TW201203606A - GaN substrate and light-emitting device - Google Patents

Abstract

The present GaN substrate can have an absorption coefficient not lower than 7 cm-1 for light having a wavelength of 380 nm and light having a wavelength of 1500 nm, an absorption coefficient lower than 7 cm-1 for at least light having a wavelength not shorter than 500 nm and not longer than 780 nm, and specific resistance not higher than 0.02 Ω cm. Here, the absorption coefficient for light having a wavelength not shorter than 500 nm and not longer than 780 nm can be lower than 7 cm-1. Thus, a GaN substrate having a low absorption coefficient for light having a wavelength within a light emission wavelength region of a light-emitting device and specific resistance not higher than a prescribed value and being suitable for the light-emitting device is provided.

Description

201203606 VI. Description of the Invention: [Technical Field] The present invention relates to a GaN substrate having high transmittance of light in a red light region or a blue to red visible light region and having high conductivity, and includes the same A light-emitting device of a G aN substrate. [Prior Art] As a substrate used in a light-emitting device, a substrate having a high light transmittance and high conductivity is being sought. For example, Japanese Patent Laid-Open Publication No. Hei. No. 2,213,075 (Patent Document 1) discloses a substrate having an absorption coefficient of 7 cm-L68 111^ for light having a wavelength of 375 nm to 5 〇〇 nm. Japanese Patent Publication No. 2007-i26320 (Patent Document 2) discloses an inner valley in which a TiN thin film having a plurality of fine pores is formed on a substrate, and impurities other than Si are prevented from being mixed on the TiN thin film. Method for growing (4) crystallization (this method is called VAS (Void-Assisted Separation)), and a GaN substrate having an absorption coefficient of less than 7 cm-1 for light having a wavelength of 380 nm or more is obtained [Prior Art Document] [ [Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-213075 [Patent Document 2] Japanese Patent Laid-Open No. 2007-126320 (Summary of the Invention) [Problems to be Solved by the Invention] However, the transmittance of light The conductivity is self-contradictory. If the impurity in the substrate is reduced in order to increase the transmittance of light, the conductivity is lowered. If the conductivity is increased and the impurity in the substrate is increased, the penetration of light is increased. Rate reduction β In JP-A-2005-213075 (Patent Document 1), in order to maintain specific conductivity, the absorption coefficient of light having a wavelength of 375 nm to 500 nm can be reduced to about 7 cm·1. JP-A-2007-126320 (Patent Document 2) discloses a GaN substrate which maintains specific conductivity and has an absorption coefficient of less than 7 cm·1 for light having a wavelength of 38 〇 nm or more, but the substrate is used. The above-mentioned special method called VAS method is very expensive, and the substrate for the light-emitting device has a lower absorption coefficient for the light of the wavelength in the wavelength region of the light emission, and does not need to be outside the wavelength region of the light-emitting region. The light of the wavelength also has a lower absorption coefficient. Therefore, in view of the above, an object of the present invention is to provide a light absorption coefficient of a wavelength in a wavelength region of a light-emitting device that has a lower absorption coefficient and has a specific value or less. a specific resistance, a GaN substrate suitable for the light-emitting device, and a light-emitting device including the GaN substrate. [Technical means for solving the problem] According to a certain aspect, the present invention is a GaN substrate, the needle thereof The absorption coefficient of light with a wavelength of 380 nm and light of a wavelength of 1500 nm is 7 cm-〗 or more, and the absorption coefficient of light having a wavelength of more than 500 nm and below 780 nm is less than 7 cm·1 ' and the specific resistance is 〇. 〇2 Qcm or less. In the GaN substrate of the present invention, the absorption coefficient for light having a wavelength of 44 〇 nm or more and 780 nm or less can be set to less than 7 cm-i. Further, according to other aspects, the present invention is a A light-emitting device comprising the above GaN substrate, and having a peak wavelength of 5 〇〇 nm or more and 78 〇 nma 155086.doc 201203606. The absorption coefficient of the GaN substrate for light having a wavelength of 380 nm and light having a wavelength of 1500 nm is 7 For cm·1 or more, the absorption coefficient of light having a wavelength of 500 nm or more and 780 nm or less is less than 7 cm·1, and the specific resistance is 〇.02 Qcm or less. According to another aspect, the present invention is a light-emitting device comprising the above GaN substrate, and the peak wavelength of the light emission is 440 nm or more and 780 nm or less. The GaN substrate has a wavelength of 38 nm and a wavelength of 1500 nm. The absorption coefficient of light is 7 cm· or more, and the absorption coefficient of light having a wavelength of 440 nm or more and 780 nm or less is less than 7 cm·1, and the specific resistance is 〇.〇2 Qcm or less. [Effects of the Invention] According to the present invention, it is possible to provide a GaN substrate having a lower absorption coefficient for light having a wavelength in a wavelength region of light emission of a light-emitting device and having a specific resistance or less, and a GaN substrate suitable for the light-emitting device and A light emitting device including the GaN substrate. [Embodiment] [GaN substrate] The absorption coefficient of the GaN substrate of the present invention for light having a wavelength of 380 nm and light having a wavelength of 1500 nm is 7 cnf1 or more, and at least for light having a wavelength of 5 〇〇 nm or more and 780 nm or less. Less than 7 cm", and the specific resistance is 〇.〇2 Qcrn or less. Here, the absorption coefficient of light is calculated by measuring the transmittance and reflectance of light of a target wavelength using a spectrophotometer. Further, the specific resistance was measured by a four-probe method using a specific resistance meter. The GaN substrate is preferably used as a GaN substrate of a light-emitting device having a peak wavelength of at least 5 〇〇 155086.doc 201203606 and 780 nm or less. Hereinafter, a more specific embodiment will be described. (Embodiment 1) The GaN substrate of the present embodiment has an absorption coefficient of 7 cm'1 or more for light having a wavelength of 380 nm and light having a wavelength of 1500 nm, and an absorption coefficient of light having a wavelength of 500 nm or more and 780 nm or less is less than 7 Cm", and the specific resistance is 0.02 Qcm or less. The GaN substrate of the present embodiment is preferably used as a substrate of a light-emitting device having a red light region having a peak wavelength of 500 nm or more and 780 nm or less. From this point of view, the absorption coefficient for light having a wavelength of 500 nm or more and 780 nm or less is preferably 5 cm·1 or less. Further, the specific resistance is preferably 0.015 Hem or less. (Embodiment 2) The absorption coefficient of the GaN substrate of the present embodiment is 7 cm·1 or more for light having a wavelength of 380 nm and light having a wavelength of 1500 nm, and the absorption coefficient of light having a wavelength of 440 nm or more and 780 nm or less is not reached. 7 cm•丨, and the specific resistance is 〇〇2 Hem or less. The GaN substrate of the present embodiment is preferably used as a substrate of a light-emitting device having a peak wavelength of 440 nm or more and a wavelength of 780 nm or less to a visible light region of a red light region. From this point of view, the absorption coefficient for light having a wavelength of 440 nm or more and 780 nm or less is preferably 5 cm-i or less. Further, the specific resistance is preferably 0.015 fiem or less. The carrier concentration of the GaN substrate according to any of the above embodiments is preferably 5 χ 1 〇 π cm · 3 or more and 2 χ 1 〇ΐ 8 cm · 3 or less. If the carrier concentration is too low, the specific resistance becomes too large. If the carrier concentration is too high, the absorption coefficient of light becomes too large. In terms of opinion, the carrier concentration is preferably 7xl 〇" cm_3 or more, llxl〇u 155086.doc 201203606 or less. Here, the carrier concentration was measured using a Cv characteristic (Current v〇hag < eharacteristic) measurement method. The average density (referred to as the average dislocation density, which is the same as τ) of the GaN substrate of any of the above embodiments which is displaced from the main surface is preferably 3 xi 〇 6 cm Å or less. The lower the average density of the misalignment, the more reliable the illuminating device can be obtained. From this point of view, the average density (average misalignment density) of the misalignment passing through the main surface is more preferably lxl 〇 6 cm -2 or less. Further, from the viewpoint of the manufacturing technique of the current substrate, the average density (average misalignment density) of the misalignment passing through the main surface is hardly less than 10 cm·2 at the present stage, so it is about 1 〇 cm 2 or more. The average density of the misalignment of the principal plane of the 9 GaN substrate was calculated from the measurement of the blind spot density of CL (Cathode luminescence 'cathode luminescence). The GaN substrate according to any of the above embodiments preferably has a flat main surface, and a crystal face having a crystal surface closest to the main surface has a radius of curvature of 1 〇 m or more. The larger the radius of curvature of the crystal plane, the more the light-emitting device having a uniform wavelength of light in the plane of the substrate can be obtained. From this point of view, the radius of curvature of the crystal face closest to the main surface is more preferably 20 m or more. Moreover, from the viewpoint of the current manufacturing technique of the substrate 5, the radius of curvature of the crystal face closest to the main surface is hardly larger than 100 m at this stage, so it is about 100 Å! or so. The crystal which is closest to the main surface of the GaN substrate. The radius of curvature of the surface is measured by X-ray diffraction which is the crystal plane of the object. The crystal surface closest to the main surface of the GaN substrate is not particularly limited, but the crystal growth of the main surface is higher. From the viewpoint of high semiconductor layer, δ is preferably {0001} plane, {10-10} plane, surface, 1550 secret.doc 201203606

