TW200840095A - Nitride semiconductor light emitting element and method for manufacturing the same - Google Patents

Abstract

A nitride semiconductor light emitting element is provided with a III nitride semiconductor laminated structure having a laminated main surface other than a c-plane. The III nitride semiconductor laminated structure includes a first active layer, which has the main surface of the prescribed crystal plane other than the c-plane and generates light having a first wavelength, and a second active layer, which has the main surface of the prescribed crystal plane and generates light having a second wavelength different from the first wavelength. Furthermore, the III nitride semiconductor laminated structure may include an N-type nitride semiconductor layer and a P-type nitride semiconductor layer.; In such case, the first active layer may be between the N-type nitride semiconductor layer and the P-type nitride semiconductor layer and the second active layer may at areas other than the area between the N-type nitride semiconductor layer and the P-type semiconductor layer.

Description

[Technical Field] The present invention relates to a nitride semiconductor light-emitting element (light-emitting diode, laser diode, etc.) and a method of manufacturing the same. Field [prior art]

A semiconductor in which a nitrogen is used as a group V element in a group III-V semiconductor is referred to as a "group III nitride semiconductor", and representative examples thereof are aluminum nitride (A1N), gallium nitride (GaN), and indium nitride (InN). . In general, it can be expressed as AlxInyGa^yN (O^x^l ', which will be referred to as "GaN semiconductor" or "GaN semiconductor" hereinafter. It is known that a method for producing a nitride semiconductor is The m-type nitride semiconductor is grown by a metal organic chemical vapor phase growth (MOCVD) method on a gallium nitride (GaN) substrate having a c-plane as a main surface, and an N-type layer can be formed by applying this method. A GaN semiconductor stacked structure of a P-type layer can produce a light-emitting element having such a laminated structure. Such a light-emitting element can be used as a light source for a backlight for a liquid crystal panel, for example, on a GaN substrate having a c-plane as a main surface. The main surface of the grown GaN semiconductor is the c-plane. The light taken out from the c-plane is randomly polarized (no polarized light). Therefore, when it is incident on the liquid crystal panel, it is shielded in addition to the specific polarized light of the incident-side polarizing plate. It does not contribute to the brightness of the emission side. Therefore, it is difficult to achieve high-brightness display (the efficiency is only 50% maximum). In order to solve this problem, the review is based on the c-plane, and even the a-plane, m-plane, etc. Nonepolar face, A GaN semiconductor having a semi-polar (Semip〇lar) surface as a main surface is grown to produce a light-emitting element, and a P-type is formed by a GaN semiconductor layer having a polarity-free 127612.doc 200840095 surface or a semipolar plane as a main surface. The light-emitting element of the layer or the N-type layer can realize the light emission in a strong polarization state. Therefore, by making the polarization direction of such a light-emitting element coincide with the direction of polarization of the light-emitting plate on the incident side of the liquid crystal panel, the incident side can be reduced. Loss of the polarizing plate. As a result, high-brightness display can be achieved. [Non-Patent Document 1] T. Takeuchi et al., Jap J_ Appl. Phys. 39, 413-416, 2000 [Non-Patent Document 2] A. Chakraborty , B. A. Haskell, H. S. Her, J. s. Speck, S, P. DenBaars, S. Nakamura and U. K.

