Semiconductor laser diode bar, wavelength beam coupling system, semiconductor substrate manufacturing method, semiconductor laser diode bar manufacturing method, and semiconductor substrate manufacturing apparatus.

Abstract

To provide a semiconductor laser diode bar capable of improving the oscillation performance of a wavelength beam combining system, the wavelength beam combining system, a semiconductor substrate manufacturing method, a semiconductor laser diode bar manufacturing method, and semiconductor substrate manufacturing equipment.SOLUTION: The semiconductor laser diode bar includes: a nitride semiconductor substrate that has an off-angle distribution on the substrate surface; a laminated structure comprising a first conductive cladding layer, an active layer, and a second conductive cladding layer which are layered on the substrate surface; and multiple emitters arranged side by side in the array direction perpendicular to the waveguide direction which are formed in stripes on the laminated structure. The wavelength distribution of the laser light emitted from the multiple emitters is different from the wavelength distribution of laser light emitted from the multiple emitters due to the off-angle distribution.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] This disclosure relates to a semiconductor laser diode bar, a wavelength beam coupling system, a method for manufacturing a semiconductor substrate, a method for manufacturing a semiconductor laser diode bar, and a semiconductor substrate manufacturing apparatus. [Background technology]

[0002] For example, Patent Document 1 discloses a Wavelength Beam Combining (WBC) system that outputs high-power laser light by combining multiple laser beams with different wavelengths.

[0003] Generally, a WBC system consists of a semiconductor laser diode (LD) bar, a diffraction grating, and an external resonant mirror. The LD bar has multiple emitters, from which laser light is emitted. The multiple laser beams are diffracted at different diffraction angles by the diffraction grating and emitted towards the external resonant mirror. A portion of the laser light incident on the external resonant mirror is reflected perpendicularly and returns to each emitter of the LD bar via the diffraction grating. As a result, external resonance (i.e., laser oscillation) occurs between each emitter and the external resonant mirror. On the other hand, another portion of the laser light incident on the external resonant mirror passes through the mirror and is output.

[0004] Thus, the WBC system combines the laser light emitted from each emitter using a diffraction grating and an external resonant mirror, enabling it to output high-power laser light.

[0005] A laser beam with a different lock wavelength for each emitter returns to the emitter from the external resonant mirror. The lock wavelength is uniquely determined by the positional relationship between the emitter and the diffraction grating. In other words, laser oscillation occurs between the external resonant mirror and the emitter at a lock wavelength corresponding to the position of that emitter.

[0006] The laser light emitted from the emitter has a predetermined wavelength distribution. If the wavelength showing the peak emission intensity within this predetermined wavelength distribution (the so-called gain peak wavelength) differs significantly from the lock wavelength, there is a risk that laser oscillation will not occur. To obtain high-power laser light from a WBC system, it is necessary to generate laser oscillation between as many emitters and external resonant mirrors as possible to improve oscillation performance.

[0007] Patent Document 2 discloses a manufacturing method that utilizes the fact that the gain peak wavelength at each emitter changes depending on the size of the off-angle of the nitride semiconductor substrate used in the manufacture of LD bars. In the manufacturing method of Patent Document 2, multiple emitters are formed so as to be aligned along the principal axis direction of the off-angle of the nitride semiconductor substrate, thereby bringing the gain peak wavelength of each emitter closer to the lock wavelength. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2015-106707 [Patent Document 2] Japanese Patent Publication No. 2021-177528 [Overview of the project] [Problems that the invention aims to solve]

[0009] The off-angle distribution of nitride semiconductor substrates varies depending on the substrate, and simply adjusting the principal axis direction of the off-angle of the nitride semiconductor substrate and the emitter alignment direction may not be sufficient to bring the gain peak wavelength of each emitter closer to the lock wavelength.

[0010] The purpose of this disclosure is to provide a semiconductor laser diode bar that improves the oscillation performance of a wavelength beam coupling system, a wavelength beam coupling system, a method for manufacturing a semiconductor substrate, a method for manufacturing a semiconductor laser diode bar, and a semiconductor substrate manufacturing apparatus. [Means for solving the problem]

[0011] A semiconductor laser diode bar according to one aspect of the present disclosure includes a nitride semiconductor substrate having an off-angle distribution on a substrate surface, a stacked structure including a first-conductive-type clad layer, an active layer, and a second-conductive-type clad layer stacked on the substrate surface, and a plurality of emitters formed in a stripe shape in the stacked structure and arranged side by side in an arrangement direction orthogonal to the waveguide direction. The wavelength distribution of the laser light emitted from the plurality of emitters is different from the wavelength distribution of the laser light emitted from the plurality of emitters due to the off-angle distribution.

[0012] A wavelength beam combining system according to one aspect of the present disclosure includes the above-described semiconductor laser diode bar, a diffraction grating that diffracts the laser light emitted from the plurality of emitters, and an external resonance mirror that reflects a part of the laser light diffracted by the diffraction grating.

[0013] A method for manufacturing a semiconductor substrate according to one aspect of the present disclosure includes stacking a first-conductive-type clad layer on a nitride semiconductor substrate having an off-angle distribution on a substrate surface, and stacking an active layer on the first-conductive-type clad layer in a state where the temperature of a first region, which is a part of the substrate surface, is higher than the temperature of a second region, which is another part of the substrate surface, and stacking a second-conductive-type clad layer on the active layer death , When the active layer is laminated onto the first conductive cladding layer, the first region is heated with a first heater and the second region is heated with a second heater. including this.

[0014] A method for manufacturing a semiconductor laser diode bar according to one aspect of the present disclosure The method includes laminating a first conductivity type cladding layer on a nitride semiconductor substrate having an off-angle distribution on its substrate surface, laminating an active layer on the first conductivity type cladding layer while the temperature of a first region, which is a part of the substrate surface, is higher than the temperature of a second region, which is another part of the substrate surface, and then laminating a second conductivity type cladding layer on the active layer. includes forming, on a semiconductor substrate manufactured by the manufacturing method, a plurality of emitters formed in a stripe shape and arranged side by side in a direction from the first region toward the second region, and cutting out a semiconductor laser diode bar having the plurality of emitters from the semiconductor substrate.

[0015] A semiconductor substrate manufacturing apparatus according to one aspect of the present disclosure comprises a susceptor supporting at least one nitride semiconductor substrate, a first heater and a second heater for heating the nitride semiconductor substrate via the susceptor, a first rotation mechanism for rotating the nitride semiconductor substrate supported by the susceptor, and a raw material supply device for supplying raw material gas to the substrate surface of the nitride semiconductor substrate.

[0016] A semiconductor substrate manufacturing apparatus according to one aspect of the present disclosure comprises: a tray that supports the edge of the back surface of a nitride semiconductor substrate and has one or more inclined surfaces facing the back surface and having a varying distance from the back surface; a susceptor on which the tray is placed; a heater that heats the nitride semiconductor substrate via the susceptor and the tray; a first rotation mechanism that rotates the nitride semiconductor substrate supported on the tray; and a raw material supply device that supplies raw material gas to the substrate surface of the nitride semiconductor substrate. [Effects of the Invention]

[0017] According to this disclosure, it is possible to provide a semiconductor laser diode bar that improves the oscillation performance of a wavelength beam coupling system, a wavelength beam coupling system, a method for manufacturing a semiconductor substrate, a method for manufacturing a semiconductor laser diode bar, and a semiconductor substrate manufacturing apparatus. [Brief explanation of the drawing]

[0018] [Figure 1] A schematic diagram of the wavelength beam coupling system according to the first embodiment. [Figure 2] A figure showing an example of a current-injected emission spectrum of laser light. [Figure 3] A diagram showing the relationship between the lock wavelength and the gain peak wavelength. [Figure 4] This diagram illustrates the configuration and gain peak wavelength of a semiconductor laser diode bar installed in a wavelength beam coupling system. [Figure 5] A schematic diagram of a semiconductor substrate manufacturing apparatus according to the first embodiment. [Figure 6] A plan view showing the vicinity of the susceptor in semiconductor substrate manufacturing equipment. [Figure 7] A diagram illustrating an example of cutting a semiconductor laser diode bar. [Figure 8] This figure shows the gain peak wavelength distribution of a semiconductor substrate according to an embodiment. [Figure 9] This figure shows the gain peak wavelength distribution of a semiconductor substrate according to an embodiment. [Figure 10] This figure shows the gain peak wavelength distribution of a semiconductor substrate according to an embodiment. [Figure 11] This figure shows the gain peak wavelength distribution of a semiconductor substrate according to an embodiment. [Figure 12] A graph showing the gain peak wavelengths at various positions in the a-axis direction of the semiconductor substrate according to the embodiment. [Figure 13] A graph showing parameters related to the wavelength difference at each position in the a-axis direction of the semiconductor substrate according to the embodiment. [Figure 14] A diagram illustrating an example of the off-angle distribution of the substrate surface of the first wafer. [Figure 15] A diagram illustrating the effect of the first heating control on the first wafer. [Figure 16] A diagram illustrating the effect of the second heating control on the first wafer. [Figure 17] A diagram illustrating an example of the off-angle distribution of the substrate surface of the second wafer. [Figure 18] A diagram illustrating the effect of the third heating control on the second wafer. [Figure 19] A diagram illustrating the effect of the fourth heating control on the second wafer. [Figure 20] A diagram illustrating an example of the off-angle distribution of the substrate surface of the third wafer. [Figure 21] A diagram illustrating the effect of the fifth heating control on the third wafer. [Figure 22] A diagram illustrating the effect of the sixth heating control on the third wafer. [Figure 23] A diagram illustrating an example of the off-angle distribution of the substrate surface of the fourth wafer. [Figure 24] A diagram illustrating the effect of the seventh heating control on the fourth wafer. [Figure 25] A diagram illustrating the effect of the eighth heating control on the fourth wafer. [Figure 26] A schematic diagram of a semiconductor substrate manufacturing apparatus according to the second embodiment. [Figure 27] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to the second embodiment. [Figure 28] A schematic diagram of a semiconductor substrate manufacturing apparatus according to the third embodiment. [Figure 29] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to the third embodiment. [Figure 30] A schematic diagram of a semiconductor substrate manufacturing apparatus according to the fourth embodiment. [Figure 31] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to the fourth embodiment. [Figure 32] A schematic diagram of a semiconductor substrate manufacturing apparatus according to modified example 1. [Figure 33] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to Modification Example 1. [Figure 34] A schematic diagram of a semiconductor substrate manufacturing apparatus according to modified example 2. [Figure 35] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to modified example 2. [Figure 36] A schematic diagram of a semiconductor substrate manufacturing apparatus according to modified example 3. [Figure 37] A plan view showing the vicinity of the susceptor of a semiconductor substrate manufacturing apparatus according to modified example 3. [Figure 38] A diagram showing a tray provided in a semiconductor substrate manufacturing apparatus according to the fifth embodiment. [Figure 39] A diagram showing a tray provided in a semiconductor substrate manufacturing apparatus according to Modification 4. [Modes for carrying out the invention]

[0019] The embodiments of this disclosure will be described below with reference to the drawings.

[0020] [First Embodiment] (WBC system) Figure 1 is a schematic diagram of the WBC system 1 according to the first embodiment.

[0021] The WBC system 1 comprises an LD bar 100, a diffraction grating 200, and an external resonant mirror 300. The WBC system 1 may have multiple LD bars 100. An optical lens 400, such as a beam twister unit (BTU), may be provided between the LD bar 100 and the diffraction grating.

[0022] The LD bar 100 is a laser diode bar array, and multiple emitters 101 are formed in a stripe pattern on the LD bar 100. The emitters 101 extend in the waveguide direction. Furthermore, the multiple emitters 101 are arranged in a direction perpendicular to the waveguide direction. Hereinafter, the direction in which the emitters 101 are arranged will be referred to as the "arrangement direction". In addition, of the two emitters 101 located at both ends of the arrangement direction in the LD bar 100, the emitter 101 at one end will be referred to as the "first end emitter", and the emitter 101 at the other end will be referred to as the "second end emitter".

[0023] Voltage is supplied to multiple emitters 101 from a power supply unit (not shown), causing laser light to be emitted from the laser light emission end face of each emitter 101.

[0024] The diffraction grating 200 diffracts the laser light emitted from the multiple emitters 101 at predetermined diffraction angles corresponding to the positions of the emitters 101, and emits the resulting beams toward the external resonant mirror 300. The diffraction grating 200 is a reflective diffraction grating, for example, as shown in Figure 1. However, the diffraction grating 200 may also be a transmissive diffraction grating.

