WO2020209014A1 - Light emitting element and method of manufacturing light emitting element - Google Patents

Light emitting element and method of manufacturing light emitting element Download PDF

Info

Publication number
WO2020209014A1
WO2020209014A1 PCT/JP2020/011575 JP2020011575W WO2020209014A1 WO 2020209014 A1 WO2020209014 A1 WO 2020209014A1 JP 2020011575 W JP2020011575 W JP 2020011575W WO 2020209014 A1 WO2020209014 A1 WO 2020209014A1
Authority
WO
WIPO (PCT)
Prior art keywords
light emitting
layer
active layer
type
atoms
Prior art date
Application number
PCT/JP2020/011575
Other languages
French (fr)
Japanese (ja)
Inventor
石崎 順也
山田 雅人
Original Assignee
信越半導体株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 信越半導体株式会社 filed Critical 信越半導体株式会社
Publication of WO2020209014A1 publication Critical patent/WO2020209014A1/en

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02367Substrates
    • H01L21/0237Materials
    • H01L21/02387Group 13/15 materials
    • H01L21/02395Arsenides
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • CCHEMISTRY; METALLURGY
    • C30CRYSTAL GROWTH
    • C30BSINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02Epitaxial-layer growth
    • CCHEMISTRY; METALLURGY
    • C30CRYSTAL GROWTH
    • C30BSINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10Inorganic compounds or compositions
    • C30B29/40AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02436Intermediate layers between substrates and deposited layers
    • H01L21/02439Materials
    • H01L21/02455Group 13/15 materials
    • H01L21/02461Phosphides
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02436Intermediate layers between substrates and deposited layers
    • H01L21/02439Materials
    • H01L21/02455Group 13/15 materials
    • H01L21/02463Arsenides
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02436Intermediate layers between substrates and deposited layers
    • H01L21/02494Structure
    • H01L21/02496Layer structure
    • H01L21/02505Layer structure consisting of more than two layers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02518Deposited layers
    • H01L21/02521Materials
    • H01L21/02538Group 13/15 materials
    • H01L21/02543Phosphides
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02518Deposited layers
    • H01L21/0257Doping during depositing
    • H01L21/02573Conductivity type
    • H01L21/02576N-type
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02518Deposited layers
    • H01L21/0257Doping during depositing
    • H01L21/02573Conductivity type
    • H01L21/02579P-type
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02365Forming inorganic semiconducting materials on a substrate
    • H01L21/02612Formation types
    • H01L21/02617Deposition types
    • H01L21/0262Reduction or decomposition of gaseous compounds, e.g. CVD
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26Materials of the light emitting region
    • H01L33/30Materials of the light emitting region containing only elements of group III and group V of the periodic system

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Led Devices (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Chemical Vapour Deposition (AREA)

Abstract

The present invention is a light emitting element having a light emitting part in which an N-type cladding layer, an active layer, and a P-type cladding layer are formed in this order, wherein the active layer includes a P-type dopant of which the concentration gradually decreases from the P-type cladding layer side to the N-type cladding layer side, and in the active layer, the average concentration of the P-type dopant in a region from the P-type cladding layer to a position corresponding to 1/3 of the thickness of the active layer is 1.0 × 1016 atoms/cm3 or more and 3.0 × 1017 atoms/cm3 or less. Accordingly, provided are: the light emitting element which has excellent luminance characteristics with respect to the environmental temperature and which suppresses the deterioration of life characteristics; and a method of manufacturing the same.