Mlshra: Jap. J. Appl. Phys. 44 (2005) L173 [Description of the Invention] [Problems to be Solved by the Invention] For example, the right to realize white light emission is the same as in the case of the conventional white LED (light emitting diode). Combined with a phosphor. That is, white light is emitted by causing the polarized light which is prepared by the light-emitting element to be incident on the phosphor and extracting the light emitted from the phosphor to the outside. The light emitted by the fluorescent body is the scattered light, which is a random source of polarization direction, and flat light. Therefore, if it is applied as a backlight for a liquid crystal panel, it is impossible to avoid a large loss in the polarizing plate, and a high-brightness display is not realized. The group 111 nitride semiconductor is formed right and has a r r or more. For the layer, it can be seen that such an active layer is resistant to thermal damage. For example, exemplified on the GaN substrate i, the egg is grown, and the layer is composed of a bismuth nitride semiconductor. (J〇c 200840095 layer, and further growth of the P-type GaN semiconductor layer to form a light-emitting diode structure. In this case, in order to obtain an emission wavelength of 5 〇〇 nm or more, it is necessary to take indium in the active layer. Therefore, the substrate temperature at the time of growth of the active layer is set to 700 ° C to 800 ° C. On the other hand, when the stray crystal of the 1 > type GaN layer formed on the active layer is grown, the substrate temperature is set to 8 〇〇 ac or more. At this time, the active layer is thermally damaged, which significantly impairs its luminous efficiency. Therefore, it is not always easy to obtain a wavelength of 500 nm or more. The object of the invention is to provide a polarized light which can take out more than two kinds of wavelength peaks. A nitride semiconductor light-emitting device which is easy to control the light-emitting wavelength and which is highly efficient, and a method for producing the same, and in general, a white light-emitting diode such as a polarized light is realized. [Technical means for solving the problem] The nitrogen of the present invention The semiconductor light-emitting device includes a group III nitride semiconductor stacked structure having a tantalum main surface other than the e-plane, and the m-nitride semiconductor layer structure includes a first active layer having a specific crystal other than the c-plane The main surface of the surface generates light of a first wavelength, and a second active layer having a main surface of a specific crystal plane of the reference, and generating light of a second wavelength different from the first wavelength. Since the first and second active layers each have a main surface of the common crystal plane, the polarized light is generated in the same direction. By simultaneously generating the first and second wavelengths of light from the first and second active layers, visually Such mixed color light is observed. Thus, polarization of the luminescent color (wavelength) which cannot be produced by controlling the composition of the active layer of the group m nitride semiconductor can be generated, and the vision can be easily controlled. The wavelength of the light emitted. 1276I2.doc 200840095 The first and second active layers are preferably composed of AlxlnyGai.x_yN (0Sx$ 1, OSy^l, O^x+y^l). Further, the N-type nitride semiconductor layer and the P-type nitride semiconductor layer may be further included. In this case, the first active layer is located between the N-type nitride semiconductor layer and the p-type nitride semiconductor layer, The two active layers may be located outside the N-type nitride semiconductor layer and the P-type nitride semiconductor layer. φ According to this structure, the N-type nitride semiconductor layer and the p-type nitride semiconductor layer ' are formed to be sandwiched. Light-emitting diode structure of the first active layer. Therefore, the first active layer can be excited to emit light by injecting a current into the first active layer. The second active layer can be excited by, for example, light generated by the first active layer to cause it to emit light. Since the second active layer is located outside the N-type nitride semiconductor layer and the p-type nitride semiconductor layer, the second active layer can be formed after the formation of the above. In this case, since the second active layer can avoid thermal damage at the time of formation of the N-type or p-type nitride semiconductor layer, the luminescence wavelength can be easily controlled. The second active layer may also be located on the opposite side of the first active layer to the P-type nitride semiconductor layer. < Moreover, the second active layer may be located on the opposite side of the first active layer to the N-type nitride semiconductor layer. Of course, the third active layer, the fourth active layer or still further active layers may be further provided in a ratio other than between the N-type nitride semiconductor layer and the p-type nitride semiconductor layer. In this case, since it is observed that the polarized light of three or more wavelengths is visually mixed, the control freedom of the emission wavelength can be increased. The nitride semiconductor device may further include a substrate having a first main surface and a second main surface which are all the specific crystal faces. In this case, the group III nitride semiconductor stacked structure may further include: a first portion including the first active layer laminated on the first main surface of the substrate; and a second portion including the laminate The second active layer on the second main surface of the substrate. According to this configuration, the group III nitride semiconductor stacked structure is distributed to one of the main surface sides and the other main surface side of the substrate. For example, the first portion laminated on the first main surface side of the substrate may be a structure including an N-type nitride semiconductor layer, a p-type nitride semiconductor layer, and a first active layer disposed therebetween. Thereby, on the first main surface side of the substrate, the first active layer is excited by current injection to cause polarized light emission, and the polarized light is guided to the second active layer on the first main surface side via the substrate. It can be polarized by light excitation. The aforementioned second main surface is preferably a mirror surface. As the substrate, a sapphire substrate (for example, a r-plane as a main surface), a LiAh〇3 substrate, a tantalum carbide substrate (for example, a melon surface as a main surface), or a gallium nitride substrate (for example, an a-plane or an m-plane as a main surface) may be used. )Wait. An a-plane lanthanide nitride semiconductor layer can be formed on the sapphire substrate, and a mesa-type nitride semiconductor layer can be formed on the LiA12〇3 substrate to form a secret (1) gallium nitride substrate on the m-plane carbon-cut substrate. Forming & the masking semiconductor layer 'on the m-plane gallium nitride substrate can be formed on the surface of the (1) group nitride 127612.doc 200840095 semiconductor layer. The aforementioned substrate preferably has a band gap wider than that of the aforementioned first active layer. In the case where the above-mentioned substrate is a conductive substrate (for example, a carbon-cut substrate or a (10) substrate), the band gap is made wider than that of the first active layer, and light absorption on the substrate can be suppressed. Thereby, the second active layer can be efficiently photoexcited. • The v60 month 1J i^ substrate should be transparent to the illuminating wavelength of the first active layer (preferably a light transmittance of 9% or more). Thereby, the light from the first impurity layer is efficiently guided to the second active layer, and the second active layer can be efficiently photoexcited.珂: The first active layer emits light by current injection, and the second active layer emits light by excitation of light from the light of the first active layer. According to this configuration, it is not necessary to inject current, or with respect to the second active layer. By constructing this, the structure becomes simple. Moreover, in the formation of the bismuth nitride semiconductor stacked structure, the second active layer may be formed after forming the FET-related structure associated with the first active layer, and the second active layer is not required.幵 / into a luminous body structure. Therefore, thermal damage at the time of formation of the light-emitting diode structure can be avoided and the second active layer can be formed. Thereby, the second active layer can have good luminous efficiency. The first active layer may also be composed of a Ι-π-type vaporized semiconductor having a larger band gap than the second active layer. The larger the band gap, the shorter the emission wavelength, and the better the heat resistance of the active layer. Therefore, the first active layer is disposed between the bismuth nitride semiconductor layer and the p-type nitride semiconductor layer to form a light-emitting diode structure, and the second active layer may be disposed outside the light-emitting diode structure. By I27612.doc 200840095, the first active layer can withstand the high temperature at the time of formation of the group III nitride semiconductor stacked structure, and the second active layer can be formed without being placed in the high temperature environment. Therefore, both the first and second active layers can perform polarized light emission with good efficiency. The specific crystal face may also be a non-polar or semi-polar face. Non-polar surface. Examples are melon (10_10) and 8 (ιυο). Examples of the semipolar surface include a surface, a (1 (M_3) plane, and a (11-22) plane. The method for producing a nitride semiconductor light-emitting device according to an aspect of the present invention has a surface other than the e-plane. The indium nitride semiconductor semiconductor layer structure of the laminated main surface; the step of forming the m-type nitride semiconductor stacked structure includes the steps of: forming a main surface having a specific crystal plane other than the c-plane to generate light of a first wavelength a step of forming a first active layer; and a second active layer having a main surface of the specific crystal face and generating light of a second wavelength longer than the first wavelength to form the cascading nitride semiconductor stacked structure In the constituent layer, a step of forming all the layers having a temperature higher than the formation temperature of the second active layer is formed. • By this method, the emission wavelength is very long, so that the second active layer having poor heat resistance can be protected from thermal damage. Therefore, both the first and second active layers can have good luminescence characteristics, and can perform visually mixed illuminating colors of the first and second wavelengths of light, for example, white polarized luminescence. ~ ΠΙ-nitride semiconductor The formation of the layer structure can be carried out by a HVPE (Hydride Vapor Phase Epitaxy) method or a metal organic chemical Vapor Deposition (MOCVD) method. In the production of a nitride semiconductor light-emitting device, 127612.doc -11 - 200840095, a group-group nitride semi-conductive t-layer structure having a laminated main surface other than the C-plane is provided, and the group 111 nitride semiconductor stacked structure is formed. Step 3 includes the steps of forming a nitride semiconductor layer of a first conductivity type: forming a main surface of a specific crystal plane having a c-plane outside the nitride semiconductor layer J1 of the first conductivity type, resulting in a a half-wavelength layer of the first wavelength of the first conductive layer; a step of forming a second conductivity type half: body layer; and a main surface having the specific crystal face, / a second active layer of light having a second wavelength of a first wavelength is formed after the nitride semiconductor layer of the first conductivity type, the first active layer, and the nitride semiconductor layer of the second conductivity type step According to this method, a second active layer is formed by forming a light-emitting diode associated with the first active layer. Therefore, the second active layer is not exposed to the light-emitting diode associated with the active layer::: The high temperature treatment during the formation of the body structure: thermal damage. Thus both the first and second active layers can produce the first and second wavelengths of polarized light with a good illuminating rate. The step of the second active layer is preferably to form the second active layer after forming all of the other constituent layers of the above-mentioned Group 111 nitride h bulk layer structure. According to this method, the second active layer can be surely prevented from being subjected to high temperature treatment. The resulting thermal damage. The second wavelength can also be above 500 nm. Therefore, the above-described method of manufacturing the nitride semiconductor light-emitting device can be modified in the same manner as in the case of the invention of the nitride semiconductor light-emitting device, for example, less than 500 nme / #. The above or further (4), features and (4) of the present invention can be clarified by the description of the embodiments described below with reference to the accompanying drawings by 127612.doc -12-200840095. [Embodiment] Fig. 1 is a schematic cross-sectional view for explaining the structure of a nitride semiconductor light-emitting element according to an embodiment of the present invention. This nitride semiconductor light-emitting element is formed on a GaN (gallium nitride) substrate 1 and is formed by growing a GaN semiconductor layer 2 which is a group III nitride semiconductor stacked structure.