[0025] The external resonant mirror 300 reflects a portion of the laser light diffracted by the diffraction grating 200. This reflected light returns to each emitter 101 of the LD bar 100 via the diffraction grating 200 and is reflected by the non-emitting end faces of the LD bar 100. In this way, an external resonance occurs between each emitter 101 of the LD bar 100 and the external resonant mirror 300. Meanwhile, the remaining portion of the laser light incident on the external resonant mirror 300 passes through the mirror and is output.

[0026] <Lock wavelength> Of the laser light emitted from the emitter 101 of the LD bar 100, the laser light that satisfies the diffraction conditions of the diffraction grating 200 and is vertically reflected by the external resonant mirror 300 returns to the emitter 101 at the source of emission.

[0027] The diffraction condition of the diffraction grating 200 is expressed by the following equation (1), where d is the period of the diffraction grooves of the diffraction grating 200, α is the angle of incidence of the laser light to the diffraction grating 200, β is the angle of exit of the laser light to the diffraction grating 200, λ is the wavelength of the laser light, and m is the order (m is an integer). Generally, the diffraction grating 200 is arranged such that m is 1 in equation (1). d(sinα+sinβ)=mλ (1)

[0028] The wavelength that satisfies this diffraction condition is called the lock wavelength. Since the multiple emitters 101 of the LD bar 100 are each in a different position relative to the diffraction grating 200, the angle at which the laser light emitted from the emitters 101 is incident on the diffraction grating 200 (incident angle α) is different for each emitter 101. Therefore, as shown in equation (1), the lock wavelength is uniquely determined by the positional relationship between the emitters 101 of the LD bar 100 and the diffraction grating 200.

[0029] The laser light returning to the emitter 101 is reflected by the non-emitting end face of the LD bar 100 and emitted from the corresponding emitter 101 toward the diffraction grating 200. In this way, laser oscillation occurs between the non-emitting end face of each emitter 101 and the external resonant mirror 300 at the lock wavelength corresponding to each emitter 101.

[0030] <Lock wavelength difference> Next, the lock wavelength difference (hereinafter sometimes simply referred to as "lock wavelength difference") Δλ between the emitters 101 located at both ends of the LD bar 100 in the alignment direction. EC_bar This will be explained using the following example where conditions (a)-(e) are met. (a) The diffraction grating 200 has 3000 grooves per millimeter. That is, the groove period d of the diffraction grating is 0.333 μm. (b) The peak wavelength of the laser light emitted from each emitter 101 is within the range of 400 nm or more and 500 nm or less. (c) The LD bar 100 is arranged such that the incident angle of the laser light emitted from the emitter 101 located in the center of the array direction is 45°. (d) The distance between the emitters 101 located at both ends in the direction of arrangement of the LD bar 100 is 10 mm. (e) The distance between the LD bar 100 and the diffraction grating 200 is 2.6 m.

[0031] If conditions (a)-(e) are met, the lock wavelength difference Δλ between the emitters 101 located at both ends in the array direction. EC_bar This is calculated to be approximately 1.0 nm.

[0032] Furthermore, if, instead of condition (e), the condition that the distance between the LD bar 100 and the diffraction grating 200 is 1.3 m is met, and conditions (a)-(d) are also met, then the lock wavelength difference Δλ EC_bar This is calculated to be approximately 2.0 nm.

[0033] In other words, if the configuration of the LD bar 100 is the same, the lock wavelength difference Δλ depends on the distance between the LD bar 100 and the diffraction grating 200. EC_bar It changes.

[0034] <Wavelength range in which laser oscillation is possible> Next, we will explain the wavelengths at which lasers can oscillate.

[0035] Of the light emitted from emitter 101, the light capable of laser oscillation is the light of wavelengths where the emission intensity of the amplified spontaneous emission (ASE) of the laser light is above a predetermined intensity. The range of wavelengths at which this emission intensity is above a predetermined intensity can be estimated based on the electroluminescence (EL) spectrum, if the electroluminescence (EL) spectrum before laser oscillation is considered as the ASE spectrum.

[0036] Figure 2 shows an example of the EL spectrum of laser light emitted from one emitter 101 of the LD bar 100. In Figure 2, the horizontal axis represents wavelength and the vertical axis represents emission intensity.

[0037] The EL spectrum generally has a shape close to a normal distribution and is generally symmetrical with respect to the peak wavelength at which the emission intensity is maximum. Since the wavelength showing the peak intensity in the ASE spectrum is the gain peak wavelength, the peak wavelength of the EL spectrum corresponds to the gain peak wavelength.

[0038] The wavelength at which the emission intensity is approximately 80% or more of the peak intensity is the wavelength at which laser oscillation is possible. For example, if the LD bar 100 is a GaN-based semiconductor light-emitting element and emits laser light by band-edge emission, the wavelength range at which the emission intensity in the EL spectrum is 80% or more of the peak intensity is 3.2 nm. In other words, the wavelength range at which oscillation is possible is within ±1.6 nm of the gain peak wavelength.

[0039] Furthermore, under the same conditions, the wavelength range at which the emission intensity is 90% or more of the peak intensity is 1.2 nm. Within the wavelength range defined by this wavelength range, i.e., within ±0.6 nm of the gain peak wavelength, not only is laser oscillation possible, but higher intensity laser light can also be obtained through laser oscillation.

[0040] <Relationship between lock wavelength and gain peak wavelength> Figure 3 shows the relationship between the lock wavelength and the gain peak wavelength. The vertical axis represents wavelength, and the horizontal axis represents the position on an axis parallel to the arrangement direction of the emitters 101 (distance from a predetermined point on that axis). The numbers 1 and 38 shown on the horizontal axis indicate the order of the emitters 101 when counted from one end. That is, the first end emitter is the 1st emitter 101, and the second end emitter is the 38th emitter 101. Lt is the distance between the emitters 101 located at both ends in the arrangement direction, i.e., the distance between the 1st emitter 101 and the 38th emitter 101. R80 is the wavelength range that shows an intensity of 80% or more of the emission intensity at the gain peak wavelength in the ASE spectrum, and R90 is the wavelength range that shows an intensity of 90% or more of the emission intensity at the gain peak wavelength in the ASE spectrum.

[0041] By reducing the difference between the gain peak wavelength and the lock wavelength at each position in the array direction, the number of emitters 101 capable of laser oscillation among the multiple emitters 101 of the LD bar 100 can be increased.

[0042] When the lock wavelength line, which indicates the lock wavelength, falls within the wavelength range R80 over its entire range, laser oscillation occurs at all emitters 101 of the LD bar 100. Furthermore, since the wavelength range R90 is a range with a stronger emission intensity than the wavelength range R80, when the lock wavelength line falls within the wavelength range R90, laser oscillation occurs under favorable conditions, and a higher intensity laser beam is obtained.

[0043] It is even more preferable to eliminate the difference between the gain peak wavelength and the lock wavelength at each position in the alignment direction, that is, to make the gain peak wavelength line representing the gain peak wavelength coincide with the lock wavelength line.

[0044] <Wavelength difference within which laser oscillation is possible> Next, the wavelength difference Δλ_o that enables laser oscillation and the arrangement conditions of the LD bar 100 with respect to the WBC system 1 will be described. The wavelength difference that enables laser oscillation is the difference between the maximum wavelength and the minimum wavelength when laser light is oscillated from all the emitters 101 included in one LD bar 100. In other words, it is the difference between the maximum wavelength and the minimum wavelength in the wavelength range R80 or the wavelength range R90.

[0045] The wavelength difference Δλ_o that enables laser oscillation can be expressed by the following formula (2.1). Δλ_o = Δλ EC_bar + 3.2 ······ (2.1)

[0046] Therefore, when the locking wavelength difference Δλ EC_bar is 2.0 nm or less, by arranging the LD bar 100 in the WBC system 1 so as to satisfy the following formula (2.2), that is, the following formula (2.3), laser oscillation occurs in all the emitters 101. Δλ_o = Δλ EC_bar + 3.2 ≤ 2.0 + 3.2 ······ (2.2) Δλ_o = Δλ EC_bar + 3.2 ≤ 5.2 ······ (2.3)

[0047] The wavelength difference Δλ_o / Lt that enables laser oscillation per unit length (1 mm (= 1 × 10 6 nm)) in the array direction satisfies the following formula (3.1). Δλ_o / Lt = 5.2 / Lt ······ (3.1)

[0048] Therefore, when the distance Lt between the emitters 101 located at both ends in the array direction of the LD bar 100 is 10 mm, that is, 10 × 10 6 nm, by arranging the LD bar 100 in the WBC system 1 so as to satisfy the following formula (3.2), laser oscillation occurs in each emitter 101. Δλ_o / Lt ≤ 0.52 × 10 -6 ······ (3.2)

[0049] In summary, by arranging the LD bar 100 in the WBC system 1 such that equation (4) below is satisfied, laser oscillation occurs in each emitter 101. (Δλ EC_bar +3.2) / Lt≦0.52×10 -6 ······(4)

[0050] Next, we will explain the wavelength difference Δλ_ob for laser oscillation and the arrangement conditions of the LD bar 100 relative to the WBC system 1 when the lock wavelength falls within the wavelength range R90.

[0051] When the lock wavelength falls within the wavelength range R90, the wavelength difference Δλ_ob at which laser oscillation is possible can be expressed by the following equation (5.1). Δλ_ob=Δλ EC_bar +1.2 ······(5.1)

[0052] Therefore, the lock wavelength difference Δλ EC_bar When the wavelength is 2.0 nm or less, by arranging the LD bar 100 in the WBC system 1 so as to satisfy equation (5.2), i.e., equation (5.3), laser oscillation occurs in all emitters 101 such that the lock wavelength falls within the wavelength range R90. Δλ_ob=Δλ EC_bar +1.2 ≤ 2.0 + 1.2 ······(5.2) Δλ_ob=Δλ EC_bar +1.2 ≤ 3.2 ······(5.3)

[0053] Per unit length in the direction of arrangement (1 mm (= 1 × 10) 6 The wavelength difference Δλ_ob / Lt for which a laser can oscillate in nm satisfies equation (6.1) below. Δλ_ob / Lt=3.2 / Lt ·······(6.1)

[0054] Therefore, the distance Lt between the emitters 101 located at both ends of the LD bar 100 in the alignment direction is 10 mm, or 10 × 10 6When the wavelength is nm, by arranging the LD bar 100 in the WBC system 1 so as to satisfy the following equation (6.2), laser oscillation occurs in each emitter 101 such that the lock wavelength falls within the wavelength range R90. Δλ_ob / Lt≦0.32×10 -6 ...(6.2)

[0055] In summary, by arranging the LD bar 100 in the WBC system 1 so as to satisfy equation (7) below, the lock wavelength at each emitter 101 falls within the wavelength range R90, that is, higher intensity laser oscillation is generated. (Δλ EC_bar +1.2) / Lt≦0.32×10 -6 ······(7)

[0056] (LD bar) Figure 4 illustrates the configuration and gain peak wavelength of the LD bar 100 installed in the WBC system 1. The lower part of Figure 4 shows a cross-sectional view of the LD bar 100, and the upper part shows the gain peak wavelength for each position in the alignment direction.

[0057] The LD bar 100 comprises a substrate portion 10, an n-side semiconductor layer 20, an emissive layer 30, a p-side semiconductor layer 40, a p-side electrode 50, a dielectric layer 60, a pad electrode 70, and an n-side electrode 80.

[0058] The substrate portion 10 is, for example, an n-type GaN substrate. More specifically, the substrate portion 10 is an n-type hexagonal GaN substrate with the (0001) plane as its main plane.

[0059] The n-side semiconductor layer 20 is a first-type conductive cladding layer stacked on the substrate portion 10. The n-side semiconductor layer 20 is, for example, an n-type cladding layer formed of Si-doped AlGaN.

[0060] The light-emitting layer 30 has a laminated structure in which an n-side optical guide layer 31, an active layer 32, and a p-side optical guide layer 33 are stacked in this order.

[0061] The n-side optical guide layer 31 is formed of, for example, n-type GaN. n-type GaN is formed by doping GaN with Si, for example.

[0062] The active layer 32 has a quantum well layer and a barrier layer, with the quantum well layer being sandwiched between barrier layers. The active layer 32 may have only one quantum well layer or two or more.

[0063] The quantum well layer and barrier layer are formed of InGaN. The quantum well layer is, for example, In 0.06 Ga 0.94 Formed of N, the barrier layer is, for example, In 0.02 Ga 0.98 It is formed by N.

[0064] The p-side optical guide layer 33 is formed of, for example, p-type GaN. p-type GaN is formed by doping GaN with Mg, for example.

[0065] The p-side semiconductor layer 40 has a structure in which a p-type electron barrier layer 41, a p-side cladding layer 42, and a p-side contact layer 43 are stacked.

