JP2008153650A - Optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical semiconductor device capable of bringing more stable optical characteristic and preventing degradation in transmittance between a sealed condition with resin and the like and an unsealed condition. <P>SOLUTION: The optical semiconductor device has a laminate 13 sequentially stacked by a first layer 13a mainly made of magnesium fluoride or silicon oxide, a second layer 13b mainly made of titanium oxynitride, and a third layer 13c mainly made of magnesium fluoride or silicon oxide in this order. A plurality of reflective surfaces is provided inside the laminate 13, and the laminate 13 serves as an antireflective film on the emitting plane of the optical semiconductor device. At least the emitting surface is sealed with resin 200. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical semiconductor device having an optical multilayer film.

  Conventionally, an optical semiconductor device such as a semiconductor laser or an optical modulator has been provided sealed with a package of metal, ceramics, or the like in order to ensure confidentiality inside the device. However, such a sealing method requires an expensive package and a complicated sealing process, and there has been a problem that it is difficult to provide this inexpensively and easily.

  Therefore, in recent years, a method of sealing an optical semiconductor device with resin or the like has been provided as the above alternative means. However, in this method, since the refractive index of the medium covering the optical semiconductor device, which is an optical element, is different between before and after sealing with resin or the like, the optical semiconductor device cannot exhibit the desired optical characteristics. There was a problem.

  As a method for solving such a problem, for example, there is a technique exemplified in Patent Document 1 below. In this conventional technique, in a configuration in which a semiconductor device having a single-layer antireflection film is sealed with resin, light reflected at the interface between the antireflection film and resin is transmitted through the inside of the antireflection film. By having a configuration that attenuates (or cancels), the optical semiconductor device is configured to suppress deterioration of optical characteristics.

  On the other hand, in order to further improve the transmittance of an optical film such as an antireflection film, it is generally known that it is formed of a multilayer film (for example, see Patent Document 2). However, in this prior art, a technique that can enhance and stabilize the optical characteristics of the optical semiconductor device has not been studied.

JP 2001-42169 A JP-A-7-113901

  Therefore, an object of the present invention is to provide an optical semiconductor device having an optical multilayer film that further stabilizes optical characteristics.

  In addition, the present invention provides an optical semiconductor device having an optical multilayer film that achieves the above object and prevents the transmittance from being deteriorated between a state sealed with a resin or the like and a state not sealed. With the goal.

  The optical semiconductor device according to the present invention has a first layer containing magnesium fluoride as a main component, a second layer containing titanium oxynitride as a main component, and magnesium fluoride as a main component. The third layer has a laminated structure laminated in this order, and includes a plurality of reflecting surfaces inside the laminated structure, and the laminated structure is provided on the light emitting surface of the optical semiconductor as an antireflection film, The light emission surface is sealed with resin. In this way, by using titanium oxynitride rich in stress controllability, the stress of magnesium fluoride, which is useful as a low refractive index optical film, can be controlled by titanium oxynitride, so an optical multilayer film with reduced stress is used. An optical semiconductor device can be manufactured. Furthermore, in the present invention, since a plurality of reflective surfaces are formed inside the optical multilayer film by having a multilayer structure of at least three layers, the film thickness of the second layer, which is a high refractive index optical film, is converted into an optical distance. Even when the thickness is smaller than the quarter wavelength, interference of reflected light can be caused. In the present invention, titanium oxynitride or magnesium fluoride is not limited to the meaning that each element is composed only of each element, and even if a trace amount of other elements are mixed in each element, If the optical characteristics or stress is equivalent, it is in that category.

  An optical semiconductor device according to the present invention includes a first layer containing silicon oxide as a main component, a second layer containing titanium oxynitride as a main component, and magnesium fluoride as a main component. The third layer is laminated in this order, and includes a plurality of reflecting surfaces inside the laminated structure, and the laminated structure is provided on the light emitting surface of the optical semiconductor as an antireflection film, and at least The light emitting surface is sealed with a resin.

  In the optical semiconductor device having the above configuration, the first layer and the second layer are preferably in contact with each other.

  In the optical semiconductor device having the above-described configuration, the second layer is preferably configured to be a layer formed by ion-assisted deposition.

  In the optical semiconductor device having the above configuration, the first layer is preferably configured so as to be in contact with a light emitting surface of the optical semiconductor.