The GaN semiconductor layer 2 has a first multi-quantum well (MQW) layer 22 which is an N-type Φ contact layer 21 and a first active layer (light-emitting layer) from the GaN substrate 1 side. a GaN final barrier layer 25, a P-type electron blocking layer 23, a P-type contact layer 24, and a stacked structure of a plurality of quantum well layers 26 as a second active layer (synthesizing layer). The surface of the P-type contact layer 24 has a lead-out portion which is drawn to the side of the second multiple quantum well layer, and the lead portion 3 as a transparent electrode is formed at the lead portion. Further, a portion of the anode electrode 3 is joined to the connecting portion 4 for wiring connection. Further, the cathode electrode 5 is bonded to the N-type contact layer 21. The Φ GaN substrate 1 is bonded to a support substrate (wiring substrate) 1A. Wirings 11, 12 are formed on the surface of the support substrate 10. Then, the connection portion 4 and the wiring n are connected by the bonding metal wires 13, and the cathode 5 and the wiring 12 are connected by the bonding metal wires 4. Further, the GaN semiconductor layer 2 anode electrode 3, the connection portion 4 and the cathode electrode 5, and the bonding wires 13 and 14 are sealed by a transparent resin such as an epoxy resin to constitute a nitride semiconductor light-emitting device. The N-type contact layer 21 is composed of a 矽2NsGaN layer added as an N-type dopant. The layer thickness should be 3 μηι. The doping concentration of cerium is, for example, 1 〇 18 em·3. More specifically, the N-type contact layer 21 is composed of an N-type GaN semiconductor grown on the GaN substrate (or Α1Ν^8 127612.doc -13-200840095). The first multiple quantum well layer 22 and the second multiple quantum well layer 26 are alternately laminated with a germanium-doped InGaN layer (for example, 3 nm thick), for example, in a characteristic period (for example, 5 cycles). A GaN final barrier layer 25 (for example, 40 nm thick) is laminated with a GaN layer (a barrier layer such as 9 nm) between the multiple quantum well layer 22 and the p-type electron blocking layer 23. The first multiple quantum well layer 22 is sandwiched between the N-type contact layer 21 and the P-type contact layer 24 to form a light-emitting diode structure. The first multiple quantum well layer 22 has an emission wavelength of less than 500 nm. More specifically, for example, 46 〇 nm (blue wavelength region). With respect to the P-type contact layer 24, the second multiple quantum well layer 26 is disposed on the opposite side of the first multiple quantum well layer 22, thereby being located outside of the above-described light-emitting diode structure. The second multiple quantum well layer 26 has an emission wavelength of 500 nm or more. More specifically, for example, 5 〇〇 nm to 600 nm (green to yellow wavelength region). That is, the second multiple quantum well layer 26 has a longer wavelength of illumination than the first multiple quantum well layer 22. In other words, the band gap of the second multiple quantum well layer 26 (more specifically, the band gap of the InGaN layer) is smaller than the f-gap of the first multiple quantum well layer 22 (more specifically, the band gap of the InGaN layer). . The adjustment of the band gap can be performed by adjusting the composition ratio of indium (In). For example, if the illuminating wavelength of the first multiple quantum well layer 22 is set to the blue wavelength region, and the illuminating wavelength of the second multiple quantum well layer 26 is set to the yellow wavelength region (560 nm to 600 nm), by visual mixing Blue light and yellow light can visually achieve white light.

