JP3825652B2 - Semiconductor optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a compound semiconductorBodyThe present invention relates to the used semiconductor optical device.
[0002]
[Prior art]
As a buried layer of a semiconductor optical device such as a semiconductor laser, there are a current blocking layer by a pn junction and a current blocking layer by a semi-insulating film. With these current blocking layers, for example, it is possible to concentrate the current on the light emitting portion in the semiconductor laser.
[0003]
Here, the current blocking layer by the pn junction has a problem that it is difficult to increase the speed of the element because of the large parasitic capacitance. On the other hand, when a current blocking layer made of indium phosphide (InP) doped with Fe as a semi-insulating film is an InP layer doped with Zn as a cladding layer, mutual diffusion between Fe in the current blocking layer and Zn in the cladding layer There was a problem that the resistivity of the current blocking layer was reduced. For this reason, a leak current is generated, which is a factor of deterioration of element characteristics.
[0004]
In order to solve such problems, there are the following techniques. Japanese Patent Application Laid-Open No. 10-22579 discloses a semiconductor laser in which a buried layer is an additive-free InAlAs. That is, since the buried layer is not doped with Fe, mutual diffusion with the p-type dopant does not occur, and characteristic deterioration does not occur. However, there was a problem that the resistivity of InAlAs was low because it was not added.
[0005]
Japanese Laid-Open Patent Publication No. 9-214045 discloses that an Fe diffusion prevention layer composed of an n-type InP layer is inserted between a Zn-added cladding layer and Fe-added InP buried layer. . That is, the Zn—Fe interdiffusion is prevented because the Zn-added cladding layer and the Fe-added InP buried layer are not in direct contact with each other. However, since there is an n-type InP layer having a low resistivity between the clad layer and the buried layer, there is a problem in that leakage current occurs.
[0006]
Furthermore, Japanese Patent Application Laid-Open No. 61-290790 discloses that an InAlAs buried layer to which Fe is added is formed by liquid phase growth. Also in this case, as described above, there was a problem that Zn—Fe interdiffusion occurred between the cladding layer added with Zn and the InAlAs buried layer added with Fe.
Recently, “A. van Geelen et.al, Appl. Physics Letters 73, No. 26 pp 3878-3880 (1998)” and “A. van Geelen et. Al, 11th International Conference on Indium Phosphorus 1” and “Tel. As shown in FIG. 2, there has been proposed a buried laser using an InP layer to which ruthenium is added as a semi-insulating film as a current blocking layer. According to this proposal, since the mutual diffusion between Ru of the buried layer and Zn of the cladding layer can be suppressed, the resistivity of the current blocking layer is not lowered, and the generation of leakage current can be suppressed. .
[0007]
[Problems to be solved by the invention]
However, since the buried layer according to the above proposal adds Ru while growing InP, Ru-P precipitates are likely to be generated, and Ru is less likely to act as a semi-insulating additive of InP. It was.
Therefore, in order to suppress the generation of Ru-P precipitates, it can be grown under reduced pressure, or phosphine (PH_Three)) Or at a low temperature of about 580 ° C., it was necessary to grow under very limited conditions. Here, by growing at a low temperature as described above, defects such as hillocks are likely to be formed on the surface of the buried layer.
[0008]
InP to which Ru is added, the crystal surface becomes very sensitive and crystal habits are likely to occur. For this reason, depending on the state of the surface layer after RIE (Reactive Ion Etching) or wet etching, as shown in FIG. 16, holes 31 are likely to be formed in the buried layer 30 made of InP to which Ru is added. In FIG. 16, reference numeral 10 denotes an n-type InP layer, 20 denotes a semiconductor stacked body, 21a denotes an n-type InP cladding layer, 22a denotes an MQW layer, 23a denotes a p-type InP cladding layer, 24a denotes a p-type InGaAsP electrode layer, and 25a denotes A p-type InGaAs electrode layer, 31a is a hole generated from the side wall of the mesa stripe, and 31b is a hole generated from the side wall containing InAlAs.
