the electrical and optical characteristics, and in the case of sapphire substrates, in particular, when the electrical load is applied due to the insulating characteristics, the reliability of the device is lowered by the electrostatic phenomenon. Have

In order to overcome the insulation of the sapphire substrate, for example, a method of forming electrodes on both sides of the back and front surfaces of a blue light emitting diode using a SiC semiconductor substrate has been proposed. According to this method, the electrostatic phenomenon can be solved, but there is still a limit in making a defect-free device due to the large distance between the lattice due to the crystal growth of heterojunction.

Recently, as a method of realizing a blue light emitting diode or the like on a sapphire substrate, a multi-layer gallium nitride compound is laminated to improve luminous efficiency.SiH ₄ gas is used as an n-type impurity and cyclodiffene is used as a p-type impurity. Tyl magnesium (Cp ₂ Mg) is used. Moreover, in order to activate p type impurity, electron beam is irradiated or the high temperature heat processing method of about 800 degreeC is used. This is because the activation energy that can be combined by hydrogen in the n-type GaN thin film layer is very high as 3.4 eV, but the activation energy in which hydrogen can react with Mg is very low as 0.7 eV in the P-type GaN.

In this way, it is possible to make a high brightness blue light emitting diode, but many problems in reliability have to be solved due to the limitation of crystallinity.

The present invention has been made in view of the above-described problems of the prior art, using a gallium nitride semiconductor substrate using a hydrogen compound vapor phase growth method (HVPE) without any lattice mismatch or stress deformation caused by thermal expansion caused by the substrate. The purpose of the present invention is to provide a method of manufacturing a high efficiency blue light emitting diode by growing a gallium nitride based semiconductor having high quality crystallinity and electrical and optical properties by lamination.

1 schematically illustrates a portion of a hydrogen compound vapor phase growth apparatus (HVPE) used in the present invention.

FIG. 2 is an enlarged photomicrograph of a surface of a gallium nitride semiconductor substrate grown by the hydrogen compound vapor phase growth apparatus of FIG.

3 is a waveform diagram showing the correlation between the film thickness in the direction of crystal growth, the X-ray intensity and the diffraction angle of a gallium nitride semiconductor substrate by X-ray diffraction;

4 is a schematic cross-sectional view of a portion of an organometallic vapor phase growth apparatus (MOCVD) reactor used in the present invention.

5 shows a cross section of a gallium nitride based thin film structure formed by a conventional crystal growth method.

6 is a cross-sectional view of a gallium nitride based thin film structure formed by the crystal growth method of the present invention.

FIG. 7 is a cross-sectional view taken along the line AA ′ of FIG. 4.

FIG. 8 is a cross-sectional view taken along line BB ′ shown in FIG. 4.

9 is a waveform diagram showing the correlation between the double crystal X-ray diffraction intensity and the X-ray locking angle indicating the molar ratio of indium (In) in the double crystal X-ray locking curve.

FIG. 10 is a correlation diagram illustrating a HALL effect of a double layer doped In _0.1 ga _0.9 N layer of silicon (Si) and zinc (Zn) according to the content of SiH ₄ .

FIG. 11 is a waveform diagram showing changes in luminescence intensity according to doping amount of In _0.1 Ga _0.9 N layer doped with silicon and zinc.

FIG. 12 is a photograph of luminescence from a grown structure photoexcited with a laser.

Fig. 13 is a characteristic diagram showing ohmic contact characteristics of a p-type GaN surface with temperature change;

14 is a characteristic curve diagram showing current-voltage characteristics of a blue light emitting diode having a double hetero structure.

Fig. 15 is a photograph showing light emission characteristics showing brightness of 0.5 candela in a bias state of 6 V and 20 mA.