Face, {11-22} face, {20-21} face, {22-44} face, etc. Further, from the viewpoint of the semiconductor layer having a high growth crystallinity on the main surface of the GaN substrate, the absolute value of the off angle of the main surface of the GaN substrate with respect to the crystal face is preferably 5. the following. Here, the plane orientation of the crystal plane closest to the GaN substrate and the deviation angle between the main surface and the crystal plane are measured by X-ray diffraction. [Manufacturing Method of GaN Substrate] Fig. 1 is a schematic cross-sectional view showing an example of a method of producing a GaN substrate of the present invention. The method for producing the GaN substrate of the present invention is not particularly limited, and the step of preparing the base substrate 丨丨, the step of growing the GaN crystal 12 to which the impurity is added on the base substrate 丨i, and the GaN crystal 12 are performed with reference to FIG. 1 ' The step of forming the GaN substrate 1 by processing. In this manufacturing method, the GaN substrate 1 of the present embodiment is obtained at a low cost by adjusting the concentration of impurities (referred to as dopants, hereinafter the same) added to the GaN crystal 12. (Step of Preparing the Base Substrate) Referring to FIG. 1(A), the base substrate 11 prepared in the step of preparing the base substrate 11 is not particularly limited as long as it is a substrate capable of growing the GaN crystal 12 by the insect crystal, but is crystallized with GaN. From the viewpoint of high lattice alignment, a (Si) base substrate, a sapphire (A1203) base substrate, a GaAs base substrate, and a π-based nitride base substrate such as a GaN base substrate and an A1N base substrate are preferably used. 'The GaN base substrate is particularly well used. It is preferable to use a GaN base substrate to suppress the incorporation of impurities from the base substrate. From this point of view, the cleanliness of the surface of the base substrate is important. In particular, the back surface of the base substrate (the 155086.doc 201203606 surface of the base substrate that is in contact with the inner wall of the growth furnace, the same applies hereinafter) cannot be etched in the growth furnace before the crystal growth, so the cleanliness must be improved before being put into the growth furnace. . Therefore, it is preferable to etch the back surface of the substrate and then put it into the growth furnace. Examples of the etching method include wet etching of an indicating solvent, dry etching of a halogen-based gas, and the like. (Step of growing GaN crystals with impurities added) Referring to FIG. 1(A), the method of growing the GaN crystal 12 to which impurities are added to the base substrate yoke is not particularly limited as long as it can be epitaxially grown, but From the viewpoint of growing GaN crystal 12 having high crystallinity, HVPE (Hydride Vapor Phase Epitaxy) method, MOCVD (Metal Organic Chemical Vapor Deposition) method, MBE is preferable. A gas phase method such as a molecular beam epitaxy (M〇lecuUr Beam Epitaxy) method, and a HVPE method is particularly preferable from the viewpoint of a high crystal growth rate. In the HVPE method, it is usually grown in a quartz reaction tube, so that the crystal in the quartz reaction tube is heated, so that the quartz reaction tube is also heated together with the crystal. Therefore, the decomposition gas from the quartz reaction tube heated to a high temperature is crystal-absorbed as an impurity. Therefore, it is preferable to cover the inside of the quartz reaction tube with a liner formed of a material which is stable at a growth temperature (e.g., pBN (thermal decomposition nitride shed)). Further, it is preferred to flow a flushing gas (e.g., H2, N2, and/or Ar) which flushes the gap between the quartz reaction tube and the liner so that impurities do not remain. Further, since the crystal holder on which the base substrate is placed also becomes high temperature, it is preferable to form the crystal holder with pBN, or use PBN, A1N,

