TW200541121A - P-type group Ⅲ nitride semiconductor and production method thereof - Google Patents

Abstract

An object of the present invention is to provide a method for producing a p-type Group III nitride semiconductor which can be used to produce a light-emitting device exhibiting a low operation voltage and a sufficiently high reverse voltage. The inventive method for producing a p-type Group III nitride semiconductor comprises, during lowering temperature after completion of growth of a Group III nitride semiconductor containing a p-type dopant, immediately after completion of the growth, starting, at a temperature at which the growth has been completed, supply of a carrier gas composed of an inert gas and reduction of the flow rate of a nitrogen source; and stopping supply of the nitrogen source at a time in the course of lowering the temperature.

Description

, 200541121 IX. Description of the invention: [Technical area to which the invention belongs] The present invention relates to a method for manufacturing a group III nitride p-type semiconductor and a group III nitride semiconductor light-emitting device manufactured using the same. In particular, it is related to a method for manufacturing a group III nitride P-type semiconductor of a light-emitting element that can obtain a low driving voltage (Vf) with a high yield and a sufficiently high reverse voltage (VO). [Prior Art]

In recent years, a semiconductor material for a light-emitting element for emitting short-wavelength light has attracted worldwide attention as a nitride semiconductor material. In general, nitride semiconductors use sapphire single crystals, various oxide crystals, and III-V compound semiconductor single crystals as substrates, and metal organic chemical vapor deposition (MOCVD) or molecular beam leaching is used thereon. Crystal growth method (MBE method) or hydride vapor phase epitaxial growth method (HVPE method) is used to perform lamination. In group III nitride semiconductors, it has been difficult to produce p-types with sufficient carrier concentration for a long period of time. semiconductor. However, according to a method of irradiating Mg-doped gallium nitride (GaN) with a low-velocity electron ray (see Japanese Patent Application Laid-Open No. 2-257679), or a method in which Similarly, a method of heat-treating gallium nitride doped with Mg (see Japanese Patent Application Laid-Open No. 5- 1 83 1 89), etc. shows that it is still possible to produce a p-type semiconductor having a sufficient carrier concentration. It is considered that a mechanism capable of obtaining a sufficient carrier concentration can be activated by dehydrogenating a p-type dopant in a semiconductor passivated with hydrogen by the above method. In fact, doping after activation annealing is applied -5- 200541121

