JP2009231609A - Production method of semiconductor light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a semiconductor light-emitting element, which can enhance the proportion of incorporated In in a step of growing an active layer containing In on a GaN substrate, having a semipolar plane as main surface. <P>SOLUTION: In a step of growing an InGaN well layer 5a on a GaN substrate 15, having a main surface where an off-angle from the c-plane is included in a range of 20° or larger and 28° or smaller; growth temperature is in a range of 600°C or higher and 700°C or lower; mol flow ratio (Q<SB>V</SB>/Q<SB>In</SB>) between an N raw material gas flow Q<SB>V</SB>and In raw material gas flow Q<SB>In</SB>is a value included in a range of 9,000 or larger and 30,000 or smaller; a growth speed of the well layer 5a is set as a speed, included in the range of 0.01 μm/hour or more and 0.1 μm/hour or less, and the thickness for each of the well layers 5a is set at 10 nm or smaller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor light emitting device.

  In recent years, there is a group III nitride semiconductor light emitting device in which an active layer containing indium (In) is formed on a gallium nitride (GaN) substrate. In such a semiconductor light emitting device, when a GaN substrate having a c-plane, that is, a (0001) plane as a main surface is used, a relatively large strain occurs in the active layer containing In. For this reason, the quantum Stark effect due to the piezo electric field is generated, and the emission efficiency is lowered due to the spatial separation of electrons and holes, or the piezo electric field is screened according to the amount of current injection, and the emission wavelength is shifted to the short wavelength side. Problem arises.

Therefore, when manufacturing such a semiconductor light emitting device, a GaN substrate having a semipolar surface as a main surface is used in order to suppress a piezoelectric field. For example, Non-Patent Document 1 discloses a technique for manufacturing an LED using a GaN substrate having a semipolar plane as a main surface. In this document, an LED structure including an InGaN active layer is formed on a GaN substrate having a (11-22) plane as a main surface, and green EL (ElectroLuminescence) is realized.
Mitsuru FUNATO etal., “Blue, Green, and Amber InGaN / GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates”, Japanese Journal of Applied Physics Vol.45, No.26, pp.L659-L662, (2006)

  However, when a semiconductor light emitting device in which an active layer containing In is formed on a GaN substrate is to be put into practical use, the following problem occurs. That is, when an active layer containing In is grown on a GaN substrate whose main surface is a semipolar plane, compared to a case where an active layer containing In is grown on a GaN substrate whose main surface is a c-plane The proportion of In taken into the active layer is reduced. For example, when an InGaN layer is grown on a GaN substrate having an off angle of 18 ° under a growth condition that allows the In composition ratio to be about 20% when an InGaN layer is grown on a c-plane GaN substrate, the In composition ratio Decreases to about 8.3%. When the off angle is further increased and an InGaN layer is grown on a GaN substrate having an off angle of 28 ° under the same conditions, the In composition ratio is greatly reduced to about 5.8%. Therefore, it is difficult to stably obtain a semiconductor light emitting device having a desired light emission wavelength such that even if it is desired to obtain a green light emission wavelength, only a blue-violet light emission wavelength can be obtained.

  The present invention has been made in view of the above-described problems, and can increase the proportion of In taken in when an active layer containing In is grown on a GaN substrate having a semipolar plane as a main surface. An object of the present invention is to provide a method for manufacturing a semiconductor light emitting device.

In order to solve the above problems, a method for manufacturing a semiconductor light emitting device according to the present invention includes a method for manufacturing a semiconductor light emitting device including an active layer having one or more group III nitride semiconductor layers containing indium on a gallium nitride substrate. And a step of growing a group III nitride semiconductor layer on a gallium nitride substrate having a main surface whose off-angle from the (0001) plane is in the range of 20 ° to 28 °, and the growth temperature in the step Is included in the range of 600 ° C. or more and 700 ° C. or less, and the molar flow rate ratio between the flow rate Q _V [mol / min] of the group V element source gas and the indium source gas flow rate Q _In [mol / min] in the process ( Q _V / Q _In ) is included in the range of 9000 to 30000, and the growth rate of the group III nitride semiconductor layer in the process is in the range of 0.01 [μm / hour] to 0.1 [μm / hour]. Included, The thickness of each group III nitride semiconductor layer is 10 nm or less.