A highly pure and stable material such as Al2〇3 or SiC is applied to the surface of the crystal holder. 155086.doc 201203606

The impurity (dopant) to be added to the GaN crystal 12 is not particularly limited, but is preferably Si from the viewpoint that the decrease in the absorption coefficient of light is small and the specific resistance is low. Further, the method of adding the GaN crystal 12 is not particularly limited. However, as the doping gas, it is preferable to use a gas containing 8 Å, for example, a gas of SiF yttrium tetrafluoride, a gas of S1H4 (decane), or a gas. Dioxane gas, si^ci gas, Sil^Cl2 gas, SiHCi3 gas, sicu gas, etc. Use SiF4 gas. The SiF4 gas is more difficult to decompose than the other gases containing Si, even if it is at a temperature below 9 Torr, and can be efficiently added to the GaN crystal 12. For example, a method of growing GaN crystal 12 in which Si is added as a dopant by the HVPE method will be described below. Fig. 2 is a schematic view showing an example of an HVPE device used for the growth of the GaN crystal 12. Referring to Fig. 2, the HvpE apparatus includes a first material gas storage tank, a doping gas storage tank 2, a second material gas storage tank 103, a first gas introduction pipe 1〇4, a doping gas introduction pipe 105, and a second gas. The introduction tube 6, the ship type disk 1〇7, the crystal holder 1〇8, the heater 109, the reaction tube 11〇, the exhaust pipe m, and the exhaust gas treatment device. The hvpe device 100 is set, for example, to a horizontally placed reaction tube. Further, the HVPE device 1 can also be an upright reaction tube. The reaction tube 110 is for holding the base substrate U therein and growing a container of the GaN crystal 12 on the base substrate 11. For the reaction tube no, for example, a quartz reaction tube or the like can be used. Further, a liner 120 made of pBN was placed inside the reaction tube 11A. Raw materials containing elements constituting the grown GaN junction 155086.doc 10 201203606 are supplied to the first material gas storage tank 1〇1, the second material gas storage tank 103, and the ship type disk 1〇7, respectively. The doping gas storage tank 102 is filled with, for example, a gas containing Si, which is a dopant gas. The first gas introduction pipe 〇4, the doping gas introduction pipe 105, and the second gas introduction pipe 1〇6 are disposed in the reaction. Each of the first material gas G1, the dopant gas G2, and the second material gas G3 is introduced into the inside of the reaction tube 110. The ship type disk 1〇7 accommodates and holds, for example, metal Ga as GaN crystal. The metal material is disposed in the second gas introduction tube 106. The surface of the crystal holder 108 is coated by a film made of pBN, and the base substrate 11» is held in the reaction tube 110 to be used by the crystal holder 1〇8. The crystal holder 1〇8 is disposed so that the surface of the base substrate 丨丨 is positioned below the first gas introduction tube 104, the doping gas introduction tube 1〇5, and the second gas introduction tube 106. The crystal holder 1〇8 is placed horizontally The pedestal 1 〇 8 is configured to horizontally arrange the main surface of the base substrate 11 in FIG. 2, but the main surface of the base substrate may be vertically disposed. Further, the HVPE device 1 〇 The crucible may further include a partial heating for the heating of the base substrate The heater 109 is disposed outside the reaction tube ho and has the entire inside of the reaction tube (7) heated to, for example, 700. (: above, i50 (capacity of rc or less. The exhaust pipe 111 is provided on the reaction tube 110, The gas after the reaction is discharged to the outside of the reaction tube 110. The exhaust gas treatment device is configured to detoxify the reaction gas discharged from the exhaust pipe 1U to reduce the load on the environment. As shown in Fig. 2, first, The prepared base substrate 丨丨 is held on the crystal holder 108. At this time, the plurality of base substrates u can be held on the crystal holders 1 to 8. Next, NH3 (ammonia) as a second raw material gas is prepared to be filled. Gas 155086.doc •11-201203606 and the i-th material gas storage tank 101 and the second raw material fluorine storage tank 1〇3 as the HC1 (gasification hydrogen) gas of the second material gas. Further, the metal is supplied to the ship type dish.