For a Mg gallium nitride-based semiconductor, the concentration of rhenium is about 1/10 of the Mg concentration. A method for growing a group III nitride semiconductor with good crystallinity is generally a metal organic chemical vapor deposition method (MOCVD method). However, in the growth device used for crystal growth in the MOCVD method, hydrogen at a high concentration exists as a carrier gas required to carry a raw material compound onto a substrate, or ammonia (NH3) is used as a group V raw material. ) Hydrogen molecules or free radical or atomic hydrogen produced by decomposition. The hydrogen will then be taken into the crystal during the growth of the crystalline layer of the group III nitride semiconductor, and when cooling from the crystalline layer growth temperature is applied, it will be generated with the p-type dopant doped in the crystal. Bonding. In this way, the p-type dopant that is passivated by hydrogen is already inactive and therefore cannot generate holes. However, as long as the sample is irradiated with electron rays or subjected to heat treatment, the bond between the p-type dopant and hydrogen in the crystal can be cut off, and hydrogen can be expelled from the crystal to activate the p-type dopant. Of the two methods described above, the method of irradiating electron rays has a limited area that can be treated at one time, and it takes time to process the entire area, which makes it impossible to apply it to industry. On the other hand, it is known that in a wafer having a light-emitting element structure of a P-type III nitride semiconductor manufactured by a method of applying heat treatment, the pn junction is reversed in the electrical characteristics measured by the formed electrode. A chip with a low voltage (Vr) when a predetermined 値 current flows in the direction will be mixed at a certain ratio. A low Vr means that a current is leaking to the pn junction, so it is not good for the product. In other words, if the wafer is removed, the yield can be greatly reduced. In general, it is known that if hydrogen is dehydrogenated from a group III nitride semiconductor due to heat treatment, nitrogen will also be detached at the same time, so that the crystallinity will be reduced to 20Q541121. This phenomenon may cause the reduction of Vr. In addition, when a gallium nitride-based compound semiconductor doped with a P-type impurity is cooled, it is disclosed that the doped doped by switching from an atmosphere containing ammonia to an atmosphere of hydrogen or nitrogen at a temperature of 400 ° C or higher. A technique for reducing the resistance of the P-type impurity layer (see Japanese Patent Application Laid-Open No. 8-1 15880). In this document, as an example, it is disclosed that after the growth of the Mg-doped layer is completed, the mixture is cooled with a mixture of NH3 and H2 until 600 ° C, and the supply of NH3 is stopped at 600 ° C to switch to only hydrogen. An example of the atmosphere. However, according to the experimental results of the inventors of the present invention, if NH3 is circulated for cooling until 600 ° C, the effect of reducing the driving voltage of the device cannot be obtained. In particular, when a metal such as Pt is used as the positive electrode material, it is known that the driving voltage that has been sufficiently reduced before the bonding is applied may actually increase due to the heat of approximately 300 ° C applied during the bonding. On the other hand, there are reports that when the III-nitride semiconductor is grown and cooled to room temperature, if the atmosphere gas is replaced with an inert gas other than H2 gas and NH3 gas for cooling, sufficient carriers can be obtained Concentration (see Japanese Patent Application Laid-Open No. 8-125222). In the examples, it is disclosed that the substitution of nitrogen is performed in a vacuum state to replace with nitrogen or an inert gas to produce a p-type semiconductor. However, even if the atmosphere gas is replaced with an inert gas other than H2 gas or NH3 gas for cooling, it is not possible to obtain a wafer with a low driving voltage at a high yield at a time. That is, it is impossible to obtain a wafer with excellent reproducibility and excellent characteristics at high yields only by controlling the conditions specified in this document. 200541121 It is also known that when Pt or the like is used as the positive electrode material, the driving voltage will increase due to the heat experienced during bonding. In addition, a technology has also been disclosed in which a nitride semiconductor is grown and then replaced with an inert gas at a growth temperature of 1,100 ° C (see Japanese Patent Application Laid-Open No. 9-1 29929). . In addition, according to these methods, it takes 2 to 3 hours after the temperature is reduced to room temperature after being replaced with an inert gas. However, when the method of substituting the inert gas immediately after the growth is completed, it has been found from our experiments that the Vr of the wafer produced will be reduced. In addition, lowering the temperature over a long period of time will also cause Vr to decrease. Finally, there have been proposals to reveal a method for cooling the crystals grown at a growth temperature above 700 ° C below 700 ° C, so that A method for growing a low-resistance p-type gallium nitride-based compound semiconductor in a gas atmosphere (see Japanese Patent Application Laid-Open No. 9-199758). In the example of this document, after the growth of the p-type gallium nitride-based compound semiconductor at 1.03 ° C, the atmosphere formed by hydrogen and ammonia was replaced with nitrogen at 700 ° C. This method We have also reviewed and found that even if cooling below 700 ° C is performed in a gas atmosphere other than hydrogen, it is not possible to obtain a wafer with a low driving voltage at a high yield. In other words, it is only controlled to meet the requirements specified in this document. It is still impossible to obtain a wafer with excellent reproducibility and excellent characteristics at a high yield. In addition, when Pt is used as the positive electrode material, the driving voltage is increased during bonding. ^ 200541121 In summary, if According to the methods of Japanese Patent Application Laid-Open No. 5- 1 83 1 89 and Japanese Patent Application Laid-Open No. 9-1 29929, the wafer with low Vr of low Vr will be "on the other side" When the methods of Japanese Patent Application Laid-open No. 8-1 1880, No. 8 "25222, and No. 9-1 99758, the driving voltage will be increased. In particular, the positive electrode material will be generated. When Pt is used, the driving voltage rises due to the heat applied during bonding. As described above, when manufacturing a III-nitride semiconductor device, the device characteristics and yield can be coexisted without any problem at all. There is no proposal for the formation method of the doped layer. Moreover, in these previous examples, it is necessary to reduce the resistance of the layer containing the P-type dopant, so it is also mentioned in any technology that a p-type semiconductor having a low resistance must be provided [Summary of the invention] The present invention is achieved in order to solve the above-mentioned problems of the prior art, and its object is to provide a low driving voltage (Vf) and a sufficiently high reverse voltage (Vr) that can be obtained at a high yield. A method for producing a group III nitride p-type semiconductor of a light-emitting device. The present invention provides the following inventions. (1) A method for producing a group III nitride p-type semiconductor, which is characterized in that a III-type nitrogen containing a P-type dopant is included. After the growth of the compound semiconductor, the temperature is the same as the temperature at the end of the growth at the same temperature as that at the end of the growth. From the beginning of the growth, the inert gas is used as the carrier gas, and the flow rate of the nitrogen source is reduced. The supply of nitrogen was stopped during the subsequent cooling process, 200541121. (2) If the manufacturing method of the scope of the patent application is applied, the temperature at the end of the growth is 90 (TC or more.) (3) If the scope of the patent application is 1 or 2 The manufacturing method, wherein the nitrogen source is a gas. (4) The manufacturing method according to any one of claims 1 to 3, wherein the carrier gas used for growing the semiconductor contains hydrogen.

