JP4426980B2 - Manufacturing method of semiconductor light emitting device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor light emitting device having a short wavelength range from blue-violet light to ultraviolet light, which is made of a nitride III-V compound semiconductor, and a semiconductor light emitting device.

  In recent years, there has been a growing demand for laser diodes that emit blue-violet light as light sources for next-generation high-density optical discs, especially gallium nitride (GaN) III-V that can operate in the short wavelength range from blue-violet light to ultraviolet light. Research and development of group compound semiconductor light-emitting devices are actively conducted. Further, since the optical disk apparatus is expected to be an optical disk apparatus for high density and high speed recording as a recorder, a GaN-based semiconductor laser with high light output and high reliability is required.

With regard to this reliability, recently, in order to extend the lifetime of GaN-based lasers, an insulating film such as silicon dioxide (SiO ₂ ) is deposited on a GaN-based semiconductor grown on a sapphire substrate, and the GaN-based semiconductor is formed on this insulating film. A method of selectively growing the crystal and thereby reducing the dislocation density is employed. There are two documents concerning this selective growth (Non-Patent Document 1 and Non-Patent Document 2).
According to Non-Patent Document 1, by selectively forming a line-and-space SiO ₂ film in the <1-100> direction of GaN, the selectively grown GaN-based semiconductor is connected flatly and used as a low dislocation substrate. It has been shown to be possible. Here, in this specification, as in “-1” in the above <1-100> direction, in the direction index or Miller index, the place that should be originally written with a bar on the number is indicated in front of the number. This is indicated with a minus sign. According to Non-Patent Document 2, the growth rate in the direction perpendicular to the substrate of the selectively grown GaN-based semiconductor (hereinafter referred to as the substrate vertical direction) and the direction parallel to the substrate (hereinafter referred to as the substrate horizontal direction) is SiO 2. It is shown that it depends on the opening ratio (Ws / (Wl + Ws)), which is the ratio of the opening part to the sum of the _two- film coating part (width: Wl) and the opening part (width: Ws). There are two documents that apply this selective growth technique to lasers (Non-Patent Document 3 and Non-Patent Document 4). According to Non-Patent Document 3, it is shown that the dislocation density of the laser structure can be reduced from about 1E10cm ^-2 to about 1E7cm ^-2 by selective growth. Further, according to Non-Patent Document 4, the above-described selective growth using an aperture ratio: Ws / (Wl + Ws) = 0.33 corresponding to the line width of the SiO ₂ film: Wl = 8 μm and the opening width: Ws = 4 μm is used. It has been shown that by reducing the dislocation density to such an extent, the threshold current of the laser is reduced and the life can be extended on the order of 1000 hours.
IEEE Journal of Selected Topics in Quantum Electronics, Vol.4 (1998) 483-489 Journal of Crystal Growth, Vol.195 (1998) 328-332 Applied Physics Letters, Vol.77 (2000) 1931-1933 '' IEICE Transuction Electron, Vol.E83-C (2000) 529-535 JP 2000-196188

  By the way, it is generally known that when a semiconductor laser is operated with a high optical output, optical damage (COD: Catastrophic Optical Damage) occurs in which a laser end face is locally thermally destroyed. Since there are many surface states at the laser end face, there are many non-light-emitting recombination through this. For this reason, COD is a phenomenon in which local heat generation becomes conspicuous because the injected carrier density decreases at the laser end face and becomes an absorption region of laser light. On the other hand, in GaN-based lasers, it is said that COD does not occur because the material GaN is strong. However, Non-Patent Document 4 shows an example in which COD is generated on a laser end face and deteriorates when a high light output operation is performed at 30 mW even in a GaN-based laser.

  As measures against COD, a method of promoting heat radiation from a laser and a method of providing a so-called window structure on the laser end face are generally employed. Among these, as a method of promoting heat dissipation from the laser, in the semiconductor laser for high light output, in order to efficiently dissipate the heat generated by the high light output operation to the heat sink, the pn junction side of the laser is brought close to the heat sink, A mounting method (p-side down) mounting through a submount and solder is effective. However, care must be taken during mounting, such as spatially separating the vicinity of the end face and the solder so that the solder does not adhere to the light emitting end face side. For this reason, even if p-side down mounting is performed, there is a possibility that heat dissipation is deteriorated near the laser end face and COD is generated.

  On the other hand, a method of providing a so-called window structure on the laser end face is not generally adopted for GaN-based lasers because it is difficult to provide a window structure because GaN as a material is hard. An example of providing a window structure in a GaN-based laser has been reported (see Patent Document 1). Therefore, in the current development of GaN-based lasers aiming at higher optical output, let's reduce the laser operating current and operating voltage to reduce power consumption, thereby suppressing the heat generation of the entire laser and preventing the generation of COD at the laser end face. It is said.

  However, in the next-generation optical disk apparatus, when aiming to achieve higher density and higher speed recording, there is a limit in suppressing the heat generation of the entire laser, and there is a concern about laser degradation due to the generation of COD.

  As a result of various studies to solve the above problems, the present inventors have realized a low dislocation structure and an end face window structure at the time of crystal growth of a GaN-based laser at the same time, thereby fundamentally suppressing COD generation. We have found that GaN-based lasers for high optical output suitable for high density and high speed recording can be manufactured at high yield and low cost.

Therefore, in the method for manufacturing a semiconductor light emitting device according to the present invention, the first width portion having a predetermined width on the first nitride-based III-V compound semiconductor layer and the predetermined width adjacent to both ends of the first width portion. A step A of forming a striped masking film having a second width portion wider than the width so as to be repeated in the width direction at a predetermined period; and the masking film and the first nitride III-V A step B of selectively growing a second nitride-based III-V compound semiconductor layer from the exposed portion so as to cover a portion exposed between the masking films on the surface of the group III compound semiconductor layer; Including an active layer extending in the stripe direction of the masking film, and a portion positioned above the second width portion is lower than a portion positioned above the first width portion, thereby extending in the width direction. A semiconductor laser structure having a level difference is formed on the second nitrogen. And a step C of stacking the object based III-V compound semiconductor layer, the width difference between the second width portion and the first width portion of the masking film, the predetermined width of the first width portion The predetermined period in the width direction of the masking film is 5 μm or more and 50 μm or less . Here, in the present invention, the “step” includes a stepped step and an inclined step and a curved step.

With such a configuration, the second nitride-based III-V group compound semiconductor layer is formed in accordance with the aperture ratio of the entire masking film corresponding to the width difference between the first width portion and the second width portion of each masking film. The film thicknesses of the masking films differ between the portions located on the first width portion and the second width portion of the masking film. This film thickness difference is reflected in the semiconductor laser structure stacked on the second nitride-based III-V compound semiconductor layer and located on the boundary between the first width portion and the second width portion. Since the stacked step is formed at the site, the end window structure of the semiconductor laser structure can be realized by using the step. In addition, since the second nitride III-V compound semiconductor layer serving as the underlayer of the semiconductor laser structure has a low dislocation structure by selective growth using a masking film, the semiconductor laser structure itself can be reduced in dislocation. . In addition, it is possible to suitably form a stacking step in the semiconductor laser structure.