  As described above, when a group III nitride semiconductor layer containing In is grown on a GaN substrate having a semipolar plane as a main surface, the proportion of In taken in is smaller than when grown on a c-plane. End up. Therefore, the present inventor considered increasing the supply amount of the In source gas. However, if only the supply amount of the In source gas is increased while maintaining the conventional growth conditions, the crystallinity of the group III nitride semiconductor layer is lowered. One way to solve this problem is to reduce the growth rate of the group III nitride semiconductor layer. However, if the growth rate is reduced, the separation of In occurs, resulting in a sufficiently increased In incorporation rate. I can't.

Therefore, the present inventor has used a GaN substrate having a main surface that is included in the range of an off angle from the c-plane of 20 ° or more and 28 ° or less even in the case of a semipolar substrate. We succeeded in increasing the In incorporation rate by lowering the growth rate while lowering the growth rate while lowering the growth temperature while lowering the growth temperature of the semiconductor layer. That is, according to the method for manufacturing a semiconductor light emitting device described above, when the group III nitride semiconductor layer is grown on the GaN substrate having the above-described off angle, the growth temperature is set in the range of 600 ° C. to 700 ° C. The molar flow rate ratio (Q _V / Q _In ) of the group element (eg, nitrogen) source gas flow rate Q _V [mol / min] and the indium source gas flow rate Q _In [mol / min] is 9000 to 30000 And the growth rate of the group III nitride semiconductor layer is in the range of 0.01 [μm / hour] to 0.1 [μm / hour], and the In incorporation ratio while maintaining good crystallinity. Can be increased.

  In addition, there is a possibility that In droplets are generated under such growth conditions, but if the thickness of each layer of the group III nitride semiconductor layer is 10 nm or less, the growth must be completed before the droplets are generated. Can do.

  According to the method for manufacturing a semiconductor light emitting device according to the present invention, when an active layer containing In is grown on a GaN substrate having a semipolar plane as a main surface, the proportion of In taken in can be increased.

  Hereinafter, embodiments of a method for manufacturing a semiconductor light emitting device according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a side sectional view schematically showing a configuration of a semiconductor light emitting device 1 as an example of a semiconductor light emitting device manufactured by the method for manufacturing a semiconductor light emitting device according to the present embodiment. As the semiconductor light emitting element 1, for example, there is a surface emitting light emitting diode. The semiconductor light emitting device 1 includes an n-type gallium nitride semiconductor layer 3, an active layer 5 having one or more group III nitride semiconductor layers containing In, a p-type AlGaN semiconductor layer 7, and a p-type gallium nitride semiconductor. A layer 9 and an electrode 11 are provided. The active layer 5 is provided on the n-type gallium nitride based semiconductor layer 3. The p-type AlGaN layer 7 is provided on the active layer 5. The p-type gallium nitride based semiconductor layer 9 is provided on the p-type AlGaN layer 7. The electrode 11 is in contact with the p-type gallium nitride semiconductor layer 9 and is, for example, an anode electrode. This contact is preferably an ohmic contact.

  The n-type gallium nitride based semiconductor layer 3 functions as a lower cladding layer. As an example of the n-type gallium nitride based semiconductor layer 3, an n-type GaN semiconductor layer having a thickness of 2000 [nm] is suitable. The p-type AlGaN semiconductor layer 7 functions as an electron block layer for reducing electron leakage from the active layer 5 and increasing luminous efficiency. The thickness of the p-type AlGaN semiconductor layer 7 is, for example, 20 [nm]. The p-type gallium nitride based semiconductor layer 9 functions as a contact layer for electrical conduction with the electrode 11. As an example of the p-type gallium nitride based semiconductor layer 9, a p-type GaN semiconductor layer having a thickness of 50 [nm] is suitable.