(5) If the manufacturing method of any one of items 1 to 4 of the scope of patent application, wherein the flow rate of the reduced nitrogen source is 0.001 to 10% of the total gas volume. (6) If the manufacturing method of any one of items 1 to 5 of the scope of patent application, the temperature at which the supply of nitrogen is stopped is 700 to 95 ° C. (7) A group I-III nitride P-type semiconductor, which is characterized by containing more than one-fifth of the hydrogen concentration of the p-type dopant and less than the concentration of the p-type dopant. (8) A group III nitride P-type semiconductor, which has a resistivity of 20 Ω cm to 10,000 Ω cm. 〇 (9) A group III nitride semiconductor light-emitting device, which is provided on a substrate and is composed of a group III nitride semiconductor. The n-type layer, the light-emitting layer, and the p-type layer, and the negative electrode and the positive electrode are respectively disposed on the n-type layer and the p-type layer. Item system method. (10) A type III nitride semiconductor light-emitting device, wherein an n-type layer, a light-emitting layer, and a p-type layer composed of a group III nitride semiconductor are provided on a substrate, and a negative electrode and a positive electrode are provided on the n-type layer and • 10-200541121 On a P-type layer 'characterized in that the p-type layer is a group III nitride p-type semiconductor of item 7 or 8 as described above. (11) If the light-emitting element of item 9 or 10 of the patent application scope, wherein the positive electrode is a platinum group metal positive electrode material selected from Pd, Pt, Rh, Os, Ir, and Ru. (12) The light-emitting element according to any one of claims 9 to 11 in the scope of patent application, wherein the light-emitting element is a flip-chip wafer type.

