JP6200158B2

JP6200158B2 - Semiconductor light emitting device and manufacturing method thereof

Info

Publication number: JP6200158B2
Application number: JP2013011460A
Authority: JP
Inventors: 昌布若葉
Original assignee: THE FURUKAW ELECTRIC CO., LTD.
Current assignee: THE FURUKAW ELECTRIC CO., LTD.
Priority date: 2013-01-24
Filing date: 2013-01-24
Publication date: 2017-09-20
Anticipated expiration: 2033-01-24
Also published as: JP2014143327A

Description

本発明は、半導体積層体および半導体発光素子ならびにその製造方法に関するものである。 The present invention relates to a semiconductor laminate, a semiconductor light emitting element, and a method for manufacturing the same.

従来のＩｎＰ系半導体材料を用いた半導体発光素子においては、ｐ型ＩｎＰからなる半導体層とｐ側電極との間には、ＩｎＰよりもよりバンドギャップが狭い半導体材料からなるｐ型コンタクト層が形成される。このようなコンタクト層を構成する半導体材料としては、ＩｎＧａＡｓ、ＧａＩｎＡｓＰなどが用いられている。 In a conventional semiconductor light emitting device using an InP-based semiconductor material, a p-type contact layer made of a semiconductor material having a narrower band gap than InP is formed between the p-type InP semiconductor layer and the p-side electrode. Is done. As a semiconductor material constituting such a contact layer, InGaAs, GaInAsP, or the like is used.

しかしながら、ＩｎＰ層とＩｎＧａＡｓ等のコンタクト層との接合界面では、バンドギャップの相違から、ｐ側電極からのホールキャリアの注入の障壁となる障壁層が形成され、素子の高抵抗化の原因となる。そこで、たとえばコンタクト層を３層構造とし、バンドギャップを段階的にＩｎＰ層のバンドギャップに近づけることで、素子の高抵抗化を抑制する構成が開示されている（非特許文献１参照）。 However, at the junction interface between the InP layer and the contact layer such as InGaAs, a barrier layer serving as a barrier for hole carrier injection from the p-side electrode is formed due to the difference in the band gap, which increases the resistance of the device. . Therefore, for example, a configuration is disclosed in which the contact layer has a three-layer structure, and the band gap is gradually brought close to the band gap of the InP layer to suppress the increase in resistance of the element (see Non-Patent Document 1).

S.Matsumoto et al., Electron. Lett., vol.31(1995),p.882.S. Matsumoto et al., Electron. Lett., Vol.31 (1995), p.882.

しかしながら、非特許文献１に記載の構成においても、コンタクト層とＩｎＰ層との接合界面で障壁は残存する。また、コンタクト層内の各層の接合界面でも障壁は形成される。これに対して、近年の半導体素子に対する低消費電力化の要求から、かかる障壁による高抵抗化をさらに抑制することが求められている。 However, even in the configuration described in Non-Patent Document 1, a barrier remains at the junction interface between the contact layer and the InP layer. A barrier is also formed at the junction interface of each layer in the contact layer. On the other hand, it is required to further suppress the increase in resistance due to such a barrier due to the recent demand for lower power consumption of semiconductor elements.

本発明は、上記に鑑みてなされたものであって、高抵抗化がよりいっそう抑制された半導体積層体および半導体発光素子ならびにその製造方法を提供することを目的とする。 This invention is made | formed in view of the above, Comprising: It aims at providing the semiconductor laminated body and the semiconductor light-emitting device in which high resistance was suppressed further, and its manufacturing method.

上述した課題を解決し、目的を達成するために、本発明に係る半導体積層体は、表面に電極が形成され、ＩＩＩ―Ｖ族化合物半導体層の積層構造を有する半導体積層体であって、不純物がドーピングされた下部半導体層と、最表層に位置し、前記電極が表面に形成され、前記下部半導体層のドーピング濃度よりも高いドーピング濃度で不純物がドーピングされたコンタクト層と、前記下部半導体層と前記コンタクト層との間に形成され、不純物がドーピングされ、所定の組成元素について前記下部半導体層の組成と前記コンタクト層の組成との間で連続的に変化する組成を有する中間層と、を備え、前記中間層のドーピング濃度は前記下部半導体層のドーピング濃度以上であることを特徴とする。 In order to solve the above-described problems and achieve the object, a semiconductor stacked body according to the present invention is a semiconductor stacked body having an electrode formed on a surface and having a stacked structure of III-V compound semiconductor layers, A doped lower semiconductor layer, a contact layer that is located on the outermost layer, the electrode is formed on the surface, and an impurity is doped at a doping concentration higher than a doping concentration of the lower semiconductor layer, and the lower semiconductor layer, An intermediate layer formed between the contact layer, doped with impurities, and having a composition that continuously changes between the composition of the lower semiconductor layer and the composition of the contact layer for a predetermined composition element. The doping concentration of the intermediate layer is not less than the doping concentration of the lower semiconductor layer.

また、本発明に係る半導体積層体は、上記発明において、前記連続的に組成が変化する組成元素はＶ族元素であることを特徴とする。 The semiconductor laminate according to the present invention is characterized in that, in the above invention, the composition element whose composition changes continuously is a group V element.

また、本発明に係る半導体積層体は、上記発明において、前記中間層のドーピング濃度は、前記下部半導体層のドーピング濃度と前記コンタクト層のドーピング濃度との間で連続的に変化することを特徴とする。 The semiconductor laminate according to the present invention is characterized in that, in the above invention, the doping concentration of the intermediate layer continuously changes between the doping concentration of the lower semiconductor layer and the doping concentration of the contact layer. To do.

また、本発明に係る半導体積層体は、上記発明において、前記コンタクト層のバンドギャップは前記下部半導体層のバンドギャップよりも狭く、前記中間層のバンドギャップは、前記下部半導体層のバンドギャップと前記コンタクト層のバンドギャップとの間で連続的に変化することを特徴とする。 In the semiconductor stacked body according to the present invention, in the above invention, a band gap of the contact layer is narrower than a band gap of the lower semiconductor layer, and a band gap of the intermediate layer is equal to a band gap of the lower semiconductor layer and the band gap of the lower semiconductor layer. The band gap of the contact layer changes continuously.

また、本発明に係る半導体積層体は、上記発明において、前記連続的に組成が変化する組成元素は熱拡散による組成分布を有することを特徴とする。 The semiconductor laminate according to the present invention is characterized in that, in the above invention, the composition element whose composition changes continuously has a composition distribution by thermal diffusion.