  The semiconductor light emitting device 1 further includes an n-type GaN substrate 15. The n-type GaN substrate 15 has a main surface 15a. The off angle from the (0001) plane, that is, the c-plane of the main surface 15a is included in the range of 20 ° to 28 °, for example, 23 °. An n-type AlGaN layer 17 is provided on the main surface 15 a of the n-type GaN substrate 15, and an electrode 19 (cathode electrode) is in contact with the back surface of the n-type GaN substrate 15. The n-type gallium nitride based semiconductor layer 3 is provided on the n-type AlGaN layer 17. The thickness of the n-type AlGaN layer 17 is, for example, 20 [nm].

  The active layer 5 can have a quantum well structure, for example, and includes an InGaN well layer 5a and a barrier layer 5b. The well layer 5a is a group III nitride semiconductor layer containing In, and can be made of, for example, InGaN. The barrier layer 5b is made of a gallium nitride-based semiconductor, and can be made of, for example, InGaN having an indium composition smaller than that of the well layer 5a. The material of the barrier layer 5b can be GaN if necessary. The structure of the active layer 5 is not limited to a single or multiple quantum well structure, and may be a single InGaN layer. The thickness of each well layer 5a is 10 [nm] or less, for example, 5 [nm]. The thickness of the barrier layer 5b is preferably thicker than that of the well layer 5a, and the thickness of each barrier layer 5b is, for example, 15 [nm]. Light L from the active layer 5 is emitted through the electrode 11.

  The semiconductor light emitting device 1 further includes an n-type gallium nitride buffer layer 21. The n-type gallium nitride buffer layer 21 is provided between the n-type gallium nitride semiconductor layer 3 and the active layer 5. The c-axis lattice constant of the well layer 5a made of InGaN is larger than the c-axis lattice constant (0.51851 nm) of the n-type gallium nitride based semiconductor layer 3 made of GaN. In this semiconductor light emitting device 1, an n-type gallium nitride buffer layer 21 is used to compensate for the difference in lattice constant between the n-type gallium nitride semiconductor layer 3 and the active layer 5. Thereby, the active layer 5 can be grown without being influenced by GaN.

  In the semiconductor light emitting device 1, the n-type gallium nitride buffer layer 21 is preferably made of low-temperature grown InGaN, and the thickness of the n-type gallium nitride buffer layer 21 is, for example, 50 [nm]. The growth temperature of the low-temperature grown InGaN is preferably 800 ° C. or lower, for example, and preferably 300 ° C. or higher.

  FIG. 2 is a flowchart showing the main steps of the method for manufacturing the semiconductor light emitting device 1 according to the present embodiment. 3 and 4 are diagrams for explaining each process shown in FIG. First, in step S101 of FIG. 2, as shown in FIG. 3A, an n-type GaN wafer 40 having a main surface 40a that includes an off angle from the c-plane in the range of 20 ° to 28 ° is prepared. To do. Next, in step S103, a substrate product such as an epitaxial wafer is manufactured. In step S103a, as shown in FIG. 3B, an n-type AlGaN layer 41, an n-type gallium nitride semiconductor layer 42, and an n-type gallium nitride buffer layer 43 are formed on the main surface 40a on the n-type GaN wafer 40. Epitaxial growth. The thicknesses of these layers are, for example, 20 [nm] for the n-type AlGaN layer 41, 2000 [nm] for the n-type gallium nitride based semiconductor layer 42, and 50 [nm] for the n-type gallium nitride based buffer layer 43. The n-type gallium nitride based semiconductor layer 42 is preferably GaN, and the n-type gallium nitride based buffer layer 43 is preferably low-temperature grown InGaN.