The p-type electron blocking layer 23 is composed of a layer of AlGaN 127612.doc -14 - 200840095 added as a P-type dopant. The layer thickness is, for example, 28 nm. The doping concentration of magnesium is, for example, 3xl019 cnT3 〇 The P-type contact layer 24 is added with high concentration as a p-type dopant of magnesium.

The GaN layer is composed of. The layer thickness is, for example, 7 〇 nm. The doping concentration of magnesium is, for example, 1020 cm'3 〇. The anode electrode 3 is composed of a transparent thin metal layer (for example, 200 A or less) composed of a fine electrode. The cathode electrode is a film composed of Ti and an A1 layer.

The GaN substrate 1 is a substrate composed of GaN having a main surface other than the facet. More specifically, it is mainly a non-polar or semi-polar surface. It is preferably such that it has a ± i orientation from the plane of the non-polar surface. The surface of the dip inside, or ±1 from the plane of the semi-polar surface. The face of the dip inside is the main face

GaN single crystal substrate. The laminated main surface of each layer of the GaN semiconductor layer 2 is in accordance with

The crystal plane of the main surface of the GaN substrate 1. That is, the main faces of the constituent layers of the GaN semiconductor layer 2 are bonded to the GaN substrate! The crystal faces of the main faces have the same crystal face 0. If the k wires 11 and 12 are applied, a forward voltage is applied between the anode electrode 3 and the cathode electrode 5, and the first multiple quantum well layer 22 is excited by current injection to emit light. The luminescence mechanism is either diode luminescence or EL (electroluminescence). Since the main surface of the GW substrate 1 is a specific crystal plane (non-polar plane or semi-polar plane) other than the c-plane, the main surface of the first multiple quantum well layer 22 also becomes a crystal plane other than the c-plane (with the GaN substrate 1) Same crystal face). Therefore, the first multiple quantum well layer 22 produces polarized light. On the other hand, if light generated from the first multiple quantum well layer 22 is incident on the second 127612.doc -15-200840095 multiple quantum well layer 26, the second multiple quantum well layer 26 is excited by light to emit light. . The main surface of the second multiple quantum well layer 26 is also the same crystal plane as the GaN substrate 1. Thus, the second multiple quantum well layer 26 produces polarized light of the same polarization direction as the first multi-weight sub-well layer 22. Thus, the respective polarized rays emitted from the first and second multiple quantum well layers 22, 26 are observed visually mixed. Therefore, the polarization of the luminescent color mixing of the first and second multiple quantum well layers 22, 26 can be visually produced.