Ga. Further, a doped gas storage tank 102 in which a SiF > 4 gas as a doping gas is filled is prepared. Thereafter, the ship type dish 107 is heated. Then, the HC1 gas (the second material gas G3) supplied from the second gas introduction pipe 106 and the metal Ga of the ship type disk 107 are reacted to generate GaC1 (gallium gas) gas (reaction gas G7). The NH 3 gas (first material gas G1), the S1F4 gas (doping gas (}2), and the GaCl gas (reaction gas G7) supplied from the first gas introduction pipe 1〇4 are formed on the main surface of the base substrate 11. The contact flows into (supply) and causes the reaction to occur, etc. At this time, a carrier gas for transporting the gases to the base substrate 11 may be used. For example, N2 (nitrogen) gas, h2 (hydrogen) may be used as the carrier gas. An inert gas such as a gas or an Ar (argon) gas. In the HVPE method, the heater 1〇9 is used to heat the inside of the reaction tube 11 to a temperature at which the GaN crystal 12 is grown at an appropriate rate. It is 900. (: Above, 13 〇〇. (: The following is more preferably 1 〇 5 〇〇 c or more and 1200 ° C or less. When GaN crystal 12 is grown at 90 〇 t: or more, GaN crystal can be prevented from crystallizing (12) A defect is generated, and a surface having a plane orientation different from a surface orientation in which the growth is made on the crystal growth surface can be suppressed (for example, when the surface orientation of the growth surface is the same, the surface orientation different from (〇〇〇1) is obtained. a facet and a pit formed by the facet, etc.), that is, for crystal growth The GaN crystal 12 having good crystallinity can be stably grown in the surface orientation of the growth. When the GaN crystal 12 is grown at a temperature of 10 Å or more, the crystallinity can be further improved. 13〇〇.匸The following makes 155086.doc •12· 201203606

When the GaN crystal 12 is grown, it is possible to suppress the growth of the (four) crystal by decomposition, so that deterioration of crystallinity can be suppressed. In the case where the GaN crystal 12 is grown in the range of rc or less, deterioration of crystallinity can be further suppressed. Here, the crystal growth surface of the grown GaN crystal preferably has a tilt angle from the (0001) plane. In the GaN crystal, the tilt angle of the crystal growth surface from the (〇〇〇1) plane is less than i, and the absorption of impurities other than the dopant gas in the crystal growth surface can be suppressed. The inclination angle of the surface of the growth surface from the (0 0 01) plane is less than i. Preferably, the crystal growth temperature is set to llGGt: or more, and the inflow mode of the raw material gas, the carrier gas, and the dopant gas is The flow rate is optimized to be approximately the entire area of the crystal growth surface (80% or more to 1% 0%), so that the inclination angle from the (〇〇〇1) surface is less than 1.

The partial pressure of the gas containing Si (SiF4 gas) when the GaN crystal 12 grows is preferably 2.0 <10-73, and 1.0><10-53 or less. When the partial pressure of the gas containing 81 (Sih gas) is 2·〇χ1〇-7 atm or more, Si which is an n-type dopant is sufficiently absorbed by the GaN crystal 12. On the other hand, when the partial pressure of the gas (SiF4 gas) is h〇xi〇·5 atni or less, the generation of the SixNy (nitridium nitride)-based compound can be further suppressed, so that it can be further favorably controlled. Doping conditions when Si is doped in GaN crystal 12. Also, if you consider