  According to the present invention, by using titanium oxynitride rich in stress controllability, the stress of magnesium fluoride useful as a low-refractive index optical film can be controlled by titanium oxynitride, and the optical multilayer film with reduced stress and An optical semiconductor device having the same can be manufactured. Furthermore, in the present invention, since a plurality of reflective surfaces are formed inside the optical multilayer film by having a multilayer structure of at least three layers, the film thickness of the second layer, which is a high refractive index optical film, is converted into an optical distance. Even when the thickness is smaller than the quarter wavelength, interference of reflected light can be caused. Further, the optical characteristics are prevented from fluctuating before and after filling with a resin or the like, and the optical characteristics measured before filling the resin or the like are not changed even after filling with the resin or the like.

〔principle〕
In an optical multilayer film having a two-layer structure that exists as a conventional technique, only one reflecting surface is present inside. For this reason, this reflection surface can only interfere with the reflected light on the reflection surface caused by the difference in refractive index from the outside (such as air) of the optical multilayer film. Therefore, when two light beams interfere with each other, the optical multilayer film having a two-layer structure is designed to have a film having a thickness of a quarter wavelength converted to an optical distance, so a film thinner than this is formed. However, it is impossible to obtain a desired function of the optical multilayer film.

  On the other hand, by forming an optical multilayer film having a laminated structure of three or more layers as in the present embodiment, a plurality of reflecting surfaces are formed inside. For this reason, if interference is caused between any of a plurality of reflecting surfaces, the function as an optical multilayer film is realized. Therefore, the thickness of each film may be made thinner than a quarter wavelength converted to an optical distance. It becomes possible, and it becomes possible to improve the stress controllability by titanium oxynitride.

  In general, an optical multilayer film realizes predetermined optical characteristics such as antireflection characteristics and high reflection characteristics by utilizing multiple reflection and interference caused by a combination of materials having different refractive indexes. For this reason, it is important for the film constituting the optical multilayer film that a predetermined refractive index difference can be realized, and generally a combination of materials capable of increasing the refractive index difference is required. Therefore, the inventor of the present invention pays attention to the fact that magnesium fluoride is a material having a low refractive index, and if this is adopted as the material of the optical multilayer film, the refractive index difference from the material on the higher refractive index side can be increased. We considered adopting this.

  However, the present inventors have to avoid that the optical multilayer film applies a large stress to the optical semiconductor. However, even if this magnesium fluoride controls the manufacturing conditions, the stress itself does not change so much. I found out. Therefore, the present invention has a configuration in which magnesium fluoride is combined with titanium oxynitride as described above.

  This titanium oxynitride is rich in controllability of stress depending on manufacturing conditions and the like. That is, the combination of titanium oxynitride and magnesium fluoride allows titanium oxynitride to control the stress of magnesium fluoride useful as a low refractive index optical film, so that an optical multilayer film with reduced stress can be expected.

  However, when an optical multilayer film having a two-layer structure of simply titanium oxynitride and magnesium fluoride is formed, the effect of reducing stress is low. This is because the optical multilayer film exhibits a predetermined optical effect due to interference between reflected lights generated on surfaces having different refractive indexes. For this reason, in the optical multilayer film having a two-layer structure, there is only one reflecting surface inside, and a thickness of at least a quarter wavelength is required to cause interference. Therefore, it is difficult to cause interference when the thickness is further reduced. In other words, in the two-layer structure of titanium oxynitride and magnesium fluoride, the thickness of each layer cannot be reduced, and stress control is possible by adopting titanium oxynitride, but the magnesium fluoride layer Limits on stress controllability occur.

  Therefore, in the present invention, as described above, a layer is further added in addition to titanium oxynitride and magnesium fluoride, and a plurality of reflecting surfaces are formed therein. With this configuration, a plurality of reflecting surfaces are formed inside the optical multilayer film, and therefore, any combination of the plurality of reflecting surfaces may be configured to cause interference. In other words, even when it is configured to be thinner than a quarter wavelength converted to an optical distance, it is possible to cause interference by design.

  Hereinafter, embodiments of the present invention for realizing this will be described in detail with reference to the drawings. In the following description, titanium oxynitride or magnesium fluoride is not limited to the meaning that it is composed only of each element, and even if a small amount of other elements are mixed in each element, If the optical characteristics or stress are equivalent, it is in that category.