[0009]
Furthermore, when an InAlAs-InGaAlAs mixed crystal multiple quantum well layer is embedded as an active layer, vacancies are likely to occur in the side wall of the active layer, and there are problems such as reliability and reproducibility.
Furthermore, it has been difficult for the InP layer to change physical constants such as a lattice constant and a refractive index.
[0010]
  Accordingly, the present invention has been made in view of the above circumstances, and suppresses the generation of leakage current and provides a highly reliable compound semiconductor.BodyIt is an object to provide a semiconductor optical device used as a buried layer.
[0011]
  In order to solve such a problem, the invention according to claim 1 includes a compound semiconductor in which ruthenium is added to indium aluminum arsenide or indium gallium aluminum arsenide.The active layer touches the side of the mesa stripe structure on the surfaceUsed as an embedded layerIn addition, ruthenium-added indium phosphide or iron-added indium phosphide was used as another burying layer on the upper surface of the burying layer.A semi-light guiding element is used.
  According to the first aspect of the present invention, by adding Ru to indium aluminum arsenide (InAlAs) or indium gallium aluminum arsenide (InGaAlAs), a p-type semiconductor crystal layer to which Zn is added is laminated before and after that. However, the semiconductor crystal layer made of InAlAs or InGaAlAs is difficult to be p-type. This is because the diffusion rate of Ru in the compound semiconductor crystal is significantly slower than that of Fe, and the diffusion rate of impurities added in the semiconductor crystal layer made of InAlAs or InGaAlAs is slower than that of the semiconductor crystal layer made of InP. is there. Therefore, since mutual diffusion of Ru and Zn is suppressed, it is possible to obtain a high-resistance current blocking layer without lowering the resistivity. Therefore, by using such a compound semiconductor as a buried layer, generation of leakage current is suppressed and vacancies are hardly formed, so that an optical semiconductor element with improved performance and reliability can be provided.
[0012]
Further, InAlAs or InGaAlAs to which Ru is added is not easily affected by a surface processing layer or an oxide layer due to RIE, wet etching, or the like in its growth, and vacancies are less likely to be formed as compared to InP to which Ru is added.
Furthermore, since the bonding force between the added Ru and As constituting InAlAs or InGaAlAs is extremely weak compared to the bonding force between Ru and P constituting InP, Ru-As during crystal growth of InAlAs or InGaAlAs. The possibility of forming such precipitates is reduced. Therefore, it is possible to easily grow a semiconductor crystal layer having a high resistance without performing under very narrow growth conditions as in conventional InP to which Ru is added.
[0013]
  Furthermore, since InAlAs and InGaAlAs are mixed crystals, the physical constants such as refractive index and band gap can be easily changed while lattice-matching with the InP substrate by changing the composition of Ga and Al in InGaAlAs. Is possible.
[0016]
   Claim1In the semiconductor optical device according to claim 2, another buried layerIsIndium phosphide with ruthenium added.
  Claim1In the invention described in claim 1, the other buried layer may be ruthenium-added indium phosphide on the lower surface thereof.1Since the buried layer described in (1) is formed, vacancies are not generated during the growth of InP. Therefore, it is possible to provide a semiconductor optical device having high performance and high reliability.
[0017]
  Also,Claim1In the semiconductor optical device according to claim 2, another buried layerIs, And indium phosphide added with iron.
  Claim1In the invention described in claim 1, the other buried layer may be an indium phosphide doped with iron, on the lower surface thereof.1Since the buried layer described in 1 is stacked, even if it is a p-type semiconductor crystal layer in which Zn is added to the clad layer, mutual diffusion between Zn and Fe is difficult to occur, and generation of leakage current is suppressed. Can do. Therefore, it is possible to provide a semiconductor optical device having high performance and high reliability.
[0018]
Here, since the compound semiconductor of the present invention is InAlAs or InGaAlAs doped with Ru, the additive-free InAlAs disclosed in Japanese Patent Laid-Open No. 10-22579 and the Fe disclosed in Japanese Patent Laid-Open No. 61-290790 are disclosed. Added InAlAs, and A.I. This is different from Ru-doped InP disclosed by van Geelen et al.