The concentration of Si doped in the GaN crystal 12 contains a partial pressure of "gas? (??? gas) of 1.00 x 5 · 5 atm. Further, the reaction of the material gas, the carrier gas, the doping gas, and the like The total partial pressure of the gas contained in the tube 110 (total) is 1 atm. The concentration of the gas containing Si (SiF4 gas) is proportional to the partial pressure. 155086.doc •13· 201203606 Adding impurities to the growth In the step of crystallizing GaN, the carrier concentration in the GaN crystal 12 is preferably 5×10 17 cm·3 or more and 1.5×10 18 cm·3 or less (corresponding to a Si concentration of 5×1ο17 cm·3 or more and 1.6×10 18 cm·3 or less). The doping gas is supplied to the base substrate 11 in such a manner that it is preferably 6·6χ10η cnT3 or more and l.lxlO18 Cm·3 or less (corresponding to a Si concentration of 6.9×10 17 cm·3 or more and l.lxl〇u cm·3 or less). When the carrier concentration is 5×10 17 cnT3 or more, the specific resistance of the GaN crystal 12 can be reduced to sufficiently ensure conductivity. When the carrier concentration is 6.6×10 17 cm·3 or more, the specific resistance of the GaN crystal 12 can be further reduced. The conductivity is more fully ensured. On the other hand, the carrier concentration is 1_5xlO18 cm·3. In the following cases, the absorption coefficient of light of GaN crystal can be reduced to sufficiently ensure the transmittance of light. When the carrier concentration is 1.1 X 1018 cm-3 or less, the absorption of light of GaN crystal can be further reduced. Further, the light transmittance is more sufficiently ensured. Further, the doping amount of impurities (oxygen, carbon, etc.) other than Si is preferably 1/5 or less, more preferably 1/10 or less, more preferably 1/10 or less. In the step of growing the GaN crystal 12 having impurities, the GaN crystal 12 is grown so that the specific resistance of the GaN crystal 12 is 〇.〇2 Qcm or less, preferably 0.015 Qcm or less. When the specific resistance is 〇.〇2 Qcm or less, the GaN crystal 12 having conductivity which is preferably used for the substrate of the light-emitting device can be grown. When the specific resistance of the GaN crystal is 〇.〇丨5 Qcm or less In the step of growing the GaN crystal 12 having impurities, in the step of growing the GaN crystal 12, the absorption coefficient of light having a wavelength of 5 〇〇 nm or more and 78 〇 nn or less is not GaN crystals are grown in a manner up to 7 cm.1 '5 cm·丨. 155086.doc . 14- 201203606

When the absorption coefficient of light of light having a wavelength of 500 nm or more and 780 nm or less is less than 7 cm-1, the GaN crystal 12 is preferably used for a peak wavelength of light emission when it is preferably 5 cm·1 or less. It is a substrate of a light-emitting device of 500 nrn or more and 780 nm or less. In the step of growing the GaN crystal 12 with impurities added, in the case of the GaN crystal 12, the absorption coefficient of light for a wavelength of 440 nm or more and 78 Å nm is less than 7 cm·1 ', preferably 5 cm - i grow GaN crystals in the following manner. When the absorption coefficient of light of light having a wavelength of 440 nm or more and 780 nm or less is less than 7 cnT1, the GaN crystal 12 is preferably used for luminescence with a peak wavelength of 44 when it is preferably 5 cm-i or less. A substrate of a light-emitting device of 〇 nm or more and 78 〇 nm or less. In the step of growing the GaN crystal to which the impurity is added, the GaN crystal 丨2 is grown so that the average density of the misalignment in the GaN crystal ruthenium 2 is preferably 3×10 6 cm −2 or less, more preferably 1×10 〇 6 cm·2 or less. By processing the GaN crystal, it is easy to obtain a GaN substrate having an average density of 3X10 Crn or less, more preferably 1×10 6 cm-2 or less, which is displaced from the main surface 12m. The average density of the dislocations in the GaN crystal 12 and the average density (average dislocation density) of the misalignment of the main surface 12m penetrating the GaN substrate are calculated based on the measurement of the blind spot density of cl (cathode luminescence). Fig. 1(A) 'In the step of growing the GaN crystal 12 with impurities added, the ruth is preferably the main surface Ilm from the {0001} plane, the {10-10} plane, and the {11-2 〇 plane (4)- (1) The surface of the (1)·22) surface, the {20-21} plane, and the {22-44} plane have an absolute value of the off-angle of 5 〇 or less of the claw-type nitride substrate (base substrate U). The main surface 12m is from {0001} face, {10-155086.doc -15- 201203606 10} face, {11^20} face, {10-11} face, {11-22} face, {20-21} face And the absolute value of the off angle of any of the {22-44} faces is 5. The following GaN crystals 12 . The main surface 10m is easily obtained from the {0001} plane, the {10-10} plane '{11-20} plane, the {10-11} plane, the {11-22} plane, the ΡΟΗ } plane, and the { 2244} The absolute value of the off angle on either side of the face is 5. The following GaN substrate 10 is used. (Step of Forming GaN Substrate by Processing GaN Crystal) The step of forming the GaN substrate 10 by processing the obtained GaN crystal i 2 to which impurities are added is not particularly limited, and may include removing the substrate. Sub-steps of the substrate 11. The method of removing the base substrate Π is not particularly limited, and there is a method of cutting by a peripheral blade, an inner peripheral blade, a wire saw, a laser or the like, and a method of polishing by a diamond grinding wheel or the like. In this way, a GaN crystal 12 having main surfaces 12m, 12n is obtained. The step of processing the GaN crystal 12 to form a GaN substrate 1 ) further includes a sub-step of slicing the GaN crystal 12 . The method of (4) crystallization (4) dicing is not particularly limited, and there is a method of cutting by a peripheral knife, an inner peripheral blade, a saw, a laser or the like. Further, it may include a method of grinding and/or surface-treating the main surface of the sliced G £ crystal 12 to the main surface of the GaN crystal 12, and twisting the method of ordering, for example, a machine.