また、本発明に係る半導体発光素子は、上記発明の半導体積層体を備える半導体発光素子であって、前記半導体積層体は前記下部半導体層の下方に形成された活性層を含むことを特徴とする。 A semiconductor light emitting device according to the present invention is a semiconductor light emitting device including the semiconductor stacked body of the above invention, wherein the semiconductor stacked body includes an active layer formed below the lower semiconductor layer. .

また、本発明に係る半導体発光素子は、上記発明において、前記コンタクト層はＩｎＧａＡｓからなり、前記下部半導体層はＩｎＰからなり、前記中間層はＧａＩｎＡｓＰからなることを特徴とする。 In the semiconductor light emitting device according to the present invention, the contact layer is made of InGaAs, the lower semiconductor layer is made of InP, and the intermediate layer is made of GaInAsP.

また、本発明に係る半導体発光素子は、上記発明において、前記連続的に組成が変化する組成元素はＡｓまたはＰであることを特徴とする。 The semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the composition element whose composition continuously changes is As or P.

また、本発明に係る半導体発光素子は、上記発明において、前記半導体積層体が表面に形成された基板を備えることを特徴とする。 Moreover, the semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the semiconductor laminate is provided with a substrate formed on a surface thereof.

また、本発明に係る半導体発光素子は、上記発明において、前記コンタクト層は１×１０^１８ｃｍ^−３〜２×１０^１９ｃｍ^−３のドーピング濃度のＺｎを含み、前記下部半導体層は１×１０^１８ｃｍ^−３〜２×１０^１８ｃｍ^−３のドーピング濃度のＺｎを含むことを特徴とする。 In the semiconductor light emitting device according to the present invention, in the above invention, the contact layer contains Zn having a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁹ cm ⁻³ , and the lower semiconductor layer is 1 × 10 6. ^It contains Zn having a doping concentration of ¹⁸ cm ^{−3 to} 2 × 10 ¹⁸ cm ⁻³ .

また、本発明に係る半導体発光素子は、上記発明において、前記活性層はＶ族元素としてＰを含まない発光層を有することを特徴とする。 The semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the active layer has a light emitting layer not containing P as a group V element.

また、本発明に係る半導体積層体の製造方法は、基板上に、不純物がドーピングされた下部半導体層と、最表層に位置するとともに前記下部半導体層の表面に形成され、前記下部半導体層のドーピング濃度よりも高いドーピング濃度で不純物がドーピングされたコンタクト層と、を含むＩＩＩ―Ｖ族化合物半導体層の積層構造を形成する半導体積層構造形成工程と、前記半導体積層構造を熱処理し、前記下部半導体層と前記コンタクト層との少なくとも一方から、前記下部半導体層と前記コンタクト層との界面に組成元素を熱拡散させ、前記組成元素について前記下部半導体層の組成と前記コンタクト層の組成との間で連続的に変化する組成を有する中間層を、前記下部半導体層と前記コンタクト層との間に形成する熱処理工程と、を含み、前記中間層のドーピング濃度は前記下部半導体層のドーピング濃度以上であることを特徴とする。 The method for manufacturing a semiconductor stacked body according to the present invention includes a lower semiconductor layer doped with an impurity on a substrate, an outermost layer and a surface of the lower semiconductor layer, and the lower semiconductor layer is doped. A semiconductor laminated structure forming step of forming a laminated structure of a group III-V compound semiconductor layer including a contact layer doped with an impurity at a doping concentration higher than the concentration; and heat-treating the semiconductor laminated structure to form the lower semiconductor layer The composition element is thermally diffused from at least one of the contact layer and the contact layer to the interface between the lower semiconductor layer and the contact layer, and the composition element continues between the composition of the lower semiconductor layer and the composition of the contact layer. A heat treatment step of forming an intermediate layer having a composition that changes in a manner between the lower semiconductor layer and the contact layer, The doping concentration of the serial intermediate layer may be equal to or more doping concentration of the lower semiconductor layer.

また、本発明に係る半導体積層体の製造方法は、上記発明において、前記連続的に組成が変化する組成元素はＶ族元素であることを特徴とする。 The method for producing a semiconductor laminate according to the present invention is characterized in that, in the above invention, the composition element whose composition changes continuously is a group V element.

また、本発明に係る半導体積層体の製造方法は、上記発明において、前記中間層のドーピング濃度は、前記下部半導体層のドーピング濃度と前記コンタクト層のドーピング濃度との間で連続的に変化することを特徴とする。 Further, in the method for manufacturing a semiconductor stacked body according to the present invention, in the above invention, the doping concentration of the intermediate layer continuously changes between the doping concentration of the lower semiconductor layer and the doping concentration of the contact layer. It is characterized by.

また、本発明に係る半導体積層体の製造方法は、上記発明において、前記コンタクト層のバンドギャップは前記下部半導体層のバンドギャップよりも狭く、前記中間層のバンドギャップ濃度は、前記下部半導体層のバンドギャップ濃度と前記コンタクト層のバンドギャップとの間で連続的に変化することを特徴とする。 Further, in the method for manufacturing a semiconductor stacked body according to the present invention, in the above invention, the band gap of the contact layer is narrower than the band gap of the lower semiconductor layer, and the band gap concentration of the intermediate layer is the same as that of the lower semiconductor layer. It is characterized by continuously changing between the band gap concentration and the band gap of the contact layer.

また、本発明に係る半導体発光素子の製造方法は、上記発明の半導体積層体の製造方法を含み、前記半導体積層構造形成工程において前記下部半導体層の下方に活性層を形成することを特徴とする。 A method for manufacturing a semiconductor light emitting device according to the present invention includes the method for manufacturing a semiconductor stacked body according to the above invention, wherein an active layer is formed below the lower semiconductor layer in the semiconductor stacked structure forming step. .

また、本発明に係る半導体発光素子の製造方法は、上記発明において、前記コンタクト層はＩｎＧａＡｓからなり、前記下部半導体層はＩｎＰからなり、前記中間層はＧａＩｎＡｓＰからなることを特徴とする。 In the method of manufacturing a semiconductor light emitting device according to the present invention, the contact layer is made of InGaAs, the lower semiconductor layer is made of InP, and the intermediate layer is made of GaInAsP.

また、本発明に係る半導体発光素子の製造方法は、上記発明において、前記連続的に組成が変化する元素はＡｓまたはＰであることを特徴とする。 The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the continuously changing element is As or P.