  In the semiconductor laser structure, the step is formed so that a portion of the active layer located above the first width portion is joined to a semiconductor layer other than the active layer located above the second width portion. May be. With such a configuration, it is possible to prevent deterioration of heat dissipation due to incomplete adhesion of solder during mounting.

  Further, in the semiconductor laser structure, the step is formed such that a portion of the active layer located above the first width portion is joined to a semiconductor layer other than the active layer located above the second width portion. It may be formed.

  Further, in the semiconductor laser structure, a portion of the active layer positioned above the first width portion is bonded to a semiconductor layer having a larger band gap energy than the active layer of the portion positioned above the second width portion. The step may be formed as described above. With such a configuration, it is possible to reduce the absorption of the laser light in the portion located above the second width portion that becomes the resonator end.

  The semiconductor laser structure may include a clad layer sandwiching the active layer in the stacking direction, and the semiconductor layer having a band gap energy larger than that of the active layer may be the clad layer. With such a configuration, a semiconductor layer having a large band gap energy that is bonded to the active layer at the end of the resonator can be easily realized.

The masking film may be made of an insulating film.
In the step C, when the semiconductor laser structure is stacked, a ridge may be formed so as to extend in the stripe direction of the masking film and to be positioned above the masking film. With such a configuration, since the light emitting portion of the semiconductor laser is positioned on the low-dislocation second nitride III-V compound semiconductor layer on the masking film, the life of the semiconductor laser can be extended. .

Further, a portion located above the second width portion of the semiconductor laser structure may have a current non-injection structure. With such a configuration, heat generation due to current injection at the laser end face is suppressed, and end face deterioration such as COD is suppressed. As a result, high light output and long life can be achieved.

Further, the current non-injection structure may be obtained by not forming an electrode in a portion located above the second width portion of the semiconductor laser structure.
Further, the current non-injection structure may be obtained by forming an insulating layer under the electrode in a portion located above the second width portion of the semiconductor laser structure.

  The nitride III-V compound semiconductor may be a GaN semiconductor. Since GaN semiconductors are strong and it is particularly difficult to provide an end window structure by physical processing, ion implantation, etc., it is possible to provide an end window structure by utilizing the stacking step formed in the process of forming the semiconductor laser structure. The application of the present invention is particularly effective.

  The first nitride-based III-V compound semiconductor layer may be formed on a sapphire substrate.

  Further, it is preferable that the second nitride-based III-V group compound semiconductor grows substantially parallel to the main surface of the substrate from between the masking films onto the masking film.

  In the second nitride III-V compound semiconductor layer, it is preferable that a transition density of a portion grown on the masking film is lower than a transition density of a portion grown between the masking films.

In the second nitride-based III-V group compound semiconductor layer, it is preferable that portions grown on the respective width portions of the masking film are planarized.
The aperture ratio of the masking film may change in a taper shape in the stripe direction.

The semiconductor light emitting device according to the present invention repeats on the first nitride-based III-V compound semiconductor layer and the first nitride-based III-V compound semiconductor layer at a predetermined cycle in the width direction. A stripe-shaped masking film having a first width portion having a predetermined width and a second width portion adjacent to both ends of the first width portion and wider than the predetermined width; and the masking film, A second nitride III-V film selectively grown from the exposed portion so as to cover the exposed portion of the surface of the first nitride III-V compound semiconductor layer between the masking films. A group compound semiconductor layer and an active layer stacked on the second nitride-based group III-V compound semiconductor layer and extending substantially in the stripe direction of the masking film, and positioned above the second width portion The portion to be lower is lower than the portion located above the first width portion And a semiconductor laser structure having a step extending in the width direction by Rukoto, width difference between said second width portion and the first width portion of the masking film, the predetermined width of the first width portion 16 % To 84%, and the predetermined period in the width direction of the masking film is 5 μm to 50 μm .

  With such a configuration, the second nitride-based III-V compound semiconductor layer is formed using a striped masking film having a different width (aperture ratio) in the longitudinal direction (stripe direction) in the process of forming the semiconductor laser structure. Since the step of the stack is formed by selectively growing, the end face window structure can be provided using this step. As a result, an end window structure can be easily realized even in a semiconductor laser made of a material that is hard and difficult to provide an end window structure by physical processing or ion implantation, such as a GaN semiconductor. Further, since the second nitride III-V compound semiconductor layer formed by selective growth has a low dislocation structure, the semiconductor laser structure itself can be reduced in dislocation.

  The masking film may be located below the active layer in a cross-sectional view in the stripe direction.

  The above object, other objects, features, and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

  The present invention has the configuration as described above, and produces an effect that a high-light-output GaN-based laser suitable for high-density and high-speed recording can be manufactured with high yield and low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a laminated film thickness control method using selective growth, which is the basis of the method for manufacturing a semiconductor light emitting device according to the present invention, will be described. In this laminated film thickness control method, in the crystal growth of a GaN-based semiconductor, selective growth is performed using insulating films having different aperture ratios, thereby reducing the dislocation of the laminated film and controlling the film thickness.

  Hereinafter, the details of the method for controlling the laminated film thickness will be described with reference to the drawings.

  FIG. 1A to FIG. 1D and FIG. 2E to FIG. 2H show cross-sectional views of a semiconductor structure according to the present laminated film thickness control method. First, the sapphire substrate 11 having the (0001) plane as a main surface is cleaned using an acid solution. Thereafter, the cleaned substrate 11 is held on a susceptor in a reaction furnace of a metal organic chemical vapor deposition (MOVPE) apparatus (not shown), and the reaction furnace is evacuated. Subsequently, the inside of the reaction furnace is set to a hydrogen atmosphere having a pressure of 300 Torr (1 Torr = 133.322 Pa), the temperature is raised to about 1100 ° C., the substrate 11 is heated, and the surface is thermally cleaned for about 10 minutes.

Next, after the temperature of the reactor is lowered to about 500 ° C., trimethyl gallium (TMG) with a supply amount of 7 sccm, ammonia (NH ₃ ) gas with a supply amount of 7.5 slm, and a carrier gas are formed on the main surface of the substrate 11. By simultaneously supplying hydrogen as a low temperature buffer layer made of GaN having a thickness of 20 nm is grown. Subsequently, the temperature of the reactor is raised to about 1000 ° C. to grow a GaN layer 12 having a thickness of about 1 μm (FIG. 1 (a)).