[First Embodiment]
First, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the optical semiconductor device 100A according to the present embodiment. 1 shows a cross-sectional view of the semiconductor chip 10 along the optical axis.

  As shown in FIG. 1, in this embodiment, an optical multilayer film 13 having a multilayer structure is formed on one end or both ends of a semiconductor chip 10. Each optical multilayer film 13 has a three-layer structure from the first layer 13 a in contact with the semiconductor chip 10 to the third layer 13 c located on the outermost side, and is not sealed with the resin 200. It is formed so as to exhibit good transmission characteristics depending on the state. In other words, the optical multilayer film 13 according to the present embodiment is configured to function as an antireflection film for both air (or vacuum) and resin. The sealing with the resin 200 is intended to protect the optical multilayer film 13 and the semiconductor chip 10 at the time of shipment and operation, and is effective, inexpensive and easy to guarantee the performance of the optical semiconductor device 100A. It is.

  In this way, the method of designing both to act as an antireflection film is to first determine the rough conditions of the third layer 13c located on the outermost side based on the refractive index of the resin 200 used, for example. The multilayer film composed of the first layer 13a and the second layer 13b is designed to act as an antireflection film for the resin 200, and finally the optical multilayer film 13 with respect to the refractive index of air (or vacuum). This is realized by the procedure of designing the third layer 13c within the above conditions so that the whole acts as an antireflection film. As the resin 200, for example, an epoxy resin or the like is applied.

  Further, when designed based on this procedure, the refractive index of each layer in the optical multilayer film 13 is highest in the second layer 13b, and the refractive index of the first layer 13a and the third layer 13c is lower than that of the second layer 13b. Have the relationship.

  By designing based on the above procedure, the optical multilayer film 13 that functions as an antireflection film is realized equally when evaluating the characteristics (performance) of the optical semiconductor device 100A and when actually using it. It is possible to realize the optical semiconductor device 100A in which the optical characteristics in use do not differ from the specifications.

  Further, the present inventors have found that when an optical multilayer film is formed by laminating layers having different stresses, stress is generated in the semiconductor chip, and the optical characteristics of the optical semiconductor device deteriorate with time. This is proved from the fact that the operation threshold current of the optical semiconductor device (minimum current for operating the optical semiconductor device) increases with time, as shown in FIGS. . In FIG. 2, the first layer (the layer in contact with the semiconductor chip) is formed of an MgF film having a thickness of 57.0 nm and a refractive index of 1.37, and the third layer (the outermost layer) is formed as a film. An MgF film having a thickness of 100.0 nm and a refractive index of 1.37 is formed, and a second layer (a layer sandwiched between the first layer and the third layer) is formed with a film thickness of 100.0 nm and a refractive index of 2.27. The results of screening on a semiconductor device formed of a TiO film of (a) is a state in which stress (compressive stress) is applied, and (b) is a state in which no stress is applied (or small). It is the result of having measured by attaching. As is clear from FIGS. 4A and 4B, when stress is applied, the characteristic (threshold value) is difficult to be stabilized by screening.

  Therefore, the optical multilayer film 13 according to the present embodiment is configured to have a structure in which layers that generate stresses having opposite properties are laminated. In other words, in the present embodiment, the tensile stress and the compressive stress are arranged to cancel each other as the entire multilayer film, thereby preventing the semiconductor chip 10 from being stressed. For example, by providing the second layer 13b for adjusting the stress between the first layer 13a and the third layer 13c, stress is generated on the end face of the semiconductor chip 10 (the face on which the optical multilayer film 13 is formed). To prevent. This will be described with reference to FIG. 1. The first layer 13a and the third layer 13c are formed by using, for example, a material that generates compressive stress, and the second layer 13b sandwiched between them has a property opposite to the above. Is formed using a material that generates tensile stress. Hereinafter, details of the optical semiconductor device 100A according to the present embodiment will be described in detail with reference to the drawings.

  FIG. 3 is a perspective view showing the configuration of the optical semiconductor device 100A according to the present embodiment, and FIG. 4 is a cross-sectional view taken along line A-A 'showing the configuration of the optical semiconductor device 100A. In this embodiment, a distributed feedback laser (DFB laser) will be described as an example of the semiconductor device 100A.