また、本発明に係る半導体発光素子の製造方法は、上記発明において、前記コンタクト層は１×１０^１８ｃｍ^−３〜２×１０^１９ｃｍ^−３のドーピング濃度のＺｎを含み、前記下部半導体層は１×１０^１８ｃｍ^−３〜２×１０^１８ｃｍ^−３のドーピング濃度のＺｎを含むことを特徴とする。 In the method for manufacturing a semiconductor light emitting device according to the present invention, in the above invention, the contact layer includes Zn having a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁹ cm ⁻³ , and the lower semiconductor layer includes It contains Zn having a doping concentration of 1 × 10 ¹⁸ cm ^{−3 to} 2 × 10 ¹⁸ cm ⁻³ .

また、本発明に係る半導体発光素子の製造方法は、上記発明において、前記活性層はＶ族元素としてＰを含まない発光層を有することを特徴とする。 The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the active layer has a light emitting layer not containing P as a group V element.

また、本発明に係る半導体発光素子の製造方法は、上記発明において、前記熱処理工程は、６００℃〜８００℃の温度範囲で、６０分以上行うことを特徴とする。 The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that, in the above invention, the heat treatment step is performed in a temperature range of 600 ° C. to 800 ° C. for 60 minutes or more.

本発明によれば、高抵抗化がよりいっそう抑制された半導体積層体および半導体発光素子を実現できるという効果を奏する。 According to the present invention, there is an effect that it is possible to realize a semiconductor stacked body and a semiconductor light emitting element in which the increase in resistance is further suppressed.

図１は、実施の形態に係る半導体レーザ素子の模式的な断面図である。FIG. 1 is a schematic cross-sectional view of a semiconductor laser device according to an embodiment. 図２は、従来の多段コンタクト層を有する半導体レーザ素子のエネルギーバンド構造を説明する図である。FIG. 2 is a diagram for explaining an energy band structure of a conventional semiconductor laser device having a multistage contact layer. 図３は、図１に示す半導体レーザ素子のエネルギーバンド構造を説明する図である。FIG. 3 is a diagram for explaining the energy band structure of the semiconductor laser device shown in FIG. 図４は、図１に示す半導体レーザ素子の製造方法を説明する図である。FIG. 4 is a diagram for explaining a method of manufacturing the semiconductor laser element shown in FIG. 図５は、図１に示す半導体レーザ素子の製造方法を説明する図である。FIG. 5 is a diagram for explaining a method of manufacturing the semiconductor laser element shown in FIG. 図６は、接合界面近傍のＡｓ組成の分布を示す図である。FIG. 6 is a diagram showing the distribution of As composition in the vicinity of the bonding interface. 図７は、接合界面近傍のＺｎ濃度の分布を示す図である。FIG. 7 is a diagram showing a distribution of Zn concentration in the vicinity of the bonding interface. 図８は、実施例、比較例の半導体レーザ素子の注入電流と微分抵抗との関係を示す図である。FIG. 8 is a diagram showing the relationship between the injection current and the differential resistance of the semiconductor laser elements of the examples and comparative examples.

以下に、図面を参照して本発明に係る半導体積層体および半導体発光素子ならびにその製造方法の実施の形態を詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。また、各図面において、同一または対応する構成要素には適宜同一の符号を付している。また、図面は模式的なものであり、各層の厚さや厚さの比率などは現実のものとは異なることに留意すべきである。また、図面相互間においても互いの寸法の関係や比率が異なる部分が含まれている。 Embodiments of a semiconductor laminate, a semiconductor light emitting device, and a manufacturing method thereof according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Moreover, in each drawing, the same code | symbol is attached | subjected suitably to the same or corresponding component. Also, it should be noted that the drawings are schematic, and the thicknesses and ratios of the layers are different from the actual ones. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

（実施の形態）
図１は、本発明の図１は、実施の形態に係る発光素子である半導体レーザ素子の模式的な断面図である。図１に示すように、この半導体レーザ素子１００は、裏面にｎ側電極１０が形成された基板２０と、基板２０の表面に順次形成された、半導体積層体３０およびｐ側電極４０を備えている。なお、半導体レーザ素子１００は端面発光型の半導体レーザ素子であり、紙面と略平行な半導体レーザ素子１００の２つの端面には、光共振器を形成する反射膜がそれぞれ形成されている。 (Embodiment)
FIG. 1 is a schematic cross-sectional view of a semiconductor laser device which is a light emitting device according to an embodiment. As shown in FIG. 1, the semiconductor laser device 100 includes a substrate 20 having an n-side electrode 10 formed on the back surface, and a semiconductor laminate 30 and a p-side electrode 40 sequentially formed on the surface of the substrate 20. Yes. The semiconductor laser element 100 is an edge-emitting semiconductor laser element, and reflection films that form optical resonators are respectively formed on two end faces of the semiconductor laser element 100 substantially parallel to the paper surface.

基板２０は、ｎ型ＩｎＰからなる。ｎ側電極１０は基板２０とオーミック接触するように構成されており、たとえばＡｕＧｅＮｉ／Ａｕ構造を有する。 The substrate 20 is made of n-type InP. The n-side electrode 10 is configured to be in ohmic contact with the substrate 20 and has, for example, an AuGeNi / Au structure.

半導体積層体３０は、機能半導体層３１、クラッド層３２、下部半導体層としての高ドーパント濃度クラッド層３３、中間層３４、およびコンタクト層３５が順次積層して半導体積層構造を形成したものである。これらの半導体層はＩＩＩ−Ｖ族化合物半導体材料からなる。 The semiconductor stacked body 30 is a semiconductor stacked structure in which a functional semiconductor layer 31, a cladding layer 32, a high dopant concentration cladding layer 33 as a lower semiconductor layer, an intermediate layer 34, and a contact layer 35 are sequentially stacked. These semiconductor layers are made of a III-V group compound semiconductor material.

機能半導体層３１は、下部クラッド層３１ａ、活性層３１ｂ、上部クラッド層３１ｃ、および埋め込み半導体層３１ｄ、３１ｅを備える。下部クラッド層３１ａ、活性層３１ｂおよび上部クラッド層３１ｃはこの順に積層し、かつメサ構造を形成している。埋め込み半導体層３１ｄ、３１ｅはメサ構造の両側を埋め込んでいる。 The functional semiconductor layer 31 includes a lower clad layer 31a, an active layer 31b, an upper clad layer 31c, and buried semiconductor layers 31d and 31e. The lower clad layer 31a, the active layer 31b, and the upper clad layer 31c are laminated in this order and form a mesa structure. The embedded semiconductor layers 31d and 31e are embedded on both sides of the mesa structure.