Thereafter, the substrate 11 is taken out of the reaction furnace, and an insulating film (masking film) 13 for selective growth is formed on the GaN layer 12. Here, the insulating film 13 is made of silicon dioxide (SiO ₂ ) and is deposited by a plasma CVD apparatus to about 100 nm (FIG. 1B). Subsequently, a resist film 14 is applied on the insulating film 13 (FIG. 1C), and the following striped resist patterns having different aperture ratios are formed by photolithography (FIG. 1D). (Width of resist film 14 (Wl): resist removal width (Ws), aperture ratio) = (3 μm: 15 μm, 0.83), (6 μm: 12 μm, 0.67), (9 μm: 9 μm, 0.50) (12 μm: 6 μm, 0.33), (15 μm: 3 μm, 0.17). However, the stripe direction is the <1-100> direction of the GaN film 12, and the period (pitch) P is all 18 μm and the same. Each resist pattern has a 20 mm square block shape, and the patterns are separated by about 5 mm so that there is no mutual influence during selective growth. Thereafter, using the resist film 14 as an etching mask, the insulating film 13 of the resist removing portion 101 ′ is removed with a hydrofluoric acid solution to form a groove-like opening 101, and the GaN layer 12 is exposed at the bottom of the opening 101. (FIG. 2 (e)). Subsequently, the resist film 14 is removed with an organic solution such as acetone (FIG. 2F). The width of the stripe-shaped insulating film 13 thus obtained, the width of the opening 101, and the opening ratio are substantially the same as the width of the resist film 14, the width of the opening 101 ′, and the opening ratio. is there.

Thereafter, in order to selectively grow the GaN layer, the substrate 11 on which the striped insulating film 13 is deposited is held on the susceptor in the reaction furnace of the MOVPE apparatus, and the reaction furnace is evacuated. Subsequently, the reactor is set to a hydrogen atmosphere with a pressure of 200 Torr, the temperature is raised to about 1000 ° C., and a supply amount of 7 sccm of trimethylgallium (TMG) and a supply amount of 7.5 slm of ammonia (NH ₃ ) gas are used. By simultaneously supplying hydrogen as a carrier gas, the GaN layer 15 is selectively grown for about 4 hours.

  After completion of the selective growth, the substrate 11 was taken out of the reactor, and the cross-sectional shape and film thickness of the selectively grown GaN layer 15 were observed using a scanning electron microscope (SEM). As a result, in each selective growth pattern (the pattern of the insulating film 13 corresponding to the above-described resist patterns having different opening ratios), it extends from the opening portion 101 of the insulating film 13 onto the insulating film 13 in the lateral direction (substrate horizontal direction). The GaN layers merged with each other and were flattened (FIGS. 2 (g) and (h)). Reference numeral 16 denotes a merged portion of the GaN layer 15. Next, in each selective growth pattern, the laminated film thickness of the GaN layer 15 selectively grown on the insulating film 13 was measured. FIG. 3 shows the result as a graph representing the aperture ratio dependence of the laminated film thickness of the GaN layer 15. From FIG. 3, it can be seen that the laminated film thickness of the GaN layer 15 monotonously decreases as the aperture ratio of the insulating layer 13 decreases. Therefore, even if the period of the insulating film 13 is constant, it was verified that the laminated film thickness of the GaN layer on the insulating film 13 can be changed by changing the aperture ratio. This result has the same tendency as “Journal of Crystal Growth, Vol.195 (1998) 328-332” of Non-Patent Document 2.

Next, threading dislocations were observed using a transmission electron microscope (TEM). As a result, although the threading dislocation density is about 1E9 cm ^{−2 at} the opening 101 of the insulating film 13 and no dislocation reduction effect is observed, the threading dislocation is bent in the horizontal direction on the insulating film 13 and the threading dislocation density is 1E7 cm ^−. see that is reduced to about ² can be verified (FIG. 2 (h). in the figure, reference numeral 102 indicates a threading dislocation, the description of the threading dislocations in other opening portion 101 other than those illustrated Omitted).

In this method for controlling the laminated film thickness, the insulating film 13 is used as a masking film for selective growth of the GaN layer 15, but the masking film may be a film on which it is difficult for the GaN layer 15 to grow epitaxially. Insulation is not necessarily required.
(First embodiment)
According to the first embodiment of the present invention, in the crystal growth of a semiconductor laser, a low dislocation structure and laser resonance are achieved by performing selective growth using insulating films having different aperture ratios based on the above-described stacked film thickness control method. A method of manufacturing a GaN-based semiconductor laser capable of simultaneously obtaining an end face window structure effective for suppressing COD generation on the end face of the vessel at a high yield and low cost is shown.

  Hereinafter, the details of the manufacturing method of the GaN-based semiconductor laser according to the first embodiment of the present invention will be described with reference to the drawings.

  4A to 7K are sectional views of the semiconductor laser according to this embodiment in the order of each process.

  First, the sapphire substrate 21 whose main surface is the (0001) plane is cleaned using an acid solution. Thereafter, the cleaned substrate 21 is held on a susceptor in a reaction furnace of a metal organic chemical vapor deposition (MOVPE) apparatus (not shown), and the reaction furnace is evacuated. Subsequently, the inside of the reaction furnace is set to a hydrogen atmosphere at a pressure of 300 Torr, the temperature is raised to about 1100 ° C., the substrate 21 is heated, and the surface is thermally cleaned for about 10 minutes.

Next, after the temperature of the reaction furnace is lowered to about 500 ° C., trimethylgallium (TMG) with a supply amount of 7 sccm, ammonia (NH ₃ ) gas with a supply amount of 7.5 slm, and hydrogen as a carrier gas are formed on the substrate 21. Are simultaneously grown to grow a low-temperature buffer layer made of GaN having a thickness of 20 nm. Subsequently, the temperature of the reactor is raised to about 1000 ° C. to grow a GaN layer 22 having a thickness of about 1 μm (FIG. 4A).

Thereafter, the substrate 21 is taken out of the reaction furnace, and an insulating film (masking film) 23 for selective growth is formed on the GaN layer 22. Here, the insulating film 23 is made of silicon dioxide (SiO ₂ ) and is deposited by a plasma CVD apparatus to about 100 nm (FIG. 4B). Subsequently, a resist film 24 is applied on the insulating film 23 (FIG. 4C), and a stripe-shaped resist film 24 is formed by photolithography.

  As shown in FIG. 5 (d), the striped resist 24 film is formed with a period P of 18 μm, and has a plurality of narrow portions (first width portions) 24a and a plurality of wide portions (first width portions) in the longitudinal direction. 2 width portions) 24b are alternately formed. The narrow width portion 24a has a length of 700 μm, and is formed to be (resist film 24 width (Wl ′): resist removal width (Ws ′), aperture ratio) = (12 μm: 6 μm, 0.33). Yes. The wide portion 24b has a length of 50 μm, and is formed such that (width of resist film 24 (Wl ″): resist removal width (Ws ″), aperture ratio) = (15 μm: 3 μm, 0.17). . As will be described later, the wide portion 24b corresponds to a region having a window structure on the end face of the laser resonator. FIG. 5E shows a cross-sectional view of the stripe pattern (pattern of the resist film 24) in the narrow width portion 24a. The extending direction of the stripe (stripe direction) was the <1-100> direction (first direction) 201 of the GaN film. The wide portions 24b are formed at the same position in the longitudinal direction of the resist films 24, and are continuous with a gap in a direction (second direction) 202 perpendicular to the first direction 201. That is, the resist film 24 is formed to repeat in the width direction. Here, the width difference (d = Wl ″ −Wl ′) between the narrow width portion 24a and the wide width portion 24b is preferably 16% to 84% of the width Wl ′ of the narrow width portion 24a.