(1 3) If applying for § 靑 Patent $ 12, the light-emitting element in any one of items 9 to 11 is a face-up assembly type. According to the present invention, it is possible to obtain a p-type group III nitride semiconductor having sufficient characteristics at a level that can be used as a semiconductor element. In addition, by using the III-nitride p-type semiconductor, a III-nitride semiconductor light-emitting device having a high Vr without causing a rise in driving voltage due to heat can be manufactured at a high yield. [Embodiment] [Best Mode of the Present Invention] A group III nitride semiconductor of a group III nitride p-type semiconductor that can be applied to the manufacturing method of the present invention, in addition to GaN, includes: InN, A1N, etc. All type III nitride semiconductors such as elementary mixed crystals, ternary mixed crystals such as InGaN and AlGaN, and quaternary mixed crystals such as InAlGaN. However, in the present invention, it also further includes Group V elements other than nitrogen, that is, a ternary mixed crystal of GaPN, GaAs, or the like, or a quaternary of InGaPN, InGaAsN, AlGaPN, AlGaAsN, etc. which further contains In or A1. Is a mixed crystal, and further contains Alin GaPN, Alin GaAsN, -11-20P541121 of both In and A1, or a pentad system of five elementary mixed crystals including AlGaPAsN, InGaPAsN including both P and As, and contains all elements AlInGaPAsN's six-element mixed crystal is also included in the Group III nitride semiconductor. The present invention is among the above, and is particularly suitable for manufacturing binary mixed crystals of GaN, InN, A1N, etc., which are relatively easy to produce without risk of decomposition, ternary mixed crystals of InGaN, AlGaN, and the like Group III nitride semiconductors such as elementary mixed crystals that contain only N as a group V. When expressed by the general formula AlxInyGabX_yN (Ogx + y ^ l), X is preferably in the range of 0 to 0.5, and y is preferably in the range of 0 to 0.1. In addition, the P-type dopants that can be used in the present invention include Mg, Ca, Zn, Cd, Hg, etc., which have been disclosed as indicated or predicted to be doped in a group III nitride semiconductor, and exhibit p-type conductivity. . Among these, Mg having a high activation rate by heat treatment is particularly suitable for use as a p-type dopant. The amount of dopant used is preferably 1 X 1018 to 1 X 1021 cnT3. If it is less than 1 X 1018 cnT3, the luminous intensity will decrease. Conversely, if it is more than lx 1 021 cm_3, crystallinity will be deteriorated, so it is not good, and more preferably 1 X 1 019 to 1 X 1 02. cm · 3. The P-type semiconductor layer 'manufactured by the method disclosed in the present invention may also contain hydrogen atoms in its crystal. In order to manufacture a device having a high reverse voltage Vr, it is sometimes preferable to include a hydrogen atom in the crystal. The amount of hydrogen atoms contained in the crystal is preferably less than the amount of the doped P-type dopant. When the content of the hydrogen atom is the same as the content of the P-type dopant 'or more than the content of the P-type dopant, it is not easy to obtain the electrical contact of the P-type electrode, so it is preferably less than . The content of hydrogen atoms is more preferably P-type -12- 200541121 X ** The dopant is 9/10 or less, and particularly preferably 7/8 or less. However, if the content of the hydrogen atom is less than 1/5 of the P-type dopant, nitrogen detachment will occur at the same time, so it is preferably more than 1/5, more preferably 1/3 or more, and if 1/2 The above is more ideal. In addition, the atomic concentrations of magnesium and hydrogen in the 'P-type semiconductor layer are quantified by a general SIMS (Primary Ion Mass Spectroscopy). In addition, the P-type layer system does not become low in resistance due to the inclusion of hydrogen in the crystal, but it does not pose a problem in device characteristics. In a device using a III-nitride semi-conductor ', since the P-type layer is mostly formed thinner than other semiconductors, the resistance of the P-type layer itself does not cause much influence on the driving voltage Vf of the device. The resistivity of the p-type layer is high, and it is desirable to maintain a high Vr. The resistivity of the P-type layer is preferably about 20 Ω cm to 10,000 Ω cm. If it is higher than 10,000 Ωοιη, the luminous intensity will be reduced. If it is lower than 20Qcm, Vr may be lowered. More preferably, it is 50 Ω cm to 2,000 Ω cm, and particularly preferably 100 Qcm to 1,000 Qcm. In addition, the resistivity is measured by a general TLM (Transfer Length Measurement) method. The method for growing the group III nitride p-type semiconductor of the present invention is not particularly limited, and MOCVD (metal organic chemical vapor growth), HVPE (hydrogen vapor phase epitaxial growth), and MBE (molecular beam) can be used. All methods known for epitaxial growth) are available for growing Group III nitride semiconductors. A preferred growth method is a MOCVD method from the viewpoint of film thickness controllability and mass productivity. -13- 200541121 €, in the MOCVD method, the carrier gas is hydrogen (h2) or nitrogen (n2), and the Ga source of Group III is trimethylgallium (TMG) or triethylgallium (TEG), A1 Source system uses trimethyl aluminum (TMA) or triethyl bromide (TEA) 'In source system uses dimethyl alcohol (TMI) or diethyl alcohol (TEI)' Nitrogen source system uses ammonia (NH3) or Ammonia (N2H4) and so on. In addition, in the p-type dopant, the Mg raw material is, for example, dicyclopentadienyl magnesium (Cp2 Mg) or diethylcyclopentyl diene ((EtCp) 2 Mg), and the Zn raw material is dimethyl zinc ( Zn (CH3) 2). The effect of the present invention is great if the carrier gas contains Η2, and / or NΗ3 is used as the nitrogen source. In order to obtain excellent crystallinity and contact resistance, the growth temperature is preferably a temperature of 1,000 ° C or more, and more preferably 1,050 ° C or more and 1,250 ° C or less. After growing a group III nitride semiconductor containing a p-type dopant, the temperature is lowered to room temperature, and then the semiconductor laminate is removed from the growth device. If the carrier gas contains hydrogen during the growth, it must be immediately after the growth is completed. The carrier gas was switched to an inert gas not containing hydrogen at the same temperature as the growth temperature. If the flow of hydrogen gas continues for about one minute behind the time required for switching, the drive voltage cannot be sufficiently reduced. The inert gas used to replace the carrier gas is preferably nitrogen, but argon, helium, and the like, and mixtures thereof may also be used. In addition, it is important to reduce the flow rate of the nitrogen source at the same time as switching the carrier gas. The nitrogen source supply during growth is usually 20% to 70% of the total gas volume, but the nitrogen source amount after reducing the nitrogen source is preferably 10% or less of the total gas volume, and more preferably 1% or less. If the amount of nitrogen source is too much, the driving voltage of the element cannot be reduced as desired. At this time, if the flow rate of the nitrogen source is also made zero, the nitrogen from the crystals constituting the P-type layer will be detached, and the Vr of the device will be reduced. The amount of nitrogen source is preferably set to 0.001% or more, and more preferably 0.01% or more of the total gas volume. In addition, it is preferable to start the temperature reduction immediately after the flow rate of the nitrogen source is changed and the carrier gas is switched. If the temperature is held for a long time after the growth is completed, not only the crystallinity will be reduced, but also the thermal damage to the light emitting layer will be accumulated and the light emission intensity will be reduced. # In addition, once the flow rate of the nitrogen source is reduced, the operation of completely reducing it to zero during the temperature reduction process must be performed. A component manufactured by reducing the temperature to a low temperature, such as 300 ° C, without stopping the flow of nitrogen source, will increase the driving voltage of the component due to the heat applied during bonding. The temperature at which the flow rate of the nitrogen source is zero during the cooling process is preferably 950 ° C or lower and 700 ° C or higher. If the nitrogen source flow rate becomes zero at a temperature higher than 950 ° C, the Vr of the device will decrease. If the nitrogen source continues to flow below 70CTC, the driving voltage will increase due to heat. B In addition, the time from the completion of growth to the time when the nitrogen source flow rate becomes zero depends on the cooling rate, but it is from about 30 seconds to about 8 minutes. The III nitride P-type semiconductor of the present invention and The manufacturing method can be used for manufacturing various semiconductor devices. For example, in addition to semiconductor light-emitting elements such as light-emitting diodes and laser diodes, as long as it is a semiconductor element that uses a group III nitride P-type semiconductor such as various high-speed transistors or light-receiving elements, it can be used in The manufacture of any element, but especially suitable for the manufacture of semiconductor light-emitting elements that need -15 · 200541121 m to form a pn junction and an electrode with excellent characteristics. FIG. 1 is a schematic diagram showing a group III nitride semiconductor light-emitting device manufactured by