Fig. 2 is a diagram showing the unit cell of the crystal structure of the group III nitride semiconductor. The crystal structure of the group III nitride semiconductor can be approximated by a hexagonal system, and the surface along the c-axis in the axial direction of the hexagonal column (the top surface of the hexagonal column) is the c-plane (0001). In the group III nitride semiconductor, the polarization direction is along the c-axis. Therefore, since the c-plane exhibits different properties on the +C axis and the -C axis, it is called Polar Plane. On the other hand, the side faces of the hexagonal columns are melon faces (10-10), respectively, and the faces of the pair of ridgelines which are not adjacent are a face (11_2〇). These are crystal planes having a right angle to the c-plane, and since they are orthogonal to the polarization direction, they are surfaces having no polarity, that is, a non-polar plane (N〇np〇lar plane). Further, the crystal faces of the c-plane tilt (non-parallel or non-right angle) intersect obliquely with respect to the polarization direction, and thus are planes having a slight polarity, that is, semi-polar planes. Specific examples of the semipolar surface are a surface, a (10-1-3) plane, a (11-22) plane, and the like. The eccentricity of the surface and the crystal surface are shown in Non-Patent Document 1 as a relationship between the polarization of the normal direction of the crystal of the c-plane. From the non-patent literature 1, it can be said that the (1)% plane, the (1〇-12) plane, and the like are also minute crystal planes, which is a promising crystal plane which may be used for taking out light in a large polarized state. 127612.doc •16- 200840095 For example, a GaN single crystal substrate having an m-plane as a main surface can be cut and produced from a GaN single crystal having a facet as a main surface. The m-plane of the cut substrate is polished by, for example, chemical mechanical polishing to produce an azimuth error of ±1 for both the (0001) direction and the (11_2〇) direction. Within (should be ±〇3.). Thus, a GaN single crystal substrate having a crystal front defect and having no indexing or lamination defects is obtained. On the surface of such a GaN single crystal substrate, only the step of the atomic level is generated.

On the GaN single crystal substrate thus obtained, the GaN semiconductor layer 2 can be grown by the m〇CVD method. Fig. 3 is a schematic view for explaining the structure of a processing apparatus for growing the layers constituting the GaN semiconductor layer 2. A susceptor 32 having a built-in heating benefit 31 is disposed in the processing chamber 3A. The base 32 is coupled to a rotating shaft 33 that is rotated by a rotary drive mechanism 34 disposed outside the processing chamber 30. Thereby, the wafer 35 to be processed is held on the susceptor 32 so that the wafer 35 can be heated to a specific temperature and rotated in the process (4). The wafer (10), for example, a GaN single crystal wafer constituting the front urarsi丞槪1. An exhaust gas distribution f 36 is observed in the processing chamber. The exhaust gas is equipped with f 36 connected to an exhaust device such as a rotary pump. Thereby, the pressure in the processing chamber 3G becomes ι/ι〇 atmospheric pressure to normal pressure (it is the degree of occupational pressure), and the atmosphere in the processing chamber is always exhausted. On the other hand, the raw material gas is introduced in the processing chamber 3G. The supply path 4 is for supplying the material gas toward the surface of the wafer 35 held by the susceptor 32. The raw material gas supply path 4〇i is taken by the technical woman. The road transport is provided with a gas raw material supply pipe 41 as a nitrogen source gas, and a gallium raw material supplied as a recording material (4)*: 127612.doc -17- 200840095 The pipe 42 is supplied with an aluminum raw material pipe 43 as an aluminum raw material gas, and a copper raw material pipe 44 as a dimethyl indium (TMIn) of the indium raw material 7 is rolled as a crucible; 5 > μ is a Zhenyuan disorder The magnesium raw material piping 4S of the ethyl cyclopentadienyl magnesium (EtChMg) and the Shixi raw material piping 46 of the decane-clearing material 4). These raw material pipes 41 to 46 are respectively provided with 阙51 to 56. Each of the material gases is supplied together with a carrier gas composed of hydrogen or nitrogen or the like.

For example, a GaN single crystal wafer having an m-plane as a main surface is held as a wafer on the susceptor 32. In this state, the valve is closed in advance, and the raw material width 51 is opened to supply the carrier gas and the ammonia gas (nitrogen source gas) into the processing chamber 30. Stepping on the heater 31, the wafer temperature is raised to 1000 ° C to 1100 ° C (for example, l 〇 5 (TC) e, thereby preventing surface turbulence and GaN semiconductor growth. Standby to wafer temperature 〇 。 。 。 ( 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮 氮Trimethylgallium and decane. As a result, on the surface of the wafer 35, an N-type contact layer 21 composed of a GaN layer doped with germanium is grown. After the formation of the N-type contact layer 21, the germanium material valve 56 is formed. Closing, the growth of the first multiple quantum well layer 22 is performed. The growth of the first multiple quantum well layer 22 is performed by interactively performing the following steps: by opening the nitrogen material valve 51, the gallium material valve 52, and the indium material a step 54 of supplying ammonia, trimethylgallium, and trimethylindium to the wafer 35 to grow the InGaN layer (quantum well layer); and closing the indium material valve 54, opening the nitrogen material valve 51 and the gallium material Valve 52, 127612.doc -18 - 200840095 Supply money and dimethyl gallium to wafer 35 for unadded GaN layer (P chapter wall

Layer) steps to grow. For example, a GaN layer is first formed, and inGaN is formed thereon.