  In the subsequent step S103b, as shown in FIG. 4A, an active layer 44 having one or a plurality of group III nitride semiconductor layers containing In is formed on the n-type gallium nitride buffer layer 43. In the present embodiment, the well layer included in the active layer 44 corresponds to the group III nitride semiconductor layer, and the well layer and the barrier layer are alternately epitaxially grown on the n-type gallium nitride-based buffer layer 43, whereby the active layer 44 is formed. The well layer of the active layer 44 is formed by growing InGaN, and the barrier layer of the active layer 44 is formed by growing InGaN or GaN. The thickness of each well layer is 10 [nm] or less, for example, 5 [nm]. The thickness of the barrier layer is, for example, 15 [nm]. In addition, since the n-type gallium nitride buffer layer 43 made of low-temperature grown InGaN is provided on the n-type gallium nitride semiconductor layer 42 having a thickness of 2000 [nm], the influence of the distortion of the InGaN well layer in the active layer 44 is affected. Alleviated. Further, as described above, the off-angle from the c-plane of the main surface 40a of the GaN wafer 40 is included in the range of 20 ° to 28 °. In other words, the normal line of the main surface 40a is inclined in the range of 20 ° to 28 ° with respect to the c-axis. Thereby, a semiconductor light emitting device capable of reducing the influence of the piezoelectric field can be manufactured.

  In the subsequent step S103c, as shown in FIG. 4B, the p-type AlGaN semiconductor layer 45 and the p-type gallium nitride semiconductor layer 46 are epitaxially grown on the active layer 44. The p-type AlGaN semiconductor layer 45 is, for example, an electron block layer, and the p-type gallium nitride semiconductor layer 46 is, for example, a contact layer. The thicknesses of these layers are, for example, 20 [nm] for the p-type AlGaN semiconductor layer 45 and 50 [nm] for the p-type gallium nitride based semiconductor layer 46. The p-type gallium nitride based semiconductor layer 46 is formed by growing GaN, for example. Through the above steps, an epitaxial wafer is manufactured.

  In step S105, a translucent electrode (anode electrode) is formed on the p-type gallium nitride based semiconductor layer 46 of the epitaxial wafer. Further, another electrode (cathode electrode) is formed on the back surface of the GaN wafer 40. Finally, this epitaxial wafer is divided into chips to complete the semiconductor light emitting device 1 of the present embodiment.

  Here, a specific example of the growth method of the active layer 44 will be described in more detail with reference to FIG. FIG. 5 is a graph showing the temperature transition (FIG. 5A) of the GaN wafer 40 when the active layer 44 is grown, and the supply / non-supply state of the source gas (FIG. 5B). . First, an InGaN crystal that becomes a well layer is grown in a period T1. In the step of growing the well layer, the growth temperature of the well layer is set to an arbitrary temperature within the range of 600 ° C. to 700 ° C. In general, the temperature at which the InGaN crystal is grown is often set to about 780 ° C. to ensure sufficient crystallinity, and the growth temperature of the well layer in this embodiment is set lower than this. A suitable growth temperature is, for example, 650 ° C. The growth temperature here can be replaced with the temperature of the GaN wafer 40 (substrate temperature).

In the step of growing the well layer, the flow rate Q _In [mol / min] of the flow rate Q _V [mol / min] and the In source gas of the source gas V group element (e.g., ammonia) (e.g. trimethyl indium) and The molar flow rate ratio (Q _V / Q _In ) is an arbitrary value included in the range of 9000 to 30000. In general, the molar flow rate ratio for growing an InGaN crystal is often set to about 40000 in order to prevent generation of droplets, and the molar flow rate ratio in this embodiment is lower than this (that is, the In raw material). It is set so that the gas is relatively high. A suitable molar flow ratio is, for example, 24000.

  Further, in the step of growing the well layer, the growth rate of the well layer is set to an arbitrary rate included in the range of 0.01 [μm / hour] to 0.1 [μm / hour]. In general, the growth rate of the InGaN crystal is often set to about 0.15 [μm / hour], and the growth rate of the well layer in this embodiment is set slower than this. A suitable growth rate is, for example, 0.06 [μm / hour].