using the group III nitride p-type semiconductor of the present invention and a manufacturing method thereof. When necessary, the n-type semiconductor layer 3, the light-emitting layer 4, and the p-type semiconductor layer 5 of the group III nitride are sequentially laminated on the substrate 1 through the buffer layer 2, and the negative electrode 6 and the positive electrode 7 are formed separately. On the n-type semiconductor layer 3 and the p-type semiconductor layer 5. The substrate 1 is a conventionally known material that can use sapphire, sic, GaN, AIN, Si, ZnO, and other oxide substrates without particular limitation. However, sapphire is preferred. The buffer layer 2 is provided for adjusting a lattice mismatch of the substrate and the n-type semiconductor layer 3 to be grown thereon as necessary. Where necessary, conventionally known buffer layer techniques can be used. The composition and structure of the n-type semiconductor layer 3 can be formed into a composition and structure that we desire using a well-known technique known in the technical field. Generally, the n-type semiconductor layer is composed of a contact layer which can obtain excellent ohmic contact with the negative electrode and a cladding layer which has a larger band gap energy than the light emitting layer. The negative electrode 6 may be formed into a composition and a structure desired by us by using a technique known in the art. The light emitting layer 4 also has a conventionally known composition and structure such as a single quantum well structure (SQW) and a multiple quantum well structure (MQW) without special restrictions. The p-type semiconductor layer 5 is formed by the manufacturing method of the present invention. Regarding its structure, the group $ & structure can use the technical form that is well known in the technical field -16- 200541121 «m into the composition and structure that I hope. Usually, the n-type semiconductor layer is composed of a contact layer which can obtain excellent ohmic contact with the negative electrode and a cladding layer having a band gap energy larger than that of the light-emitting layer. As the material for contacting the positive electrode 7 of the P-type layer produced by the method of the present invention, metals such as Au, Ni, Co, Cu, Pd, Pt, Rh, Os, Ir, Ru, and the like can be used. Further, it may contain transparent oxides such as IT0, Ni0, and co0. The transparent oxide-containing form may be formed as a block and included in the above-mentioned metal film, or may be formed in a layered form and laminated with the above-mentioned metal film. In particular, when platinum group metals such as Pd, Pt, Rh, Os, Ir, and Ru are used as the positive electrode material, the use of the present invention can prevent the driving voltage from being increased due to heat during bonding, and thus can exert greater efficacy. . Among them, Pd, Pt, and Rh are relatively easy to obtain with high purity, so they are easier to use. In addition, the positive electrode may be formed so as to cover the entire surface, or may be formed in a grid or tree shape with a gap therebetween. After the positive electrode is formed, a thermal annealing treatment may be applied for the purpose of alloying or transparency, but it may not be applied. The form of the device may be a so-called "face-up assembly (FU) type" that uses a transparent positive electrode to emit light from the semiconductor side, or a so-called "chip-on-chip (FC)" that uses a reflective positive electrode to emit light from the substrate side. )type". [Embodiments] The present invention will be described in detail based on the embodiments, but the present invention is not limited to these embodiments. [Embodiment 1] A schematic cross-sectional view of an epitaxial -17-200541121 laminated structure 11 used in the LED 10 manufactured according to this embodiment is shown in FIG. In addition, the top view (planar) view of the LED 10 is shown in FIG. 3. The laminated structure 11 is non-doped on the substrate 1 01 composed of the c-plane ((001) crystal surface) of sapphire through a buffer layer (not shown) composed of A1N. GaN layer (layer thickness = 8 microns) 102, Si-doped η-type GaN layer (layer thickness = 2 microns, carrier concentration = lxl019cm · 3) 103, Si-doped η-type Al0.07Ga0.93N cladding (layer Thickness = 25 nm, carrier concentration = 1 X 1018 cnT3) 104. Six layers of Si-doped GaN barrier layer (layer thickness = 14.0 nm, carrier concentration = lxl018 cm · 3) Multi-quantum structure light emitting layer 105 composed of 5 layers of non-doped InQ.2 () Ga0.8. (N) well layer (layer thickness = 2.5nm), Mg-doped p-type Al0.07Ga0 A .93N cladding (layer thickness = 10 nm) 106 and a M-doped p-type AlG () 2Ga (). 98N contact layer (layer thickness = 150 nm) 107 are laminated in this order. Each of the constituent layers i 02 to 107 of the laminated structure 11 is grown by a general reduced pressure MOCVD method. In particular, the Mg-doped p-type A1 GaN contact layer 107 is grown in the following order: (0) After the growth of the M-doped p-type Alo.07Gao.93N cladding layer 106 is completed, the pressure in the growth reaction furnace is increased. Set to 2 × 104 Pascal < pa): Hydrogen was used as the carrier gas. (2) Trimethylgallium, trimethylaluminum, and ammonia are used as raw materials, and dicyclopentane dilute magnesium is used as the doping source of Mg, and the concentration is 1.02. < 3 Begin vapor-phase growth of a Mg-doped p-type AlGaN layer. (3) Continue supplying trimethylgallium, trimethylaluminum, ammonia and dicyclopentene magnesium to the growth reaction furnace at -18-20.0541121 for 4 minutes, so that the thickness of the layer is 0.15 μm. A p-type Al.02Ga.98N layer was grown. (4) Stop supplying trimethylgallium, trimethylaluminum, ammonia and dicyclopentenemagnesium to the growth reactor to stop the growth of the M-doped p-type Alo.o2Gao.98N layer. Immediately after the vapor phase growth of the contact layer 107 composed of the Mg-doped p-type AlGaN layer was completed, the carrier gas was immediately switched from hydrogen to nitrogen, and the ammonia flow rate was reduced and the load was increased by an amount equivalent to the reduced portion Gas nitrogen flow. Specifically, § 50% by volume of ammonia, which is the total circulating gas volume, will be reduced to 0.2% during growth. At the same time, the energization of the high-frequency induction heating heater used for heating the substrate 101 is stopped. After this state was maintained for 2 minutes, the circulation of ammonia was stopped. At this time, the substrate temperature is 85 ° C. The schematic diagram of the cooling process is shown in Fig. 4. After cooling to room temperature in this state, the laminated structure 11 is taken out from the growth reaction furnace, and the general SIMS analysis method is used. The atomic concentrations of magnesium and hydrogen in the contact layer 107 were quantified. As a result, the Mg atoms were distributed at a concentration of § 7 X 1019 cnT3 and were approximately constant from the surface to the depth. On the other hand, the hydrogen atom system contained 6 X 1019 cnT3 is about a certain concentration. In addition, the resistivity is estimated by the general TLM (telemetry) measurement result to be approximately 15 0 Ω cm. Using the above epitaxial laminated structure 1 with a P-type contact layer 1 to manufacture the LED 10. First, general dry etching is applied to a predetermined region where the negative electrode 108 is to be formed, and the surface of the Si-doped GaN layer 103 is exposed only in this region. A laminated titanium is formed on the exposed surface portion. (Ti) / aluminum (A1) structure -19- 200541121 into the negative electrode 108. In the entire area of the surface of the remaining contact layer 107, it is formed to have a structure capable of reflecting the light emitted from the light-emitting layer to the sapphire substrate 101 side. Functional and economical The positive electrode 109 composed of a platinum (Pt) film / germanium (Rh) film / gold (Au) film. The metal film in contact with the surface of the p-type contact layer 107 is a platinum film. After forming the negative electrode 108 and the positive electrode 109, The back surface of the sapphire substrate 101 is honed with diamond particles and finally polished into a mirror surface. Then the laminated structure 11 is cut and separated into individual LEDs of 350 micron square 1 0. Then, the negative electrode and the positive electrode are respectively attached to the sub-mounting frame to make a flip-chip type wafer. At this time, about 300 ° C of heat is applied to the wafer electrode. Then it is further placed behind the lead frame ' A gold (Au) wire is connected to the lead frame. In the LED chip manufactured in the above steps, a forward current is passed between the negative electrode 108 and the positive electrode 109 to evaluate the electrical characteristics and light emission characteristics. The forward current setting The forward drive voltage (Vf) at 20 mA is 3.0 β V, and the reverse voltage (Vr) when the current is set to 10 // A is 20 V or more. In this way, no heat caused by the heat during bonding occurs. The driving voltage rises. The wavelength of the light transmitted from the outside to the outside is 455 nanometers, and the luminous output measured by a general integrating sphere is 10 mW. In addition, the appearance is removed from a 5 · 1 cm (2 inch) wafer After defective products, although about 10,000 LEDs were obtained, all of them exhibited the characteristics as described above without change. [Example 2] -20-200541121 »· Manufactured in Example 2 The laminated structure has the following structure.