After repeating this, the GaN final barrier layer 25 is finally formed on the InGaN layer. The temperature of the wafer 35 is preferably, for example, 7 (10) (10), in the formation of the first multiple quantum well layer 22 and the GaN final barrier layer 25. ◦ (for example, 730 ° 〇〇, then, a P-type electron blocking layer 23 is formed. That is, the nitrogen raw material valve 5 丨, the gallium raw material valve 52, the aluminum raw material valve 53 and the magnesium raw material valve 55 are opened, and the other valves are "closed." Thus, ammonia, trimethylgallium, trimethylaluminum, and ethylpentadienyl magnesium are supplied toward the wafer 35 to form a P-type electron blocking layer 23 composed of a magnesium-doped AlGaN layer. When the formation of the stopper layer 23 is formed, the temperature of the wafer 35 is preferably 800 ° C or more (for example, 1 Å.) Next, the P-type contact layer 24 is formed. That is, the nitrogen raw material valve 5 丨, the gallium raw material valve 52 And the magnesium material valve 55 opens 'other valves 53, 5 [% closed. Thereby, ammonia, trimethylgallium and ethylcyclopentadienyl magnesium are supplied toward the wafer 35 to form a GaN layer doped with magnesium. The p-type contact layer 24. When the p-type contact layer is formed thereon, the temperature of the wafer 35 is preferably 80 (rc or more (for example, 1 Å. 〇. Then, next to the P-type contact layer 24, and The second multiple quantum well layer 26 is formed identically in the case of a multiple quantum well layer 22. By adjusting the indium during the formation of the first and second multiple reset subwell layers 22, The flow ratio of the source gas, the gallium source gas, and the nitrogen source gas adjusts the composition of the InGaN layer. Thereby, the band gap of the InGaN layer is adjusted, and as a result, the first and second multiple quantum well layers 22, 26 are controlled. Thus, if the GaN semiconductor layer 2 is grown on the wafer 35, the wafer 127612.doc -19·200840095 35 is moved to an etching apparatus, for example, by plasma etching, as shown in FIG. The concave portion 7 exposing the N-type contact layer 21 and the concave portion 8 exposing the N-type contact layer. The concave portion 7 may also form the first multiple quantum well layer 22, the P-type electron blocking layer 23, and the p. The contact layer is formed so that the first multi-weight sub-layer 22, the P-type electron blocking layer 23 and the ?-type contact layer 24 can be shaped into a topography. Similarly, the recess 8 can also be formed to surround the second Multiple quantum well layers 26, whereby the second multiple quantum well layer % can be shaped into a topography. φ Also, the anode electrode 3 is formed by resistance heating or a metal vapor deposition device using an electron beam beam. The connecting portion 4 and the cathode electrode 5. Thereby, the light emitting diode structure shown in Fig. 1 can be obtained. After the wafer process, individual wafers are cut by opening the wafer 35. The individual components are connected to the lead electrodes by die bonding and metal wire bonding, and then sealed in a transparent resin such as an epoxy resin. Thus, a nitride semiconductor light-emitting device is fabricated. As described above, the second multiple quantum well layer 26 is formed in the group III nitride semiconductor stacked layer structure, that is, finally formed in the constituent layers of the GaN semiconductor layer 2. More specifically, After the formation of the light-emitting diode structure in which the first plurality of reset sub-well layers 22 are sandwiched by the N-type contact layer 21 and the p-type contact layer 24, the second multiple quantum well layer 26 is formed. Therefore, the second multiple quantum well layer 26 does not experience a temperature of 8 时 when the p-type contact layer 24 is formed. (: above (for example, 100 (rc). Further, the first multiple dice well layer 26 is formed in the constituent layer of the GaN semiconductor layer 2, and is formed after all the layers forming the temperature 咼 are formed. Therefore, The two multiple quantum well layers 26 are not thermally damaged during the formation of other layers. Therefore, the second multiple Xiazi well layer 26, although it is a light-emitting layer with a longer wavelength of light, can still have good 127612.doc -20- 200840095 In other respects, since the first multiple quantum well layer 22 is a light-emitting layer having a short emission wavelength, it can withstand the high temperature at the time of formation of the P-type contact layer 24, and thus still has good luminous efficiency. The second multiple quantum well layers 22, 26 are all luminescent layers that emit polarized light, and their polarization directions are also the same. Therefore, the illuminating rays from the first and second multiple quantum well layers 22, 26 are mixed and observed. The polarized light of the mixed color is visually observed. Thus, the polarized light whose color is controlled can be taken out from the nitride semiconductor light-emitting element. FIG. 4 is a view for explaining the nitride semiconductor light emission according to another embodiment of the present invention. Component BRIEF DESCRIPTION OF THE DRAWINGS In Fig. 4, portions corresponding to the respective portions shown in Fig. 1 are denoted by the same reference numerals. This embodiment is a GaN semiconductor layer which is a group III nitride semiconductor stacked structure. 2 is a main surface (first main surface) side of the GaN substrate 1, and has a first portion 2A including the first multiple quantum well layer 22 on the other main surface (second main surface) side of the GaN substrate. The second portion 2B of the second multiple quantum well layer 26. The other main surface (second main surface) is a mirror surface. The first portion 2A is from the GaN substrate 1 side, sequentially laminating the n-type contact layer 21, first The multiple quantum well layer 22, the final barrier layer 25, the P-type electron blocking layer 23, and the P-type contact layer 24 are formed. In this embodiment, the second portion 2B includes only the second multiple quantum well layer 26. The multiple quantum well layer 26 is disposed on the opposite side of the first multiple quantum well layer 22 from the N-type contact layer 21, and is disposed on the first multiple quantum well layer sandwiched by the N-type and P-type contact layers 21, 24. The outer side of the light-emitting diode structure of 22. The second multiple quantum well layer 26 side is a light extraction surface. 127612.doc -21- 20 0840095 The anode electrode 3 formed on the surface of the P-type contact layer 24 is bonded to the wiring 11 (die bonding) on the support substrate 110. Thereby, the light-emitting diode structure is reversed in the same manner as in FIG. It is fixed to the support substrate 10.