  Subsequently, a GaN crystal serving as a barrier layer is grown in the period T2. In the step of growing the barrier layer, the supply of trimethylindium, which is an In source gas, is stopped, and the temperature of the GaN wafer 40 is raised to, for example, 820 ° C. to grow a GaN crystal. In the case where an InGaN crystal is grown as the barrier layer, the temperature of the GaN wafer 40 may be increased to, for example, 820 ° C. while decreasing the supply amount of trimethylindium from the period T1.

  In the growth process of the active layer 44, the active layer and the barrier layer are alternately grown in the period T3 to T6 after the period T2. That is, in the period T3 and the period T5 after the period T2, the well layer is grown under the same growth conditions as the period T1, and the barrier layer is grown under the same growth conditions as the period T2 in the period T4 after the period T3 and T6 after the period T5. Grow.

  The effects obtained by the manufacturing method described above will be described together with the process in which the present inventor obtained a solution problem and reached the solution. First, in order to determine the growth conditions for obtaining green light emission in an active layer having a group III nitride semiconductor layer containing In (for example, an InGaN well layer), a plurality of GaN wafers having different off angles with respect to the c-plane are prepared. InGaN crystal was grown on the same GaN wafer under the same growth conditions. FIG. 6 is a graph showing the results, showing the relationship between the off angle with respect to the c-plane and the In composition ratio in the InGaN crystal. As shown in FIG. 6, when the off angle is larger than 0 ° as compared with the case where the off angle is 0 ° (that is, when the InGaN crystal is grown on the GaN wafer having the c-plane as the main surface). It has been found that the In composition ratio is small, and that the In composition ratio becomes smaller as the off-angle increases. For example, when an InGaN crystal is grown on a GaN wafer having a c-plane as a main surface at a growth temperature of 750 ° C. and a growth rate of 0.15 [μm / h], about 20% of In capable of obtaining blue light emission. The composition ratio could be realized. However, when an InGaN crystal is grown on a GaN wafer having an off angle of 18 ° and 28 ° under the same growth conditions, the In composition ratios are 8.3% and 5.8%, respectively, and the In composition increases as the off angle increases. The ratio has decreased. When these GaN wafers having off angles of 18 ° and 28 ° were used to produce a light emitting diode according to a conventional method, the emission wavelength was in the blue-violet region of 410 [nm] to 430 [nm], and the desired green emission was Not observed.

  Therefore, the present inventors have sought a method for increasing the In composition ratio in order to increase the wavelength of a group III nitride semiconductor layer containing In grown on a GaN wafer having an off angle. As a result, the growth temperature and growth rate of the group III nitride semiconductor layer are lowered and the molar flow rate ratio of the In source gas is increased compared with the growth conditions that have been generally adopted so far, thereby solving the above problem. I found out that I can do it.

That is, the present inventor uses a GaN wafer having a main surface that is included in the range of 20 ° or more and 28 ° or less from the c-plane even in the case of a semipolar substrate. We succeeded in increasing the In incorporation rate by lowering the growth rate while lowering the growth rate while lowering the growth temperature while lowering the growth temperature of the semiconductor layer. Specifically, when the group III nitride semiconductor layer is grown on the GaN wafer having the off-angle, the growth temperature is set in the range of 600 ° C. to 700 ° C., and the source gas of the group V element (for example, N) The molar flow rate ratio (Q _V / Q _In ) between the flow rate Q _V [mol / min] and the flow rate Q _In [mol / min] of the _In source gas is in the range of 9000 to 30000, and the group III nitride semiconductor layer It has been found that by setting the growth rate in the range of 0.01 [μm / hour] to 0.1 [μm / hour], the In incorporation ratio can be increased while maintaining good crystallinity.