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

11: quartz boat (Ga raw material) 12,13: gas inlet

14 silicon substrate 15 quartz tube

16 gas outlet 17 electric furnace

18 flowmeter 41 gas inlet

42: ammonia gas inlet 43: fine circular hole plate

44: internal quartz tube 45: external quartz tube

48 gallium nitride semiconductor substrate 49 high frequency induction heating apparatus

40: graphite hot plate 50: sapphire substrate

51,68: n-type electrode 52,61: p-type electrode

53,54,55,56,57,62,63,64,65,66: gallium nitride based thin film layer

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

1 is a schematic partial cross-sectional view of an HVPE apparatus used in the present invention. Hydrogen gas and hydrochloric acid (HCl) gas are introduced into the Ga raw material quartz boat 11 in front of the reactor through the gas inlet 12, and ammonia gas is introduced through the gas inlet 13 to deposit an AlN layer. After reaching the silicon substrate 14, a thermochemical reaction is performed to form a GaN bulk layer, and then the residual gas is discharged through the outlet 16 of the quartz tube 15. By using the reactor 17 as an electric furnace 17, a silicon-doped gallium (Ga) ingot raw material is heated to 850 ° C, and a silicon substrate portion is heated to about 1030 ° C to react gallium chloride (GaCl) gas and ammonia gas. Let's do it. 18 in the figure shows a flow meter.

An aluminum nitride (AlN) layer on the silicon substrate is deposited by high frequency (RF) sputtering. In the reactor of the HVPE apparatus, the hydrochloric acid gas and the gallium chunk are reacted as shown in the following [Scheme 1], and then reacted again with the ammonia gas as shown in the [Scheme 2] to grow the gallium nitride layer to 550㎛ thickness.

GaCl (g) + NH ₃ (g) → GaN (s) + HCl (g) + H ₂ (g)

To separate the gallium nitride on the silicon, the silicon is immersed in an etching solution having a mixture ratio of hydrofluoric acid (HF) and water (H ₂ O) of about 1: 10, and the silicon is etched, and the substrate is polished so that the unevenness is 10 Å or less. To polish. In the HVPE crystal growth state, the surface is very rough and mechanically polished, and then polished to diamond powder 10, 5, 1, 1 / 10㎛ particle size and finally sulfuric acid (H ₂ SO ₄ ) and phosphoric acid (H ₃ PO ₄ ) Perform wet etching of the surface in solution.

FIG. 2 is a micrograph after 1 탆 gloss of a gallium nitride semiconductor substrate grown by the HVPE crystal growth method. FIG. Referring to FIG. 3, the direction of the crystal structure according to the thickness of the gallium nitride semiconductor substrate is found to be aligned with the Wurtzite GaN (0002) as the thin film layer becomes thicker. The waveform diagram a) shown in FIG. 3 is X-ray intensity and X- when the thickness of the thin film layer is 10 μm, b) is 32 μm, c) is 65 μm, d) is 130 μm, and e) is 260 μm. Correlation between line diffraction angles is shown.

Next, after the prepared gallium nitride semiconductor substrate is washed, a thin film layer is laminated in a MOCVD reactor.

As shown in FIG. 4, the MOCVD reactor includes a gallium nitride semiconductor substrate 48 for forming a gallium nitride based thin film layer, and a graphite hot plate for heating the gallium nitride semiconductor substrate 48 with a high frequency induction heating device 49. 40), a gas inlet 41 for sucking the organometallic source gas and hydrogen gas, and an ammonia gas inlet 42, and a local of the organic metal source gas and the hydrogen gas sucked through the gas inlet 41 The pressure is lowered to increase the speed so as to sufficiently mix with the ammonia gas introduced through the gas inlet 42. In order to form a turbulent flow state, a plurality of pinholes are formed using a laser and are formed of an inner quartz tube 44 and an outer quartz tube 45 formed of a fine circular hole plate 43.

The gallium nitride based thin film stacked structure using the conventional sapphire substrate shown in FIG. 5 has a p-GaN layer 53 and p-Al _0.15 to form the n-type electrode 51 due to the insulating properties of the sapphire substrate 50. A portion of the gallium nitride thin film layer comprising Ga _0.85 N layer 54, In _0.05 Ga _0.94 N layer 55, n-Al _0.15 Ga _0.85 N layer 56, and n-GaN layer 57 must be dry etched. . In the figure, reference numeral 52 denotes a p-type electrode. After crystal growth of gallium nitride-based thin film due to the use of sapphire substrate, an insulating layer of silicon oxide film (SiO ₂ ) or silicon nitride film (Si ₃ N ₄ ) must be introduced as a shadow mask for dry etching. In order to form the n, p surface metal electrode on the same surface with a step, it has a lot of complicated influences in the production process. The gallium nitride semiconductor substrate was used as a method to apply the existing mass production process by simplifying the complicated mass production process. A high quality blue light emitting diode is manufactured by optimizing a gallium nitride based thin film stack growth condition on a gallium nitride semiconductor substrate.