下部クラッド層３１ａ、上部クラッド層３１ｃは、それぞれｎ型ＩｎＰ、ｐ型ＩｎＰからなる。活性層３１ｂは、ＧａＩｎＡｓＰやＡｌＧａＩｎＡｓなどの、たとえば１５５０ｎｍ波長帯の所望の波長で発光できる組成のＩＩＩ−Ｖ族化合物半導体材料からなる。また、活性層３１ｂは、複数の障壁層と複数の井戸層（発光層）とからなる多重量子井戸（ＭＱＷ：Multi Quantum Well）構造のＭＱＷ層と、ＭＱＷ層を挟むように配置された分離閉じ込めヘテロ構造（ＳＣＨ：Separate Confinement Heterostructure）層とからなるＭＱＷ−ＳＣＨ構造を有する。ただし、活性層３１ｂの構造は上記に限定されず、ＳＨＣ構造が無くてもよいし、さらにはバルク構造でもよい。埋め込み半導体層３１ｄ、３１ｅは、それぞれｐ型ＩｎＰ、ｎ型ＩｎＰからなり、電流狭窄層として機能する。 The lower cladding layer 31a and the upper cladding layer 31c are made of n-type InP and p-type InP, respectively. The active layer 31b is made of a III-V group compound semiconductor material such as GaInAsP or AlGaInAs that can emit light at a desired wavelength in the 1550 nm wavelength band, for example. The active layer 31b includes an MQW layer having a multiple quantum well (MQW) structure composed of a plurality of barrier layers and a plurality of well layers (light emitting layers), and a separate confinement arranged so as to sandwich the MQW layer. It has an MQW-SCH structure consisting of a heterostructure (SCH: Separate Confinement Heterostructure) layer. However, the structure of the active layer 31b is not limited to the above, and there may be no SHC structure, or a bulk structure. The embedded semiconductor layers 31d and 31e are made of p-type InP and n-type InP, respectively, and function as current confinement layers.

クラッド層３２はｐ型ＩｎＰからなる。高ドーパント濃度クラッド層３３は、ｐ型ドーパントを高濃度にドーピングしたｐ型ＩｎＰからなる。高ドーパント濃度クラッド層３３はたとえば１×１０^１８ｃｍ^−３〜２×１０^１８ｃｍ^−３のドーピング濃度のＺｎを含む。高ドーパント濃度クラッド層３３の層厚は１０ｎｍ以上が好ましく、たとえば５０ｎｍである。 The clad layer 32 is made of p-type InP. The high dopant concentration cladding layer 33 is made of p-type InP doped with a high concentration of a p-type dopant. The high dopant concentration cladding layer 33 contains Zn having a doping concentration of, for example, 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁸ cm ⁻³ . The layer thickness of the high dopant concentration cladding layer 33 is preferably 10 nm or more, for example, 50 nm.

コンタクト層３５は半導体積層体３０の最表層に位置し、ｐ型ドーパントを高濃度にドーピングしたｐ型ＩｎＧａＡｓからなる。したがって、コンタクト層３５のバンドギャップは高ドーパント濃度クラッド層３３のバンドギャップよりも狭い。コンタクト層３５はたとえば１×１０^１８ｃｍ^−３〜２×１０^１９ｃｍ^−３のドーピング濃度のＺｎを含む。さらに、コンタクト層３５は高ドーパント濃度クラッド層３３よりも高いドーピング濃度でＺｎを含む。コンタクト層３５の層厚は１０ｎｍ以上が好ましく、たとえば４００ｎｍ〜５００ｎｍである。 The contact layer 35 is located on the outermost layer of the semiconductor stacked body 30 and is made of p-type InGaAs doped with a p-type dopant at a high concentration. Therefore, the band gap of the contact layer 35 is narrower than the band gap of the high dopant concentration cladding layer 33. The contact layer 35 contains Zn having a doping concentration of, for example, 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁹ cm ⁻³ . Further, the contact layer 35 contains Zn at a higher doping concentration than the high dopant concentration cladding layer 33. The layer thickness of the contact layer 35 is preferably 10 nm or more, for example, 400 nm to 500 nm.

ｐ側電極４０はコンタクト層３５の表面に、コンタクト層３５とオーミック接触するように形成されており、たとえばＴｉ／Ｐｔ／Ａｕ構造やＡｕからなる。 The p-side electrode 40 is formed on the surface of the contact layer 35 so as to be in ohmic contact with the contact layer 35, and is made of, for example, a Ti / Pt / Au structure or Au.

中間層３４は、ｐ型ＧａＩｎＡｓＰからなる。中間層３４は高ドーパント濃度クラッド層３３よりも高いドーピング濃度、かつコンタクト層３５よりも低いドーピング濃度のＺｎを含む。 The intermediate layer 34 is made of p-type GaInAsP. The intermediate layer 34 includes Zn having a doping concentration higher than that of the high dopant concentration cladding layer 33 and lower than that of the contact layer 35.

ここで、中間層３４は、所定の組成元素について、高ドーパント濃度クラッド層３３の組成とコンタクト層３５の組成との間で連続的に変化する組成を有する。具体的には、中間層３４のＶ族組成元素であるＡｓ組成は、高ドーパント濃度クラッド層３３のＡｓ組成（組成比：０）とコンタクト層３５のＡｓ組成（組成比：１）との間で連続的に変化している。同様に、中間層３４のＶ族組成元素であるＰ組成は、高ドーパント濃度クラッド層３３のＰ組成（組成比：１）とコンタクト層３５のＰ組成（組成比：０）との間で連続的に変化している。これによって、中間層３４のバンドギャップは、高ドーパント濃度クラッド層３３のバンドギャップとコンタクト層３５のバンドギャップとの間で連続的に変化する。 Here, the intermediate layer 34 has a composition that continuously changes between the composition of the high dopant concentration cladding layer 33 and the composition of the contact layer 35 with respect to a predetermined composition element. Specifically, the As composition which is a group V composition element of the intermediate layer 34 is between the As composition (composition ratio: 0) of the high dopant concentration cladding layer 33 and the As composition (composition ratio: 1) of the contact layer 35. It is changing continuously. Similarly, the P composition which is a group V composition element of the intermediate layer 34 is continuous between the P composition (composition ratio: 1) of the high dopant concentration cladding layer 33 and the P composition (composition ratio: 0) of the contact layer 35. Is changing. As a result, the band gap of the intermediate layer 34 continuously changes between the band gap of the high dopant concentration cladding layer 33 and the band gap of the contact layer 35.