[0019]
That is, it differs from the technique of JP-A-10-22579 in that Ru is added to increase the resistivity. Moreover, it differs from the technique of Unexamined-Japanese-Patent No. 61-290790 using the different Ru from Fe as an impurity to add. Therefore, mutual diffusion with Zn added to the cladding layer does not occur. In addition, A. It differs from the technique disclosed by van Geelen et al in that the element to which Ru is added is not InP but InAlAs or InGaAlAs. Therefore, the physical constants such as the refractive index and the band gap can be changed depending on the composition, and there is a new effect that the degree of freedom in element design is increased.
[0020]
  Further, the claims in the present invention1The semiconductor optical device according to the present invention has an upper surface of a buried layer made of InAlAs or InGaAlAs doped with Ru.Made of Ru-doped InP or Fe-doped InPSince the buried layer is laminated, the technique is different from the technique disclosed in Japanese Patent Laid-Open No. 9-214045.
  That is, in the technique of Japanese Patent Laid-Open No. 9-214045, an Fe diffusion prevention layer composed of a low-resistance n-type InP layer is inserted between a cladding layer added with Zn and an InP buried layer added with Fe. However, in the present invention, a buried layer made of high resistance InAlAs or InGaAlAs doped with Ru is inserted between the cladding layer and another buried layer. Therefore, there is no problem that leakage current occurs.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Examples of the present inventionAnd reference examplesThe embodiment will be described with reference to the drawings.
  1 to 6 show the present invention, respectively.Examples and reference examplesIt is sectional drawing explaining one manufacturing process of the optical modulator which used the compound semiconductor in in as an embedding layer.
  The first of the present inventionreferenceAs shown in FIG. 6, the optical modulator 100 in the example includes a semiconductor substrate 1 made of n-type InP, a semiconductor stacked body 2 provided on the upper surface of the semiconductor substrate 1, and having a resonator. It is composed of a compound semiconductor 3 a embedded so as to cover the periphery, a p-type electrode 4 a provided on the upper surface, and an n-type electrode 4 b provided on the lower surface of the semiconductor substrate 1.
[0022]
The semiconductor stacked body 2 includes an n-type InP layer 21 having a thickness of about 1 μm, a light absorption layer 22 having a thickness of about 0.2 μm, and a p-type InP layer having a thickness of about 1.5 μm, which are sequentially stacked on the semiconductor substrate 1. 23, a p-type InGaAsP layer 24 having a thickness of about 0.5 μm, and an electrode layer 25 made of p-type InGaAs having a thickness of about 0.3 μm. The compound semiconductor constituting each semiconductor film has a composition lattice-matched to the semiconductor substrate 1 made of InP.
[0023]
Here, the light absorption layer 22 is an MQW (multiple quantum) in which six pairs of additive-free InGaAsP layers having a thickness of about 40 nm, InGaAlAs well layers having a thickness of about 5 nm, and InAlAs barrier layers having a thickness of about 11 nm are alternately stacked. Well) layer and an additive-free InGaAsP layer having a thickness of about 40 nm. The raw materials for the compound semiconductor constituting this layer are trimethylindium, triethylgallium, trimethylaluminum, diethylzinc, phosphine, arsine, and silane.
[0024]
The semiconductor stacked body 2 in which these layers are sequentially stacked is processed into a mesa stripe, and both sides of the mesa stripe are embedded with an InAlAs layer 3a to which ruthenium (Ru) is added.
Here, trimethylindium, triethylgallium, trimethylaluminum, and arsine were used as raw materials for the compound semiconductor constituting the InAlAs layer 3a. As a raw material for Ru, bisdimethylpentadiruthenium (bis (η^Five2-4-dimethylpentadienyl) ruthenium) was used.
[0025]
The material for forming the p-type electrode 4a is made of AuZn / Au, and the material for forming the n-type electrode 4b is made of AuGeNi.
Next, a method for manufacturing the optical modulator 100 according to the present invention will be described.
First, as shown in FIG. 1, an n-type InP layer 21, a light absorption layer 22, a p-type InP layer 23, a p-type InGaAsP layer 24, and a p-type InGaAs electrode layer 25 are sequentially formed on a semiconductor substrate 1 made of n-type InP. Laminate.