  The semiconductor device 100 </ b> A includes the semiconductor chip 10 and the optical multilayer film 13. As shown in FIGS. 3 and 4, the semiconductor chip 10 has an n-type cladding layer 3, an active layer 4, a p-type cladding layer 5, a p-type layer 6, and contacts on the semiconductor substrate 1 on which the diffraction grating 2 is formed. The layer 7 has a configuration formed in a mesa shape. The active layer 4 is formed of, for example, MQW (Multi-Quantum Well). A semi-insulating buried hetero region 9 is formed in a region other than the mesa structure.

  An upper electrode 11 and a lower electrode 12 are formed on the upper and lower portions of this layer structure, respectively. A cap layer 8 is formed in a region other than the upper electrode 11 on the contact layer 7.

  The above configuration can be formed using a method such as selective epitaxial growth on the semiconductor substrate 1, selective etching, mesa embedding growth, substrate polishing, electrode deposition, patterning, or cleavage.

  Optical multilayer films 13 each functioning as an antireflection film are formed on both ends of the semiconductor chip 10 having such a configuration. The optical multilayer film 13 has a three-layer structure (13a, 13b, 13c), and the central layer 13b is formed of a material that generates stress having a property different from that of the two layers (13a, 13c) sandwiching it. Has been. That is, the optical multilayer film 13 according to the present embodiment has a configuration in which the stress generated between the adjacent materials is offset by the adhesiveness and crystal structure generated by the material and the manufacturing method. As a result, it is possible to prevent the end face of the semiconductor chip 10 from being stressed and obtain stable optical characteristics.

  In the optical multilayer film 13, the second layer 13b located at the center is formed of, for example, titanium oxynitride (TiON). TiON is a material that generates tensile stress. Therefore, the layers (first layer 13a, third layer 13c) sandwiching the layers are formed of a material that generates compressive stress, which is a property opposite to that of the second layer 13b. An example of this material is magnesium fluoride (MgF). However, for example, silicon fluoride (SiF) may be used. In the present embodiment, the composition ratio of each material is not limited and will be described by omitting it.

  Moreover, each layer in the optical multilayer film 13 is designed to function as an antireflection film under each condition as described above. Hereinafter, the manufacturing method of the optical semiconductor device 100A including this design procedure will be described in detail with reference to the drawings. However, in the present embodiment, the semiconductor chip 10 is not limited to the DFB laser described above, and any optical semiconductor element may be used. Therefore, the method for manufacturing the semiconductor chip 10 is omitted in the following description.

  FIG. 5 is a cross-sectional view showing the manufacturing process of the optical semiconductor device 100A according to the present embodiment. In FIG. 5, the A-A ′ sectional view is used in the same manner as described above.

  In this manufacturing process, first, the conditions (material, film thickness, film forming method, etc.) of the third layer 13c are roughly determined based on the refractive index of the resin 200 for sealing the completed optical semiconductor device 100A. To do. That is, the light having the same refractive index as that of the resin 200 and the light reflected by the outer surface (opposite side of the semiconductor chip 10) of the third layer 13c is attenuated (or canceled) by the light propagating through the third layer 13c. The conditions for forming the third layer 13c having the desired film thickness are roughly determined.

  Next, the first layer 13 a and the second layer 13 b are designed so that the multilayer film composed of the first layer 13 a and the second layer 13 b acts as an antireflection film for the resin 200. This is performed by determining the material, film thickness, and film forming method of the first layer 13a and the second layer 13b based on the refractive index of the resin 200.

  Thereafter, the third layer 13c is formed so that the optical multilayer film 13 composed of the first layer 13a, the second layer 13b, and the third layer 13c functions as an antireflection film under the conditions (atmosphere or vacuum) in the characteristic evaluation. design. This is performed in consideration of the conditions determined above and the configurations of the first layer 13a and the second layer 13b.

  When the configuration of the optical multilayer film 13 is designed in this way, next, as shown in FIG. 5A, the optical multilayer film 13 is formed on the manufactured semiconductor chip 10. In this process, first, the first layer 13 a is formed on a predetermined surface of the semiconductor chip 10. For this, any method such as vapor deposition or epitaxial growth may be used. In the present embodiment, the first layer 13a is formed of an MgF film having a thickness of 62.0 nm. At this time, the first layer 13a is formed to have a refractive index of 1.37.

  Next, as shown in FIG. 5B, the second layer 13b is formed on the formed first layer 13a. However, ion-assisted deposition is used for this film formation in consideration of adhesion to the first layer 13a and stress. FIG. 6 shows an apparatus configuration for ion-assisted deposition. However, in the present embodiment, a case where a TiON film having a thickness of 70.0 nm is formed as the second layer 13b will be described. In addition, the second layer 13b is formed so that the refractive index is 2.48.