つぎに、半導体レーザ素子１００の動作について説明する。ｎ側電極１０とｐ側電極４０との間に電圧を印加して、駆動電流を注入すると、ｐ側電極４０側からはキャリアとしてホールが注入され、ｎ側電極１０側からはキャリアとして電子が注入される。ホールは、コンタクト層３５、中間層３４、高ドーパント濃度クラッド層３３、クラッド層３２を経由して、埋め込み半導体層３１ｄ、３１ｅによって電流経路が狭窄されて上部クラッド層３１ｃを流れ、高ドーパント濃度クラッド層３３の下方に形成された活性層３１ｂに注入される。活性層３１ｂに注入された各キャリアは結合して発光し、発光は活性層３１ｂの光増幅作用と光共振器の作用とによって所定の波長でレーザ発振する。 Next, the operation of the semiconductor laser element 100 will be described. When a voltage is applied between the n-side electrode 10 and the p-side electrode 40 to inject a driving current, holes are injected as carriers from the p-side electrode 40 side, and electrons as carriers are injected from the n-side electrode 10 side. Injected. The holes flow through the upper cladding layer 31c through the contact layer 35, the intermediate layer 34, the high dopant concentration cladding layer 33, and the cladding layer 32, with the current path narrowed by the embedded semiconductor layers 31d and 31e, and the high dopant concentration cladding. Implanted into the active layer 31 b formed below the layer 33. Each carrier injected into the active layer 31b is combined to emit light, and the light emission is laser-oscillated at a predetermined wavelength by the optical amplification action of the active layer 31b and the action of the optical resonator.

ここで、図２は、従来の多段コンタクト層を有する半導体レーザ素子のエネルギーバンド構造を説明する図である。Ｅｖは価電子帯の上端、Ｅｃは伝導帯の下端のレベルを示している。コンタクト層１３５０は、クラッド層１３３０に向かって第１コンタクト層１３５１、第２コンタクト層１３５２、および第３コンタクト層１３５３が順次積層して構成されている。 Here, FIG. 2 is a diagram for explaining the energy band structure of a semiconductor laser device having a conventional multi-stage contact layer. Ev represents the upper end of the valence band, and Ec represents the lower end of the conduction band. The contact layer 1350 is configured by sequentially laminating a first contact layer 1351, a second contact layer 1352, and a third contact layer 1353 toward the cladding layer 1330.

図２に示すように、Ｅｖにおいて、第１コンタクト層１３５１、第２コンタクト層１３５２、第３コンタクト層１３５３、およびクラッド層１３３０の接合界面でスパイク状のエネルギー障壁Ｂが形成され、これがホールに対して障壁となり、素子の高抵抗化の原因となる。 As shown in FIG. 2, in Ev, a spike-like energy barrier B is formed at the junction interface of the first contact layer 1351, the second contact layer 1352, the third contact layer 1353, and the clad layer 1330, which is against the holes. It becomes a barrier and causes high resistance of the element.

これに対して、図３は、図１に示す半導体レーザ素子１００のエネルギーバンド構造を説明する図である。半導体レーザ素子１００では、中間層３４が、高ドーパント濃度クラッド層３３の組成とコンタクト層３５の組成との間で連続的に変化する組成を有するので、中間層３４のバンドギャップも、高ドーパント濃度クラッド層３３のバンドギャップとコンタクト層３５のバンドギャップとの間で連続的に変化する。その結果、図３に示すように、Ｅｖにおいて、コンタクト層３５、中間層３４および高ドーパント濃度クラッド層３３の接合界面でエネルギー障壁は形成されず、素子の高抵抗化がよりいっそう抑制ないし防止される。 On the other hand, FIG. 3 is a diagram for explaining the energy band structure of the semiconductor laser device 100 shown in FIG. In the semiconductor laser device 100, since the intermediate layer 34 has a composition that continuously changes between the composition of the high dopant concentration cladding layer 33 and the composition of the contact layer 35, the band gap of the intermediate layer 34 also has a high dopant concentration. It changes continuously between the band gap of the cladding layer 33 and the band gap of the contact layer 35. As a result, as shown in FIG. 3, in Ev, an energy barrier is not formed at the junction interface of the contact layer 35, the intermediate layer 34, and the high dopant concentration cladding layer 33, and the increase in resistance of the device is further suppressed or prevented. The

つぎに、図１に示す実施の形態に係る半導体レーザ素子１００の製造方法の一例について説明する。図４、図５は、半導体レーザ素子１００の製造方法を説明する図である。 Next, an example of a method for manufacturing the semiconductor laser device 100 according to the embodiment shown in FIG. 1 will be described. 4 and 5 are diagrams for explaining a method of manufacturing the semiconductor laser device 100. FIG.

はじめに、ＭＯＣＶＤ（Metal Organic Chemical Vapor Deposition）結晶成長装置等の結晶成長装置を用い、基板２０上に、下部クラッド層３１ａ、活性層３１ｂ、上部クラッド層３１ｃを結晶成長し、フォトリソグラフィ技術とエッチングとでメサ構造を形成し、さらに埋め込み半導体層３１ｄ、３１ｅを再成長してメサ構造を埋め込む。これによって、機能半導体層３１の構造を形成する。さらに、機能半導体層３１上にクラッド層３２、高ドーパント濃度クラッド層３３Ａ、コンタクト層３５Ａ、およびＩｎＰからなるキャップ層６０を形成し、半導体積層構造を形成する（図４参照）。接合界面Ｉは高ドーパント濃度クラッド層３３Ａとコンタクト層３５Ａとの接合界面である。 First, using a crystal growth apparatus such as a MOCVD (Metal Organic Chemical Vapor Deposition) crystal growth apparatus, the lower clad layer 31a, the active layer 31b, and the upper clad layer 31c are crystal-grown on the substrate 20, and photolithography and etching are performed. Then, the mesa structure is formed, and the embedded semiconductor layers 31d and 31e are regrown to embed the mesa structure. Thereby, the structure of the functional semiconductor layer 31 is formed. Further, a clad layer 32, a high dopant concentration clad layer 33A, a contact layer 35A, and a cap layer 60 made of InP are formed on the functional semiconductor layer 31 to form a semiconductor multilayer structure (see FIG. 4). The junction interface I is a junction interface between the high dopant concentration cladding layer 33A and the contact layer 35A.