FIG. 6 shows an example of an AlGaN / InGaN blue light emitting diode double hetero structure (DH) in which a gallium nitride-based thin film is grown by MOCVD on a gallium nitride semiconductor substrate on which crystals are grown by the HVPE method according to the present invention. As a schematic diagram, referring to this figure, a p-type electrode 61, a p-GaN layer 62 having a thickness of about 0.5 μm, and an Al _0.15 Ga _0.85 N layer having a thickness of about 0.15 μm ( 63), In _0.1 Ga _0.9 N layer 64 having a thickness of about 700 μs, Al _0.15 Ga _0.85 N layer 65 having a thickness of about 0.15 μm, n-GaN layer 66 having a thickness of about 0.25 μm, n- GaN substrate 67, and n-type electrode 68

FIG. 7 is a cross-sectional view of an n-type metal electrode part partially cut along the line A-A 'shown in FIG. 6 and showing an 800 nm thick gold thin film layer 71 having germanium added on an n-GaN substrate 77. ), The nickel layer 72 having a thickness of 500 mW and the gold thin film layer 73 having a thickness of 4000 mW are sequentially formed to form a metal electrode. 8 is a cross-sectional view of the p-type metal electrode part partially enlarged and cut along the line BB ′ shown in FIG. 6. On the p-GaN layer 82, a 200 Å thick gold thin film layer 71, a 700 Å thick beryllium is added, and a 1.2 탆 thick pure gold thin film layer 73 are sequentially stacked to form a p-type metal. Form an electrode.

Referring to the thin film stack of the gallium nitride compound semiconductor on the gallium nitride semiconductor substrate of the present invention with reference to the drawings, first, the gallium nitride semiconductor substrate is chemically washed, and then put into a MOCVD reactor in a hydrogen gas atmosphere 1000 ℃ ~ 1200 ℃ ( Preferably, the substrate is heated at a temperature of about 1100 ° C. for 5 to 15 minutes (preferably 10 minutes) to sufficiently desorb the foreign matter, and then the substrate is nitrided by lowering the temperature to form an ammonia gas atmosphere. Trimethylgallium in the atmosphere is added and thermochemically reacted to perform a surface reaction on the gallium nitride semiconductor substrate.

In order to form a thin film stacked structure as shown in FIG. 6, a buffer layer was formed on the gallium nitride semiconductor substrate at a thickness of 500 to 600 占 폚 (preferably around 520 占 폚) of 200 to 800 占 Å (preferably around 500 Å). The temperature is raised in an ammonia gas atmosphere to form an n-type GaN layer 66 at 1000 ° C to 1100 ° C (preferably around 1050 ° C), and n-type Al at 800 ° C to 900 ° C (preferably around 850 ° C). _{The X} Ga _1-X N layer 65 was laminated and formed at a thickness of 600 to 800 kPa on the n-type Al _X Ga _1-X N layer at 750 ° C. to 850 ° C. (preferably around 800 ° C.). In the In _X Ga _1-X N layer 64, an active layer that simultaneously dopes two types of silicon (Si) and zinc (Zn) atoms is formed or a quantum structure is introduced to use a superlattice. The active layer of the light emitting diode structure can be formed. Then, the p-type Al _X Ga _1-X N layer 63 and the GaN layer 62 are laminated and formed thereon at the same temperature as the n-type.

The n-type GaN layer 66 can be formed by substituting Si atoms for Ga sites using SiH ₄ gas. In general, silicon atoms are similar in size to gallium atoms and are easy to dop with relatively small activation energy. As the flow rate of SiH ₄ increases, the degree of doping increases proportionally. The carrier concentration and electron mobility of the grown n-type GaN layer were 10 ¹⁸ cm ^-3 and 250 cm ² / V · sec, respectively, and the thickness was approximately 2.5 μm.