  Referring to FIG. 6, in the ion-assisted vapor deposition apparatus, a rotating dome 52 for mounting the semiconductor chip 10 is attached to the upper side of the apparatus chamber 51 by a rotating part 52a. Further, a cartridge-type hearth 53 for storing source material is attached to one corner on the lower side of the vapor deposition chamber 51 so as to face the substrate mounting surface of the rotating dome 52. Further, an electron gun 54 for irradiating the raw material in the cartridge hearth 53 with electrons is provided.

  Further, a Kaufman-type ion gun 56 (diameter 80 mm, 1100 mm to the center of the dome) is attached to another corner below the vapor deposition chamber 51 so as to face the substrate mounting surface of the rotating dome 52. The ion gun 56 ionizes the gas introduced from the ionized gas introduction port 57 by the thermal electrons emitted from the filament inside, and emits the gas toward the rotating dome 52 by the applied voltage of the ion acceleration electrode 58.

  A gas introduction port 59 is provided in a region between the ion gun 56 and the rotating dome 52 in the side wall of the vapor deposition chamber 51. The flow rate of the gas introduced from the gas inlet 59 is adjusted by the automatic pressure regulator 60. Further, an exhaust port 61 is formed in the side wall of the vapor deposition chamber 51 opposite to the gas introduction port 59, and a quartz vibrator type vapor deposition rate monitor 62 is attached in the vicinity thereof.

  A first photoelectric film thickness monitor 63 that monitors the film thickness by reflected light is provided on the center of the rotating dome 52. The first photoelectric film thickness monitor 63 monitors the film thickness of the film formed on the surface of the monitor glass substrate 64 at the center of the rotating dome 52. In addition, a second photoelectric film thickness monitor 65 is attached at a position opposite to the first photoelectric film thickness monitor 63 and between the ion gun 56 and the electron gun 54. The second photoelectric film thickness monitor 65 measures the film thickness on the surface of the monitor glass substrate 64 with transmitted light.

In forming a TiON film using such an ion-assisted deposition apparatus, first, the semiconductor chip 10 on which the first layer 13a is formed is mounted on the lower surface of the rotating dome 52 around the monitor glass substrate 64, and A cartridge type hearth 53 filled with Ti ₃ O ₅ as a raw material is mounted in the vapor deposition chamber 51. Next, the gas in the vapor deposition chamber 51 is exhausted from the exhaust port 61. Further, oxygen (O ₂ ) gas is supplied into the ion gun 56 through the ionized gas introduction port 57, a voltage of 1 kV is applied to the ion acceleration electrode 58, and an ion current of 20 mA flows in the ion gun 56. Thereby, oxygen is ionized and released into the vapor deposition chamber 51.

Further, nitrogen (N ₂ ) gas is introduced into the vapor deposition chamber 51 through the gas introduction port 59. At this time, the flow rate of the gas introduced from the gas introduction port 59 is adjusted to a predetermined flow rate by the automatic pressure regulator 60. The trajectory of the electron beam emitted from the electron gun 54 is changed by 180 degrees by the magnetic field, and is irradiated onto Ti ₃ O ₅ in the cartridge hearth 53. As a result, the vaporized Ti ₃ O ₅ is discharged to the lower surface of the rotating dome 52 through the opened shutter 55.

  At this time, a voltage of, for example, 6.0 kV is applied to the electrode in the electron gun 54. By supplying the vaporized titanium oxide and the ionized oxygen and nitrogen to the semiconductor chip 10 under the rotating dome 52 and the monitor glass substrate 64 on the side thereof, the TiON film is formed. The film is formed at a deposition rate of 0.03 to 0.08 nm / s. The vapor deposition rate can be adjusted by the amount of current flowing through the electron gun 54.

  The degree of growth of the TiON film is detected by the first photoelectric thick film monitor 63 on the rotating dome 52 side. The first photoelectric thick film monitor 63 has a light source and a light detector, and measures the light from the light source reflected by the monitor glass substrate 64 or the TiON film deposited on the surface of the monitor glass substrate 64 to thereby measure the film thickness of TiON. Measure.