  The period P in the width direction of the resist film 24 shown in FIG. 5 (that is, the period P in the width direction of the insulating film 13) is 18 μm in the above example, but is preferably 5 μm or more and 50 μm or less. When the thickness is less than 5 μm, the difference between the narrow portion 24a and the wide portion 24b cannot be widened, and as a result, the effects of the present invention may not be obtained. On the other hand, if it exceeds 50 μm, the area of the insulating film 13 becomes too small, and threading dislocations tend not to be effectively suppressed.

  Next, using the resist film 24 as an etching mask, the insulating film 23 of the resist removing portion 101 ′ is removed with a hydrofluoric acid solution to form a groove-like opening 101, and the GaN layer 22 is exposed at the bottom of the opening 101. (FIG. 5 (f)). Subsequently, the resist film 24 is removed with an organic solution such as acetone (FIG. 6G). The width of the stripe-shaped insulating film 23 thus obtained, the width of the opening 101, and the opening ratio are substantially the same as the width of the resist film 24, the width of the opening 101, and the opening ratio. .

Thereafter, in order to selectively grow the GaN layer, the substrate 21 on which the striped insulating film 23 is deposited is held again on the susceptor in the reaction furnace of the MOVPE apparatus, and the reaction furnace is evacuated. Subsequently, the reactor is set to a hydrogen atmosphere with a pressure of 200 Torr, the temperature is raised to about 1000 ° C., and a supply amount of 7 sccm of trimethylgallium (TMG) and a supply amount of 7.5 slm of ammonia (NH ₃ ) gas are used. By simultaneously supplying hydrogen as a carrier gas, the GaN layer 25 is selectively grown on the selective growth mask pattern (insulating film 24) shown in FIG. At this time, the opening ratio in the longitudinal direction (first direction) 201 of the insulating film 23 is different, so that a difference in film thickness occurs in the first direction 201 in the laminated film thickness of the GaN layer 25 ((FIG. 6 ( h)))). As a result, a convex stripe 1 corresponding to the narrow portion of the insulating film 23 and a concave stripe 2 corresponding to the wide portion of the insulating film 23 are formed so as to extend in the second direction. In the case of the present embodiment, when the GaN layer 25 in the stripe 1 region is selectively grown by about 4 μm (FIG. 7 (i)), the film thickness is reduced in the stripe 2 region having a different aperture ratio of the insulating film 23 by about 3%. It is 0.5 μm (FIG. 7 (j)). This tendency is as shown in FIG. In this embodiment, the aperture ratio of the insulating film 13 is changed stepwise in the longitudinal direction. However, if the aperture ratio is gradually changed in a taper shape, the change in the film thickness of the GaN layer 25 also becomes gentle. Introduction of defects such as dislocations is suppressed.

Subsequently, silane (SiH ₄ ) gas is also supplied as an n-type dopant to grow an n-type contact layer 26 made of n-type GaN having a thickness of about 2 μm and a Si impurity concentration of about 1E18 cm ⁻³ . Next, while supplying trimethylaluminum (TMA), an n-type cladding layer 27 made of n-type Al _0.07 Ga _0.93 N having a thickness of about 0.7 μm and a Si impurity concentration of 5E17 cm ⁻³ is grown. Subsequently, after growing the first optical guide layer 28 made of n-type GaN having a thickness of about 120 nm and a Si impurity concentration of about 1E18 cm ⁻³ , the temperature is lowered to about 800 ° C., and the carrier gas is made from hydrogen. By changing to nitrogen, trimethylindium (TMI) and TMG are supplied and a quantum well (three layers) made of In _0.1 Ga _0.9 N with a thickness of about 3 nm and a GaN barrier layer (two layers) with a thickness of about 9 nm A multiple quantum well active layer 29 is grown. Thereafter, the temperature in the reactor is again raised to about 1000 ° C., the carrier gas is returned from nitrogen to hydrogen, and the p-type dopant biscyclopentadienylmagnesium (Cp ₂ Mg) gas is supplied while the thickness is increased. A cap layer 30 made of p-type Al _0.15 Ga _0.85 N having a thickness of about 20 nm and an Mg impurity concentration of 5E17 cm ⁻³ is grown. Next, a second optical guide layer 31 made of p-type GaN having a thickness of about 120 nm and an Mg impurity concentration of 1E18 cm ⁻³ is grown. Subsequently, a p-type cladding layer 32 made of p-type Al _0.07 Ga _0.93 N having a thickness of about 0.7 μm and an Mg impurity concentration of 5E17 cm ⁻³ is grown. Finally, a p-type contact layer 33 made of p-type GaN having a thickness of about 0.1 μm and an Mg impurity concentration of 1E18 cm ⁻³ is grown (FIG. 7 (k)). After the crystal growth was completed, the thickness of the laminated laser structure was confirmed by cross-sectional SEM. As shown in FIGS. 8A and 8B, the stripe 1 region was about 0.5 μm than the stripe 2 region. It was thick. That is, a step 301 (fault) of the laminated film occurred between the stripe 1 region and the stripe 2 region. This seems to be caused by the continued difference in film thickness of the GaN layer 25. The step 301 extends in the width direction (the left-right direction in the drawing) as shown as “stripe 2” in FIG. That is, it is orthogonal to the stripe direction of the insulating film 13 (see FIG. 5D, the vertical direction in the drawing).

Further, due to this film thickness difference, the active layer 29 in the stripe 1 region is positioned within the range where the p-type Al _0.07 Ga _0.93 N cladding layer 32 in the stripe 2 region is located in the thickness direction of the laminated film. It was confirmed that Therefore, the laser beam generated in the active layer 29 in the stripe 1 region propagates in the Al _0.07 Ga _0.93 N cladding layer 32 having a band gap energy larger than that in the active layer 29 in the stripe 2 region corresponding to the end face window structure region. It will be. As a result, the absorption of laser light in the end face region is reduced.

  After completion of the growth, first, activation heat treatment of the p-type semiconductor layer is performed. The substrate is taken out from the reaction furnace of the MOVPE apparatus, and is transferred into an annealing furnace to perform heat treatment for p-type impurity activation. Next, after evacuating the annealing furnace, a supply amount of 3 slm nitrogen gas is introduced to atmospheric pressure, and then a heat treatment is performed at 750 ° C. for 20 minutes. After the heat treatment, the substrate is cooled to room temperature and removed from the annealing furnace.

  Hereinafter, the laser processing process will be described with reference to FIG. 9 showing a sectional view of the laser structure.