The laminated structure 11 is a substrate 101 composed of the C-plane ((0 0 0 1) crystal plane) of sapphire, and a non-doped GaN is interposed therebetween via a buffer layer (not shown) composed of A1N. Layer (layer thickness = 8 microns) 102, Ge-doped η-type GaN layer (layer thickness = 2 microns, carrier concentration = 7xl018cnT3) 103, Si-doped η-type Ino.cnGaowN cladding (layer thickness = 18 nm, Carrier concentration = 1 x 1018 cm · 3) 104. Six layers of Si-doped GaN barrier layer (layer thickness = 14.0 nm, carrier concentration = 1 X 1017 cnT3) and 5 layers Non-doped In (). 2 () Ga.8 () N well layer (layer thickness = 2.5nm) composed of a multiple quantum structure light emitting layer 105, Mg-doped p-type Al0.07Ga0. The 93N cladding (layer thickness = 12 nm) 106 and the Mg-doped Alo.o2Gao.98N contact layer (layer thickness = 175 nm) 107 are laminated in this order. Each of the constituent layers 102 to 107 of the laminated structure 11 is grown using a general reduced pressure MOCVD method. The Mg-doped AlGaN contact layer 107 was grown in the same order as in Example 1. After the vapor phase growth was completed, the laminated structure 11 was cooled to room temperature in the same procedure as in Example 1. After cooling to room temperature, the laminated structure 11 was taken out from the growth reaction furnace, and the atomic concentrations of magnesium and hydrogen in the contact layer 107 were quantified by a general SIMS analysis method. As a result, the Mg atomic system was distributed at a concentration of 1.5 X 102G cnT3 and a constant concentration from the surface toward the depth. On the other hand, the hydrogen atom system contains about a certain concentration of 8 X 1019 cnT3. In addition, the resistivity is estimated by the measurement result of the general TLM method to be approximately 1 80 Ω cm -21 · 200541121. The above-mentioned epitaxial laminated structure 11 having a P-type contact layer is used to manufacture LED 10. The manufacturing procedure, the structure of the electrodes, and the like are the same as those of the first embodiment. With the LED chip manufactured by the steps described above, a forward current is passed between the negative electrode 108 and the positive electrode 109 to evaluate electrical characteristics and light emission characteristics. When the forward current is set to 20 mA, the forward drive voltage (Vf) is 3.3 V, and when the current is set to 10 // A, the reverse voltage (Vr) is 20 V or more. In this way, the driving voltage did not occur due to the heat at the time of bonding, and the wavelength of the light transmitted from the sapphire substrate 101 to the outside was 470 nm, and the light output measured by a general integrating sphere was 12 m W. In addition, after removing defective appearance products from a wafer with a diameter of 5.1 cm (2 inches), although about 100,000 LEDs were obtained, all of them exhibited the characteristics as described above without change. . [Comparative Example 1] A Mg-doped p-type AlGaN contact layer was formed in the same manner as in Example 1 except that the treatment method after growth was changed. That is, in this comparative example, after forming the laminated structure disclosed in Example 1 under the same sequence and conditions as those disclosed in Example 1, the hydrogen of the carrier gas used in the vapor phase growth was switched to Nitrogen, but ammonia was reduced to 0.2% at the end of the growth, and then continued to circulate and cooled to 350t. Figure 5 is a diagram showing the cooling process in a pattern. With respect to the sample prepared in Comparative Example 1, the Mg and scandium concentrations were measured by SIMS in the same manner as in the Example. As a result, the Mg atomic concentration was 7 X 1019 cnT3, which was the same as that in Example 1. On the one hand, the hydrogen atom-22-200541121 contains a concentration of 7 x 1019 cm · 3. The resistivity measurement result by the same TLM method as in Example 丨 was roughly estimated to be 15,000 Qcm. A wafer fabricated as an FC-type element in the same manner as in Example 1 was placed on a lead frame, and a forward current was passed between the negative electrode 108 and the positive electrode 109 to evaluate electrical characteristics and light emission characteristics. When the forward current is set to 20 mA, the forward drive voltage (Vf) rises to 4.0 V, and the light emission output is 8 mW. [Comparative Example 2] A p-type GaN contact layer doped with Mg was formed in the same manner as in Example 1 except that the treatment method after growth was changed. That is, in this comparative example, after forming the laminated structure disclosed in Example 1 under the same sequence and conditions as those disclosed in Example 1, the hydrogen of the carrier gas used in the vapor phase growth was switched to nitrogen. At the same time, stop the circulation of ammonia and reduce the temperature to 350 ° C. Figure 6 is a diagram showing the cooling process in a pattern. For the sample prepared in Comparative Example 2, the Mg and rhenium concentrations were measured by the SIMS method in the same manner as in the Example. As a result, the Mg atomic concentration was 7 X 1019 cnT3, which was the same as that in Example 1. On the one hand, the hydrogen atom contains a concentration of 1 X 1019 cm_3. The resistivity measured by the same TLM method as in Example 1 was estimated to be about 10 Ω cm. The wafer fabricated as an FC-type element in the same manner as in Example 1 was placed on a lead frame, and then a forward current was passed between the negative electrode 108 and the positive electrode 109 to evaluate electrical characteristics and light emission characteristics. When the forward current is set to 20 mA, the forward drive voltage (Vf) is 3.0 V, and the light-emitting output is 10 mW. However, when the current is set to 1 〇 # A, the reverse voltage (Vr) is 5 V. -23- 200541121 [Example 3] In Example 3, the same laminated structure as that disclosed in Example 1 was used, and a FU-type electrode was formed to obtain an LED. Fig. 7 is a plan (planar) view of an electrode formed according to this embodiment. In the entire area of the surface of the remaining contact layer 107, a positive electrode 109 composed of laminated platinum (PO film / gold (Aluminum film)) having a light-transmitting property that can emit light from the light-emitting layer to the outside is formed. The metal film that is in contact with the surface of the p-type contact layer 107 is a platinum film. Β Further, the outermost surface formed on the light-transmitting electrode 109 is a bonding pad 1 1 0 made of Al. In Example 1, the individual LEDs 20 are separated into 350 micron squares in the same order.