As a barrier layer that collects electrons and holes in the active layer for luminescent recombination, a cladding is formed by covering an Al _X Ga _1-X N layer having a relatively large energy band gap on both sides of the active layer. Trimethyl aluminum (TMAl) is reacted with TMGa at 1100 ° C. and 300 Torr to form an Al _X Ga _1-X N layer. Flow conditions were TMGa = 15 sccm, TMAl = 9 sccm, NH ₃ = 2000 sccm, H ₂ = 4000 sccm. Aluminum (Al) atoms are relatively small compared to gallium (Ga) atoms, which greatly affects the morphology of the thin film. As the aluminum content increases, it cracks into hexagons to form cracks. The aluminum mole ratio is about 0.15 to avoid the surface morphology phenomenon and to perform the desired barrier role. In addition, SiH ₄ is added and doped to make an n-type Al _X Ga _1-X N layer. The carrier concentration and mobility of the electrons of the grown sample were about 10 ¹⁸ cm ^-3 and 110 cm ² / V · sec, respectively, and the thickness was about 0.15 μm.

An In _X Ga _1-X N layer is grown as an active layer of a light emitting recombination structure having a DH structure. Indium (In) atoms are larger than gallium (Ga) atoms, so the chemical bonding energy is small and the dissociation partial pressure is relatively high. Therefore, since the desorption efficiency of ammonia hydrogen is lowered at a relatively low temperature, nitrogen gas is used as a carrier gas to increase the V / III ratio and reduce dissociation during the chemical reaction of indium.

That is, in order to grow the In _X Ga _1-X N layer, the low TMGa flow rate, high trimethylindium (TMIn) amount, and ammonia gas flow rate were performed under relatively high growth conditions. As the mole ratio of indium increases, the energy band gap decreases to control the wavelength of light emitted upon recombination. However, it is very useful to form an In _X Ga _1-X N layer by increasing the molar ratio. it's difficult. If the molar ratio of optimized indium is 0.1, the growth temperature is 850 ° C, the growth pressure is 300 Torr, and the flow conditions are TMIn = 150sccm, TMGa = 1.5sccm, NH ₃ = 2000sccm, H ₂ = 4000sccm. Growth thickness is 700Å. Characterization by X-ray diffraction experiments of the crystals can grow a good In _X Ga _1-X N layer with a molar ratio of 0.1 as indicated by the double crystal locking curve of FIG. 9.

Silicon and zinc atoms were simultaneously doped to form an emission center of In _0.1 Ga _0.9 N layer. Zinc is doped using a diethyl zinc (DeZn) organometallic source. First, the flow rate of the diethyl zinc is optimized to 2 sccm to maximize the light emission intensity by the acceptor in the energy bandgap, and then the SiH ₄ flow rate is changed to change the electrical characteristics of FIG. 10 and the light emission characteristics PL of FIG. 11. Optimize from. As the SiH ₄ flow rate increases, the electron carrier concentration increases but the electron mobility decreases. In addition, when the amount of zinc and the silicon impurity level are optimized to (DeZn = 2sccm, SiH ₄ = 0.5sccm) as shown in FIG. 11 (a), it exhibits strong emission intensity and is not doped at all as shown in 11 (b). As shown in FIG. 11 (c), it can be seen that the emission intensity is weak even when there are relatively many SiH ₄ (DeZn = 2sccm, SiH ₄ = 0.8sccm). In the state of photoexcitation with a He-Cd laser, light emission of 470 nm is shown as shown in FIG. 12.

To form the p-type Al _X Ga _1-X N layer, a bis-cyclopentadienyl magnesium (Cp ₂ Mg) organometallic source is used as an impurity source of magnesium (Mg). Magnesium atoms with relatively high electrical affinity must be accompanied by high activation energy in order to easily form Mg-H species by reacting with hydrogen during ammonia and surface chemical reactions. As a method for activating p-type by desorption of hydrogen, an electric, optical, or thermal method is possible, and thus, a method of injecting an electron beam, irradiating ultraviolet rays, or performing heat treatment. As the doping amount of magnesium increases, a relatively small amount of magnesium atoms are substituted in place of gallium atoms, thereby deforming the electrostatic potential between crystal lattice, causing stress on the surface, and forming hexagonal cracks. a p-type Al _X Ga _1-X N layer thickness is the same as the n-type Al _X Ga _1-X N layer, and was approximately 0.15㎛.