[0026]
The semiconductor stacked body 2 is epitaxially grown by a known metal-organic vapor phase epitaxy (MOVPE) (Metal-Organic Vapor Phase Epitaxy). Here, not limited to the MOVPE method, a molecular beam epitaxy (MBE) method or a liquid phase epitaxy (LPE) method may be used.
[0027]
Next, as shown in FIG. 2, a silicon oxide film (SiO 2) is formed on the upper surface of the p-type InGaAs electrode layer 25 by plasma CVD or sputtering.₂) Is formed, and SiO is formed by ordinary photolithography.₂Leave the mask in stripes. This SiO₂As shown in FIG. 3, a vertical mesa stripe structure cut into the n-type InP layer 21 is formed by reactive ion etching (RIE), using as a mask. Then, as shown in FIG. 4, the side surfaces of the vertical mesa stripe structure and the n-type InP layer 21 are further etched with hydrochloric acid and sulfuric acid.
[0028]
Next, as shown in FIG. 5, the InAlAs layer 3 a is epitaxially grown on the n-type InP layer 21, which is the bottom surface of the groove covering the periphery of the vertical mesa stripe structure, while adding Ru by the MOVPE method as described above. Let Here, epitaxial growth is performed under the conditions of a growth temperature of 620 ° C., a growth pressure of 70 torr, and a V / III ratio of 100, and bisdimethylpentadienyl ruthenium as a Ru raw material is bubbled at 20 ° C., 1 atm, 0 700cm under the condition of ℃^Three/ Min.
[0029]
Then SiO₂After removing the mask, a photoresist (not shown) is applied to the upper surface of the InAlAs layer 3a to which Ru is added, except for the upper surface of the p-type InGaAs electrode layer 25 which is the uppermost layer of the vertical mesa stripe structure. By patterning this photoresist by photolithography, a resist layer (not shown) having a predetermined pattern is formed. Then, as shown in FIG. 6, after a metal layer made of AuZn / Au is formed on the upper surface of the resist layer by a vacuum deposition method, the metal layer deposited on the resist layer is removed together with the resist layer by a lift-off method. .
[0030]
A metal layer made of AuGeNi is formed on the lower surface of the semiconductor substrate 1. Here, a p-type electrode 4a is formed on the upper surface of the semiconductor stacked body 2 and an n-type electrode 4b is formed on the lower surface so that a current flows in the stacking direction of the semiconductor stacked body 2 of the resonator having the vertical mesa stripe structure. Become.
Here, a high-quality buried layer 3 in which abnormal growth such as vacancies and angular projections was hardly observed was observed in the cross section of the optical modulator 100 having the above configuration. The resistivity of this buried layer is about 10⁹The resistance was higher than that of a conventional buried layer made of InP to which Ru was added. Furthermore, the growth conditions of the Ru-added InAlAs layer by the MOVPE method were changed in the temperature range of 580 to 640 ° C., the pressure of 20 to 150 torr, and the V / III ratio in the range of 10 to 500. A resistive buried layer was obtained with good reproducibility.
[0031]
Further, in the buried layer composed of Ru-doped InP having a mesa stripe structure height of 2 μm, vacancies were observed in 30% of the semiconductor elements, whereas in the buried layer composed of Ru-doped InAlAs in the present invention. In 3a, it was 1% or less of the semiconductor element, and the yield was improved.
Furthermore, the leakage current was 1 nA or less with 90% of the elements when the reverse bias was 2 V, and it was confirmed that the generation of the leakage current could be suppressed.
[0032]
In the optical modulator 100 configured as described above, the compound semiconductor constituting the buried layer 3a in the groove covering the periphery of the vertical mesa stripe structure is made of InAlAs to which Ru is added, so that a p-type is formed so as to be in contact therewith. Even if a clad layer doped with Zn as an impurity is laminated, mutual diffusion between Zn and Ru can be suppressed. This is because the diffusion rate of Ru in the compound semiconductor crystal is significantly slower than that of Fe, and further, the diffusion rate of impurities in InAlAs is extremely slower than that of conventional InP. Therefore, it is possible to provide a highly reliable optical modulator in which the resistivity of the buried layer does not decrease and the leakage current is suppressed. Here, the optical modulator in the present embodiment was able to obtain a modulation characteristic with an extinction ratio of 15 dB and 15 GHz with an applied voltage of 1.5V.