[0066] The p-type electron barrier layer 41 is, for example, p-type Al 0.35 Ga 0.65 It is formed of N. 0.35 Ga 0.65 N is, for example, Al 0.35 Ga 0.65 It is formed by doping N with Mg.

[0067] The p-side cladding layer 42 is a second-conductivity cladding layer, and is composed of a strained superlattice formed by repeatedly stacking a set of p-type AlGaN layers and p-type GaN layers at a predetermined period. The p-side cladding layer 42 may also be composed of an AlGaN layer doped with Mg. In the following description, it will be assumed that the p-side cladding layer 42 is composed of an AlGaN layer doped with Mg.

[0068] Multiple ridges are formed in a stripe pattern on the p-side cladding layer 42. The ridges protrude toward the p-side electrode 50 and extend in the direction of the resonator length (depth direction in Figure 4). The portion directly below the ridges constitutes the emitter 101.

[0069] The p-side cladding layer 42 has, for example, 38 ridges formed thereon, and the distance between the ridges located at both ends in the alignment direction is 10 mm. The resonator length (longitudinal dimension) of the ridges is, for example, 1300 μm.

[0070] The p-side contact layer 43 is formed, for example, from a Mg-doped GaN layer.

[0071] The p-side electrode 50 is formed of a transparent conductive oxide material that makes ohmic contact with the p-side contact layer 43, such as ITO, In2O3, or ZnO, or a laminated structure of palladium (Pd), platinum (Pt), or Pd / Pt.

[0072] The dielectric layer 60 is an insulating layer that covers the p-side semiconductor layer 40. The dielectric layer 60 is made of a low refractive index material, such as SiO2.

[0073] The pad electrode 70 covers the p-side electrode 50 and the dielectric layer 60. The pad electrode 70 is made of a metallic material such as Ti, Ni, Pt, or Au.

[0074] The n-side electrode 80 is an ohmic electrode positioned on the back surface of the substrate portion 10 and making ohmic contact with the substrate portion 10. The n-side electrode 80 has a laminated structure composed of, for example, a Ti layer, a Pt layer, and an Au layer.

[0075] A first conductivity type cladding layer is formed by a layer laminated between the active layer 32 and the substrate portion 10. A second conductivity type cladding layer is formed by a layer laminated on the opposite side of the active layer 32 from the first conductivity type cladding layer. The first conductivity type cladding layer may include, for example, an n-side semiconductor layer 20 and an n-side optical guide layer 31. The second conductivity type cladding layer may include, for example, a p-side optical guide layer 33, a p-type electron barrier layer 41, and a p-side cladding layer 42. The first conductivity type cladding layer, the active layer 32, and the second conductivity type cladding layer constitute a laminated structure.

[0076] The gain peak wavelength at each emitter 101 of the LD bar 100 is preferably gradually larger or smaller from one end to the other in the direction of the array, as illustrated in the upper part of Figure 4. In the LD bar 100 of this embodiment, the gain peak wavelength difference between the first end emitter and the second end emitter (hereinafter sometimes simply referred to as "gain peak wavelength difference") is 5.2 nm or less, preferably 3.2 nm or less. A gain peak wavelength difference of 5.2 nm or less enables laser oscillation at all emitters 101 of the LD bar 100 when mounted on the WBC system 1. A gain peak wavelength difference of 3.2 nm or less enables laser oscillation at higher intensity at all emitters 101 of the LD bar 100 when mounted on the WBC system 1.

[0077] (Semiconductor substrate manufacturing equipment) First, the general outline of the semiconductor substrate manufacturing apparatus 500 according to this embodiment will be described. In this specification, a right-handed Cartesian coordinate system will be used for the explanation. The X and Y axes extend horizontally. The Z axis extends vertically, with upward in the vertical direction being positive.

[0078] Figure 5 is a schematic diagram of the semiconductor substrate manufacturing apparatus 500 according to this embodiment. Figure 6 is a plan view showing the vicinity of the susceptor 503 (described later) of the semiconductor substrate manufacturing apparatus 500.

[0079] The semiconductor substrate manufacturing apparatus 500 is a device for manufacturing semiconductor substrates used in the production of LD bars 100 by forming layers on the substrate surface Ws of a nitride semiconductor substrate (hereinafter simply referred to as "wafer") W. The semiconductor substrate manufacturing apparatus 500 epitaxially grows layers on the substrate surface Ws of the wafer W by, for example, metal-organic chemical vapor deposition (MOCVD).

[0080] The semiconductor substrate manufacturing apparatus 500 includes a raw material supply device 501, a flow channel 502, a susceptor 503, heaters 504 and 505, and a control unit (not shown).

[0081] The raw material supply device 501, under the control of the control unit, supplies gases necessary for semiconductor substrate manufacturing toward the substrate surface Ws of the wafer W within the flow channel 502. For example, the raw material supply device 501 supplies a first raw material-containing gas G1, a second raw material-containing gas G2, and a suppressor gas G3 through the lower, middle, and upper flow channels within the flow channel 502, respectively. Exhaust gas G4 is also discharged from the flow channel 502. The flow channel 502 is made of, for example, quartz.

[0082] The first raw material containing gas G1 includes NH3 (ammonia) gas, which is a raw material for N (nitrogen).

[0083] The second raw material containing gas G2 includes organometallic gases. The organometallic gases vary depending on the manufacturing process; for example, they are gases used as raw materials for Ga (gallium), In (indium), and Al (aluminum).

[0084] The gas used as a raw material for gallium (Ga) is, for example, TMG (trimethylgallium) gas or TEG (triethylgallium) gas. The gas used as a raw material for indium (In) is, for example, TMI (trimethylindium) gas. The gas used as a raw material for aluminum (Al) is TMA (trimethylaluminum) gas.

[0085] The second raw material gas may contain impurity gases containing raw materials for impurities, as needed. The impurity gases are, for example, gases that are raw materials for n-type impurities such as Si (silicon), or gases that are raw materials for p-type impurities such as Mg.

[0086] The gas used as a raw material for silicon (Si) is, for example, monosilane (SiH4) gas. The gas used as a raw material for magnesium (Mg) is, for example, cyclopentadienylmagnesium (Cp2Mg) gas.

[0087] The raw material supply device 501 supplies the transport gas along with the first raw material-containing gas G1 and the second raw material-containing gas G2 via the lower and middle flow paths. The transport gas is used to smoothly transport the first raw material-containing gas G1 and the second raw material-containing gas G2 toward the wafer W. In this embodiment, depending on the layer to be formed, the transport gas can be H2 (hydrogen), N2 (nitrogen), or a mixed gas of H2 (hydrogen) and N2 (nitrogen).

[0088] The retaining gas G3 is, for example, a mixed gas of NH3 (ammonia) and N2 (nitrogen). The raw material-containing gases G1 and G2 are pushed away from the substrate surface Ws by thermal convection near the substrate surface Ws. By supplying the retaining gas G3 through the upper flow path in the flow channel 502, the raw material-containing gases G1 and G2 can be kept near the substrate surface Ws.

[0089] The susceptor 503 is formed, for example, from graphite coated with SiC. The susceptor 503 is a mounting platform on which the wafer W is placed and supports the placed wafer W from the back side. The susceptor 503 is equipped with a first rotation mechanism.

[0090] The first rotation mechanism is, for example, a servo motor, which, under the control of the control unit, rotates and stops the rotation of the wafer W. When stopping the rotation of the wafer W, the first rotation mechanism also positions the wafer W so that it is in a predetermined orientation relative to the heaters 504 and 505. The semiconductor substrate manufacturing apparatus 500 may further have a rotation stop position sensor that detects the orientation of the wafer W. As a result, the first rotation mechanism can always position the wafer W in the same orientation, even if the wafer W placed on the susceptor 503 is replaced.

[0091] Heaters 504 and 505 are positioned directly below the rear end region in the X-axis direction and directly below the front end region in the X-axis direction of the susceptor 503, respectively. Therefore, heaters 504 and 505 heat the substrate surface Ws of the wafer W via the rear end region and the front end region in the X-axis direction of the susceptor 503, respectively. The output of heaters 504 and 505 is individually controlled by the control unit.

[0092] The control unit performs overall control of the semiconductor substrate manufacturing apparatus 500.

[0093] (Method of manufacturing semiconductor substrates) A method for manufacturing a semiconductor substrate according to this embodiment will be described.

[0094] First, prepare wafer W. For example, wafer W satisfies the following conditions (f)-(h). (f) Diameter approximately 50mm (2 inches φ) (g) An orientation flat is formed along the a-axis. (h) The direction of the principal axis of the off-angle on the substrate surface Ws is opposite to the direction of the a-axis. Furthermore, if the orientation flat in (g) is formed along the m-axis direction, the principal axis direction of the off-angle on the substrate surface Ws in (h) shall be opposite to the m-axis direction.

[0095] The principal axis direction of the off-angle refers to the direction from the region with a small off-angle to the region with a large off-angle on the substrate surface Ws.

[0096] Furthermore, as wafer W, wafers with a diameter larger than 50 mm may be used, such as wafers of approximately 76 mm (3 inches in diameter) or approximately 102 mm (4 inches in diameter).

[0097] Furthermore, a first region R1 and a second region R2 are defined on the substrate surface Ws. For example, the second region and the first region are set to be arranged in this order along the a-axis direction (see Figure 6). In this case, the off-angle in the first region R1 is smaller than the off-angle in the second region R2.

[0098] Next, the wafer W is placed on the susceptor 503. The first rotation mechanism then rotates the susceptor 503 around the Z-axis, causing the wafer W to rotate on its own. Heaters 504 and 505 heat the wafer W via the susceptor 503 with different outputs. For example, heater 504 has a higher output than heater 505. Since the wafer W is rotating, the substrate surface Ws is heated almost uniformly. Hereinafter, the ratio of the output of heater 504 to the output of heater 505 will be referred to as the "heater output ratio".

[0099] Next, the raw material supply device 501 supplies the first raw material-containing gas G1, the second raw material-containing gas G2, and the pressing gas G3 to the substrate surface Ws to form a laminated structure.

[0100] When a first raw material-containing gas G1, a second raw material-containing gas G2, and a restraining gas G3 are supplied to a heated substrate surface Ws, the gaseous compounds contained in the first raw material-containing gas G1 and the second raw material-containing gas G2 are decomposed. Then, gas G5, consisting of the decomposed elements, accumulates on the substrate surface Ws. The elements contained in gas G5 are then adsorbed onto the substrate surface Ws or a layer laminated on the substrate surface Ws, forming a layer.

[0101] First, the raw material supply device 501 supplies a first raw material-containing gas G1 containing NH3 gas (N source) and a second raw material-containing gas G2 containing TMA gas (Al source), TMG gas (Ga source), and SiH4 gas (Si source) to the substrate surface Ws. Here, for example, a mixed gas of H2 and N2 is used as the transport gas. As a result, the n-side semiconductor layer 20 is formed on the substrate surface Ws.

[0102] Next, the raw material supply device 501 supplies the susceptor 503 with a first raw material-containing gas G1 containing NH3 gas (N source), a second raw material-containing gas G2 containing TMG gas (Ga source), and SiH4 gas (Si source). Here, a mixed gas of H2 and N2 is used as the transport gas. As a result, the n-side optical guide layer 31 is formed on the n-side semiconductor layer 20.

[0103] Next, the first rotation mechanism stops the rotation of the susceptor 503 and stops the rotation of the wafer W. Here, the first rotation mechanism positions the wafer W so that it faces a predetermined direction. For example, the first rotation mechanism positions the wafer W so that the orthogonal projection of the first region R1 onto the susceptor 503 falls on the heating surface of the heater 504 in a plan view, and the orthogonal projection of the second region R2 onto the susceptor 503 falls on the heating surface of the heater 505 in a plan view. Here, the first rotation mechanism may be positioned, for example, based on the detection result of the rotation stop position sensor.

[0104] As a result, the first region R1 is heated by heater 504, and the second region R2 is heated by heater 505. Therefore, the temperature of the first region R1 becomes higher than the temperature of the second region R2.

[0105] Furthermore, when forming the active layer 32, the control unit may set the output of heater 504 higher than the output of heater 505, and when forming layers other than the active layer 32 in the laminated structure, it may set the outputs of heater 504 and heater 505 to be equal.

[0106] Then, the raw material supply device 501 supplies the susceptor 503 with a first raw material-containing gas G1 containing NH3 gas (N source) and a second raw material-containing gas G2 containing TMI gas (In source) and TEG gas (Ga source), while a temperature difference is created between the first region R1 and the second region R2. Here, N2 gas is used as the transport gas. As a result, the active layer 32 is laminated on the n-side optical guide layer 31.