つぎに、形成した半導体積層構造を熱処理する。熱処理は、たとえばＰＨ_３雰囲気下、６００℃〜８００℃で６０分以上行うことが好ましい。すると、高ドーパント濃度クラッド層３３Ａとコンタクト層３５Ａとの接合界面でＶ族の組成元素であるＰおよびＡｓが熱拡散し、高ドーパント濃度クラッド層３３Ａの一部とコンタクト層３５Ａの一部とから中間層３４が形成される。図５は中間層３４が形成された状態である。中間層３４は高ドーパント濃度クラッド層３３Ａとコンタクト層３５Ａとの接合界面Ｉを含むように形成される。中間層３４が形成された後、高ドーパント濃度クラッド層３３Ａとコンタクト層３５Ａとはそれぞれ高ドーパント濃度クラッド層３３とコンタクト層３５とになる。 Next, the formed semiconductor multilayer structure is heat-treated. The heat treatment is preferably performed, for example, at 600 ° C. to 800 ° C. for 60 minutes or more in a PH ₃ atmosphere. Then, P and As, which are Group V composition elements, are thermally diffused at the junction interface between the high dopant concentration clad layer 33A and the contact layer 35A, and from part of the high dopant concentration clad layer 33A and part of the contact layer 35A. An intermediate layer 34 is formed. FIG. 5 shows a state in which the intermediate layer 34 is formed. The intermediate layer 34 is formed so as to include the junction interface I between the high dopant concentration cladding layer 33A and the contact layer 35A. After the intermediate layer 34 is formed, the high dopant concentration cladding layer 33A and the contact layer 35A become the high dopant concentration cladding layer 33 and the contact layer 35, respectively.

図６は、接合界面近傍のＡｓ組成の分布を示す図である。横軸は層厚方向での接合界面Ｉからの距離を示し、縦軸はその距離でのＡｓ組成を示す。図６に示すように、熱処理による拡散前では、接合界面Ｉを挟んで高ドーパント濃度クラッド層３３ＡではＡｓ組成は０であり、コンタクト層３５ＡではＡｓ組成は１である。一方、熱処理による拡散後には、高ドーパント濃度クラッド層３３のＡｓ組成（組成比：０）とコンタクト層３５のＡｓ組成（組成比：１）との間で連続的に変化するＡｓ組成を有する中間層３４が形成される。中間層３４において、Ａｓは熱拡散による組成分布を有することになる。なお、Ｐについても熱処理により熱拡散し、高ドーパント濃度クラッド層３３のＰ組成（組成比：１）とコンタクト層３５のＰ組成（組成比：０）との間で連続的に変化する組成の分布となる。具体的には、中間層３４のＧａＩｎＡｓＰにおいては、Ａｓ組成とＰ組成との和が１となるようなＰ組成となる。また、図６の場合は、中間層３４の層厚は約４ｎｍであるが、中間層３４の層厚は熱処理条件によって調整でき、たとえば熱処理時間を長くすると層厚は厚くなる。中間層３４の層厚はたとえば４ｎｍ〜１０ｎｍである。 FIG. 6 is a diagram showing the distribution of As composition in the vicinity of the bonding interface. The horizontal axis indicates the distance from the bonding interface I in the layer thickness direction, and the vertical axis indicates the As composition at that distance. As shown in FIG. 6, before diffusion by heat treatment, the As composition is 0 in the high dopant concentration cladding layer 33A across the junction interface I, and the As composition is 1 in the contact layer 35A. On the other hand, after diffusion by heat treatment, an intermediate having an As composition that continuously changes between the As composition of the high dopant concentration cladding layer 33 (composition ratio: 0) and the As composition of the contact layer 35 (composition ratio: 1). Layer 34 is formed. In the intermediate layer 34, As has a composition distribution due to thermal diffusion. P is also thermally diffused by heat treatment and has a composition that continuously changes between the P composition of the high dopant concentration cladding layer 33 (composition ratio: 1) and the P composition of the contact layer 35 (composition ratio: 0). Distribution. Specifically, the GaInAsP of the intermediate layer 34 has a P composition such that the sum of the As composition and the P composition is 1. In the case of FIG. 6, the layer thickness of the intermediate layer 34 is about 4 nm, but the layer thickness of the intermediate layer 34 can be adjusted according to the heat treatment conditions. The layer thickness of the intermediate layer 34 is, for example, 4 nm to 10 nm.

一方、図７は、接合界面近傍のＺｎ濃度の分布を示す図である。横軸は層厚方向での接合界面Ｉからの距離を示し、縦軸はその距離でのＺｎ濃度を示す。図７に示すように、熱処理によるＡｓまたはＰの拡散前では、接合界面Ｉを挟んで高ドーパント濃度クラッド層３３Ａとコンタクト層３５ＡとでＺｎ濃度に不連続な差がある。一方、熱処理による拡散後に形成される中間層３４では、Ｚｎが高ドーパント濃度クラッド層３３およびコンタクト層３５の一方または両方から拡散する。その結果、中間層３４は、高ドーパント濃度クラッド層３３のＺｎ濃度とコンタクト層３５のＺｎ濃度との間で連続的に変化するＺｎ濃度を有することになる。 On the other hand, FIG. 7 is a diagram showing a distribution of Zn concentration in the vicinity of the bonding interface. The horizontal axis indicates the distance from the bonding interface I in the layer thickness direction, and the vertical axis indicates the Zn concentration at that distance. As shown in FIG. 7, before the diffusion of As or P by heat treatment, there is a discontinuous difference in Zn concentration between the high dopant concentration cladding layer 33A and the contact layer 35A across the junction interface I. On the other hand, in the intermediate layer 34 formed after diffusion by heat treatment, Zn diffuses from one or both of the high dopant concentration cladding layer 33 and the contact layer 35. As a result, the intermediate layer 34 has a Zn concentration that continuously changes between the Zn concentration of the high dopant concentration cladding layer 33 and the Zn concentration of the contact layer 35.

その後、キャップ層６０を除去し、反射膜の形成や素子分離などの必要な工程を行って、半導体レーザ素子１００が完成する。 Thereafter, the cap layer 60 is removed, and necessary processes such as formation of a reflective film and element isolation are performed to complete the semiconductor laser element 100.