After completion of the heat treatment, an insulating film made of SiO ₂ is deposited on the surface of the substrate 21. Subsequently, a resist film is deposited on the insulating film, and the resist film remains only at the ridge formation position (ridge width is about 2 μm) of the p-type contact layer 33 by photolithography. At this time, by forming the ridge in a selective growth region (low dislocation density region) on the insulating film 23, it is possible to reduce the operating current and extend the life of the laser element. Thereafter, using the resist film as an etching mask, the insulating film in the resist removal portion is removed with a hydrofluoric acid solution to expose the p-type contact layer 33. Subsequently, the region other than the ridge formation position is etched with a dry etching apparatus so that the remaining film thickness of the p-type layer on the active layer 29 is about 50 nm. Thereafter, the resist film is removed with an organic solution such as acetone. Thereby, the ridge 103 composed of the p-type contact layer 33 and the Al _0.07 Ga _0.93 N cladding layer 32 is formed. The extending direction of the ridge 103 is a direction parallel to the extending direction of the stripe, that is, the first direction 201.

Next, a region other than the n-type electrode formation position is covered with an insulating film made of SiO ₂ and the n-type contact layer 26 is exposed by dry etching. Further, the p-side and n-side electrical separation is performed by the insulating film 34 made of SiO ₂ , and the insulating film 34 on the p-type contact layer 33 located on the ridge 103 is removed with a hydrofluoric acid solution. Thereafter, Ti / Al is formed as the n-side electrode 35 and Ni / Pt / Au is formed as the p-side electrode 36 in the portion where the insulating film 34 is removed.

  Subsequently, the process proceeds to a cleavage step of the laser resonator end face. First, the substrate 21 is polished from the back surface of the sapphire substrate to reduce the total film thickness to about 120 μm. Thereafter, the substrate 21 is cleaved with a cleaving device (not shown) so that the resonator end face is in the <1-100> direction of the sapphire substrate (the cleavage plane is the (11-20) plane). At this time, by cleaving at the center of the stripe 2 (end face window structure) region, a bar-shaped laser element A (resonator length: 750 μm) having end face window structure regions (length: 25 μm) on both end faces is manufactured. can do.

Next, a highly reflective coating is applied to the rear end face of the laser resonator in the following procedure. The highly reflective film has a dielectric multilayer structure composed of three pairs of SiO ₂ and titanium dioxide (TiO ₂ ).

  A silicon bar shorter than the laser resonator length (750 μm) is sandwiched between the laser elements A in a bar state and fixed to a jig. The reason why the silicon bar is designed to be shorter than the resonator length is to prevent the silicon bar from becoming an obstacle at the time of sputtering so that the dielectric cannot be coated on the laser end face as designed. Subsequently, end face coating is performed by sputtering the dielectric film on the entire jig surface on which the laser element A is fixed. The height of the silicon bar used this time was 735 μm. Therefore, on the rear end face of the laser element A, the dielectric multilayer film adheres to both the electrode side and the substrate side of the laser element A in a region (within the end face window structure region) from the end face to the resonator direction of 15 μm. It will be.

Finally, the laser element A in the bar state is subjected to secondary cleavage, separated into laser chips, and mounted on the laser can in a p-side down manner. At the time of mounting, the laser chip is mounted on a submount made of silicon carbide (SiC) via solder. It should be noted that the light emitting end face is mounted with being slightly exposed (about 10 μm) from the submount so that the solder does not adhere. FIG. 10 shows an external view of the laser chip drawn excluding the insulating film 34, the n-side electrode 35, and the p-side electrode 36 so that the uneven state of the laser surface becomes clear (the same applies to FIGS. 11 and 14). ).
[First Comparative Example]
As a first comparative example, a laser element B composed only of a region corresponding to the stripe 1 region without the stripe 2 (end window structure) region was manufactured (FIG. 11).

  The first embodiment has the following major features in laser element characteristics.

In the laser device A manufactured according to the present embodiment, gain was generated in the stripe 1 region by current injection, and room temperature continuous oscillation was reached. The threshold current and slope efficiency at this time were 50 mA and 1.0 W / A, respectively (FIG. 12). In addition, the threshold current and slope efficiency of the laser element B produced for comparison were 45 mA and 1.0 W / A, respectively (FIG. 12). The reason why the threshold current is increased in the laser element A is that an end window structure region (length: 25 μm) is provided on both end surfaces, and therefore there is a reactive current that does not contribute to laser oscillation in this region. Next, a room temperature constant light output lifetime test at a high light output of 30 mW was performed on the laser element A and the laser element B (FIG. 13). The laser element B has a deterioration rate of about 0.2 mA / h, whereas the laser element A has a rate of about 0.05 mA / h, demonstrating a stable operation for 1000 hours (less than twice the operating current). After the life test, an electroluminescence (EL) image of each laser element was observed from the back surface of the sapphire substrate (not shown). In the laser element A, the entire resonator length emitted uniformly along the ridge 103, but in the laser element B, the light emission was weak in the vicinity of both end faces, and the tendency was particularly strong on the light emitting end face side. This is because the laser element B does not have an end face window structure region, so non-radiative recombination proceeds at the surface level of the end face, the amount of heat generation near the end face increases, and a kind of COD is generated. I think that the. Further, in p-side down mounting, the vicinity of the end face and the solder are spatially separated so that the solder does not adhere to the light emitting end face. Therefore, in the laser element B, heat radiation is deteriorated and COD is likely to occur. Seem. GaN-based semiconductor lasers inevitably have high power consumption due to their high operating voltage. For this reason, it became phenomenologically clear that heat dissipation (particularly in the vicinity of the end face), which was not a problem with conventional semiconductor lasers other than GaN-based semiconductors, becomes very important. From the above, in the laser device according to the present invention, the low dislocation structure and the end face window structure, which are essential for the long life in the high light output operation, can be formed at the same time by one selective growth, thereby simplifying the manufacturing method. It was found that the yield can be improved and the manufacturing cost can be reduced. Since the laser element A has an end face window structure, it is not easily affected by the return light when the optical disk is reproduced, and there is a possibility that the noise can be reduced from a low light output of 2 to 3 mW to a high light output of 30 mW.
[Second Comparative Example]
The following experiment was conducted as a second comparative example.

  For comparison with the laser element A, a laser element C was manufactured in which the aperture ratio of the laser resonator end face was increased and the laminated film thickness was increased (FIG. 14).

  The manufacturing procedure of the laser device C is the same as that of the laser device A except for the aperture ratio of the stripe 2 for crystal growth. Here, the stripe 2 of the laser element C is formed by (width of resist film 24: resist removal width, aperture ratio) = (9 μm: 9 μm, 0.5). Since the stripe 1 is formed by (resist film 24 width: resist removal width, aperture ratio) = (12 μm: 6 μm, 0.33), the aperture ratio of the insulating film increases at the end face of the laser resonator. After the crystal growth, when the laminated film thickness of the entire laser structure is measured by cross-sectional SEM, it is about 6.5 μm in the stripe 2 region and about 6 μm in the stripe 1 region, and the laminated film thickness increases at the cavity end face. all right. This tendency is as shown in FIG.