  Here, FIG. 7 is an example of current-EL (electroluminescence) characteristics of the semiconductor light-emitting element obtained by the manufacturing method according to the above embodiment, the horizontal axis indicates the supply current value (mA), and the vertical axis indicates the EL intensity. (ΜW) is shown. FIG. 8 is an example of an emission spectrum of the semiconductor light emitting device obtained by the manufacturing method according to the above embodiment, the horizontal axis indicates the wavelength (nm), and the vertical axis indicates the light intensity (the output of the spectrometer, the unit is mV). ). As shown in FIG. 8, green light emission having a wavelength of 510 [nm] could be observed by the manufacturing method according to the embodiment.

  Thus, according to the method for manufacturing a semiconductor light emitting device according to this embodiment, in the active layer having a small piezoelectric field and a high In composition compared to the case of using a GaN wafer having a c-plane as a main surface. A green light-emitting semiconductor light-emitting element in which blue shift is suppressed can be manufactured.

  In this embodiment, the active layer 44 has a multiple quantum well structure, and the growth temperature of the GaN barrier layer grown on the InGaN well layer is 820 ° C., which is higher than the growth temperature of the InGaN well layer. Thereby, an annealing effect on the InGaN well layer can be obtained when the GaN barrier layer is grown.

  Further, in order to investigate the In composition of the group III nitride semiconductor layer obtained by the above method, an InGaN single layer having a thickness of 50 [nm] was grown on the GaN wafer by the above method. A granular material of 10 [nm] was observed. As a result of specifying this granular material by X-ray diffraction and composition analysis, it was found to be an In droplet. However, when an InGaN well layer having a thickness of 3 nm was grown on a GaN wafer by the above method, it was confirmed by TEM observation that no In droplet was generated. That is, when the thickness of the InGaN layer grown by the above method is extremely thin (10 nm or less), it is considered that the growth is completed before the In droplet is generated.

  As described above, the growth condition according to the above method is a growth condition in which the supply amount of In source gas is large enough to produce In droplets when a thick InGaN layer having a thickness of 50 [nm], for example, is formed. On the main surface of a GaN wafer having a relatively large off angle, the surface step density is large and the c-plane terrace width is small, so that In acts as a surfactant due to a large supply amount of In source gas, and is difficult to be taken in at the step end. It is considered that the amount of In supplied has increased, and a large amount of In has been incorporated into the InGaN crystal. Moreover, since In migrates as a surfactant on the main surface of the GaN wafer having a small terrace width, it is considered that the deterioration of the crystal quality is suppressed even when the growth temperature of the InGaN crystal is low.

  Note that when the InGaN single layer having a thickness of 50 [nm] is grown, if the molar flow ratio of the In source gas is decreased, In droplets are gradually not observed, but the In composition ratio is decreased and the emission wavelength is decreased. The wavelength was shortened and green light emission could not be realized. For comparison, when an InGaN crystal was grown under the growth conditions according to the above method using a GaN wafer having a c-plane as a main surface, the occurrence of In droplets was determined when a GaN wafer having an off angle was used. It became equivalent. However, when the molar flow rate ratio of the In source gas was lowered to such an extent that no In droplet was formed in the thick film, sufficient light emission was not obtained.

<Example>
Next, as an example, an example in which an active layer having a multiple quantum well structure is grown on a GaN wafer having a semipolar plane as a main surface will be described. First, a GaN wafer having an off angle with respect to the c-plane of 23 ° in the a-axis direction was prepared. Then, three layers of InGaN well layers and GaN barrier layers were alternately grown on the GaN wafer. When the InGaN well layer is grown, the growth temperature is 650 ° C., the flow rate of trimethylgallium (TMG), which is a Ga source gas, is 1.5 [sccm (standard cubic centimeter / min)], and trimethylindium (TMI) Was set to 190 [sccm] and ammonia (NH ₃ ) was set to 29.6 [slm (standard liter / min)]. That is, the molar flow rate ratio (Q _In / Q _Ga ) between the molar flow rate Q _In [mol / min] of the In raw material gas and the molar flow rate Q _Ga [mol / min] of the _Ga raw material gas is set to 0.75, and the N raw material gas The molar flow rate ratio (Q _V / Q _In ) between the molar flow rate Q _V [mol / min] and the molar flow rate Q _In was 24000. As a result, the growth rate for growing this InGaN well layer was 0.06 [μm / hour]. The thickness of the InGaN well layer was 5 [nm].