[0033]
Further, InAlAs to which Ru is added is not easily affected by the surface processed layer or the oxide layer in its growth, and the surface layer subjected to dry etching or wet etching for forming a mesa stripe or the like is also vacant. A buried layer 3a having no holes can be realized.
Furthermore, since the binding force between the added Ru and As constituting InAlAs is extremely weak compared to the binding force between Ru and conventional P constituting InP, precipitates are hardly formed during the growth of InAlAs crystals. Therefore, it is not necessary to perform growth under very narrow conditions like InP to which Ru is added, and it becomes possible to easily grow a semiconductor crystal layer having a high resistance.
[0034]
  Next, in the present invention1The embodiment will be described with reference to FIGS. FIGS. 7 to 9 are cross-sectional views illustrating one manufacturing process of an optical modulator using a compound semiconductor doped with Ru according to the present invention and a conventional Ru-doped InP layer as a buried layer.
  The optical modulator 100a in the present embodiment includes the firstReference exampleAs a compound semiconductor that has the same configuration as that of the embodiment and is embedded so as to cover the side wall of the mesa stripe structure,Reference exampleThe InP layer 3b to which Ru is added is formed on the upper surface of the added InAlAs layer 3a to which Ru is added in the same manner as the form. Here, trimethylindium, phosphine, and bisdimethylpentadienylruthenium were used as raw materials for the InP layer 3b to which Ru was added.
[0035]
As a manufacturing method of this embodiment, first, after the manufacturing steps shown in FIGS. 1 to 3, as shown in FIG. 7, the upper surface of the p-type InGaAs electrode layer 25 that is the uppermost layer of the resonator having the mesa stripe structure. And SiO₂A mask 5 is formed. Next, as shown in FIG. 8, InAlAs is epitaxially grown by 0.2 μm while adding Ru by a known MOVPE method in the same manner as in Example 1, and then InP is epitaxially grown by 2 μm while adding Ru on the upper surface. I let you. Here, as growth conditions, the growth temperature was 580 ° C., the growth pressure was 40 torr, the V / III ratio was 200 for Ru-added InAlAs and 10 for Ru-added InP.
[0036]
  In this way, due to the plane orientation dependence of the growth rate in the compound semiconductor, as shown in FIG. 8, the InAlAs layer 3a doped with Ru is deposited on the side wall of the mesa stripe structure by 0.2 μm. Therefore, the growth of the next Ru-added InP is not affected by the surface processed layer or the oxide layer.
  Then the firstReference exampleThe p-type electrode 4a and the n-type electrode 4b are formed as shown in FIG. 9 by the same method as the embodiment, thereby completing the optical modulator 100a.
[0037]
Here, in the cross section of the optical modulator 100a having the above-described configuration, a high-quality buried layer 3 in which abnormal growth such as vacancies and square protrusions is hardly observed is observed, and the ratio of vacancies in the element is as follows: 2% or less. This is because vacancies are not generated during the growth of the Ru-doped InP layer 3b by growing the InP layer 3b doped with Ru immediately after the growth of the InAlAs layer 3a doped with Ru. Here, even if the InAlAs layer to which Ru is added is as thin as possible, it is possible to form the buried layer 3 without voids.
[0038]
  Further, as the buried layer 3, the InAlAs layer 3 a to which Ru is added is first laminated, and then the InP layer 3 b to which Ru is added is laminated on the upper surface, so that the layer containing Al is not exposed on the surface. Therefore, it is effective for manufacturing a composite light modulator such as a light receiving element mounted modulator.
  Then, in the present invention2This embodiment will be described with reference to FIGS. FIG. 10 to FIG. 15 are cross-sectional views illustrating one manufacturing process of a semiconductor laser in which a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added are used in combination as a buried layer.