従来の多段コンタクト層を用いた構成では、各層のバンドギャップエネルギーの差を適正に調整するためのＧａＩｎＡｓＰの成長条件を見出すのが困難であるが、上記の製造方法では、そのような成長条件を考慮する必要がないので、より簡易かついっそう効果的に高抵抗化を抑制できる。 In the configuration using the conventional multi-stage contact layer, it is difficult to find the growth conditions of GaInAsP for appropriately adjusting the difference in the band gap energy of each layer. Since there is no need to consider, it is possible to suppress the increase in resistance more easily and more effectively.

なお、上記製造方法の組成元素を拡散させる熱処理においてＰが熱拡散する。ここで、活性層３１ｂの発光層である井戸層の材料として、ＧａＩｎＡｓＰ等のＰを含む半導体材料を用いると、熱処理によってＰが拡散して発光波長が短波長化する場合がある。これに対して、井戸層の材料として、ＡｌＧａＩｎＡｓ等のＰを含まない半導体材料を用いると、熱処理によるＰの拡散が発生しないため、発光波長の短波長化が防止されるので好ましい。 Note that P is thermally diffused in the heat treatment for diffusing the composition element in the above manufacturing method. Here, when a semiconductor material containing P, such as GaInAsP, is used as the material of the well layer that is the light emitting layer of the active layer 31b, P may diffuse due to heat treatment and the emission wavelength may be shortened. On the other hand, it is preferable to use a semiconductor material that does not contain P, such as AlGaInAs, as the material of the well layer, because P diffusion does not occur due to heat treatment, and thus shortening of the emission wavelength is prevented.

つぎに、上記の製造方法にて製造した実施例の半導体レーザ素子と、上記の製造方法において組成元素を拡散させる熱処理を行わずに製造した比較例の半導体レーザ素子とについて、微分抵抗特性を調べた。 Next, the differential resistance characteristics of the semiconductor laser device of the example manufactured by the above manufacturing method and the semiconductor laser device of the comparative example manufactured without performing the heat treatment for diffusing the composition element in the above manufacturing method were examined. It was.

図８は、実施例、比較例の半導体レーザ素子の注入電流と微分抵抗との関係を示す図である。図８に示すように、比較例の半導体レーザ素子では、しきい値電流である約２０ｍＡより上の注入電流の領域で、微分抵抗値が注入電流に対してすぐに一定にならずゆるやかに減少する領域があった。この現象はコンタクト層と高ドーパント濃度クラッド層との接合界面でのホールの障壁によるものと考えられる。一方、実施例の半導体レーザ素子では、約２０ｍＡより上の注入電流の領域で、微分抵抗値がすぐに一定になった。この現象はホールの障壁の影響が解消されたことによるものと考えられる。 FIG. 8 is a diagram showing the relationship between the injection current and the differential resistance of the semiconductor laser elements of the examples and comparative examples. As shown in FIG. 8, in the semiconductor laser device of the comparative example, the differential resistance value does not become constant immediately with respect to the injection current but gradually decreases in the region of the injection current above the threshold current of about 20 mA. There was an area to do. This phenomenon is considered to be due to a hole barrier at the junction interface between the contact layer and the high dopant concentration cladding layer. On the other hand, in the semiconductor laser device of the example, the differential resistance value immediately became constant in the region of the injection current above about 20 mA. This phenomenon is thought to be due to the elimination of the influence of the hole barrier.

なお、上記実施の形態に係る半導体レーザ素子は、レーザ発振波長が波長１５５０ｎｍ帯になるようにその化合物半導体や電極等の材料、サイズ、設計パラメータ等が設定されている。しかしながら、各材料やサイズ等は、たとえば光通信波長帯域内の所望の波長のレーザ光を発振させるよう適宜設定することができ、特に限定はされない。 In the semiconductor laser device according to the above embodiment, the material, size, design parameters, etc. of the compound semiconductor and electrodes are set so that the laser oscillation wavelength is in the wavelength 1550 nm band. However, each material, size, and the like can be appropriately set to oscillate laser light having a desired wavelength within the optical communication wavelength band, and are not particularly limited.

また、上記実施の形態では、中間層において連続的に組成が変化する組成元素はＶ族元素であるが、ＩＩＩ族元素でもよい。また、上記実施の形態では、下部半導体層、コンタクト層、および中間層にドーピングされるドーパントはＺｎであるが、他のｐ型ドーパントでもよい。 In the above embodiment, the composition element whose composition continuously changes in the intermediate layer is a group V element, but may be a group III element. In the above embodiment, the dopant doped in the lower semiconductor layer, the contact layer, and the intermediate layer is Zn, but other p-type dopants may be used.

また、上記製造方法では、中間層を熱拡散によって形成しているが、中間層を結晶成長によって形成してもよい。この場合、たとえば、結晶成長の際に、対象となる組成元素を含む結晶材料の供給量を連続的に変化させることによって、組成が連続して変化する中間層を形成できる。 In the above manufacturing method, the intermediate layer is formed by thermal diffusion, but the intermediate layer may be formed by crystal growth. In this case, for example, an intermediate layer whose composition changes continuously can be formed by continuously changing the supply amount of the crystal material containing the target composition element during crystal growth.

また、本発明は、端面発光型の半導体レーザ素子に限らず、発光ダイオード素子や面発光レーザ素子などの他の半導体発光素子にも適用できる。また、本発明に係る半導体積層体は、半導体発光素子に限らず、他の半導体素子にも適用できる。 The present invention is not limited to the edge emitting semiconductor laser element, but can be applied to other semiconductor light emitting elements such as a light emitting diode element and a surface emitting laser element. Moreover, the semiconductor laminated body according to the present invention is not limited to a semiconductor light emitting element, but can be applied to other semiconductor elements.