  The film thickness of the TiON film is also detected by the second photoelectric thick film monitor 65. Further, a part of the material vaporized from the cartridge hearth 53 is deposited on the quartz plate in the quartz vibration deposition rate monitor 62. Therefore, the quartz vibration type deposition rate monitor 62 measures the deposition rate based on the fluctuation of the vibration frequency of the quartz plate caused by the increase in the amount of deposition.

  When the layers up to the second layer 13b are thus formed, a third layer is formed on the formed second layer 13b as shown in FIG. For this, any method such as vapor deposition or epitaxial growth may be used. In the present embodiment, the third layer 13c is formed of an MgF film having a thickness of 100.0 nm. At this time, the third layer 13c is formed to have a refractive index of 1.37.

  FIG. 7 shows changes over time in the operating threshold current for the optical semiconductor device 100A designed and manufactured as described above. As shown in FIG. 7, according to the present embodiment, it is possible to stabilize the operation threshold current of the optical semiconductor device 100A over time. That is, by having the configuration of the present embodiment, stress is prevented from occurring on the end face of the semiconductor chip 10, and the optical characteristics of the optical semiconductor device 100A are stabilized. This can be easily understood by comparing with the graph shown in FIG.

  As described above, according to the present embodiment, the optical multilayer film 13 that functions as an antireflection film is realized in the same manner when evaluating characteristics (performance) and when actually using it. An optical semiconductor device 100A whose optical characteristics are not different from the specifications can be realized. Furthermore, by arranging the tensile and compressive stresses together, it is possible to prevent the semiconductor chip 10 from being stressed and to stabilize the characteristics of the optical semiconductor device 100A. This effect is more prominent when the optical semiconductor device 100A is sealed with the resin 200.

  In the present embodiment, the semiconductor chip 10 is not limited to the above-described DFB laser, and various optical semiconductor elements such as a Fabry-Perot laser, a surface emitting laser, a light emitting diode, and an optical modulator can be applied. It is.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In the first embodiment, the first layer 13a in contact with the semiconductor chip 10 is formed of MgF. However, when the MgF film is applied to the first layer 13a, the present inventors have a possibility of causing a crack of about 1 μm square in the MgF film (only the first layer 13a) as shown in FIG. I found out.

  Therefore, in the present embodiment, in order to solve such a problem, the first layer 13a is formed of, for example, silicon oxide (SiO). Thereby, the optical multilayer film 13 in which no crack is generated is formed, and the optical characteristics of the optical semiconductor device 100A can be stabilized.

  The first layer 13a using SiO may be formed by any method such as a vapor deposition method or an epitaxial growth method. In the present embodiment, the first layer 13a is formed of a SiO film having a thickness of 50.0 μm. At this time, the first layer 13a is formed to have a refractive index of 1.45.

  With the configuration as described above, in this embodiment, in addition to the effects of the first embodiment, it is possible to prevent the first layer 13a from being cracked, and to further stabilize the optical characteristics of the optical semiconductor device 100A. be able to. Since other configurations are the same as those of the first embodiment, description thereof is omitted here.

[Third Embodiment]
Next, a third embodiment of the present invention will be described in detail with reference to the drawings. In the first embodiment, the optical multilayer film 13 having a three-layer structure functions as an antireflection film. In this embodiment, a case where a reflective film or a semi-transmissive film is formed by adding a new layer to the same configuration will be described in detail with reference to the drawings.

  FIG. 9 is a cross-sectional view showing a schematic configuration of the optical semiconductor device 300 according to the present embodiment. 9 shows a cross-sectional view of the semiconductor chip 10 along the optical axis.

  As is apparent from FIG. 9, in the optical semiconductor device 300, the fourth layer 14 is formed on one end face or both end faces of the semiconductor chip 10 similar to that of the first embodiment. An optical multilayer film 13 similar to that of the first embodiment is formed thereon. The fourth layer 14 is configured to have a higher refractive index than the first layer 13 a in the optical multilayer film 13. Thus, by providing the fourth layer 14 having a higher refractive index than the first layer 13a between the optical multilayer film 13 and the semiconductor chip 10, the entire optical multilayer film including the fourth layer 14 functions as a reflective film. It becomes possible to make it. Other configurations are the same as those of the first embodiment, and thus description thereof is omitted here.

[Other Embodiments]
The embodiment described above is merely a preferred embodiment of the present invention, and the present invention can be variously modified and implemented without departing from the gist thereof.