In the LED chip manufactured by the steps described above, a forward current is passed between the negative electrode 108 and the positive electrode 109 to evaluate electrical characteristics and light emission characteristics. When the forward current is set to 20 mA, the forward drive voltage (Vf) is 3.0 V, and when the current is set to 10 # A, the reverse drive voltage (V0 is 20 V or more. In addition, the semiconductor layer side is transmitted to the outside. The light emission wavelength is ® 455 nm, and the light emission output measured by a general integrating sphere is 6 mW. In addition, after removing a defective appearance from a wafer having a diameter of 5.1 cm (2 inches), 10,000 LEDs, but all of them show the above-mentioned characteristics without change. [Industrial Applicability] According to the method for manufacturing a group III nitride p-type semiconductor provided by the present invention, it can be simultaneously Realize the characteristics of high Vr and low driving voltage. Therefore, it is extremely useful in the manufacture of III-nitride semiconductor light-emitting devices. -24- 200541121 [Brief Description of the Drawings] Figure 1 shows the III-nitride of the present invention in a pattern. Figure of a semiconductor light-emitting element. Figure 2 is a schematic cross-sectional view of an epitaxial laminated structure manufactured in Example 1. Figure 3 is a plan (planar) schematic view of an LED manufactured in Example 1. Figure 4 is a Shown in Example 1 Temperature method pattern diagram.