The first portion 2A of the GaN semiconductor layer 2 is etched (for example, plasma etched) to expose the N-type contact layer 21 from the side of the support substrate 10, and the recess 17 is formed. In the recess 17, a cathode electrode 5 which is in contact with the N-type contact layer 21 is formed. The cathode electrode 5 and the wiring 12 on the support substrate 1 are connected by a metal post 18. By the structure of the first portion 2A of the GaN semiconductor layer 2, the diode structure of the first multiple quantum well layer 22 sandwiched by the N-type contact layer 21 and the P-type contact layer 24 is formed. Therefore, if a forward voltage is applied between the anode electrode 3 and the cathode electrode 5, the first multiple quantum well layer 22 is excited by current injection, resulting in polarization depending on the crystal plane of the principal surface. This light penetrates the GaN substrate 1 and reaches the second multiple quantum well layer 26, thereby photoexciting the second multiple quantum well layer 26 to produce a polarization depending on the crystal plane of the major surface. Since both main faces of the GaN substrate 1 are co-crystal faces other than the c-plane, the polarization directions of the first and second multiple quantum well layers 22, 26 are equal. Therefore, on the side of the second multiple quantum well layer 26, the polarization of the luminescent color mixing of the first and second multi-weight sub-well layers 22, 26 is observed. In order to suppress the polarized light generated by the first multiple quantum well layer 22 from being absorbed by the GaN substrate 1, the GaN substrate 1 preferably has a wider band gap than the first multiple quantum well layer 22. Further, the substrate 1 is preferably transparent to the light-emitting wavelength of the first multiple quantum well layer 22 (preferably having a light transmittance of 90% or more). When the nitride semiconductor light-emitting device having such a structure is produced, the first portion 2A of the GaN semiconductor layer 2 is grown on one of the main surface sides of the GaN substrate 1 by epitaxial growth 127612.doc-22-200840095, and then on the other side of the GaN substrate 1. On the main surface side, the first ridge layer 26 constituting the second portion 2B is subjected to stray crystal growth. Therefore, since the second radiant well layer 26 is formed later than the light-emitting diode structure of the first portion 2A, it does not cause thermal damage caused by the high temperature at the time of formation of the P-type contact layer 24 or the like. Thereby, it is possible to emit light with good efficiency. • The above description relates to the embodiment of the present invention, but the present invention can be further implemented in other forms. For example, in the above-described embodiment, an example in which the invention is applied to the light-emitting body structure is described. However, the present invention is also applicable to other light-emitting elements such as a laser diode. Further, in the above-described embodiment, an example in which the GaN substrate 1 having the melon surface as the main surface is used is mainly described, but a GaN* plate having the a-plane as the main surface may be used, and (10-11) plane may also be used. , such as (10-13) plane, (11-22) and the like, such a semi-polar surface is the main surface of the GaN substrate. Further, in the above-described example, an example is described in which the GaN semiconductor layer 2 is grown again on the GaN substrate 1. However, for example, on a tantalum carbide substrate having an m-plane as a main surface, and a GaN semiconductor having an m-plane as a growth main surface The GaN semiconductor having the a-plane as the main surface can be grown on the orphanite substrate on the main surface of the core surface. Further, an example in which the GaN semiconductor is epitaxially grown on the GaN substrate 1 by the M CVD method will be described in the above-described embodiment, but other stray crystal growth methods using the H VPE method may be applied. Moreover, in the foregoing embodiment, the structure having the first and second multiple quantum well layers (light emitting layers) 22, 26 is illustrated, but as shown in, for example, FIGS. j and 4, the second multiple quantum well layer 26 is stacked. The third active layer 27 may also be used. The third activity 127612.doc -23- 200840095 layer 27 is, for example, any of the first and second multiple quantum well layers 22, % of which are composed of a group III nitride semiconductor layer having a different emission wavelength (more specifically, multiple A quantum well layer consisting of receiving light from the first multiple quantum well layer 22 and performing photoexcitation to emit light. Thereby, the three-color polarized light is visually mixed and observed. Of course, the fourth active layer or the fifth active layer may be laminated in a stepwise manner to perform polarized light emission of a mixed color of four or more colors. The embodiments of the present invention are described in detail, but are merely intended to clarify the specific examples of the technical contents of the present invention. The present invention is not limited to the specific examples, and the spirit and scope of the present invention are only The scope of the patent application is limited. The present application is hereby incorporated by reference in its entirety to the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing the structure of a nitride semiconductor light-emitting device according to an embodiment of the present invention. Fig. 2 is a view showing a unit cell of a crystal structure of a lanthanum nitride semiconductor. Fig. 3 is a schematic view for explaining the structure of a processing apparatus for growing the layers constituting the GaN semiconductor layer. Fig. 4 is a schematic cross-sectional view for explaining the configuration of a nitride semiconductor light-emitting element according to another embodiment of the present invention. [Major component symbol description] 1 GaN substrate 127612.doc -24- 200840095 2 GaN semiconductor layer 2A First portion 2B Second portion 3 1% pole electrode 4 Connection portion 5 Cathode 7, 8 Recessed portion 10 Support substrate 11, 12 wiring 13 , 14 bonding wire 17 recess 18 metal column 21 N-type contact layer 22 first multiple quantum well layer (first active layer) 23 P-type electron blocking layer • 24 P-type contact layer 25 final barrier layer 26 second multiple Quantum well layer (second active layer) - 27 third active layer. 30 processing chamber 31 heater 32 base 33 rotating shaft 34 rotary drive mechanism 127612.doc -25- 200840095