[0107] Furthermore, using N2 gas as the transport gas makes it easier for In elements to be incorporated into the layers more efficiently.

[0108] After the active layer 32 is formed, the first rotation mechanism rotates the susceptor 503 and causes the wafer W to rotate again.

[0109] Next, the raw material supply device 501 supplies the susceptor 503 with a first raw material-containing gas G1 containing NH3 gas (N source), a second raw material-containing gas G2 containing TMG gas (Ga source), and Cp2Mg gas (Mg source). Here, a mixed gas of H2 and N2 is used as the transport gas. This causes the p-side optical guide layer 33 to be laminated on the active layer 32.

[0110] Next, the raw material supply device 501 supplies a first raw material-containing gas G1 containing NH3 gas (N source) and a second raw material-containing gas G2 containing TMA gas (Al source), TMG gas (Ga source), and Cp2Mg gas (Mg source) to the substrate surface Ws. Here, for example, a mixed gas of H2 and N2 is used as the transport gas. As a result, a P-type electron barrier layer 41 is formed on the p-side optical guide layer 33.

[0111] Next, the raw material supply device 501 supplies the susceptor 503 with a first raw material-containing gas G1 containing NH3 gas (N source) and a second raw material-containing gas G2 containing TMA gas (Al source), TMG gas (Ga source), and Cp2Mg gas (Mg source). Here, for example, a mixed gas of H2 and N2 is used as the transport gas. As a result, a p-side cladding layer 42 is formed on the p-type electron barrier layer 41.

[0112] Next, the raw material supply device 501 supplies the susceptor 503 with a first raw material-containing gas G1 containing NH3 gas (N source), a second raw material-containing gas G2 containing TMG gas (Ga source), and Cp2Mg gas (Mg source). Here, a mixed gas of H2 and N2 is used as the transport gas. As a result, the p-side contact layer 43 is formed on the p-side cladding layer 42.

[0113] Heaters 504 and 505 heat the susceptor 503 so that the temperature of the substrate surface Ws is in the range of approximately 1000°C to 1100°C when forming the n-side semiconductor layer 20, the n-side optical guide layer 31, the p-side optical guide layer 33, and the p-side semiconductor layer 40. Furthermore, when forming the active layer 32, heaters 504 and 505 heat the susceptor 503 so that the temperature of the first and second regions of the substrate surface Ws is both around 800°C. Note that the temperature of the substrate surface Ws corresponds to the layer growth temperature.

[0114] During the formation of the n-side semiconductor layer 20, the n-side optical guide layer 31, the p-side optical guide layer 33, and the p-side semiconductor layer 40, the wafer W rotates, making it possible to achieve a uniform elemental composition in these layers of the semiconductor substrate.

[0115] Through the above process, a semiconductor substrate containing a multilayer structure is manufactured.

[0116] (Manufacturing method for LD bars) Next, a method for manufacturing the LD bar 100 according to this embodiment will be described.

[0117] First, multiple emitters 101 are formed in a stripe pattern by etching the p-side semiconductor layer 40 of the multilayer structure on the semiconductor substrate, so that they are aligned in the a-axis direction. As a result, multiple emitters 101 are formed on the multilayer structure, aligned in the direction from the first region R1 to the second region R2. In addition, the arrangement direction of the emitters 101 on the multilayer structure is parallel to the a-axis direction.

[0118] Next, a p-side electrode 50, a dielectric layer 60, and a pad electrode 70 are formed in order on the laminated structure on which the emitter 101 is formed, and an n-side electrode 80 is formed on the back surface of the wafer W.

[0119] Hereinafter, a semiconductor substrate on which a p-side electrode 50, a dielectric layer 60, a pad electrode 70, and an n-side electrode 80 are formed will be referred to as an "LD substrate".

[0120] Next, cut out the LD bar 100 from the LD substrate.

[0121] Figure 7 illustrates an example of cutting LD bars 100 from an LD substrate 800. In the LD substrate 800 shown in Figure 7, the right-hand region is the first region R1, and the left-hand region is the second region R2. 100R in Figure 7 represents a unit region. A large number of LD bars 100 (for example, 100) can be cut from a unit region of 100R.

[0122] Since the distance Lt between the emitters 101 located at both ends of the LD bar 100 is 10 mm, four unit regions 100R can be laid out in the a-axis direction at the center of the m-axis direction on the LD substrate 800 (diameter approximately 50 mm).

[0123] By cutting according to this layout, a maximum of four LD bars 100 can be cut from an LD substrate 800 (approximately 50 mm in diameter) in the a-axis direction.

[0124] The LD bar 100 is manufactured through the above process.

[0125] Then, the LD bar 100, diffraction grating 200, and external resonant mirror 300 are prepared and arranged, for example, so that the above conditions (a), (c), and (e) are satisfied, thereby forming the WBC system 1. Hereafter, the WBC system 1 will be described assuming that the above conditions (a)-(e) are satisfied.

[0126] <Factors that cause changes in the gain peak wavelength distribution> The gain peak wavelength distribution in LD bar 100 changes under the influence of the following factors (1) and (2).

[0127] Factor (1) As the growth temperature during the formation of the active layer 32 (InGaN layer) increases, the In composition ratio in the active layer 32 decreases. The gain peak wavelength of the emitter 101 formed on the region of the active layer 32 with a low In composition ratio becomes shorter.

[0128] Factor (2) The gain peak wavelength distribution in a semiconductor substrate changes according to the off-angle distribution of the substrate surface Ws of the wafer W. For example, the larger the off-angle with respect to the main surface C-plane ((0001) plane) of the wafer W, the less likely In is to be deposited on that location during the process of forming the active layer 32. Therefore, the In composition ratio of the active layer 32 decreases at locations with a large off-angle on the substrate surface Ws. The gain peak wavelength of the emitter 101 formed on the area with a low In composition ratio in the active layer 32 becomes shorter. Therefore, if the off-angle differs depending on the location on the substrate surface Ws, the gain peak wavelength will differ at each location, even if the growth temperature of the active layer 32 is uniform across the entire substrate surface Ws.

[0129] <Upper limit of gain peak wavelength difference> The difference in gain peak wavelength Δλ between the two emitters 101 formed at both ends of the LD substrate 800 in the a-axis direction. sub I will explain this.

[0130] The maximum dimension in the a-axis direction of the cutting area of ​​the LD substrate 800 is L sub Therefore, in the a-axis direction from the LD substrate 800, the maximum is L sub / Lt LD bars 100 can be cut out. Note that Lt is the distance between the emitters 101 located at both ends of the LD bar 100, but it can be considered as the dimension of the LD bar 100 in the arrangement direction.

[0131] The gain peak wavelength difference Δλ_g between the emitters 101 located at both ends of the LD bar 100 can be expressed by the following equation (8). Δλ_g = Δλ sub / (L sub / Lt) ······(8)

[0132] The wavelength difference Δλ_o at which emitter 101 can perform laser oscillation can be expressed by equation (2.1). Therefore, by satisfying equation (9) below, all emitters 101 of the LD bar 100 can perform laser oscillation. Δλ_g ≤ Δλ EC_bar +3.2 ······(9)

[0133] Furthermore, by satisfying the following equation (10), laser oscillation becomes possible in all emitters 101 of the LD bar 100 such that the lock wavelength falls within the wavelength range R90. Δλ_g ≤ Δλ EC_bar +1.2 ······(10)

[0134] In this embodiment, when forming the active layer 32, a difference is made in the output of heater 504 and heater 505, thereby creating a difference in growth temperature between the first region and the second region of the substrate surface Ws. Therefore, when the LD bar 100 is mounted on the WBC system 1, the gain peak wavelength distribution can be brought closer to the lock wavelength distribution due to factor (1). That is, the above equation (9), and more preferably equation (10), can be satisfied.

[0135] (Examples) The inventors investigated the effect of differentiating the growth temperature between the first and second regions of the substrate surface Ws. The results are described below with reference to Figures 8 to 13.

[0136] The inventors manufactured semiconductor substrates 710 and 720 under the following conditions (i) and (j), respectively, and semiconductor substrates 730 and 740 under the following condition (k). (i) The heater output ratio is 1 (100%). That is, when the active layer 32 is formed, the first region R1 and the second region R2 of the substrate surface Ws are heated with the same heater output. (j) The heater output ratio is 1.1 (110%). That is, when the active layer 32 is formed, the first region of the substrate surface Ws is heated with a heater output 1.1 times that of the second region. (k) The heater output ratio is 1.06 (106%). That is, when the active layer 32 is formed, the first region R1 of the substrate surface Ws is heated with a heater output 1.06 times that of the second region R2.

[0137] During the manufacturing of semiconductor substrates 710-740, wafers W satisfying the following conditions (l) and (m) were used, and the first region R1 and the second region R2 of the substrate surface Ws were heated with heaters 504 and 505, respectively. (l) Diameter approximately 50mm (2 inches φ) (m) The principal axis direction of the off-angle on the substrate surface Ws is directed from the first region R1 to the second region R2.

[0138] Figures 8 to 11 show the gain peak wavelength distributions of semiconductor substrates 710 to 740, respectively. In Figures 8 to 11, the right-hand region of semiconductor substrates 710 to 740 corresponds to the first region R1, and the left-hand region corresponds to the second region R2.

[0139] Figure 8 shows that the gain peak wavelength gradually decreases from the right-hand region to the left-hand region. This gain peak wavelength distribution is due to the off-angle distribution of the substrate surface Ws.

[0140] Figure 9 shows that the gain peak wavelength gradually increases from the right-hand region to the left-hand region. This gain peak wavelength distribution is due to the fact that the growth temperature was high in the first region R1 and low in the second region R2 during the formation of the active layer 32.

[0141] The results in Figure 9 show that the gain peak wavelength distribution at the substrate surface Ws can be freely changed by changing the heater output ratio.

[0142] Figures 10 and 11 show that the gain peak wavelength distribution is nearly uniform across the entire substrate surface Ws of the wafer W. It was found that by setting the heater output ratio to 1.06, the gain peak wavelength distribution caused by the off-angle distribution of the substrate surface Ws can be smoothed out, resulting in a uniform gain peak wavelength distribution.

[0143] <Investigation of gain-peak wavelength difference> Next, we will explain the gain peak wavelength difference Δλ_g in semiconductor substrates 710-740.

[0144] For example, in WBC system 1, the lock wavelength difference Δλ between the emitters 101 located at both ends of the LD bar 100 in the alignment direction EC_bar It is approximately 1.0 nm.

[0145] Based on equation (9) above, when the LD bar 100 manufactured from a semiconductor substrate is mounted on the WBC system 1, in order to generate laser oscillation at all emitters 101, Δλ_g must be 4.2 nm (= 1.0 nm + 3.2 nm) or less.

[0146] Furthermore, when the LD bar 100 is mounted on the WBC system 1, in order to generate laser oscillation in all emitters 101 such that the lock wavelength falls within the wavelength range R90, Δλ_g must be 2.2 nm (= 1.0 nm + 1.2 nm) or less, according to equation (10).

[0147] Figure 12 is a graph showing the gain peak wavelengths at each position along the a-axis of the semiconductor substrate 710-740. Figure 13 is a graph showing the wavelength difference parameter at each position along the a-axis of the semiconductor substrate 710-740. The wavelength difference parameter is the absolute value of the difference between the reference value and the gain peak wavelength, with the longest gain peak wavelength as the reference value.

[0148] The graphs labeled "100%", "110%", "106%-1", and "106%-2" in Figures 12 and 13 show the gain peak wavelength distribution for semiconductor substrates 710-740, respectively.

[0149] Figure 12 directly reflects the results from Figures 8 to 11. For example, the "100%" graph shows a tendency for the gain peak wavelength to increase as the graph moves along the a-axis, while the "110%" graph shows a tendency for the gain peak wavelength to decrease as the graph moves along the a-axis. Additionally, the "106%-1" and "106%-2" graphs show that the gain peak wavelength is approximately uniform along the a-axis.

[0150] Figure 13 shows that the gain peak wavelength difference in the a-axis direction of the substrate surface Ws of the semiconductor substrate 710 ("100%) is at most approximately 19 nm. When emitters 101 are formed on the semiconductor substrate 710 so as to be aligned in the a-axis direction, and four LD bars 100 are cut out in the a-axis direction, the gain peak wavelength difference Δλ_g becomes approximately 4.8 nm (= 19 nm ÷ 4). In other words, the gain peak wavelength difference Δλ_g becomes larger than 4.2 nm.

[0151] Therefore, when the LD bar 100 manufactured from the semiconductor substrate 710 is mounted on the WBC system 1, there will be an emitter 101 that does not produce laser oscillation.