The p-type GaN layer was also doped with magnesium using a Cp ₂ Mg organometallic source. After finishing the blue gallium nitride based lamination of the DH structure, a rapid thermal annealing process in which a sample is taken out and heated by a halogen lamp is carried out simultaneously in a p-type Al _X Ga _1-X N layer and a p-type GaN layer in a nitrogen atmosphere. Activated by annealing heat treatment for about 10 minutes at a temperature of about 850 ℃. The carrier concentration and mobility of the holes of the p-type GaN layer were about 10 ¹⁷ cm ^-3 and 10 cm ² / V · sec, and the layer thickness was approximately 0.5 μm.

Ohmic contact for attaching metal electrode pads on the n-type and p-type GaN layers can be understood from the transport mechanism of the carrier. In general, in order to form an ohmic contact between the low-resistance semiconductor and the metal interface, a metal having a high work function is adopted to tunnel the potential barrier. In particular, the GaN layer requires a very high work function due to the wide band gap of about 3.4 eV and electron affinity, but due to the limited work function, the depletion of the interface depletion is increased by increasing the carrier concentration on the semiconductor / metal interface. The width can be reduced to improve the tunneling of the carrier.

In order to form an n-type ohmic state, as shown in FIG. 7, a gold (Au) layer 71 containing 2% germanium (Ge), which is an n-type impurity, is deposited to a thickness of about 800 Å and to aid in ohmic contact of germanium. The pure nickel (Ni) metal thin film layer 72 serving as a gettering layer (72) is laminated to a thickness of about 500 kPa, and the gold thin film (73) is sequentially laminated to a thickness of about 4000 kPa, and then the temperature of about 500 ° C. Heat treatment at to form ohmic contact. As shown in FIG. 8, first, the gold thin film layer 83 is thermally deposited to a thickness of about 200 μs, and the gold thin film layer 84 containing 12% beryllium (Be), which is a p-type impurity, is laminated again by about 700 μs. The gold thin film layer 85 is formed thereon and subsequently deposited to a thickness of about 1.2 mu m, and heat treated at a temperature of about 500 deg. C under a nitrogen atmosphere. The ohmic characteristics according to the heat treatment temperature are shown in FIG. 13. Referring to the ohmic characteristic diagram of FIG. 13, it can be seen that a schottky effect is shown at a relatively low temperature, but a good ohmic state is shown at a temperature of approximately 500 ° C. FIG.

FIG. 14 is a diagram showing current-voltage characteristics of a double-hetero blue LED, and a forward bias of about 6 volts (V) is applied at a current of 20 mA. Fig. 15 shows the light emission characteristics of the electroluminescence giving a brightness of 0.5 candela (cd) after wire bonding in a light emitting diode chip having a size of 0.3 mm x 0.3 mm in a bias state of 8 volts (V) and 20 mA. It is a picture showing.

As described above, according to the gallium nitride-based blue light emitting diode manufacturing method on the gallium nitride semiconductor substrate according to the present invention, the difference in lattice constant between the substrate and the multilayer thin film growth layer by using the same type of GaN semiconductor bulk Since the thermal expansion coefficient does not show any difference, there is little lattice defect in the shape of the humanoid dislocation in the thin film layer, and it is possible to prevent distortion of the electronic state due to the defect, thereby improving the crystal characteristics and the electrical and optical properties. Brings improved reliability in manufacturing.

Also, unlike the case of using a conventional sapphire substrate that is dry-etched to the n-GaN plane in order to form n-type metal electrodes horizontally from the top like the p-type electrode, the upper part of the n-type and p-type GaN planes at both ends, The mass production process can be simplified by the method of the present invention for forming the lower electrode surface, respectively. That is, the silicon oxide film or silicon nitride film for dry etching can greatly reduce the deposition of the shadow mask, the etching process of the mask, and the complex combination of the mask during electrode formation, and can be applied to the existing mass production technology as it is. have. By forming electrodes on both sides of the upper and lower sides, the work process is simplified, and the light emitting area of the device is not reduced as well as an efficient mass production process, thereby providing an effect of directing a relatively high quality device.