35 36 40 41 42 43 44 45 51 52 53 54 55 56 Wafer exhaust pipe raw material gas supply route nitrogen raw material piping gallium raw material piping aluminum raw material piping raw material piping magnesium raw material piping raw material piping nitrogen raw material valve gallium raw material valve Cui Lu raw material Wide indium raw material valve magnesium raw material valve 矽 raw material valve

1276I2.doc -26-

Claims (1)

200840095 X. Patent Application Range: 1 . A nitride semiconductor light-emitting device comprising a group III nitride semiconductor stacked structure having a laminated main surface other than a c-plane; the III-nitride semiconductor stacked structure comprises: An active layer having a major surface of a specific crystal plane other than the C plane to generate light of a first wavelength; and a second active layer having a major surface of the specific crystal plane, which is different from the first wavelength Light of the second wavelength. 2. The nitride semiconductor light-emitting device of claim 1, wherein the first and second active layers are composed of AlxIriyGa^yN (OSxgl, OSy^l, 〇Sx+y$1). 3. The nitride semiconductor light-emitting device of claim 1, wherein the bismuth nitride semiconductor stacked structure further comprises: a bismuth nitride semiconductor layer and a bismuth nitride semiconductor layer; wherein the first active layer is located in the Ν type The second active layer is located between the nitride semiconductor layer and the p-type nitride semiconductor layer. 4. The nitride semiconductor light-emitting device of claim 3, wherein the second active layer is located on a side opposite to the first active layer to the germanium-type nitride semiconductor layer. The nitride semiconductor light-emitting device of claim 3, wherein the second active layer is located on a side opposite to the first active layer to the germanium-type nitride semiconductor layer. 127612.doc 200840095 6. The nitride semiconductor light-emitting device of claim 1, wherein the re-attack ^ /, T further comprises a substrate having a plurality of main faces and a second main surface which are specific crystal faces; The III-nitride semiconductor stacked structure includes a part of the first active layer ′′ and a second portion laminated on the first main surface of the substrate, and includes a layer stacked on the substrate - • The second active layer of the aforementioned coin. The nitride semiconductor light-emitting device of claim 6, wherein the first main surface is a mirror surface. 8. The nitride semiconductor light-emitting device of claim 6, wherein the substrate has a band gap wider than the first active layer. 9. The nitride semiconductor light-emitting device of claim 6, wherein the substrate is transparent to an emission wavelength of the first active layer. 10. The nitride semiconductor light-emitting device of claim 1, wherein the first active layer emits light by current injection, and the second active layer is excited by light caused by light from the first active layer. Glowing. The nitride semiconductor light-emitting device of claim 1, wherein the first active layer comprises a lanthanide nitride semiconductor having a larger band gap than the second active layer. 12·If requested! A nitride semiconductor light-emitting device according to any one of the preceding claims, wherein the two characteristic crystal faces are non-polar or semi-polar faces. 13. A method of fabricating a nitride semiconductor light-emitting device, wherein the nitride semiconductor light-emitting device comprises a group III nitride semiconductor stacked structure having a laminated main surface other than a c-plane; 127612.doc 200840095 forming the aforementioned πι nitride The step of constructing the semiconductor laminate structure comprises the steps of: forming a main surface having a specific crystal plane other than the c-plane, generating a first active layer of light of a first wavelength; and forming the layer 111 nitride semiconductor stacked structure Forming in the constituent layer. The temperature is higher than the formation temperature of the second active layer, and all the layers are formed to form a main surface having the specific crystal face and generating a light longer than the first wavelength. The step of the active layer. 14. A method of fabricating a nitride semiconductor light-emitting device, wherein the nitride semiconductor light-emitting device comprises a nitride nitride semiconductor stacked structure having a laminated main surface other than a c-plane; 'forming a uranium-group III nitride semiconductor stack The step of the layer structure includes the steps of: forming a nitride-type semiconductor layer of a conductivity type; forming a main surface having a specific crystal plane other than the e • surface on the nitride semiconductor layer of the first conductivity type a step of forming a first active layer of light of a wavelength; a step of forming a nitride semiconductor layer of a second conductivity type on the first active layer; and a step of forming a nitride semiconductor layer of the first conductivity type, the foregoing — a step of forming a second active layer having a principal surface of the specific crystal plane and generating light of a second wavelength longer than the first wavelength, after the active layer and the nitride semiconductor layer of the second conductivity type. 15. The method of manufacturing a nitride semiconductor light-emitting device according to claim 13 or 14, 127,612.doc 200840095, wherein the step of forming the second active portion to form the first active layer is performed on the formed semiconductor stacked structure After all other constituent layers, the steps of the sexual layer. The method of producing a nitride semiconductor light-emitting device according to claim 13 or 14, wherein the second wavelength is 500 nm or more. 127612.doc