[0152] Figure 13 shows that the gain peak wavelength difference in the a-axis direction of the substrate surface Ws of the semiconductor substrate 720 ("110%") is approximately 12 nm at its maximum. When emitters 101 are formed on the semiconductor substrate 720 so as to be aligned in the a-axis direction, and four LD bars 100 are cut out in the a-axis direction, the gain peak wavelength difference Δλ_g is approximately 3.0 nm (= 12 nm ÷ 4). In other words, the Δλ_g of the LD bar 100 manufactured from the semiconductor substrate 720 is 4.2 nm or less, but is greater than 2.2 nm.

[0153] Therefore, when the LD bar 100 manufactured from the semiconductor substrate 720 is mounted on the WBC system 1, laser oscillation occurs at all emitters 101. However, the light emitted from some emitters 101 will not fall within the wavelength range R90, resulting in laser oscillation. In other words, higher intensity laser oscillation will not occur.

[0154] Figure 13 shows that the gain peak wavelength difference in the a-axis direction of the substrate surface Ws of the semiconductor substrate 730 is approximately 7 nm at its maximum. When emitters 101 are formed on the semiconductor substrate 730 so as to be aligned in the a-axis direction, and four LD bars 100 are cut out in the a-axis direction, the gain peak wavelength difference Δλ_g is approximately 1.8 nm (= 7 nm ÷ 4). In other words, the Δλ_g of the LD bar 100 manufactured from the semiconductor substrate 730 is 2.2 nm or less.

[0155] Figure 13 shows that the gain peak wavelength difference in the a-axis direction of the substrate surface Ws of the semiconductor substrate 740 is approximately 4 nm at its maximum. When emitters 101 are formed on the semiconductor substrate 740 so as to be aligned in the a-axis direction, and four LD bars 100 are cut out in the a-axis direction, the gain peak wavelength difference Δλ_g is approximately 1.0 nm (= 4 nm ÷ 4). In other words, the Δλ_g of the LD bar 100 manufactured from the semiconductor substrate 740 is 2.2 nm or less.

[0156] Therefore, when an LD bar 100 manufactured from a semiconductor substrate 730 or 740 is mounted on the WBC system 1, laser oscillation occurs in all emitters 101 such that the lock wavelength falls within the wavelength range R90.

[0157] Therefore, by appropriately setting the heater output ratio of heaters 504 and 505, the gain peak wavelength distribution of the manufactured LD bar 100 can be brought closer to the lock wavelength distribution of the WBC system 1, thereby improving the oscillation characteristics.

[0158] The inventors of this disclosure calculated wavelength-off-angle parameters that show the off-angle dependence of the gain peak wavelength on semiconductor substrates 710, 730, and 740. The wavelength-off-angle parameters are calculated by dividing the gain peak wavelength gradient in the a-axis direction of the semiconductor substrate by the off-angle gradient in the a-axis direction (unit: nm / °). A larger absolute value of the wavelength-off-angle parameter indicates a greater influence of the off-angle distribution of the substrate surface Ws. The calculation results of the wavelength-off-angle parameters for semiconductor substrates 710, 730, and 740 are shown in Table 1 below.

[0159] [Table 1]

[0160] While the absolute values ​​of the wavelength and off-angle parameters of semiconductor substrate 710 are large, the absolute values ​​of the wavelength and off-angle parameters of semiconductor substrates 730 and 740 are small. In other words, by setting the heater output ratio of heaters 504 and 505 to an appropriate value, the influence of the off-angle distribution of the substrate surface Ws can be canceled out, and a desirable gain peak wavelength distribution can be formed on the semiconductor substrate.

[0161] Furthermore, the inventors investigated the yield rates Y80 and Y90 when manufacturing LD bars 100 from semiconductor substrates 710, 720, 730, and 740.

[0162] The yield rate Y80 is the percentage of all LD bars 100 manufactured from the semiconductor substrate that have a gain peak wavelength difference Δλ_g of 4.2 nm or less. When the gain peak wavelength difference Δλ_g in an LD bar 100 is 4.2 nm or less, laser oscillation is possible in all emitters 101.

[0163] The yield rate Y90 is the percentage of all LD bars 100 manufactured from the semiconductor substrate that have a gain peak wavelength difference Δλ_g of 2.2 nm or less. When the gain peak wavelength difference Δλ_g in an LD bar 100 is 2.2 nm or less, all emitters 101 can oscillate with higher intensity.

[0164] [Table 2]

[0165] The yield rate Y80 for semiconductor substrate 710 was 38.3%, while the yield rates Y80 for semiconductor substrates 730 and 740 were 83.3% and 91.7%, respectively.

[0166] Furthermore, while the yield rate Y90 for semiconductor substrate 710 was 25.0%, the yield rates Y90 for semiconductor substrates 730 and 740 were 63.3% and 68.3%, respectively.

[0167] Thus, by changing the heater output ratio from 100% to 106%, both the yield rates Y80 and Y90 more than doubled. Therefore, by appropriately controlling the heater output ratio, it is possible to efficiently manufacture LD bars 100 with a gain peak wavelength distribution suitable for use as LD bars 100 mounted on WBC system 1.

[0168] (Example of heating control) The following describes the heating control of the first region R1 and the second region R2 by heaters 504 and 505, using the heating of four types of wafers as an example. In the following description, the four types of wafers will be referred to as the first wafer W1, the second wafer W2, the third wafer W3, and the fourth wafer W4, respectively.

[0169] <Heat control for the first wafer> The heating control for the first wafer W1 will be explained with reference to Figures 14-16. Figure 14 is a diagram illustrating the off-angle distribution of the substrate surface Ws of the first wafer W1. Figures 15 and 16 are diagrams illustrating the effects of the first heating control and the second heating control on the first wafer W1.

[0170] The substrate surface Ws of the first wafer W1 has an off-angle distribution in which the off-angle is larger in the rear end region (left side of Figure 14) than in the front end region (right side of Figure 14) in the a-axis direction. In addition, the amount of change in the off-angle is relatively large from the front end to the rear end in the a-axis direction.

[0171] When the entire substrate surface Ws of the first wafer W1 is uniformly heated during the formation of the active layer 32 to manufacture a semiconductor substrate, and an LD bar 100 is manufactured from this semiconductor substrate, the LD bar 100 has a wavelength characteristic in which the gain peak wavelength increases towards the front end in the a-axis direction (dashed lines in Figures 15 and 16). This means that the gain peak wavelength of the emitter 101 at the rear end in the a-axis direction of the LD bar 100 (i.e., the first end emitter) is smaller than the gain peak wavelength of the emitter 101 at the front end in the a-axis direction (i.e., the second end emitter). This wavelength characteristic is due to the off-angle distribution of the first wafer W1. The slope Dth1 of this wavelength characteristic is large enough that the gain peak wavelength difference Δλ_g does not satisfy equation (9).

[0172] <<First Heating Control>> Therefore, the control unit sets the front end region of the substrate surface Ws in the a-axis direction as the first region R1 and the rear end region in the a-axis direction as the second region R2. The control unit then sets the output of heater 504 so that the first region R1 is at a predetermined temperature higher than the reference growth temperature, and sets the output of heater 505 so that the second region R2 is at the reference growth temperature. At this time, the heater output ratio is, for example, 106%. The reference growth temperature is, for example, 800°C.

[0173] By controlling the heating in this way, the In composition ratio in the active layer 32 on the first region R1 (front end region) of the substrate surface Ws decreases. Therefore, in the LD bar 100 manufactured from the first wafer W1, the gain peak wavelength of the emitter 101 (second end emitter) on the front end side in the a-axis direction becomes shorter.

[0174] As a result, the LD bar 100 has wavelength characteristics in which the gain peak wavelength increases towards the front end in the a-axis direction and has a slope smaller than the slope Dth1 (solid line in Figure 15). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is smaller than the gain peak wavelength of the second end emitter.

[0175] <<Second Heating Control>> The control unit may perform heating control other than the first heating control. The control unit sets the first region R1 and the second region R2 in the same way as the first heating control. The control unit then sets the output of heater 504 so that the first region R1 is at a predetermined temperature higher than the reference growth temperature, and sets the output of heater 505 so that the second region R2 is at a lower temperature than the reference growth temperature.

[0176] By controlling the heating in this manner, the In composition ratio in the active layer 32 on the first region R1 (front end region) of the substrate surface Ws decreases, while the In composition ratio in the active layer 32 on the second region R2 (rear end region) increases. Therefore, in the LD bar 100 manufactured from the first wafer W1, the gain peak wavelength of the emitter 101 (second end emitter) on the front end side in the a-axis direction becomes shorter, and the gain peak wavelength of the emitter 101 (first end emitter) on the rear end side in the a-axis direction becomes longer.

[0177] As a result, the wavelength characteristics of the LD bar 100 show that the gain peak wavelength decreases as it approaches the front end in the a-axis direction, and the slope has an absolute value smaller than the slope Dth1 (solid line in Figure 16). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is greater than the gain peak wavelength of the second end emitter.

[0178] In either heating control method, the gain peak wavelength difference Δλ_g in the LD bar 100 is smaller than the gain peak wavelength difference caused by the off-angle distribution of the substrate surface Ws of the first wafer W1. That is, by heating the substrate surface Ws of the first wafer W1 according to the first or second heating control described above, an LD bar 100 is obtained in which the gain peak wavelength difference Δλ_g satisfies equation (9), and more preferably equation (10).

[0179] <Heat control for the second wafer> The heating control for the second wafer W2 will be explained with reference to Figures 17-19. Figure 17 is a diagram illustrating the off-angle distribution of the substrate surface Ws of the second wafer W2. Figures 18 and 19 are diagrams illustrating the effects of the third and fourth heating controls on the second wafer W2.

[0180] The substrate surface Ws of the second wafer W2 has an off-angle distribution in which the off-angle is larger in the rear end region than in the front end region in the a-axis direction. On the other hand, the amount of change in the off-angle from the front end to the rear end in the a-axis direction of the substrate surface Ws of the second wafer W2 is larger than that of the first wafer W1.

[0181] If the semiconductor substrate is manufactured by uniformly heating the entire substrate surface Ws of the second wafer W2 during the formation of the active layer 32, and the LD bar 100 is manufactured from that semiconductor substrate, the LD bar 100 will have a wavelength characteristic in which the gain peak wavelength increases towards the front end in the a-axis direction (dashed lines in Figures 18 and 19). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is smaller than the gain peak wavelength of the second end emitter. However, the gain peak wavelength difference Δλ_g based on the slope Dth2 of this wavelength characteristic is the lock wavelength difference Δλ when the LD bar 100 is mounted on the WBC system 1. EC_bar This becomes smaller than the slope of the lock wavelength line (see Figure 3) based on this.

[0182] <<Third Heating Control>> Therefore, the control unit sets the front end region of the substrate surface Ws as the second region R2 and the rear end region as the first region R1. The control unit then sets the output of heater 504 so that the first region R1 reaches the reference growth temperature, and sets the output of heater 505 so that the second region R2 is at a predetermined temperature lower than the reference growth temperature. At this time, the heater output ratio is, for example, 106%.

[0183] By controlling the heating in this way, the In composition ratio in the active layer 32 on the second region R2 (front end region) of the substrate surface Ws increases. As a result, in the LD bar 100 manufactured from the second wafer W2, the gain peak wavelength of the emitter 101 (second end emitter) on the front end side in the a-axis direction becomes longer.

[0184] As a result, the LD bar 100 exhibits wavelength characteristics in which the gain peak wavelength increases towards the front end in the a-axis direction, and the slope is greater than that of the slope Dth2 (solid line in Figure 18). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is smaller than the gain peak wavelength of the second end emitter.

[0185] <<Fourth Heating Control>> The control unit may perform a fourth heating control. The fourth heating control has the same region setting and output setting as the second heating control described above. That is, the control unit sets the front end region of the substrate surface Ws as the first region R1 and the rear end region in the a-axis direction as the second region R2. The control unit then sets the output of the heater 504 so that the first region R1 is at a predetermined temperature higher than the reference growth temperature, and sets the output of the heater 505 so that the second region R2 is at the reference growth temperature.

[0186] By controlling the heating in this way, the gain peak wavelength of the second-end emitter and the gain peak wavelength of the first-end emitter are shortened and lengthened in the LD bar 100 manufactured from the second wafer W2.

[0187] As a result, the wavelength characteristics of the LD bar 100 show that the gain peak wavelength decreases as it approaches the front end in the a-axis direction, and the slope has an absolute value greater than the slope Dth2 (solid line in Figure 19). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is greater than the gain peak wavelength of the second end emitter.

[0188] The gain peak wavelength difference Δλ_g in the LD bar 100 manufactured through the third or fourth heating control is greater than the gain peak wavelength difference caused by the off-angle distribution of the substrate surface Ws of the second wafer W2. Furthermore, the gain peak wavelength difference Δλ_g in the LD bar 100 satisfies equation (9), and more preferably equation (10).