  When a current was supplied to such a light emitting element, green light emission could be suitably obtained. Further, when the emission wavelength was shortened (blue shift), the wavelength change in the range of the supplied current amount of 20 [mA] to 200 [mA] was 17 [nm]. A multi-quantum well structure similar to this is fabricated on a GaN wafer having the c-plane as the main surface (however, the growth temperature of the InGaN well layer is set to 750 ° C. at which EL emission can be obtained), and the emission wavelength is blue. When the shift was examined, the wavelength change in the current range was 27 [nm]. Therefore, it was confirmed that the piezoelectric field was reduced and the blue shift was suppressed. Further, using a GaN wafer having an off-angle with respect to the c-plane of 28 ° in the a-axis direction, a multi-quantum well structure similar to the above was fabricated and the blue shift of the emission wavelength was examined. Was 10 [nm], and it was confirmed that the blue shift was further suppressed.

  The method for manufacturing a semiconductor light emitting device according to the present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, in the above embodiment, a well layer made of InGaN has been exemplified as an example of a group III nitride semiconductor layer grown on a GaN wafer (GaN substrate). The group III nitride semiconductor layer in the present invention is not limited to this, and may have other compositions as long as it is a group III nitride semiconductor containing In.

FIG. 1 is a side sectional view schematically showing an example of a semiconductor light emitting device manufactured by the method for manufacturing a semiconductor light emitting device according to the embodiment. FIG. 2 is a flowchart showing main steps of a method for manufacturing a semiconductor light emitting device according to the embodiment. FIG. 3 is a diagram for explaining each step shown in FIG. FIG. 4 is a diagram for explaining each step shown in FIG. FIG. 5 is a graph showing (a) the transition of the temperature of the GaN wafer when the active layer is grown, and (b) the supply / non-supply state of the source gas. FIG. 6 shows the relationship between the off angle with respect to the c-plane and the In composition ratio in the InGaN crystal. FIG. 7 is an example of current-EL characteristics of the semiconductor light emitting device obtained by the manufacturing method according to the embodiment, the horizontal axis indicates the supply current value, and the vertical axis indicates the EL intensity. FIG. 8 is an example of an emission spectrum of the semiconductor light emitting device obtained by the manufacturing method according to the embodiment, the horizontal axis indicates the wavelength, and the vertical axis indicates the light intensity.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor light-emitting device, 3, 42 ... n-type gallium nitride semiconductor layer, 5,44 ... Active layer, 5a ... Well layer, 5b ... Barrier layer, 7, 45 ... p-type AlGaN semiconductor layer, 9, 46 ... p ... Type electrode gallium nitride semiconductor layer, 11, 19... Electrode, 15... N type GaN substrate, 15a... Main surface, 17, 41... N type AlGaN layer, 21, 43. GaN wafer.

Claims (1)

A method of manufacturing a semiconductor light emitting device comprising an active layer having one or more group III nitride semiconductor layers containing indium on a gallium nitride substrate,
A step of growing the group III nitride semiconductor layer on the gallium nitride substrate having a main surface with an off angle from the (0001) plane of 20 ° or more and 28 ° or less,
The growth temperature in the step is included in a range of 600 ° C. or more and 700 ° C. or less,
The molar flow rate ratio (Q _V / Q _In ) between the flow rate Q _V [mol / min] of the group V element source gas and the indium source gas flow rate Q _In [mol / min] in the above process is 9000 or more and 30000 or less. Included in the scope,
The growth rate of the group III nitride semiconductor layer in the step is included in a range of 0.01 [μm / hour] to 0.1 [μm / hour],
A method of manufacturing a semiconductor light emitting device, wherein the thickness of each group III nitride semiconductor layer is 10 nm or less.

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