Description

発光素子および発光素子の製造方法Light emitting element and manufacturing method of light emitting element
 本発明は、発光素子および発光素子の製造方法に関し、特に環境温度に対する輝度特性が良好で、かつ、寿命特性の悪化が抑制された発光素子および発光素子の製造方法に関する。 The present invention relates to a method for manufacturing a light emitting element and a light emitting element, and particularly to a method for manufacturing a light emitting element and a light emitting element having good luminance characteristics with respect to an environmental temperature and suppressing deterioration of life characteristics.
 AlGaInP系材料は、窒化物を除くIII-V族化合物半導体混晶中で最大の直接遷移型エネルギーギャップを有し、550~650nm帯(緑色~赤色域)の可視光発光装置の材料として注目されている。このような大きな直接遷移型エネルギーギャップを持つAlGaInPからなる活性層を有するAlGaInP系発光素子は、GaP、GaAsP等の間接遷移型の材料を用いたものと比べて高輝度の発光が可能である(例えば特許文献1)。 The AlGaInP-based material has the largest direct transition energy gap in the III-V compound semiconductor mixed crystal excluding nitrides, and is attracting attention as a material for visible light emitting devices in the 550 to 650 nm band (green to red region). ing. An AlGaInP-based light emitting element having an active layer made of AlGaInP having such a large direct transition type energy gap can emit light with higher brightness than those using an indirect transition type material such as GaP or GaAsP (). For example, Patent Document 1).
 図4は、従来のAlGaInP系発光素子の一例を示す概略断面図である。
 この発光素子310はGaAs出発基板300上に厚さ0.1~1.0μmのGaAsバッファ層、例えば厚さ1.0μmのAlInPエッチストップ層302、例えば厚さ1.0μmのN型AlGaInPクラッド層303、例えば厚さ0.9μmのAlGaInP活性層304、例えば厚さ1.0μmのP型AlGaInPクラッド層305、電流伝播層との格子不整を緩和するP型InGaP緩衝層306、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ5.0μmのP型GaP電流伝播層307を有する。GaAsバッファ層は特になくてもよい。なお、図4においては発光素子の電極等は省略されている。
FIG. 4 is a schematic cross-sectional view showing an example of a conventional AlGaInP-based light emitting device.
The light emitting device 310 is formed on a GaAs starting substrate 300 with a GaAs buffer layer having a thickness of 0.1 to 1.0 μm, for example, an AlInP etch stop layer 302 having a thickness of 1.0 μm, for example, an N-type AlGaInP clad layer having a thickness of 1.0 μm. 303, for example, an AlGaInP active layer 304 with a thickness of 0.9 μm, for example, a P-type AlGaInP clad layer 305 with a thickness of 1.0 μm, a P-type InGaP buffer layer 306 for alleviating lattice irregularities with a current propagation layer, and applied to the device. It has, for example, a 5.0 μm-thick P-type GaP current propagation layer 307 that propagates and diffuses current and has a function of extracting light. The GaAs buffer layer may not be particularly provided. In FIG. 4, the electrodes of the light emitting element and the like are omitted.
 ここでN型ドーパントとして、例えばSi、S、Se等がN型クラッド層303にドーピングされる。またP型ドーパントとしては、Zn、Mg、Te等がP型クラッド層305及びP型緩衝層306及びP型電流伝播層307にドーピングされる。 Here, as an N-type dopant, for example, Si, S, Se, etc. are doped into the N-type clad layer 303. As the P-type dopant, Zn, Mg, Te and the like are doped into the P-type clad layer 305, the P-type buffer layer 306 and the P-type current propagation layer 307.
 N型クラッド層303は、1層以上の組成及びドーピング水準のエピタキシャル層で構成され、P型クラッド層305は、1層以上の組成及びドーピング水準のエピタキシャル層で構成される。活性層304は均一組成のバルク型活性層、または、発光再結合層と該発光再結合層の組成よりも大きなバンドギャップ組成を有する障壁層とが多重接合した多重接合型活性層から成る。 The N-type clad layer 303 is composed of an epitaxial layer having one or more compositions and a doping level, and the P-type clad layer 305 is composed of an epitaxial layer having one or more layers and a doping level. The active layer 304 is composed of a bulk-type active layer having a uniform composition or a multi-bonded active layer in which a luminescent recombination layer and a barrier layer having a bandgap composition larger than the composition of the luminescent recombination layer are multi-bonded.