[0189] In other words, by heating the substrate surface Ws of the second wafer W2 according to the third or fourth heating control described above, the gain peak wavelength distribution can be brought closer to the lock wavelength distribution. Therefore, when the LD bar 100 manufactured via the third or fourth heating control is mounted on the WBC system 1, the wavelength showing a stronger emission intensity is selected as the lock wavelength, thus further improving the laser oscillation performance.

[0190] <Heat control for the third wafer> The heating control for the third wafer W3 will be explained with reference to Figures 20-22. Figure 20 is a diagram illustrating the off-angle distribution of the substrate surface Ws of the third wafer W3. Figures 21 and 22 are diagrams illustrating the effects of the fifth and sixth heating controls on the third wafer W3.

[0191] In the third wafer W3, the principal axis direction and the a-axis direction of the off-angle of the substrate surface Ws are almost orthogonal. Therefore, the off-angle is almost the same in the front-end region and the rear-end region along the a-axis.

[0192] If the semiconductor substrate is manufactured by uniformly heating the entire substrate surface Ws of the third wafer W3 during the formation of the active layer 32, and the LD bar 100 is manufactured from that semiconductor substrate, the LD bar 100 will have wavelength characteristics in which the gain peak wavelength in the a-axis direction is approximately constant (dashed lines in Figures 21 and 22). That is, the gain peak wavelength of the first end emitter and the gain peak wavelength of the second end emitter are approximately equal to each other. The slope Dth3 of this wavelength characteristic is small, and the lock wavelength difference Δλ when the LD bar 100 is mounted on the WBC system 1 is small. EC_bar The slope of the lock wavelength line (see Figure 3) based on this becomes much smaller.

[0193] <<Fifth Heating Control>> Therefore, the control unit sets the front end region of the substrate surface Ws as the second region R2 and the rear end region as the first region R1. The control unit then sets the output of heater 504 so that the first region R1 is at a predetermined temperature higher than the reference growth temperature, and sets the output of heater 505 so that the second region R2 is at a temperature lower than the reference growth temperature. In this case, the heater output ratio is, for example, 106%.

[0194] By controlling the heating in this manner, the In composition ratio in the active layer 32 on the first region R1 (rear end region) of the substrate surface Ws decreases, while the In composition ratio in the active layer 32 on the second region R2 (front end region) increases. As a result, in the LD bar 100 manufactured from the third wafer W3, the gain peak wavelength of the second end emitter becomes longer, and the gain peak wavelength of the first end emitter becomes shorter.

[0195] As a result, the LD bar 100 exhibits wavelength characteristics in which the gain peak wavelength increases towards the front end in the a-axis direction, and the slope is greater than that of the slope Dth3 (solid line in Figure 21). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is smaller than the gain peak wavelength of the second end emitter.

[0196] <<Sixth Heating Control>> The control unit may perform a sixth heating control. The range setting and output setting for the sixth heating control are the same as those for the second heating control described above.

[0197] By controlling the heating in this way, the gain peak wavelength of the second-end emitter and the gain peak wavelength of the first-end emitter are shortened and lengthened in the LD bar 100 manufactured from the third wafer W3.

[0198] As a result, the wavelength characteristics of the LD bar 100 show that the gain peak wavelength decreases as it approaches the front end in the a-axis direction, and the slope has an absolute value greater than the slope Dth3 (solid line in Figure 22). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is greater than the gain peak wavelength of the second end emitter.

[0199] The gain peak wavelength difference Δλ_g in the LD bar 100 manufactured via the fifth or sixth heating control is greater in the a-axis direction than the gain peak wavelength difference caused by the off-angle distribution of the substrate surface Ws of the third wafer W3. Furthermore, the gain peak wavelength difference Δλ_g in the LD bar 100 satisfies equation (9), and more preferably equation (10).

[0200] In other words, by heating the substrate surface Ws of the third wafer W3 according to the fifth or sixth heating control described above, the gain peak wavelength distribution in the array direction can be brought closer to the lock wavelength distribution. Therefore, when the LD bar 100 is mounted on the WBC system 1, the wavelength showing a stronger emission intensity is selected as the lock wavelength, thus further improving the laser oscillation performance.

[0201] <Heat control for the fourth wafer> The heating control for the fourth wafer W4 will be explained with reference to Figures 23-25. Figure 23 is a diagram illustrating the off-angle distribution of the substrate surface Ws of the fourth wafer W4. Figures 24 and 25 are diagrams illustrating the effects of the seventh and eighth heating controls on the fourth wafer W4.

[0202] The off-angle is uniform across the entire substrate surface Ws of the fourth wafer W4. That is, the off-angle is approximately equal at every position on the substrate surface Ws of the fourth wafer W4.

[0203] If the semiconductor substrate is manufactured by uniformly heating the entire substrate surface Ws of the fourth wafer W4 during the formation of the active layer 32, and an LD bar 100 is manufactured from that semiconductor substrate, the LD bar 100 will have a wavelength characteristic in which the gain peak wavelength is constant in the a-axis direction (dashed line in Figures 24 and 25). That is, the gain peak wavelength of the first end emitter and the gain peak wavelength of the second end emitter are approximately equal to each other. Furthermore, the slope Dth4 of this wavelength characteristic is approximately 0.

[0204] <<Seventh Heating Control>> Therefore, the control unit performs the seventh heating control. The region setting and output setting for the seventh heating control are the same as those for the fifth heating control described above.

[0205] By controlling the heating in this manner, the gain peak wavelength of the second-end emitter and the gain peak wavelength of the first-end emitter in the LD bar 100 manufactured from the fourth wafer W4 become longer.

[0206] As a result, the LD bar 100 exhibits wavelength characteristics in which the gain peak wavelength increases towards the front end in the a-axis direction and has a slope greater than the slope Dth4 (solid line in Figure 24). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is smaller than the gain peak wavelength of the second end emitter.

[0207] <<8th Heating Control>> Furthermore, the control unit may perform an eighth heating control. The eighth heating control has the same region setting and output setting as the second heating control described above.

[0208] By controlling the heating in this way, the gain peak wavelength of the second-end emitter and the gain peak wavelength of the first-end emitter in the LD bar 100 manufactured from the fourth wafer W4 become shorter.

[0209] As a result, the wavelength characteristics of the LD bar 100 show that the gain peak wavelength decreases as it approaches the front end in the a-axis direction, and the slope has an absolute value greater than the slope Dth4 (solid line in Figure 25). This means that the gain peak wavelength of the first end emitter in the LD bar 100 is greater than the gain peak wavelength of the second end emitter.

[0210] The gain peak wavelength difference Δλ_g in the LD bar 100 manufactured via the 7th or 8th heating control is greater than the gain peak wavelength difference caused by the off-angle distribution of the substrate surface Ws of the 4th wafer W4. Furthermore, the gain peak wavelength difference Δλ_g in the LD bar 100 satisfies equation (9), and more preferably equation (10).

[0211] In other words, by heating the substrate surface Ws of the fourth wafer W4 according to the seventh or eighth heating control described above, the gain peak wavelength distribution in the array direction can be brought closer to the lock wavelength distribution. Therefore, when the LD bar 100 is mounted on the WBC system 1, the wavelength showing a stronger emission intensity is selected as the lock wavelength, thus further improving the laser oscillation performance.

[0212] (summary) According to the embodiment, an LD bar 100 according to the embodiment can be manufactured. The LD bar 100 comprises a wafer W having an off-angle distribution on the substrate surface Ws, a laminated structure including a first conductivity type cladding layer, an active layer 32, and a second conductivity type cladding layer laminated on the substrate surface Ws, and a plurality of emitters 101 formed in a stripe shape on the laminated structure and arranged in an array direction perpendicular to the waveguide direction. In the LD bar 100, the wavelength distribution of the laser light emitted from the plurality of emitters 101 is different from the wavelength distribution of the laser light emitted from the plurality of emitters 101 due to the off-angle distribution.

[0213] In other words, regardless of the off-angle distribution of the wafer W, the gain peak wavelength distribution in the alignment direction of the LD bar 100 can be made to approximate the lock wavelength distribution when the LD bar 100 is mounted on the WBC system 1. Therefore, since laser oscillation occurs at a wavelength close to the gain peak wavelength in each emitter 101, the oscillation performance of the WBC system 1 can be improved.

[0214] Specifically, when equation (9) is satisfied, laser oscillation occurs at all emitters 101 of the LD bar 100. When equation (10) is satisfied, laser oscillation occurs at all emitters 101 of the LD bar 100 at wavelengths that show 90% or more of the peak intensity of the laser light.

[0215] By mounting the LD bar 100 on the WBC system 1 such that equation (4) is satisfied, laser oscillation can be made at all emitters 101 of the LD bar 100.

[0216] By mounting the LD bar 100 on the WBC system 1 in such a way that equation (9) is satisfied, laser oscillation occurs at all emitters 101 of the LD bar 100 at wavelengths that show 90% or more of the peak intensity of the laser light.

[0217] Furthermore, the incorporation of the aforementioned LD bar 100 enables the realization of a WBC system 1 with high oscillation performance.

[0218] According to this embodiment, an active layer 32 is laminated on the first conductive cladding layer while the temperature of the first region R1 on the substrate surface Ws is higher than the temperature of the second region R2, and a second conductive cladding layer is laminated on the active layer 32.

[0219] This makes the gain peak wavelength distribution in the alignment direction of the LD bar 100 different from the gain peak wavelength distribution of light emitted due to the off-angle distribution of the substrate surface Ws, and brings it closer to the lock wavelength distribution when the LD bar 100 is mounted on the WBC system 1.

[0220] In this embodiment, when the active layer 32 is laminated onto the first conductive cladding layer, the first region R1 is heated by the heater 504 and the second region R2 is heated by the heater 505. Also in this embodiment, when the first conductive cladding layer is laminated onto the wafer W, the wafer W is rotated, and when the active layer 32 is laminated onto the first conductive cladding layer, the rotation of the wafer is stopped.

[0221] Therefore, by aligning the positions of the first region R1 and the second region R2 with respect to the heaters 504 and 505, the first region R1 and the second region R2 can be heated at different temperatures during the formation of the active layer 32. Furthermore, when forming layers other than the active layer 32 of the laminated structure, the elemental composition and thickness of those layers can be made uniform by rotating the wafer W.

[0222] The semiconductor substrate manufacturing apparatus 500 according to this embodiment includes a susceptor 503 that supports at least one wafer W, heaters 504 and 505 that heat the wafer W via the susceptor 503, a first rotation mechanism that rotates the wafer W supported by the susceptor 503, and a raw material supply apparatus 501 that supplies raw material gas to the substrate surface Ws of the wafer W.

[0223] Therefore, it is possible to manufacture semiconductor substrates used in the production of the LD bar 100 described above.

[0224] The first rotation mechanism stops the rotation of the wafer W when raw materials for forming the active layer 32 are supplied by the raw material supply device 501, and positions the wafer W so that a first region R1 of the wafer W is heated by the heater 504 and a second region R2 of the wafer W is heated by the heater 505.

[0225] Therefore, the active layer 32 can be formed when the temperature of the first region R1 is higher than the temperature of the second region R2.

[0226] According to the embodiment, a plurality of emitters 101 formed in a stripe shape and arranged side by side in the direction from the first region R1 to the second region R2 are formed on the semiconductor substrate described above, and by cutting out the LD bar, the LD bar 100 described above can be manufactured.

[0227] [Second Embodiment] Hereinafter, the second embodiment will be mainly described with differences from the first embodiment.

[0228] (Semiconductor Substrate Manufacturing Apparatus) FIG. 26 is a schematic diagram of a semiconductor substrate manufacturing apparatus 500 according to the second embodiment. FIG. 27 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to the second embodiment.

[0229] The semiconductor substrate manufacturing apparatus 500 according to the first embodiment includes two heaters 504 and 505, while the semiconductor substrate manufacturing apparatus 500 according to the second embodiment includes three heaters 504 to 506. For example, the heaters 504 to 506 are arranged in the order of heaters 504, 506, and 505 along the X-axis direction.

[0230] (Method for Manufacturing Semiconductor Substrate) When forming at least the active layer 32, the control unit makes the output of the heater 504 the highest and the output of the heater 505 the lowest.

[0231] In addition, the control unit divides the substrate surface Ws of the wafer W into three regions, and sets the first region R1, the second region R2, and the third region R3 for the three regions according to the off-angle distribution of the substrate surface Ws. The three regions are the front-end region, the rear-end region, and the central region located between them in the a-axis direction of the substrate surface Ws.