  As described above, according to the present invention, by using titanium oxynitride rich in stress controllability, the stress of magnesium fluoride useful as a low refractive index optical film can be controlled by titanium oxynitride, thereby reducing the stress. The optical multilayer film and the optical semiconductor device having the same can be manufactured. Furthermore, in the present invention, since a plurality of reflective surfaces are formed inside the optical multilayer film by having a multilayer structure of at least three layers, the film thickness of the second layer, which is a high refractive index optical film, is converted into an optical distance. Even when the thickness is smaller than the quarter wavelength, interference of reflected light can be caused. In the present invention, titanium oxynitride or magnesium fluoride is not limited to the meaning that each element is composed only of each element, and even if a trace amount of other elements are mixed in each element, If the optical characteristics or stress is equivalent, it is in that category.

  In addition, according to the present invention, it is possible to suppress fluctuations in optical characteristics between the case where the outermost layer of the optical multilayer film is in contact with gas and the case where the outermost layer is sealed with a resin similar to the refractive index of the outermost layer. It is. That is, when sealing with a resin having a refractive index similar to the material of the outermost layer, paying attention to the fact that the outermost layer can be approximated optically homogeneous with the outer material, A first optical characteristic generated by taking into account a refractive index difference between the layer and air or an inert gas, and a second optical characteristic produced when not taking into account the refractive index difference between the outermost layer and the material outside thereof Is designed so that the optical characteristics before and after filling with resin, etc. are prevented, and the optical characteristics measured before filling with resin etc. do not change after filling with resin etc. Is done.

  Furthermore, according to the present invention, the first optical characteristic and the second optical characteristic satisfy both of the optical characteristics required in the final device form (for example, a resin-sealed form), so that the outermost layer is formed. The desired optical characteristics can be obtained regardless of whether the gas is a gas or filled with other materials.

1 is a cross-sectional view showing a schematic configuration of an optical semiconductor device 100A according to a first embodiment of the present invention. It is a graph which shows a time-dependent change of the operation threshold current in an optical semiconductor device, (a) shows the characteristic of the optical semiconductor device which has an optical multilayer film which generates stress, (b) shows the optical multilayer film which does not generate stress. The characteristic of the optical semiconductor device which has is shown. 1 is a perspective view showing a configuration of an optical semiconductor device 100A according to a first embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line A-A ′ of the optical semiconductor device 100 </ b> A illustrated in FIG. 3. It is sectional drawing which shows the manufacturing process of 100 A of optical semiconductor devices by the 1st Embodiment of this invention. It is a figure which shows the structure of the ion assist vapor deposition apparatus used when forming the 2nd layer 13b into a film in the manufacturing process shown in FIG. 6 is a graph showing a change with time of an operation threshold current in the optical semiconductor device 100A according to the first embodiment of the present invention. It is a figure which shows the crack which arose in the 1st layer 13a when using magnesium fluoride for the 1st layer 13a and using titanium oxynitride for the 2nd layer 13b. It is sectional drawing which shows the structure of the optical semiconductor device 300 by the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor chip 13 Optical multilayer film 13a 1st layer 13b 2nd layer 13c 3rd layer 100A, 300 Optical semiconductor device 200 Resin

Claims (5)

  A first layer mainly composed of magnesium fluoride, a second layer mainly composed of titanium oxynitride, and a third layer composed mainly of magnesium fluoride have a stacked structure in which the layers are stacked in this order, The laminated structure includes a plurality of reflecting surfaces, and the laminated structure is provided on a light emitting surface of an optical semiconductor as an antireflection film, and at least the light emitting surface is sealed with a resin. Optical semiconductor device.   The first layer mainly composed of silicon oxide, the second layer mainly composed of titanium oxynitride, and the third layer mainly composed of magnesium fluoride have a stacked structure in which the layers are stacked in this order, A light having a plurality of reflecting surfaces inside the laminated structure, the laminated structure being provided on a light emitting surface of an optical semiconductor as an antireflection film, and at least the light emitting surface being sealed with a resin Semiconductor device.   The optical semiconductor device according to claim 1, wherein the first layer and the second layer are in contact with each other.   The optical semiconductor device according to claim 1, wherein the second layer is a layer formed by ion-assisted deposition.   The optical semiconductor device according to claim 1, wherein the first layer is provided in contact with a light emitting surface of the optical semiconductor.

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