  In the laser element C, the threshold current and the slope efficiency were 60 mA and 0.6 W / A, respectively. Next, a constant room temperature light output life test with a high light output of 30 mW was performed with the laser element C, and showed a rapid deterioration tendency in which the operating current reached 300 mA in about 10 hours. Next, the laser element C was removed from the submount, and the state of solder adhesion on the surface of the laser element was observed using an SEM (not shown). It has been found that the solder is not attached to the region other than the end face window structure (stripe 2) region, and it seems that the deterioration of heat dissipation affects the life of the laser element. This incomplete adhesion of the solder is caused by the fact that the laminated film thickness is increased in the stripe 2 region, so that the solder adhesion is given priority in this region.

  From the above, it has been found that when the end face window structure is manufactured, the laminated film thickness of this region needs to be at least equal to or less than that other than the end face window structure region.

(Second Embodiment)
In the second embodiment of the present invention, in the crystal growth of a semiconductor laser, a low dislocation structure and laser resonance are achieved by performing selective growth using insulating films having different aperture ratios based on the above-described stacked film thickness control method. A method of manufacturing a GaN-based semiconductor laser capable of simultaneously obtaining an end face window structure effective for suppressing COD generation on the end face of the vessel at a high yield and low cost is shown.

  A method for manufacturing a GaN-based laser according to the second embodiment of the present invention will be described below.

  The procedure up to crystal growth and electrode formation is the same as in the first embodiment. However, in this embodiment, a step of removing the p-side electrode by wet etching in a region corresponding to the stripe 2 (end window structure) region in the first embodiment is introduced. The cleaving, end surface coating, and mounting procedures are the same as in the first embodiment. The laser element D manufactured in this way has an end face current non-injection structure because no p-side electrode exists in the end face window structure region. A cross-sectional view of the structure of the laser element D near the ridge is shown in FIG.

  The second embodiment has the following major features in laser element characteristics.

  In the laser device D manufactured according to the present embodiment, gain was generated in regions other than the end face window structure region due to current injection, and continuous oscillation at room temperature was reached. The threshold current and slope efficiency at this time were 45 mA and 1.0 W / A, respectively. The reason why the threshold current (50 mA) of the laser device A manufactured in the first embodiment can be lowered is that the laser device A has a problem because the end face window structure region has a current non-injection structure. This is because the reactive current that does not contribute to laser oscillation in this region is suppressed. Next, a room temperature constant light output life test with a high light output of 30 mW was performed with the laser element D (FIG. 16). In the laser element D, the deterioration rate was about 0.02 mA / h, and a stable operation for 1000 hours (below twice the operating current) was demonstrated. After the life test, the EL image of the laser element was observed from the back surface of the sapphire substrate (not shown). In the laser element D, even after the life test, the entire resonator length emitted light uniformly along the ridge, and no COD was observed. As described above, it has been found that the laser element having the end face window structure and the end face current non-injection structure can further improve the reliability in the high light output operation and contribute to the high yield and cost reduction. In addition, since the laser element D has an end face window structure, it is not easily affected by the return light when the optical disk is reproduced, and there is a possibility that the noise can be reduced from a low light output of 2 to 3 mW to a high light output of 30 mW.

(Third embodiment)
According to the third embodiment of the present invention, in the crystal growth of a semiconductor laser, a low dislocation structure and laser resonance are achieved by performing selective growth using insulating films having different aperture ratios based on the above-described stacked film thickness control method. A method of manufacturing a GaN-based semiconductor laser capable of simultaneously obtaining an end face window structure effective for suppressing COD generation at the end face of the vessel at a high yield is shown.

  A method for manufacturing a GaN-based laser according to the third embodiment of the present invention will be described below.

Procedures such as crystal growth are substantially the same as those in the first embodiment. However, in this embodiment, a step of forming an insulating film 37 made of SiO ₂ under the p-side electrode is introduced at a position corresponding to the stripe 2 (end window structure) region in the first embodiment. The procedures for electrode formation, cleavage, end surface coating, and mounting are the same as in the first embodiment. The laser element E manufactured in this way has an end face current non-injection structure because an insulating film exists under the p-side electrode in the end face window structure region. A sectional view of the structure of the laser element E near the ridge is shown in FIG.

  The third embodiment has the following great features in laser element characteristics.

In the laser device E manufactured according to the present embodiment, gain was generated in regions other than the end face window structure region due to current injection, and continuous oscillation at room temperature was reached. The threshold current and slope efficiency at this time were 45 mA and 1.0 W / A, respectively. The reason why the threshold current (50 mA) of the laser device A manufactured in the first embodiment can be lowered is that the laser device A has a problem because the end face window structure region has a current non-injection structure. This is because the reactive current that does not contribute to laser oscillation in this region is suppressed. Next, a room temperature constant light output lifetime test with a high light output of 30 mW was performed with the laser element E. Laser element E, like laser element D, has a degradation rate of about 0.02 mA / h, and has demonstrated stable operation for 1000 hours or more. After the life test, the EL image of the laser element E was observed from the back surface of the sapphire substrate (not shown). In the laser device E, even after the life test, the entire resonator length emitted light uniformly along the ridge, and no COD was observed. As described above, it has been found that the laser element having the end face window structure and the end face current non-injection structure can further improve the reliability in the high light output operation and contribute to the high yield and cost reduction. Since the laser element E has an end face window structure, it is not easily affected by the return light during reproduction of the optical disk, and there is a possibility that the noise can be reduced from a low light output of 2 to 3 mW to a high light output of 30 mW.

[Third comparative example]
In order to compare with the laser element E, the following experiment was performed.

  As a third comparative example, a laser element F to which the end face current non-injection structure of the third embodiment was applied was manufactured in the laser element B of the first embodiment (no end face window structure region).

  In the laser element F, the threshold current and the slope efficiency were 45 mA and 1.0 W / A, respectively, and current-light output characteristics equivalent to those of the laser element D and the laser element E were exhibited. Next, a room temperature constant light output lifetime test with a high light output of 30 mW was performed with the laser element F (FIG. 18). In the laser element F, the deterioration rate is about 0.08 mA / h, which is an improvement over the deterioration rate of the laser element B (0.2 mA / h), but it reaches the deterioration rate of the laser element A (0.05 mA / h). I knew it was n’t there. After the life test, the EL image of the laser element F was observed from the back surface of the sapphire substrate (not shown). In the laser element F, even after the life test, the entire resonator length emitted light substantially uniformly along the ridge, and no significant COD generation was observed.

  As described above, when the end face window structure is not provided, the end face current non-injection structure can suppress the heat generation near the end face and is effective for extending the life of the laser element. It turned out that it does not reach the life of D and E. In the laser elements A, D, and E, by adding an end face window structure to the end face current non-injection structure, heat generation at the end face is suppressed to the extent that laser light absorption at the end face is suppressed, thereby extending the life. I think that the.