[0232] FIG. 27 illustrates a wafer W whose main axis direction of the off-angle is opposite to the a-axis direction. Also, FIG. 27 illustrates that for the wafer W, the front-end region in the a-axis direction is set as the first region R1, the rear-end region is set as the second region R2, and the central region is set as the third region R3.

[0233] The first rotation mechanism positions the wafer W so that the first region R1, the second region R2, and the third region R3 are heated by heaters 504, 505, and 506, respectively, during the formation of the active layer 32, and stops the wafer W from rotating. This makes it possible to create a growth temperature gradient along the a-axis.

[0234] With the temperature gradient thus established, the semiconductor substrate manufacturing apparatus 500 forms the active layer 32.

[0235] (Manufacturing method for LD bars) An LD substrate 800 is formed from a semiconductor substrate manufactured by the semiconductor substrate manufacturing method according to the second embodiment, and an LD bar 100 is cut from the LD substrate 800.

[0236] As described above, the second embodiment provides the same effects as the first embodiment. Furthermore, compared to the first embodiment, the growth temperature gradient of the substrate surface Ws of the wafer W can be controlled more precisely when forming the active layer 32.

[0237] [Third Embodiment] The following describes the third embodiment, focusing primarily on its differences from the first embodiment.

[0238] (Semiconductor substrate manufacturing equipment) Figure 28 is a schematic diagram of the semiconductor substrate manufacturing apparatus 500 according to the third embodiment. Figure 29 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to the third embodiment.

[0239] In the third embodiment, the susceptor 503 is configured to support a plurality of wafers W. For example, up to three wafers W can be placed on the susceptor 503.

[0240] In the third embodiment, the first rotation mechanism rotates multiple wafers W individually.

[0241] Furthermore, the susceptor 503 is equipped with a second rotation mechanism in addition to the first rotation mechanism. The second rotation mechanism causes multiple wafers W to revolve around the vertical axis (Z axis).

[0242] In the first embodiment, heaters 504 and 505 were arranged in the X-axis direction, but in the third embodiment, heaters 504 and 505 are arranged concentrically. For example, heater 504 has a circular heating surface, and heater 505 has an annular heating surface surrounding the heating surface of heater 504 (see Figure 29).

[0243] (Method of manufacturing semiconductor substrates) When the wafer W is placed on the susceptor 503, the first rotation mechanism rotates each of the multiple wafers W on its own axis, while the second rotation mechanism revolves the multiple wafers W around the Z axis. Then, with the wafers W rotating and revolving, the n-side semiconductor layer 20 and the n-side optical guide layer 31 are formed in sequence.

[0244] After the n-side optical guide layer 31 is formed, the first rotation mechanism positions the first region R1 and the second region R2 so that they are heated by heaters 504 and 505, respectively, and stops the rotation of the wafer W. By setting the regions on the substrate surface Ws of the wafer W so that the first region R1 and the second region R2 are aligned along the a-axis, a growth temperature gradient can be created along the a-axis.

[0245] With the temperature gradient thus established, the semiconductor substrate manufacturing apparatus 500 forms the active layer 32. While the active layer 32 is being formed, the second rotation mechanism continues to revolve the wafer W.

[0246] (Manufacturing method for LD bars) An LD substrate 800 is formed from a semiconductor substrate manufactured by the semiconductor substrate manufacturing method according to the third embodiment, and an LD bar 100 is cut from the LD substrate 800.

[0247] As described above, the third embodiment provides the same effects and advantages as the first embodiment.

[0248] According to the third embodiment, the susceptor 503 is configured to support a plurality of wafers W, and includes a second rotation mechanism that rotates the plurality of wafers W supported by the susceptor 503. Further, the heaters 504 are arranged concentrically.

[0249] Thereby, when forming a stacked structure on a plurality of wafers W simultaneously, each layer can be formed so that the elemental composition and thickness are uniform.

[0250] Therefore, according to the third embodiment, compared with the first embodiment, a large number of high-quality semiconductor substrates can be manufactured in a short time.

[0251] [Fourth Embodiment] Hereinafter, regarding the fourth embodiment, mainly the differences from the first embodiment will be described.

[0252] (Semiconductor Substrate Manufacturing Apparatus) FIG. 30 is a schematic view of a semiconductor substrate manufacturing apparatus 500 according to the fourth embodiment. FIG. 31 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to the fourth embodiment.

[0253] In the fourth embodiment, the susceptor 503 is configured to support a large number of wafers W. For example, the susceptor 503 has an annular placement surface, and 12 wafers W can be placed on the placement surface (see FIG. 31).

[0254] In the fourth embodiment, similar to the third embodiment, the first rotation mechanism rotates the plurality of wafers W individually. Further, the susceptor 503 includes a second rotation mechanism that rotates the plurality of wafers W around the vertical axis (Z-axis).

[0255] Furthermore, the semiconductor substrate manufacturing apparatus 500 according to the fourth embodiment is equipped with three heaters 504, 505, and 506, which are arranged concentrically. For example, the heaters 504, 505, and 506 have annular heating surfaces, with heater 504 being the innermost and heater 505 being the outermost.

[0256] In the fourth embodiment, the flow channel 502 is configured to allow the first raw material-containing gas G1, the second raw material-containing gas G2, and the suppression gas G3 to flow radially from the center of the susceptor 503 outwards. This configuration allows the raw material gas to be uniformly supplied to the substrate surfaces Ws of a large number of wafers W.

[0257] (Method of manufacturing semiconductor substrates) Similar to the second embodiment, the control unit sets the output of heater 504 to its highest level and the output of heater 505 to its lowest level when forming the active layer 32. Also, similar to the second embodiment, the control unit sets a region on the substrate surface Ws of the wafer W. Furthermore, the rotation control by the first rotation mechanism and the revolution control by the second rotation mechanism are the same as in the third embodiment.

[0258] This allows a growth temperature gradient to be created along the a-axis direction on the substrate surface Ws of the wafer W. With this temperature gradient in place, the semiconductor substrate manufacturing apparatus 500 forms the active layer 32.

[0259] (Manufacturing method for LD bars) An LD substrate 800 is formed from a semiconductor substrate manufactured by the semiconductor substrate manufacturing method according to the fourth embodiment, and an LD bar 100 is cut from the LD substrate 800.

[0260] As described above, the fourth embodiment provides the same effects and advantages as the first embodiment.

[0261] According to the fourth embodiment, the susceptor 503 can support more wafers W than in the third embodiment, so that even more high-quality semiconductor substrates can be manufactured in a shorter time.

[0262] [Example 1] The following describes the differences between Modification 1 and the second embodiment.

[0263] (Semiconductor substrate manufacturing equipment) Figure 32 is a schematic diagram of the semiconductor substrate manufacturing apparatus 500 according to Modification 1. Figure 33 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to Modification 1.

[0264] The semiconductor substrate manufacturing apparatus 500 according to Modification 1 is a shower-type apparatus.

[0265] The flow channel 502 is configured to supply the first raw material-containing gas G1 and the second raw material-containing gas G2 to the wafer W from above the substrate surface Ws. In the modified example 1, the raw material supply device 501 does not need to supply the retaining gas G3.

[0266] Furthermore, the flow channel 502 is configured to exhaust the exhaust gas G4 downwards (towards the negative side in the Z-axis direction) of the susceptor 503.

[0267] According to Modification 1, the same effects and advantages as in the second embodiment can be obtained.

[0268] [Differentiation 2] The following describes the differences between Modification 2 and the third embodiment.

[0269] (Semiconductor substrate manufacturing equipment) Figure 34 is a schematic diagram of the semiconductor substrate manufacturing apparatus 500 according to Modification 2. Figure 35 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to Modification 2.

[0270] The semiconductor substrate manufacturing apparatus 500 in Modification 2 is a shower-type apparatus, similar to that in Modification 1.

[0271] The flow channel 502 is configured to supply the first raw material-containing gas G1 and the second raw material-containing gas G2 to multiple wafers W on the susceptor 503 from above the substrate surface Ws. In the modified example 2, as in the modified example 1, the raw material supply device 501 does not need to supply the suppression gas G3.

[0272] Furthermore, the flow channel 502 is configured to exhaust the exhaust gas G4 downwards (towards the negative side in the Z-axis direction) of the susceptor 503.

[0273] According to Modification 2, the same effects and advantages as in the third embodiment can be obtained.

[0274] [Difference 3] The following describes the differences between Modification 3 and the fourth embodiment.

[0275] (Semiconductor substrate manufacturing equipment) Figure 36 is a schematic diagram of the semiconductor substrate manufacturing apparatus 500 according to Modification 3. Figure 37 is a plan view showing the vicinity of the susceptor 503 of the semiconductor substrate manufacturing apparatus 500 according to Modification 3.

[0276] The semiconductor substrate manufacturing apparatus 500 in Modification 3 is a shower-type apparatus, similar to that in Modification 1.

[0277] The flow channel 502 is configured to supply the first raw material-containing gas G1 and the second raw material-containing gas G2 from above the substrate surface Ws to a number of wafers W arranged in a circular pattern on the susceptor 503. In the modified example 3, as in the modified example 1, the raw material supply device 501 does not need to supply the suppression gas G3.

[0278] Furthermore, the flow channel 502 is configured to exhaust the exhaust gas G4 downwards (towards the negative side in the Z-axis direction) of the susceptor 503.

[0279] According to Modification 3, the same effects and advantages as in the third embodiment can be obtained.

[0280] In the modified example 3, the susceptor 503 may have a circular mounting surface. Also, the number of wafers W may include the wafers W shown by the dashed line in Figure 37. In other words, the number of wafers W may be arranged so as to be tiled within a circular area, rather than being arranged in a ring shape on the mounting surface of the susceptor 503.

[0281] In this case, the semiconductor substrate manufacturing apparatus 500 has a plurality of heaters arranged so as to provide a growth temperature gradient along the a-axis with respect to the substrate surface Ws of each wafer W when forming the active layer 32, and controls the temperature of these heaters. Furthermore, the first rotation mechanism positions the wafer W so as to provide a growth temperature gradient along the a-axis with respect to the substrate surface Ws of each wafer W when forming the active layer 32, using its plurality of heaters.

[0282] [Fifth Embodiment] The following describes the fifth embodiment, focusing mainly on the differences from the first embodiment.

[0283] (Semiconductor substrate manufacturing equipment) The semiconductor substrate manufacturing apparatus 500 according to the fifth embodiment has the same configuration as the semiconductor substrate manufacturing apparatus 500 shown in Figure 5. That is, the semiconductor substrate manufacturing apparatus 500 according to the fifth embodiment includes a raw material supply device 501, a flow channel 502, a susceptor 503, heaters 504 and 505, and a control unit. The semiconductor substrate manufacturing apparatus 500 according to the fifth embodiment further includes a tray 507 on which wafers W are placed. Figure 38 is a side view of the tray 507 and a plan view of the wafer W placed on the tray 507.

[0284] A tray 507 is placed on the susceptor 503. The first rotation mechanism rotates the wafer W supported by the tray 507.

[0285] In the fifth embodiment, the multiple heaters 504, 505 are controlled to have the same output. However, the semiconductor substrate manufacturing apparatus 500 according to the fifth embodiment may have only one heater, for example, only heater 504. In this case, heater 504 has a heating surface that can evenly heat the entire mounting surface of the susceptor 503. In either case, the heater heats the wafer W via the tray 507.

[0286] The tray 507 has a two-tiered recessed structure and is equipped with a support section 508.

[0287] The support portion 508 supports the edge of the back surface of the wafer W so that a gap is created between the back surface of the wafer W and the tray 507. As a result, the wafer W is heated by radiant heat from the heated tray 507.

[0288] When a wafer W is placed directly on the mounting surface of the susceptor 503 to form a laminated structure, after the n-side semiconductor layer 20 is formed on the wafer W, the wafer W warps due to the difference in lattice constants between the wafer W (GaN layer) and the n-side semiconductor layer 20 (AlGaN layer). As a result, only the center of the wafer W comes into contact with the susceptor 503, and the edges of the wafer W no longer come into contact with the susceptor 503. For example, when the susceptor 503 is uniformly heated using a single heater, a concentric temperature distribution occurs in the wafer W, where the growth temperature decreases from the center towards the edges. However, by using the tray 507, even if the wafer W warps during the manufacturing of the semiconductor substrate, the occurrence of a concentric temperature distribution can be prevented.

[0289] In this embodiment, the tray 507 is provided with an inclined surface 509. The inclined surface 509 is located inside the support portion 508 and is formed such that the distance from the back surface of the wafer W changes when the wafer W is supported by the support portion 508. For example, the inclined surface 509 is formed to become deeper from the rear end in the X-axis direction toward the front end in the X-axis direction.