また、上記実施の形態により本発明が限定されるものではない。上述した各構成要素を適宜組み合わせて構成したものも本発明に含まれる。また、さらなる効果や変形例は、当業者によって容易に導き出すことができる。よって、本発明のより広範な態様は、上記の実施の形態に限定されるものではなく、様々な変更が可能である。 Further, the present invention is not limited by the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

１０ｎ側電極
２０基板
３０半導体積層体
３１機能半導体層
３１ａ下部クラッド層
３１ｂ活性層
３１ｃ上部クラッド層
３１ｄ、３１ｅ埋め込み半導体層
３２クラッド層
３３、３３Ａ高ドーパント濃度クラッド層
３４中間層
３５、３５Ａコンタクト層
４０ｐ側電極
６０キャップ層
１００半導体レーザ素子
Ｂエネルギー障壁
Ｉ接合界面 10 n-side electrode 20 substrate 30 semiconductor laminate 31 functional semiconductor layer 31a lower cladding layer 31b active layer 31c upper cladding layer 31d, 31e buried semiconductor layer 32 cladding layer 33, 33A high dopant concentration cladding layer 34 intermediate layer 35, 35A contact layer 40 p-side electrode 60 cap layer 100 semiconductor laser element B energy barrier I junction interface

Claims

A semiconductor light emitting device comprising a semiconductor laminate having an electrode formed on the surface and having a laminated structure of III-V compound semiconductor layers, wherein the semiconductor laminate is
A lower semiconductor layer doped with impurities; and
A contact layer located on the outermost layer, wherein the electrode is formed on the surface and doped with impurities at a doping concentration higher than the doping concentration of the lower semiconductor layer;
A composition formed between the lower semiconductor layer and the contact layer, doped with impurities, and having a composition that continuously changes between the composition of the lower semiconductor layer and the composition of the contact layer for a predetermined composition element. And an intermediate layer having a concentration that continuously varies between the concentration of the lower semiconductor layer and the concentration of the contact layer for the impurities,
An active layer formed below the lower semiconductor layer;
With
The contact layer is made of InGaAs, the lower semiconductor layer is made of InP, the intermediate layer is made of GaInAsP,
The active layer has a light-emitting layer that does not contain P as a group V element, and the light-emitting layer is made of AlGaInAs in which emission wavelength is prevented from being shortened by not containing P diffused by heat treatment,
The intermediate layer has a composition element and an impurity thermally diffused from at least one of the lower semiconductor layer and the contact layer to an interface between the lower semiconductor layer and the contact layer. The lower semiconductor layer has a lower semiconductor layer that is not thermally diffused among the lower semiconductor layers before thermal diffusion in the lower semiconductor layer. A semiconductor light emitting device , wherein a doping concentration of the intermediate layer is equal to or higher than a doping concentration of the lower semiconductor layer.

The semiconductor light emitting device according to claim 1, wherein the composition element whose composition changes continuously is a group V element .

3. The semiconductor light emitting device according to claim 1, wherein a doping concentration of the intermediate layer continuously changes between a doping concentration of the lower semiconductor layer and a doping concentration of the contact layer.

The band gap of the contact layer is narrower than the band gap of the lower semiconductor layer, and the band gap of the intermediate layer continuously changes between the band gap of the lower semiconductor layer and the band gap of the contact layer. The semiconductor light-emitting device according to claim 1, wherein

The semiconductor light emitting element according to claim 1, wherein the composition element whose composition changes continuously has a composition distribution by thermal diffusion.

6. The semiconductor light emitting device according to claim 1, wherein the light emitting layer of the active layer formed below the lower semiconductor layer emits light at a wavelength of 1550 nm wavelength band .

The semiconductor light-emitting element according to claim 1, wherein the composition element whose composition changes continuously is As or P.

The semiconductor light-emitting element according to claim 1, further comprising a substrate having a surface on which the semiconductor laminate is formed.

The contact layer includes Zn having a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁹ cm ⁻³ , and the lower semiconductor layer has a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁸ cm ⁻³ . the semiconductor light emitting device according to any one of claims 1 to 8, characterized in that it comprises a Zn.

A lower semiconductor layer doped with an impurity on a substrate, and a contact layer located on the surface of the lower semiconductor layer and positioned on the surface of the lower semiconductor layer and doped with an impurity at a doping concentration higher than the doping concentration of the lower semiconductor layer And a semiconductor laminated structure forming step of forming a laminated structure of III-V group compound semiconductor layers,
The semiconductor multilayer structure is heat-treated, and a composition element and an impurity are thermally diffused from at least one of the lower semiconductor layer and the contact layer to an interface between the lower semiconductor layer and the contact layer, and the lower semiconductor Having a composition that continuously changes between the composition of the layer and the composition of the contact layer, and the concentration of the impurity that changes continuously between the concentration of the lower semiconductor layer and the concentration of the contact layer. A heat treatment step of forming an intermediate layer between the lower semiconductor layer and the contact layer;
Including
Forming an active layer below the lower semiconductor layer in the semiconductor multilayer structure forming step;
In the semiconductor multilayer structure forming step, the lower semiconductor layer is formed so that the thickness thereof is larger than the thickness at which the composition element is thermally diffused, and in the heat treatment step, the composition element is formed below the intermediate layer. Heat treatment is performed so that the lower semiconductor layer that is not thermally diffused remains,
Doping concentration of the intermediate layer is Ri der doping concentration than the lower semiconductor layer,
The active layer has a light-emitting layer that does not contain P as a group V element, and the light-emitting layer is made of AlGaInAs in which emission wavelength is prevented from being shortened by not containing P diffused by heat treatment,
The contact layer is made of InGaAs, the lower semiconductor layer is made of InP, the intermediate layer is a method of manufacturing a semiconductor light emitting element characterized GaInAsP Tona Rukoto.

11. The method of manufacturing a semiconductor light emitting device according to claim 10 , wherein the composition element whose composition changes continuously is a group V element.

Doping concentration of the intermediate layer, a method of manufacturing a semiconductor light emitting device according to claim 10 or 11, characterized in that continuously changes between the doping concentration of the doping concentration and the contact layer of the lower semiconductor layer .

The band gap of the contact layer is narrower than the band gap of the lower semiconductor layer, and the band gap concentration of the intermediate layer continuously changes between the band gap concentration of the lower semiconductor layer and the band gap of the contact layer. the method of manufacturing a semiconductor light emitting device according to any one of claims 10 to 12, characterized in that.

Manufacturing the semiconductor light emitting element according to any one of claims 10 to 13, characterized in that to form the active layer having the light emitting layer emitting before Symbol semiconductor laminated structure formation step at a wavelength of 1550nm wavelength band Method.

15. The method of manufacturing a semiconductor light-emitting element according to claim 10, wherein the element whose composition changes continuously is As or P.

The contact layer includes Zn having a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁹ cm ⁻³ , and the lower semiconductor layer has a doping concentration of 1 × 10 ¹⁸ cm ⁻³ to 2 × 10 ¹⁸ cm ⁻³ . The method for manufacturing a semiconductor light-emitting element according to claim 10 , wherein Zn is contained.

The heat treatment process, 600 ° C. in a temperature range of to 800 ° C., a method of manufacturing a semiconductor light emitting device according to any one of claims 10 to 16, characterized in that 60 minutes or more.