Grinding, chemical mechanical grinding, square 4tl ^ XT A L Q 5 search method. For the method of treating the main surface of the GaN crystal 12, for example, there is a dry am# method. Processing the GaN crystal 12 to form g may include the step of removing GaN (4). ...the sub-step of the outer edge of the day 12 is removed from the outer edge of the crystal 12 _ method is not made (four), there is #彳 155086.doc -16- 201203606 The method of grinding, etc. Obtaining one or more substeps by one or more of the above GaN crystals 12

GaN substrate 10. In the GaN substrate 10 of the present embodiment obtained by the above-described method for producing a GaN substrate, the average density (average displacement density) of the displacement across the main surface is preferably 3 x 16 cm 2 or less, more preferably 〇6 cm-2 or less. The lower the average density of the misalignment, the more reliable the illuminating device can be obtained. Further, from the viewpoint of the manufacturing technique of the current substrate, the average density of the misalignment passing through the main surface is hardly less than 1χ1〇4 cm·2 at the present stage, so it is about 1×104 cm-2 or more. Further, in the GaN substrate of the present embodiment obtained by the above-described method for producing a GaN substrate, the main surface is preferably flat, and the crystal face having the closest surface to the main surface has a radius of curvature of 10 m or more, more preferably 2 〇m or more. The larger the radius of curvature of the crystal face, the more the in-plane uniformity of the emission wavelength can be obtained. In addition, from the viewpoint of the manufacturing technology of the current substrate, the radius of curvature of the crystal face closest to the main surface is At this stage, it is difficult to be larger than 100 m, so it is about 1 〇〇 m or less. [Light-emitting device] Fig. 3 is a schematic cross-sectional view showing an example of a light-emitting device of the present invention. Referring to Fig. 3, the light-emitting device of the present invention includes the GaN substrate 10' of the first embodiment or the second embodiment, and has a peak wavelength of light emission of 500 nm or more, 780 nm or less, 440 nm or more, and 780 nm or less. The light-emitting device of the present invention is directed to light having a wavelength region of 500 nm or more, 780 nm or less, or 440 nm or more and 780 nm or less, and the light absorption coefficient in the substrate is low, and the luminous efficiency is high. 155086.doc -17-201203606 Referring to Fig. 3, more specifically, the light-emitting device of the present invention includes the GaN substrate 10 of the first embodiment or the second embodiment, and at least 1 formed on one main surface 10m of the GaN substrate 1 The semiconductor layer 20 of the layer, the first electrode 30 formed on the outermost layer of the semiconductor layer 20, and the second electrode 40 formed on the other main surface 10n of the GaN substrate 10. This light-emitting device includes a light-emitting layer in the semiconductor layer 2, and emits light from the side of the GaN substrate 10. Hereinafter, a more specific embodiment will be described. (Embodiment 3) Referring to Fig. 3, the light-emitting device of the present embodiment includes light having an absorption coefficient of light having a wavelength of 38 〇 nm and light having a wavelength of 1500 nm of 7 cm or more, and light having a wavelength of 500 nm or more and 780 nm or less. a GaN substrate having an absorption coefficient of less than 7 cnT1 and a specific resistance of 〇.〇2 Qcm or less; at least one semiconductor layer 2 formed on one main surface 10m of the GaN substrate 10; formed in the semiconductor The first electrode 30 on the outermost layer of the layer 20; and the second electrode 40 formed on the other main surface 10n of the GaN substrate 10; and the peak wavelength of the light emission is 500 nm or more and 780 nm or less. (Embodiment 4) Referring to Fig. 3, the light-emitting device of the present embodiment includes an absorption coefficient of 7 cm or more for light having a wavelength of 3 8 〇 nm and light having a wavelength of 1500 nm, and a wavelength of 440 nm or more and 780 nm or less. a GaN substrate having a light absorption coefficient of less than 7 cm -1 ' and a specific resistance of 0.02 Ω οηη or less; at least one semiconductor layer 2 形成 formed on one main surface 10 m of the GaN substrate 10; formed on the semiconductor layer 20 The first electrode 30 on the outermost layer; and the second electrode 40 formed on the other main surface 10n of the GaN substrate 10; and the light-emitting 155086.doc • 18· 201203606 peak wavelength is 440 nm or more and 780 nm or less . In the light-emitting devices of the third embodiment and the fourth embodiment, the wavelength region and the peak wavelength of the light emission can be changed by changing the chemical composition and/or configuration of the semiconductor layer 20. [Manufacturing Method of Light-Emitting Device] The method for producing the light-emitting device of the present invention is not particularly limited. For example, referring to FIG. 3', the step of preparing the GaN substrate 1 of the first embodiment or the second embodiment is performed on one main surface of the GaN substrate 10. a step of forming at least one semiconductor layer 20 thereon, a step of forming the ith electrode 30 formed on the outermost layer of the semiconductor layer 20, and forming a second electrode 40 on the other main surface 1 〇n of the GaN substrate 10. The steps. Here, form the first! The order of the steps of the electrode 3 and the step of forming the second electrode 40 may be reversed. Thereby, the light-emitting device of the third embodiment or the fourth embodiment is obtained. (Step of Preparing GaN Substrate) The method of preparing the GaN substrate of Embodiment 1 or Embodiment 2 is as described above for the method of manufacturing the GaN substrate. (Step of Forming At least One Layer of Semiconductor Layer on GaN Substrate) The method of forming at least the germanium layer on at least one main surface 1 〇m of the GaN substrate 1 is not particularly limited, but is performed on a GaN substrate. From the viewpoint of the semiconductor layer 2 having good crystal growth and crystallinity, a gas phase method such as M〇c ν〇 method, MBE method, or HVPE method is preferable. Further, by changing the chemical composition and/or configuration of the semiconductor layer 2, the wavelength region of the light emission and the peak wavelength can be changed. (Step of forming the first electrode and the second electrode)] 55086.doc 201203606 The method of forming the first electrode and the second electrode is not particularly limited, but from the viewpoint of improving productivity and reducing production cost, it is preferably splashed. Plating, vapor deposition, etc. [Examples] [Example 1] In the present embodiment, the partial pressure of the doping gas containing Si was changed in the HVPE method by the following method, whereby the carrier concentration, the specific resistance, and the absorption coefficient of light were obtained. A plurality of GaN substrates that are different. 1. Preparation of base substrate Referring to Fig. 1(A), first, a diameter of 60 mm and a thickness of 400 μm are prepared.