FIG. 5 is a schematic diagram showing a cooling method in Comparative Example 1. FIG. FIG. 6 is a schematic diagram showing a cooling method in Comparative Example 1. FIG. FIG. 7 is a plan view (planar view) of the LED manufactured in Example 2. FIG. [Description of main component symbols] 1 substrate 2 buffer layer 3 n-type semiconductor layer 4 light-emitting layer 5 P-type semiconductor layer 6 negative electrode 7 positive electrode 10 LED 11 laminated structure 20 LED 101 substrate -25- • 200541121

102 undoped 103 η-type GaN 104 cladding 105 luminescent layer 106 cladding 107 contact layer 108 negative electrode 109 positive electrode 1 10 bonding pad

GaN layer layer

-26-

Claims (1)

200541121 I. X. Patent application scope: 1. A method for manufacturing a III-nitride P-type semiconductor, which is characterized in that when a III-nitride semiconductor containing a P-type dopant is grown, the temperature is reduced and the temperature at the end of the growth is reduced. At the same temperature, the inert gas is used as the carrier gas immediately after the growth, and the flow rate of the nitrogen source is reduced, and the supply of the nitrogen source is stopped during the subsequent cooling process. 2. If the manufacturing method of item 1 of the scope of patent application, the temperature at the end of growth is above 900 ° C. ® 3 · The manufacturing method of item 1 in the scope of patent application, where the nitrogen source is ammonia. 4 · The manufacturing method of item 1 in the scope of patent application, wherein the carrier gas used in growing the semiconductor contains hydrogen. 5 · If the manufacturing method of item 1 of the scope of patent application, the flow rate of the reduced nitrogen source is 0.001 ~ 10% of the total gas volume. 6. If the method of applying for the scope of patent No. 1 is adopted, the temperature at which the supply of nitrogen source is stopped is 700 ~ 950 ° C. 7. A type III nitride p-type semiconductor, which is characterized by containing more than one-fifth the hydrogen atoms of the p-type dopant concentration and less than the p-type dopant concentration. 8 · — A type III nitride p-type semiconductor, which has a resistivity of 20 Ω cm to 10,000 Ω cm 〇9 · A type III nitride semiconductor light-emitting device, which is composed of a group III nitride semiconductor on a substrate The n-type layer, the light-emitting layer, and the P-type layer, and the negative electrode and the positive electrode are respectively disposed on the η-type layer and the ρ-type layer, which is characterized in that the manufacturing method of the P-type layer is as described in any one of the scope of patent applications 1 to Item system method. -27- 200541121 m 10. —A type III nitride semiconductor light-emitting device, which is provided with an n-type layer, a light-emitting layer, and a P-type layer composed of a III-nitride semiconductor on a substrate, and a negative electrode and a positive electrode are provided respectively The n-type layer and the p-type layer are characterized in that the p-type layer is a group 111 nitride p-type semiconductor as in item 7 or 8 of the scope of patent application. 11. For the light-emitting element according to claim 9 or 10, the positive electrode is a platinum group metal selected from the group consisting of Pd, Pt, Rh, Os, IΓ, and Ru as the positive electrode material. 12. The light-emitting element according to claim 9 or 10, wherein the light-emitting element is a flip-chip wafer type. 1 3 · The light-emitting element according to item 9 or 10 of the scope of patent application, wherein the light-emitting element is a face-up assembly type. -28-