Claims (10)

Multi-layered gallium nitride-based thin film without stress strain due to lattice mismatch or thermal expansion through gallium nitride semiconductor substrate formed by forming a gallium nitride bulk layer on a silicon substrate by a gallium nitride bulk layer A gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate, wherein n-type and p-type metal electrodes are formed on the lower part of the gallium nitride semiconductor substrate and the upper layer of the multi-layer gallium nitride-based thin film layer, respectively. Manufacturing method. The method of claim 1, wherein the multi-layer gallium nitride-based thin film formed on the n-type gallium nitride semiconductor substrate is n-type GaN buffer layer, n-type Al _X Ga _1-X N layer, In _X Ga _1-X N layer, A method of manufacturing a gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate, characterized in that the p-type Al _X Ga _1-X N layer and the p-type GaN layer is formed in a stack. The gallium nitride semiconductor substrate of claim 1, wherein a small amount of silicon ingot is added to the gallium ingot to form an n-type substrate doped with silicon on the gallium nitride substrate by hydrogen phase vapor deposition. Gallium nitride semiconductor substrate comprising mechanically polishing roughness to a diamond grain size of 10 μm, 6 μm, 1 μm and 1/10 and wet etching the gallium nitride substrate surface in a KOH solution. Method of manufacturing a gallium nitride-based blue light emitting diode using. The nitride-based gallium nitride semiconductor substrate according to claim 2, wherein the n-type GaN buffer layer formed on the gallium nitride semiconductor substrate is formed in the high frequency MOCVD reactor at a thickness of about 200 to 800 Pa at a low temperature of 500 to 600 ° C. Method of manufacturing a gallium-based blue light emitting diode. The n-type GaN buffer layer is formed in the high frequency MOCVD reactor at a temperature of 2-3 μm at 1,000 ° C.-1,100 ° C. by raising the temperature in an ammonia gas atmosphere, and the n-type Al _X Ga _1-X N. The layer is formed on the n-type GaN layer at a temperature of 800 ℃ to 900 ℃ to a thickness of about 0.1-0.2㎛, n-type impurity doped gallium nitride-based blue using a gallium nitride semiconductor substrate, characterized in that each using a SiH ₄ gas Method of manufacturing a light emitting diode. The Al _X Ga _1-X N layer has a thickness of 600 Pa-800 Pa over the n-type Al _X Ga _1-X N layer at a temperature of 750 ° C.-850 ° C. in an ammonia gas atmosphere in the high frequency MOCVD reactor. And a gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate, wherein the active layer is formed by simultaneously doping silicon and zinc atoms to form a light emitting center. The Al _X Ga _1-X N layer has a thickness of 600 Pa-800 Pa over the n-type Al _X Ga _1-X N layer at a temperature of 750 ° C.-850 ° C. in an ammonia gas atmosphere in the high frequency MOCVD reactor. And a gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate, wherein the active layer is formed using a superlattice that periodically changes the indium molar ratio x so as to form a light emitting center. . The method of claim 2, wherein the p-type Al _X Ga _1-X N layer is laminated on the Al _X Ga _1-X N layer to a thickness of about 0.1 to 0.2㎛ at 800 ℃ to 900 ℃ temperature of ammonia gas atmosphere In addition, a p-type GaN layer is laminated on the p-type Al _X Ga _1-X N layer at a thickness of 2-3 μm at 1,000 ° C.-1,100 ° C., and each p-type impurity doping is performed using the organic metal source Cp 2 Mg. A method of manufacturing a gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate, characterized in that the magnesium (Mg) atoms are laminated and implanted in the Al _X Ga _1-X N layer and the GaN layer. 8. The method of claim 7, wherein the p-type In _X Ga _1-X N layer and the p-type GaN layer doped with magnesium (Mg) at the same time at a temperature of about 800 ℃ to 900 ℃ in a rapid heat treatment apparatus equipped with a halogen lamp A method of manufacturing a gallium nitride-based blue light emitting diode using a gallium nitride semiconductor substrate characterized in that the heat treatment for -15 minutes to activate magnesium ions. 2. The n-type metal electrode of claim 1, wherein the n-type metal electrode is formed by sequentially stacking a gold thin film layer, a nickel layer, and a gold thin film layer to which germanium, which is n-type impurity, is added, at a predetermined thickness under the n-GaN substrate. A blue light emitting diode manufacturing method using a gallium nitride semiconductor substrate.