GaN base substrate 11. The main surface llm of the base substrate η is flat, and the crystal face closest to the main surface 1 lm is an (oooi) plane. (〇〇〇1) The radius of curvature of the surface is measured by X-ray diffraction and is 2 〇 m. The average density of the misalignment of the main surface 11 m penetrating through the base substrate 11 (referred to as the average dislocation density, the same applies hereinafter) is calculated based on the measurement of the blind spot density of CL (cathode luminescence), which is 5 X 105 cm '3 ° 2. GaN Growth of crystals Next, referring to FIG. 1(A), seven GaN crystals 12 having different concentrations of growth and concentration were grown on the base substrate 11 by using the S1F4 gas as a doping gas by the HVPE method (Experiment No. 1- 7). In the growth of these GaN crystals, the HvpE device shown in Fig. 2 was used. The helium gas is prepared as the second raw material gas (1), the Hci gas is used as the second raw material gas G3, the SiF4 gas is used as the doping gas G2, and the 112 gas having a purity of 99.999% or more is used as the carrier gas, respectively, from the i-th gas guiding tube 1 () 4. The second gas I55086.doc -20· 201203606 The introduction pipe 106 and the doping gas introduction pipe ι〇5 introduce the carrier gas into the inside of the reaction tube 11〇 and raise the temperature of the heater 1〇9 to 11〇(rc Thereafter, the metal Ga is supplied to the ship type disc 107, and the ship type disc 1 〇7 is heated. The HC1 gas supplied from the 苐2 gas introduction pipe and the Ga of the ship type dish 1〇7 are Ga+HCl-GaCl+l In the case of the reaction of /2H2, GaCl gas is generated as the reaction gas G7. Next, the ruthenium gas as the first source gas G1 supplied from the first gas introduction pipe 1 〇4 is obtained as the reaction. The GaCl gas of the reaction gas G7 flows in contact with the carrier gas in contact with the main surface of the grown GaN crystal of the base substrate η, and is equal to the manner of GaCl+NH3-GaN+HCl+I^ on the main surface. Reaction occurred. As seven GaN crystals ι2 with different Si concentrations (Experiment N〇K7) The long condition 'the partial pressure of the doping gas is adjusted to the value shown in Table 1. Thus, the growth temperature is 60 mm and the thickness is 5 mm with a crystal growth temperature of 1 loot and a crystal growth time of 16 67 hours. Seven GaN crystals having different Si concentrations. The growth rate of the GaN crystal is 3 〇〇gm/hr. 3. Formation of GaN substrate Next, referring to FIG. 1(B), the GaN crystal 12 obtained separately is used with a microtome. The chipping process is performed in the thickness direction. Then, the outer edge region of the sliced GaN crystal 12 is removed. Then, the GaN crystal which is sliced and further removed from the outer edge region is subjected to CMP (Chemical Mechanical Polishing) to remove the processed metamorphic layer. In this way, five GaN substrates having a diameter of 2 inches (50.8 mm) and a thickness of 400 μm were obtained by crystallization of each GaN. 4. Physical property measurement of GaN substrate 155086.doc -21- 201203606 5 pieces of GaN obtained Among the substrates 10a, 10b, 10c, 10d, and 10e, the Si concentration, the carrier concentration, and the ratio were measured at five measurement points of the third GaN substrate 10c from the base substrate 11 side. Resistance, and for wavelengths 38〇nm, 500 nm-780 nm, 440 nm - The absorption coefficient of light at -780 nm and 1500 nm 'and the minimum and maximum values of the light. Here, the five measurement points of one GaN substrate are set as the center point and the self-center point on the main surface. A point deviating from -2 cm in the {11-20} direction and a point deviating from +2 cm, and a point deviating from -2 cm from the center point to the {10-10} direction and a point deviating from +2 cm, totaling 5 points . The 'Si concentration is determined by SIMS (Secondary Ion Mass Spectroscopy). The carrier concentration was determined by CV characterization. The specific resistance was measured by a four-probe method using a specific resistance meter. The absorption coefficient of light was calculated by measuring the transmittance and reflectance using a spectrophotometer. Here, it is assumed that the absorption coefficient in the GaN substrate is not fixed with respect to depth' and multipath reflection is also considered. The results are summarized in Table 1. Here, the fluctuation of the carrier concentration in the main surface of the GaN substrate is within ±5% of the average value. The fluctuation of the carrier concentration in the thickness direction is also within ±5 % of the average value. Further, the average density (average misalignment density) of the misalignment of the main surfaces of the three measurement points of the third GaN substrate 10c located in each of the GaN crystals 12 is 