[0039]
The semiconductor laser 100A in the present embodiment includes a semiconductor substrate 1A made of p-type InP, a semiconductor stacked body 2A provided on the upper surface thereof and having a light emitting part, and a compound semiconductor embedded so as to cover the periphery of the light emitting part. 3 and an n-type electrode 4B provided on the upper surface, and a p-type electrode 4A provided on the lower surface of the semiconductor substrate 1A.
[0040]
The semiconductor stacked body 2A includes a p-type InP cladding layer 21A having a thickness of about 0.5 μm, an additive-free InGaAsP layer 22A having a thickness of about 0.1 μm, and a layer thickness of 0.1 μm, which are sequentially stacked on the semiconductor substrate 1A. Additive-free InGaAsP layer 23A, additive-free InGaAsP layer 24A having a thickness of about 0.1 μm, n-type InP cladding layer 25A having a thickness of about 0.5 μm, n-type InGaAsP layer 26A having a thickness of about 0.1 μm, layer thickness And an electrode layer 27A made of n-type InGaAs of about 0.3 μm.
[0041]
Of these stacked semiconductor stacked bodies 2A, a concave groove is formed around the resonator having the mesa stripe structure. In the groove, the InAlAs layer 3A to which Ru is added and Fe on the upper surface thereof are formed. And an InP layer 3B to which is added. Here, the material of the compound semiconductor and the material for forming the p-type electrode 4A and the n-type electrode 4B constituting the InAlAs layer 3A and the InP layer 3B are the same as those in the first embodiment.
[0042]
In addition, the manufacturing method of the semiconductor laser 100A in the present embodiment is as follows.1'sSimilar to the embodiment, first, as shown in FIGS. 10 to 12, a mesa stripe structure is formed in the semiconductor stacked body 2 </ b> A stacked on the semiconductor substrate 1 </ b> A. Next, as shown in FIG. 13, on the n-type InGaAs electrode layer 27A which is the uppermost surface of the resonator, SiO 2₂A mask 5A is formed.
[0043]
Thereafter, an InAlAs layer 3A was grown on the bottom surface of the groove formed around the mesa stripe structure by adding the Ru by the MOVPE method described above. Here, as the growth conditions, the growth temperature is 620 ° C., the growth pressure is 100 torr, the V / III ratio is 100, bisdimethylpentadienyl ruthenium bubbles at 20 ° C., and the condition is 1000 cm under the conditions of 1 atm and 0 ° C.^Three/ Min. Further, an InP layer 3B was grown on the upper surface while adding Fe. Here, bis (pentadienyl) iron was used as a raw material for Fe.
[0044]
And SiO₂After removing the mask 5A, the n-type electrode 4B is formed on the upper surface of the resonator and the buried layer 3, and the p-type electrode 4A is formed on the lower surface of the semiconductor substrate 1A, thereby completing the semiconductor laser 100A in the present embodiment.
In the semiconductor laser 100A having the above-described configuration, the growth conditions of the Ru-added InAlAs layer 3A by the MOVPE method described above were changed in the range of a growth temperature of 580 to 640 ° C., a growth pressure of 20 to 150 torr, and a V / III ratio of 10 to 500. In any range, it was possible to obtain a high-quality buried layer 3 with almost no voids with good reproducibility. Therefore, it is possible to form a high-power laser that hardly generates leak current.
[0045]
In addition, the active layer of the semiconductor laser 100A in the present embodiment is composed of an InAlAs-InGaAlAs mixed crystal multiple quantum well layer, and the side wall is embedded, but no holes are generated in the side wall of the active layer. A semiconductor laser 100A having high reliability can be obtained.
Furthermore, even if the InP layer 3B added with Fe is stacked on the upper surface of the buried layer 3 composed of the InAlAs layer 3A added with Ru, it is possible to realize a highly efficient semiconductor laser 100A with less leakage current. Become.
[0046]
Where 1st to 1st2In this embodiment, the compound semiconductor to which Ru is added is InAlAs. However, the present invention is not limited to this, and the same effect can be obtained by using a compound semiconductor made of InGaAlAs. In particular, by changing the composition of Ga and Al in InGaAlAs, the physical constants such as refractive index and band gap can be easily changed while lattice matching with the InP substrate, so that the light propagation mode can be adjusted. It becomes possible.