 ところで発光素子(例えばAlGaInP系発光素子)の発光部をエピタキシャル成長で形成する際に、寿命特性の悪化を回避するため、活性層中に残留、もしくは寿命試験中に拡散・泳動するドーパントの濃度を極小に設計する必要があった。しかし、活性層中のドーパント濃度を極小にすることで寿命特性は改善できるが、一方で、環境温度に対する輝度の変化は大きくなる傾向にあった。
 また、環境温度に対する輝度特性を改善するためには、活性層中にドーパントを過剰に入れることが効果的であることが分かっている。しかし、過剰に活性層中に投入されたドーパントは輝度特性を改善するものの、転位・欠陥発生源となり、寿命特性を著しく悪化させる。
By the way, when the light emitting portion of a light emitting device (for example, an AlGaInP type light emitting device) is formed by epitaxial growth, the concentration of the dopant remaining in the active layer or diffused / electrophoresed during the life test is minimized in order to avoid deterioration of the life characteristics. Had to be designed. However, although the lifetime characteristics can be improved by minimizing the dopant concentration in the active layer, the change in brightness with respect to the ambient temperature tends to be large.
Further, it has been found that it is effective to add an excessive amount of dopant in the active layer in order to improve the luminance characteristics with respect to the ambient temperature. However, although the dopant excessively charged into the active layer improves the luminance characteristics, it becomes a source of dislocations and defects and significantly deteriorates the lifetime characteristics.
 従って、環境温度に対する輝度特性が良好な発光素子は寿命特性が悪く、一方、寿命特性が良好な発光素子では環境温度に対する輝度特性が悪く、二つの特性が良好である発光素子の実現が望まれていた。 Therefore, it is desired to realize a light emitting device having a good luminance characteristic with respect to the ambient temperature, which has a poor lifetime characteristic, while a light emitting device having a good lifetime characteristic has a poor luminance characteristic with respect to the ambient temperature and has good two characteristics. Was there.
特開2005-150645号公報Japanese Unexamined Patent Publication No. 2005-150645
 本発明は上記の課題に鑑みてなされたもので、環境温度に対する輝度特性が良好であり、かつ、寿命特性の悪化が抑制された発光素子およびその製造方法を提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device having good luminance characteristics with respect to environmental temperature and suppressing deterioration of life characteristics, and a method for manufacturing the same.
 上記目的を達成するために、本発明は、N型クラッド層と活性層とP型クラッド層がこの順序で形成された発光部を有する発光素子であって、
 前記活性層は、前記P型クラッド層側から前記N型クラッド層側へ濃度が漸減するP型ドーパントを含み、
 前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が1.0×1016atoms/cm以上3.0×1017atoms/cm以下であることを特徴とする発光素子を提供する。
In order to achieve the above object, the present invention is a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
The active layer contains a P-type dopant whose concentration gradually decreases from the P-type clad layer side to the N-type clad layer side.
2. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. Provided is a light emitting element having a concentration of 0 × 10 17 atoms / cm 3 or less.
 このように活性層において、P型クラッド層から活性層の1/3の厚さ分の位置までの領域の平均のP型ドーパントの濃度が1.0×1016atoms/cm以上であれば、光出力が向上するとともに環境温度に対する輝度特性が向上する。
 また、P型クラッド層から活性層の1/3の厚さ分の位置までの領域の平均のP型ドーパントの濃度が3.0×1017atoms/cm以下であり、かつ、活性層においてP型クラッド層側からN型クラッド層側へ漸減するP型ドーパントの濃度プロファイルであることで、寿命特性の悪化を抑制することができる。
As described above, in the active layer, if the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. , The light output is improved and the brightness characteristic with respect to the ambient temperature is improved.
Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 3.0 × 10 17 atoms / cm 3 or less, and in the active layer. The concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side can suppress deterioration of the life characteristics.
 また、前記発光部は、AlGaInP系の化合物半導体からなるものとすることができる。 Further, the light emitting unit can be made of an AlGaInP-based compound semiconductor.
 本発明は、発光部がAlGaInP系の化合物半導体からなる発光素子に特に好適に用いることができる。 The present invention can be particularly preferably used for a light emitting device in which the light emitting portion is made of an AlGaInP-based compound semiconductor.
 また、前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置から2/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下のものとすることができる。 Further, in the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer to the position of 2/3 of the thickness is 0. .3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
 このようにP型ドーパント濃度が上記領域で上記数値範囲のものであれば、より確実に寿命特性の悪化を抑制できる。 If the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.
 このとき、前記活性層において、前記P型クラッド層から前記活性層の2/3の厚さ分の位置からN型クラッド層までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以下のものとすることができる。 At this time, in the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10. It can be 16 atoms / cm 3 or less.
 このようにP型ドーパント濃度が上記領域で上記数値範囲のものであれば、より一層確実に寿命特性の悪化を抑制することができる。 If the P-type dopant concentration is in the above-mentioned numerical range in the above-mentioned region as described above, the deterioration of the life characteristic can be suppressed more reliably.
 また本発明は、N型クラッド層と活性層とP型クラッド層をこの順序で形成した発光部を有する発光素子の製造方法であって、
 前記活性層において、前記P型クラッド層側から前記N型クラッド層側へP型ドーパントの濃度が漸減し、かつ、
 前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が1.0×1016atoms/cm以上3.0×1017atoms/cm以下となるように前記P型ドーパントをドープして製造することを特徴とする発光素子の製造方法を提供する。
The present invention is a method for manufacturing a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
In the active layer, the concentration of the P-type dopant gradually decreases from the P-type clad layer side to the N-type clad layer side, and
3. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. Provided is a method for manufacturing a light emitting device, which comprises doping the P-type dopant so as to be 0 × 10 17 atoms / cm 3 or less.
 このように活性層において、P型クラッド層から活性層の1/3の厚さ分の位置までの領域の平均のP型ドーパントの濃度が1.0×1016atoms/cm以上となるように製造すれば、光出力が向上するとともに環境温度に対する輝度特性が向上する。
 また、P型クラッド層から活性層の1/3の厚さ分の位置までの領域の平均のP型ドーパントの濃度が3.0×1017atoms/cm以下となるようにし、かつ、活性層においてP型クラッド層側からN型クラッド層側へ漸減するP型ドーパントの濃度プロファイルとすることで、寿命特性の悪化を抑制することができる。
In this way, in the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. If manufactured in, the light output will be improved and the brightness characteristics with respect to the ambient temperature will be improved.
Further, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is set to 3.0 × 10 17 atoms / cm 3 or less, and the activity is increased. By setting the concentration profile of the P-type dopant that gradually decreases from the P-type clad layer side to the N-type clad layer side in the layer, deterioration of the life characteristics can be suppressed.
 このとき、前記発光部を、AlGaInP系の化合物半導体からなるものとすることができる。 At this time, the light emitting unit can be made of an AlGaInP-based compound semiconductor.
 本発明は、発光部がAlGaInP系の化合物半導体からなる発光素子を製造するのに特に好適に用いることができる。 The present invention can be particularly preferably used for manufacturing a light emitting device in which the light emitting unit is made of an AlGaInP-based compound semiconductor.
 また、前記活性層に前記P型ドーパントをドープするとき、
 前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置から2/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下となるようにドープすることができる。