5×10 〇5 cm·2, and the base substrate 丨The same low density. Further, the radius of curvature of the (0001) plane on the five measurement points of the third G aN substrate 10 c of each of the GaN crystals 12 is measured by X-ray diffraction, and is 2 μm' and the base substrate. Equally big. Moreover, none of the obtained GaN substrates were cracked 155086.doc •22· 201203606. [Table 1] Experiment No. 1 2 3 4 5 6 7 Partial pressure of doping gas (xl(T6 atm) 2.0 1.5 1.0 0.8 0.6 04 03 Si concentration (xlO18 cm·3) 2.2 1.6 1.1 0.85 0.69 0 45 0 36 Carrier concentration (xlO18 cm·3) 2.1 1.5 1.1 0.82 0.66 0 42 0 35 Specific resistance (Qcm) 0.095 0.011 0.014 1 0.017 0.02 0 031 0 035 380 nm 48 33 24 19 15 11 9 Absorption coefficient of light 500-780 nm 11 -15 7-10 5-7 4-5 4-5 4 3 (cm·1) 440-780 nm 11-22 7-15 5-10 4-6 4-5 4 3-4 1500 nm 29 20 16 12 10 8 6 Referring to Table 1, in the HVPE method, the crystal growth temperature is adjusted to 丨〇〇〇. 匸 or more, 1200 C or less, and the partial pressure of the doping gas containing Si is adjusted to 0.6 ΧΗΓ 6 atm or more, l. Oxlo·6 atm or less and a carrier concentration of 0.66×10 18 cm −3 or more and 11°·1·8 cm −3 or less, thereby obtaining an absorption coefficient of light having a specific resistance of 0.02 Dcm or less and a wavelength of 380 nm. A GaN substrate having an absorption coefficient of 7 cm·1 or more for light having a wavelength of 500 nm to 780 nm and a absorption coefficient of 7 cm·1 or more for light having a wavelength of 15 〇〇 nm, and a crystal growth temperature of 7 cm or more Adjusted to 1〇〇〇〇c or more Below 1200 °C, the partial pressure of the doping gas containing si is adjusted to be 〇6χ10_6 atm or more, 0·8χ10-6 atm or less, and the carrier concentration is 〇66χΐ〇18 cm·3 or more, 〇.82xi〇u em -3 or less, thereby obtaining a specific resistance of 〇〇2 ncm or less, an absorption coefficient of light of 7 cm·丨 or more for light having a wavelength of 380 nm, and an absorption coefficient of light of not more than 7 cm for light having a wavelength of 440 nm to 780 nm. GaN GaN substrate with an absorption coefficient of light having a wavelength of 妒1500 nm of 7 cm·1 or more. The impurity concentration of elements other than Si in all crystals grown by 'the growth' is measured by SIMS, and 〇 (oxygen) is 5x10丨6 cm·3 or less, c(carbon) 155086.doc •23· 201203606 is 5xl〇16, and the other elements are also lxl〇i6 crn·3 or less. V Example: Making the crystal surface closest to the main surface It is the If shape of the (0001) surface plate, but the crystal face closest to the main surface is (10-10) face, face face, (10-11) face, (11_22) face, (20_21) or (22). 44) The same results were obtained for the case of the GaN substrate. It is to be understood that the scope of the embodiments and examples disclosed herein are not intended to be limiting. The scope of the present invention is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an example of a method of producing a G a N substrate of the present invention. Here, (A) shows a step of preparing a base substrate and a step of growing a GaN crystal having impurities added to the base substrate, and (B) shows a step of forming a GaN substrate by processing the GaN crystal. Fig. 2 is a schematic view showing an example of an HVPE device used for growing GaN crystals. Fig. 3 is a schematic cross-sectional view showing an example of a light-emitting device of the present invention. [Description of main component symbols] 10, 10a, 10b, 10c, GaN substrate 10d, l〇e 10m, 1 〇n, 11 m, main surface 12m ' 12n 11 Base substrate 12 GaN crystal 155086.doc -24- 201203606 20 Semiconductor Layer 30 First electrode 40 Second electrode 100 HVPE device 101 First material gas storage tank 102 Doped gas storage tank 103 Second material gas storage tank 104 First gas introduction pipe 105 Doping gas introduction pipe 106 Second gas introduction pipe 107 Ship type disc 108 Crystal holder 109 Heater 110 Reaction tube 111 Exhaust pipe 120 Liner G1 First material gas G2 Doping gas G3 Second material gas G7 Reaction gas 155086.doc -25-

Claims (1)

201203606 VII. Patent application scope: 1 · A GaN substrate with an absorption coefficient of 7 cm·1 or more for light with a wavelength of 380 nm and light with a wavelength of 1 500 nm, at least for light with a wavelength of 500 nm or more and 780 nm or less The absorption coefficient is less than 7 cnT1, and the specific resistance is 0.02 Ωοιη or less. • 2. The GaN substrate of claim 1 which has an absorption coefficient of less than 7 cnT1 for light having a wavelength of 440 nm or more and 780 nm or less. A light-emitting device comprising the GaN substrate of claim 2, wherein the peak wavelength of the light emission is 440 nm or more and 780 nm or less. A light-emitting device comprising the GaN substrate of claim 1, wherein the peak wavelength of the light emission is 500 nm or more and 780 nm or less. 155086.doc