[0047]
Also, first to first2In this embodiment, the semiconductor optical device is an optical modulator and a semiconductor laser. However, the present invention is not limited to this, and the present invention can be applied to other semiconductor optical devices such as a semiconductor optical amplifier and a waveguide type light receiving device.
  Furthermore, as a multiple quantum well layer, an MQW layer made of InAlAs-InGaAlAs is handled, but a bulk layer in all systems using InP as a substrate, such as InGaAsP-InGaAs (P) MQW, InGaAs (P) bulk layer, Needless to say, it is effective for a structure such as a multiple quantum well layer.
[0048]
【The invention's effect】
  As explained above, the present inventionByIfAs an embedded layer,Without narrowing the growth conditions, it is possible to obtain a high-quality semiconductor crystal layer that is less likely to generate vacancies and less likely to generate leakage current.Because you canIt is possible to provide a semiconductor optical device that suppresses the occurrence of leakage current and has no voids and good reproducibility, such as a semiconductor optical amplifier and a waveguide type light receiver.
[Brief description of the drawings]
FIG. 1 shows the present invention.Examples and reference examplesIt is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 2Examples and reference examplesIt is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 3Examples and reference examplesIt is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 4 The present inventionExamples and reference examplesIt is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 5 shows the present invention.Reference example form 1It is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 6Reference example form 1It is sectional drawing explaining the manufacturing method of the semiconductor optical element which uses the compound semiconductor which added Ru in (2) as a buried layer.
FIG. 7 is a cross-sectional view illustrating another method of manufacturing a semiconductor optical device using a compound semiconductor to which Ru is added according to the present invention and a conventional Ru-added InP layer in combination as a buried layer.
FIG. 8 is a cross-sectional view illustrating another method for manufacturing a semiconductor optical device using a compound semiconductor to which Ru is added according to the present invention and a conventional Ru-added InP layer in combination as a buried layer.
FIG. 9 is a cross-sectional view illustrating another method for manufacturing a semiconductor optical device in which a compound semiconductor to which Ru is added in the present invention and a conventional InP layer to which Ru is added are used in combination as a buried layer.
FIG. 10 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser in which a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added are used in combination as a buried layer.
FIG. 11 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser using a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added as a buried layer.
12 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser using a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added as a buried layer. FIG.
FIG. 13 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser in which a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added are used in combination as a buried layer.
FIG. 14 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser in which a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added are used in combination as a buried layer.
FIG. 15 is a cross-sectional view illustrating one manufacturing process of a semiconductor laser using a compound semiconductor to which Ru is added according to the present invention and a conventional InP layer to which Fe is added as a buried layer.
FIG. 16 is a cross-sectional view showing one manufacturing process of a semiconductor optical device using a conventional compound semiconductor as a buried layer.
[Explanation of symbols]
  1, 1A Semiconductor substrate
  2, 2A Semiconductor stack
  3a, 3A Ru-added InAlAs layer
  3b Ru-doped InP layer
  3B Fe-doped InP layer
  4a, 4A p-type electrode
  4b, 4B n-type electrode
  5, 5A Insulating layer (SiO₂)
  21 n-type InP layer
  21A p-type InP cladding layer
  22 MQW layer
  22A InGaAsP layer
  23 p-type InP layer
  23A InGaAsP layer
  24 p-type InGaAsP layer
  24A InGaAsP layer
  25 p-type InGaAs electrode layer
  25A n-type InP cladding layer
  26A n-type InGaAsP layer
  27A Electrode layer made of n-type InGaAs
  100, 100a optical modulator
  100A semiconductor laser

Claims (1)

A compound semiconductor in which ruthenium is added to indium aluminum arsenide or indium gallium aluminum arsenide is used as a buried layer in contact with the side surface of the mesa stripe structure with the active layer on the surface, and the addition of ruthenium on the upper surface of the buried layer Indium phosphide or indium phosphide added with iron is used as another buried layer.

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