[0290] For example, if a wafer W is placed on a tray 507 so that the a-axis direction is parallel to the X-axis direction, and the tray 507 is placed on a susceptor 503, the portion of the wafer W facing the inclined surface 509 will be heated by radiant heat from the inclined surface 509. However, the distance from the inclined surface 509 decreases as the wafer W moves towards the rear end in the a-axis direction. Therefore, a temperature gradient is provided in the wafer W such that the growth temperature increases as it moves towards the rear end in the a-axis direction.

[0291] When the distance between the back surface of the wafer W and the inclined surface 509 increases by 10 μm, the growth temperature decreases by approximately 1°C. Furthermore, when the growth temperature changes by 1°C during the formation of the active layer 32, the gain peak wavelength of the emitter 101 formed above the active layer 32 changes by approximately 2 nm. For example, the angle of the inclined surface 509 may be set based on this ratio (2 nm / °C).

[0292] The semiconductor substrate manufacturing apparatus 500 according to the fifth embodiment includes a tray 507 that supports the edge of the back surface of a wafer W and has an inclined surface 509 facing the back surface of the wafer W and whose distance from the back surface changes; a susceptor 503 on which the tray 507 is placed; a heater 504 that heats the wafer W via the susceptor 503 and the tray 507; a first rotation mechanism that rotates the wafer W supported by the tray 507; and a raw material supply device 501 that supplies raw material gas to the substrate surface Ws of the wafer W.

[0293] Therefore, the same effects and advantages as in the first embodiment can be obtained. Furthermore, a growth temperature gradient can be created for the wafer W by using only one heater.

[0294] Furthermore, since the wafer W is not placed directly on the susceptor 503, the mounting surface of the susceptor 503 is less likely to be damaged. In addition, when the semiconductor substrate is completed, it can be removed from the semiconductor substrate manufacturing apparatus 500 along with the tray, thus increasing work efficiency.

[0295] [Differentiation Example 4] The following describes the differences between Modification 4 and the Fifth Embodiment, primarily.

[0296] (Semiconductor substrate manufacturing equipment) Figure 39 shows a tray 507 provided in the semiconductor substrate manufacturing apparatus 500 according to Modification 4.

[0297] The tray 507 of the modified example 4 has multiple inclined surfaces 510. Specifically, multiple predetermined regions are defined inside the support portion 508, and in each predetermined region, an inclined surface 510 is formed such that it becomes deeper from the rear end in the X-axis direction towards the front end.

[0298] For example, when a wafer W is placed on a tray 507 such that the a-axis direction is parallel to the X-axis direction, and the tray 507 is placed on a susceptor 503, the regions of the wafer W that face each inclined surface 510 (hereinafter referred to as the "inclined opposing region") are heated by radiant heat from each inclined surface 510. Here, a temperature gradient is provided in each inclined opposing region such that the growth temperature increases as you move towards the rear end in the a-axis direction.

[0299] A semiconductor substrate is manufactured using tray 507, and emitters 101 are formed on the semiconductor substrate so as to be aligned in the a-axis direction. Furthermore, an LD substrate 800 is formed by creating a p-side electrode 50, a dielectric layer 60, a pad electrode 70, and an n-side electrode 80. Subsequently, a unit region 100R (see Figure 7) is set on the LD substrate 800 to correspond to the tilted opposing region, and cutting is performed. This results in an LD bar 100 in which an appropriate gain peak wavelength difference is generated in the direction of the emitter 101 arrangement.

[0300] According to Modification 4, the same effects and advantages as in the fifth embodiment can be obtained. Furthermore, since the tray 507 is equipped with multiple inclined surfaces 510, the wafer W can be heated so that a temperature gradient is generated in predetermined area units. Therefore, the gain peak wavelength distribution can be precisely adjusted in units of LD bars 100.

[0301] [Other variations] The semiconductor substrate manufacturing apparatus 500 according to the first to fourth embodiments and modifications 1 to 3 is a face-up type apparatus, in which the wafer W is positioned on the susceptor 503 such that the substrate surface Ws faces in the positive Z-axis direction. However, this disclosure is also applicable to a face-down type semiconductor substrate manufacturing apparatus in which the wafer W is positioned so that the substrate surface Ws faces in the negative Z-axis direction.

[0302] The tray 507 of the fifth embodiment and modified example 4 is also applicable to the second to fourth embodiments and modified examples 1 to 3. That is, the semiconductor substrate manufacturing apparatus 500 according to the second to fourth embodiments and modified examples 1 to 3 may be equipped with the tray 507 of the fifth embodiment or modified example 4.

[0303] Furthermore, the orientation flat of the wafer W does not necessarily have to be formed along the a-axis direction.

[0304] This disclosure also includes forms that can be obtained by applying various modifications to each of the above embodiments and variations that a person skilled in the art can conceive of, as well as forms that can be realized by arbitrarily combining the components and functions of each of the above embodiments without departing from the spirit of this disclosure. [Industrial applicability]

[0305] This disclosure is suitable for semiconductor laser devices that require high-power and high-quality laser light emission. [Explanation of symbols]

[0306] 1. Wavelength beam coupling (WBC) system 10. Circuit board section 20 n-side semiconductor layer 30. Emitting layer 31 n-side optical guide layer 32 Active layer 33 p-side optical guide layer 40 p-side semiconductor layer 41. P-type electron barrier layer 42 p-side cladding layer 43 p-side contact layer 50 p side electrode 60 Dielectric layer 70 Pad electrodes 80 n-side electrode 100 Semiconductor Laser Bars 101 Emitter 200 diffraction gratings 300 External Resonance Mirror 400 Optical Lenses 500 Semiconductor Substrate Manufacturing Equipment 501 Raw material supply equipment 502 Flow Channel 503 Susceptor 504, 505, 506 Heater 507 Tray 508 Support part 509, 510 Slope G1 Primary raw material gas G2 Second raw material containing gas G3 Retaining Gas G4 exhaust gas G5 Gas W wafer Ws substrate surface

Claims

1. A nitride semiconductor substrate having an off-angle distribution on the substrate surface, A laminated structure comprising a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer laminated on the substrate surface, The laminated structure comprises a plurality of emitters formed in a stripe pattern and arranged in a line perpendicular to the waveguide direction, The wavelength distribution of the laser light emitted from the plurality of emitters is different from the wavelength distribution of the laser light emitted from the plurality of emitters due to the off-angle distribution. Semiconductor laser diode bar.

2. The difference in gain peak wavelength of the laser light emitted from two emitters located at both ends of the array direction among the plurality of emitters is smaller than the difference in gain peak wavelength of the laser light emitted from the two emitters due to the off-angle distribution. The semiconductor laser diode bar according to claim 1.

3. Of the plurality of emitters, the gain peak wavelength difference of the laser light emitted from the two emitters located at both ends in the arrangement direction is greater than the gain peak wavelength difference of the laser light emitted from the two emitters due to the off-angle distribution. The semiconductor laser diode bar according to claim 1.

4. The gain peak wavelength of the laser light emitted from the first end emitter, which is one of the two emitters, is smaller than the gain peak wavelength of the laser light emitted from the second end emitter, which is the other of the two emitters. The gain peak wavelength of the laser light emitted from the first end emitter due to the off-angle distribution is smaller than the gain peak wavelength of the laser light emitted from the second end emitter due to the off-angle distribution. The semiconductor laser diode bar according to claim 2 or 3.

5. The gain peak wavelength of the laser light emitted from the first end emitter, which is one of the two emitters, is greater than the gain peak wavelength of the laser light emitted from the second end emitter, which is the other of the two emitters. The gain peak wavelength of the laser light emitted from the first end emitter due to the off-angle distribution is smaller than the gain peak wavelength of the laser light emitted from the second end emitter due to the off-angle distribution. The semiconductor laser diode bar according to claim 2 or 3.

6. The gain peak wavelengths of the laser light emitted from two emitters located at both ends of the array direction, due to the off-angle distribution, are equal to each other. The semiconductor laser diode bar according to claim 1.

7. At each position on the substrate surface, the off-angle is approximately equal. The semiconductor laser diode bar according to claim 6.

8. The distance between two emitters located at both ends in the arrangement direction among the plurality of emitters is L. ｔ The lock wavelength difference between the laser beams emitted from the two emitters is Δλ. ＥＣ＿ｂａｒ The semiconductor laser diode bar according to claim 1, which satisfies the following equation. (Dl) ＥＣ＿ｂａｒ +3.2) / L ｔ ≦0.52×10 －６

9. The distance between two emitters located at both ends in the arrangement direction among the plurality of emitters is L. ｔ The lock wavelength difference between the laser beams emitted from the two emitters is Δλ. ＥＣ＿ｂａｒ The semiconductor laser diode bar according to claim 1, which satisfies the following equation. (Dl) ＥＣ＿ｂａｒ +1.2) / L ｔ ≦0.32×10 －６

10. The aforementioned arrangement direction is parallel to the a-axis direction of the nitride semiconductor substrate. The semiconductor laser diode bar according to claim 1.

11. A semiconductor laser diode bar according to claim 1, A diffraction grating that diffracts the laser light emitted from the plurality of emitters, The system includes an external resonant mirror that reflects a portion of the laser light diffracted by the diffraction grating. Wavelength beam coupling system.

12. A first conductivity type cladding layer is laminated on a nitride semiconductor substrate having an off-angle distribution on the substrate surface. The temperature of the first region, which is a part of the substrate surface, is higher than the temperature of the second region, which is another part of the substrate surface, while the active layer is laminated onto the first conductive cladding layer. A second conductive cladding layer is laminated onto the aforementioned active layer. When the active layer is laminated onto the first conductive cladding layer, the first region is heated with a first heater and the second region is heated with a second heater. A method for manufacturing a semiconductor substrate, including the following.

13. When the first conductive cladding layer is laminated on the nitride semiconductor substrate, the nitride semiconductor substrate is rotated. When the active layer is laminated onto the first conductive cladding layer, the rotation of the nitride semiconductor substrate is stopped. The method for manufacturing a semiconductor substrate according to claim 12.

14. The present invention further includes placing the nitride semiconductor substrate on a tray that supports the edge of the back surface of the nitride semiconductor substrate and has one or more inclined surfaces facing the back surface and having a varying distance from the back surface, When the active layer is laminated onto the first conductive cladding layer, the first region is heated by radiant heat from the portion of the inclined surface near the back surface, and the second region is heated by radiant heat from the portion of the inclined surface far from the back surface. The method for manufacturing a semiconductor substrate according to claim 12.

15. A semiconductor substrate manufactured by a manufacturing method comprising: laminating a first conductivity type cladding layer on a nitride semiconductor substrate having an off-angle distribution on the substrate surface; laminating an active layer on the first conductivity type cladding layer while the temperature of a first region, which is a part of the substrate surface, is higher than the temperature of a second region, which is another part of the substrate surface; and laminating a second conductivity type cladding layer on the active layer, wherein a plurality of emitters are formed in a stripe shape and arranged in a line from the first region toward the second region, A semiconductor laser diode bar having the plurality of emitters is cut out from the semiconductor substrate. A method for manufacturing a semiconductor laser diode bar, including the following.

16. A susceptor supporting at least one nitride semiconductor substrate, A first heater and a second heater that heat the nitride semiconductor substrate via the susceptor, A first rotation mechanism for rotating the nitride semiconductor substrate supported by the susceptor, The system includes a raw material supply device that supplies a raw material gas to the substrate surface of the nitride semiconductor substrate. Semiconductor substrate manufacturing equipment.

17. The susceptor is configured to support a plurality of nitride semiconductor substrates, The system further comprises a second rotation mechanism for revolving a plurality of nitride semiconductor substrates supported by the susceptor, The first heater and the second heater are arranged concentrically. The semiconductor substrate manufacturing apparatus according to claim 16.

18. The first rotation mechanism stops the rotation of the nitride semiconductor substrate when raw materials for forming the active layer are supplied by the raw material supply device, and positions the nitride semiconductor substrate so that a first region of the nitride semiconductor substrate is heated by the first heater and a second region of the nitride semiconductor substrate is heated by the second heater. The semiconductor substrate manufacturing apparatus according to claim 16 or 17.

19. A tray that supports the edge of the back surface of a nitride semiconductor substrate and has one or more inclined surfaces facing the back surface and having a varying distance from the back surface, A susceptor on which the aforementioned tray is placed, A heater that heats the nitride semiconductor substrate via the susceptor and the tray, A first rotation mechanism for rotating the nitride semiconductor substrate supported on the tray, The system includes a raw material supply device that supplies a raw material gas to the substrate surface of the nitride semiconductor substrate. Semiconductor substrate manufacturing equipment.

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