(Fourth embodiment)
According to the fourth embodiment of the present invention, in the crystal growth of a semiconductor laser, a low dislocation structure and laser resonance are achieved by performing selective growth using insulating films having different aperture ratios based on the above-described stacked film thickness control method. A method of manufacturing a GaN-based semiconductor laser capable of simultaneously obtaining an end face window structure effective for suppressing COD generation at the end face of the vessel at a high yield is shown.

  A method for manufacturing a GaN-based laser according to the fourth embodiment of the present invention will be described below.

  The crystal growth procedure is substantially the same as in the first embodiment. However, the resonator direction length of the stripe 2 (end face window structure) region in the first embodiment was variously changed. Further, the end face current non-injection structure of the third embodiment is introduced. The cleaving, end surface coating, and mounting procedures are the same as in the first embodiment. Thus, each laser element group 7 (resonator length: 750 μm, not shown) having end face window structure regions (length: 15, 25, 35, 50, 75 μm) on both end faces was manufactured this time. Here, the laser element having the end face window structure region (length: 25 μm) on both end faces is the laser element E. When the end face window structure region occupancy in the resonator length is defined as (end face window structure region) / (resonator length), the end face window structure region (length: 15, 25, 38, 55, 75 μm) The occupancy ratios in the laser elements are (4, 7, 10, 15, 20%), respectively.

  The characteristics of the laser element G manufactured according to the fourth embodiment are shown below.

  The current-light output characteristics of each laser element G were measured, and the relationship between the threshold current and the end face window structure region occupancy is shown in FIG. From FIG. 19, when the occupation ratio is 10% or less, the increase in the threshold current is not remarkable. However, when the occupation ratio exceeds 10%, the threshold current increases due to the substantial short resonator. The increase in threshold current leads to an increase in operating current in a constant light output life test at a high light output of 30 mW, and the life time is shortened. From the above, it has been found that the end face window structure area occupation ratio of the laser element G is desirably 10% or less.

(Fifth embodiment)
In the fifth embodiment of the present invention, in the crystal growth of a semiconductor laser, a low dislocation structure and laser resonance are achieved by performing selective growth using insulating films having different aperture ratios based on the above-described stacked film thickness control method. A method of manufacturing a GaN-based semiconductor laser capable of simultaneously obtaining an end face window structure effective for suppressing COD generation at the end face of the vessel at a high yield is shown.

  Hereinafter, a method of manufacturing a GaN-based laser according to the fifth embodiment of the present invention will be described.

  The procedures for crystal growth, electrode formation, and cleavage are the same as in the third embodiment. However, in the end face coating, the electrode side adhesion region of the dielectric film is within the end window structure region in the first embodiment, but the dielectric film adhesion region is changed in the fifth embodiment. The mounting procedure is the same as in the first embodiment. This time, by adjusting the height of the silicon bar during the dielectric film sputtering, the dielectric film adhesion region was set to a range extending from the resonator end face and the resonator end face to 15, 25, 50, and 75 μm. Hereinafter, the resonator end face and the dielectric film attachment region in the range extending from the resonator end face to X μm are referred to as X μm dielectric film attachment region. Here, the laser element having a 25 μm dielectric film adhesion region at both ends is the laser element E.

  The characteristics of the laser elements H, I, and J (dielectric film adhesion regions: 15, 50, and 75 μm) manufactured in this way are shown below.

  The current-light output characteristics of the laser elements H, I, and J were almost the same as those of the laser element E. Next, a room temperature constant light output life test with a high light output of 30 mW was performed with the laser elements H, I, and J. The deterioration rates were 0.02 mA / h for laser element H, 0.1 mA / h for element I, and about 0.4 mA / h for element J. Incidentally, the degradation rate of the laser element E is about 0.02 mA / h, similar to the element H. FIG. 20 shows the relationship between the deterioration rate of each laser element and the dielectric film region. Next, the laser element J was removed from the submount, and the state of solder adhesion on the surface of the laser element was observed using an SEM (not shown). It was found that solder was not attached in the dielectric film adhesion region, and it was expected that the heat radiation deteriorated in this region, which had an influence on the life of the laser element. From the above, it has been found that by designing the dielectric film adhesion region to be within the end face window structure region and the end face current non-injection region, deterioration of heat dissipation of the laser element is suppressed and it contributes to a longer life. In the embodiment of the present invention, the end face coat is applied to the rear end face of the laser resonator. However, the front end face (light emitting side) of the laser resonator is provided with the low reflection film coat, the protective film coat and the high reflection film coat. But it has the above effect. This effect is the same in the laser element F.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The method for manufacturing a semiconductor light-emitting stop element according to the present invention is useful as a method for manufacturing a semiconductor light-emitting element as a light source for a high-density optical disk.

  The semiconductor light-emitting stop element according to the present invention is useful as a light source for a high-density optical disc.

FIG. 1A to FIG. 1D are cross-sectional views of a GaN-based semiconductor selectively grown on a sapphire substrate in a method for controlling a laminated film thickness that is the basis of a method for manufacturing a semiconductor light emitting device of the present invention. FIGS. 2E to 2H are cross-sectional views of a GaN-based semiconductor selectively grown on a sapphire substrate in a stacked film thickness control method that is the basis of the method for manufacturing a semiconductor light emitting device of the present invention. It is a figure which shows the relationship between the laminated film thickness of the GaN-type semiconductor selectively grown on the sapphire substrate in the laminated film thickness control method used as the foundation of the manufacturing method of the semiconductor light-emitting device of this invention, and an insulating-film aperture ratio. FIGS. 4A to 4C are cross-sectional views of a GaN-based laser structure selectively grown on the sapphire substrate according to the first embodiment of the present invention. FIGS. 5D to 5F are cross-sectional views of a GaN-based laser structure selectively grown on the sapphire substrate according to the first embodiment of the present invention. 6 (g) to 6 (h) are cross-sectional views of a GaN-based laser structure selectively grown on the sapphire substrate according to the first embodiment of the present invention. FIGS. 7 (i) to 7 (k) are cross-sectional views of a GaN-based laser structure selectively grown on the sapphire substrate according to the first embodiment of the present invention. 8 (a) and 8 (b) are diagrams showing the configuration in the cavity length direction of the selectively grown GaN-based lasers having different insulating film aperture ratios according to the first embodiment of the present invention. (a) is sectional drawing along the VIIIa-VIIIa cutting | disconnection line of FIG.7 (k), FIG.8 (b) is sectional drawing along the VIIIb-VIIIb cutting | disconnection line of FIG.7 (k). 1 is a cross-sectional view of a selective growth GaN-based laser according to a first embodiment of the present invention. 1 is a perspective view showing a structure in a state where an electrode and an insulating film of a selectively grown GaN laser having an end face window structure according to a first embodiment of the present invention are removed. FIG. It is a perspective view which shows the structure in the state which removed the electrode and insulating film of the selective growth GaN-type laser which does not have the end surface window structure concerning the 1st comparative example in the 1st Embodiment of this invention. It is a figure which shows the electric current-light output characteristic of each selective growth GaN-type laser (Laser element A, B) which concerns on the 1st Embodiment of this invention. It is a figure which shows the result of the 30 mW room temperature fixed optical output lifetime test of each selective growth GaN-type laser (Laser element A, B) which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure in the state which removed the electrode and insulating film of the selective growth GaN-type laser which has the end surface window structure which concerns on the 2nd comparative example in the 1st Embodiment of this invention. FIG. 6 is a cross-sectional view of a selective growth GaN-based laser having a facet window structure and a facet current non-injection structure according to a second embodiment of the present invention in the cavity length direction. It is a figure which shows the result of the 30 mW room temperature fixed optical output lifetime test of the selective growth GaN-type laser (Laser element D) based on the 2nd Embodiment of this invention. FIG. 6 is a cross-sectional view in the cavity length direction of a selectively grown GaN laser having an end face window structure and an end face current non-injection structure according to a third embodiment of the present invention. It is a figure which shows the result of the 30 mW room temperature constant optical output lifetime test of the selective growth GaN-type laser (laser element F) which concerns on the comparative example 3 in the 3rd Embodiment of this invention. It is a figure which shows the relationship between the threshold current of the selective growth GaN-type laser (laser element G) which concerns on the 4th Embodiment of this invention, and an end surface window structure occupation rate. It is a figure which shows the relationship between the deterioration rate of the selective growth GaN-type laser (Laser element E, HJ) based on the 5th Embodiment of this invention, and a dielectric film adhesion area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12 GaN layer 13 Insulating film 14 Resist film 15 GaN layer 21 Sapphire substrate 22 GaN layer 23 Insulating film 24 Resist film 24a Narrow part 24b Wide part 25 GaN layer 26 n-type contact layer 27 n-type cladding layer 28 1st Optical guide layer 29 multiple quantum well active layer 30 cap layer 31 second optical guide layer 32 p-type cladding layer 33 p-type contact layer 34 insulating film 35 n-side electrode 36 p-side electrode 101 opening 102 threading dislocation 103 ridge 201 first 1 direction 202 2nd direction 301 Step

Claims (17)

A stripe having a first width portion having a predetermined width and a second width portion having a width wider than the predetermined width adjacent to both ends of the first width portion on the first nitride-based III-V compound semiconductor layer Forming a masking film having a shape to repeat in the width direction at a predetermined cycle;
A second nitride III-V compound is formed from the exposed portion so as to cover the masking film and a portion of the surface of the first nitride III-V compound semiconductor layer exposed between the masking films. A step B of selectively growing a semiconductor layer;
The active layer extending substantially in the stripe direction of the masking film and including a portion located above the second width portion is lower than a portion located above the first width portion. a semiconductor laser structure having an extending step, have a step C of stacking the second nitride III-V compound semiconductor layer,
A width difference between the first width portion and the second width portion in the masking film is not less than 16% and not more than 84% of a predetermined width of the first width portion;
A method for manufacturing a semiconductor light emitting element , wherein the predetermined period in the width direction of the masking film is 5 μm or more and 50 μm or less .   In the semiconductor laser structure, the step is formed so that a portion of the active layer located above the first width portion is joined to a semiconductor layer other than the active layer located above the second width portion. The method for manufacturing a semiconductor light emitting device according to claim 1.   In the semiconductor laser structure, the active layer in a portion located above the first width portion is joined to a semiconductor layer having a larger band gap energy than the active layer in a portion located above the second width portion. The method of manufacturing a semiconductor light emitting element according to claim 2, wherein a step is formed. The semiconductor laser structure includes a cladding layer sandwiching the active layer in the stacking direction;
4. The method of manufacturing a semiconductor light emitting element according to claim 3, wherein the semiconductor layer having a larger band gap energy than the active layer is the cladding layer.   The method of manufacturing a semiconductor light emitting element according to claim 1, wherein the masking film is made of an insulating film.   2. The method of manufacturing a semiconductor light emitting device according to claim 1, wherein, in the step C, when the semiconductor laser structure is stacked, a ridge is formed so as to extend in a stripe direction of the masking film and to be positioned above the masking film. .   The method for manufacturing a semiconductor light emitting element according to claim 1, wherein a portion of the semiconductor laser structure located above the second width portion has a current non-injection structure. 8. The method of manufacturing a semiconductor light emitting element according to claim 7 , wherein the current non-injection structure is obtained by not forming an electrode in a portion located above the second width portion of the semiconductor laser structure. 8. The method of manufacturing a semiconductor light emitting element according to claim 7 , wherein the current non-injection structure is obtained by forming an insulating layer under the electrode in a portion located above the second width portion of the semiconductor laser structure.   The method for manufacturing a semiconductor light emitting device according to claim 1, wherein the nitride-based III-V group compound semiconductor is a GaN semiconductor.   The method for manufacturing a semiconductor light emitting device according to claim 1, wherein the first nitride-based III-V compound semiconductor layer is formed on a sapphire substrate.   2. The semiconductor light emitting device according to claim 1, wherein the second nitride-based III-V group compound semiconductor grows substantially parallel to the main surface of the substrate from between the masking films onto the masking film. Method.   2. The semiconductor according to claim 1, wherein a transition density of a portion grown on the masking film is lower than a transition density of a portion grown between the masking films in the second nitride-based III-V compound semiconductor layer. Manufacturing method of light emitting element.   2. The method of manufacturing a semiconductor light emitting element according to claim 1, wherein the second nitride-based III-V compound semiconductor layer is planarized at a portion grown on each width portion of the masking film.   The method for manufacturing a semiconductor light emitting element according to claim 1, wherein an aperture ratio of the masking film changes in a taper shape in the stripe direction. A first nitride-based III-V compound semiconductor layer;
The first nitride-based III-V compound semiconductor layer is formed on the first nitride-based III-V compound semiconductor layer so as to repeat in the width direction at a predetermined cycle, and is adjacent to both ends of the first width portion having a predetermined width and the predetermined width portion. A striped masking film having a second width portion wider than the width;
Second nitride selectively grown from the exposed portion so as to cover the masking film and the portion of the surface of the first nitride-based III-V compound semiconductor layer exposed between the masking films A III-V compound semiconductor layer,
A portion that is stacked on the second nitride-based III-V compound semiconductor layer and includes an active layer substantially extending in a stripe direction of the masking film, and a portion positioned above the second width portion is the first width portion. A semiconductor laser structure having a step extending in the width direction by being lower than a portion located above the width portion , and
A width difference between the first width portion and the second width portion in the masking film is not less than 16% and not more than 84% of a predetermined width of the first width portion;
The semiconductor light emitting element whose predetermined period of the said width direction of the said masking film is 5 micrometers or more and 50 micrometers or less . The semiconductor light emitting element according to claim 16 , wherein the masking film is located below the active layer in a cross-sectional view in the stripe direction.

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