When the active layer is doped with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. It can be doped so as to be × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
 このようにP型ドーパント濃度を上記領域で上記数値範囲のものとすれば、より確実に寿命特性の悪化を抑制できる。 If the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed more reliably.
 このとき、前記活性層に前記P型ドーパントをドープするとき、
 前記活性層において、前記P型クラッド層から前記活性層の2/3の厚さ分の位置からN型クラッド層までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以下となるようにドープすることができる。
At this time, when the active layer is doped with the P-type dopant,
In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10 16 atoms /. It can be doped so as to be cm 3 or less.
 このようにP型ドーパント濃度を上記領域で上記数値範囲のものとすれば、より一層確実に寿命特性の悪化を抑制することができる。 If the P-type dopant concentration is set within the above numerical range in the above region in this way, deterioration of the life characteristics can be suppressed even more reliably.
 また、前記活性層への前記P型ドーパントのドープを、
 前記活性層を形成しつつガスドープにより行うことができる。
 または、前記活性層への前記P型ドーパントのドープを、
 前記活性層を形成した後、前記P型ドーパントをドープした前記P型クラッド層を形成してから熱処理を施して、前記P型クラッド層にドープした前記P型ドーパントを前記活性層に拡散させることにより行うことができる。
In addition, the active layer is doped with the P-type dopant.
This can be done by gas doping while forming the active layer.
Alternatively, the active layer is doped with the P-type dopant.
After forming the active layer, the P-type clad layer doped with the P-type dopant is formed and then heat-treated to diffuse the P-type dopant doped in the P-type clad layer into the active layer. Can be done by.
 このようにガスドープまたは熱処理によるドープによって、上記各領域に上記の濃度プロファイルで簡便にドープすることができる。 By doping by gas doping or heat treatment in this way, each of the above regions can be easily doped with the above concentration profile.
 以上のように、本発明の発光素子および発光素子の製造方法であれば、光出力が向上するとともに環境温度に対する輝度特性が良好であり、かつ、寿命特性の悪化が抑制されたものとすることができる。 As described above, according to the light emitting element and the method for manufacturing the light emitting element of the present invention, it is assumed that the light output is improved, the brightness characteristic with respect to the ambient temperature is good, and the deterioration of the life characteristic is suppressed. Can be done.
本発明の発光素子の一例を示す概略図である。It is the schematic which shows an example of the light emitting element of this invention. 活性層中の平均のP型ドーパントの濃度を示す説明図である。It is explanatory drawing which shows the average concentration of P-type dopant in an active layer. 本発明の発光素子の他の一例を示す概略図である。It is the schematic which shows another example of the light emitting element of this invention. 従来の発光素子の一例を示す概略図である。It is the schematic which shows an example of the conventional light emitting element.
 上述したように、寿命特性及び環境温度に対する輝度特性の両方が良好な発光素子(特にはAlGaInP系LED)の開発が望まれていた。本発明者らはこのような課題に対し、鋭意検討を重ねたところ、少なくともN型クラッド層と活性層とP型クラッド層がこの順序で形成された発光部を有する発光素子において、環境温度に対する輝度特性を変える大きな要因は活性層領域におけるP型キャリアリッチの領域でのキャリアの挙動であるため、P型クラッド層寄りの活性層領域、具体的には、活性層全厚の1/3の厚さで、P型クラッド層寄りの領域をP型活性層領域とし、該P型活性層領域のP型ドーパントの濃度を1.0×1016atoms/cm以上3×1017atoms/cm以下とすること、更に活性層中に過剰に拡散することを防止するため、エピタキシャル成長時に、P型クラッド層側からN型クラッド層側に向かって活性層中にかけて漸減する濃度プロファイルとなるように活性層中にP型のドーパント不純物をドーピングすることで、環境温度に対する輝度特性と寿命特性の両方の特性が良好な発光素子を製造できることが判り、更に検討を加えて本発明を完成した。 As described above, it has been desired to develop a light emitting element (particularly an AlGaInP LED) having good life characteristics and brightness characteristics with respect to the environmental temperature. As a result of diligent studies on such issues, the present inventors have found that at least in a light emitting element having a light emitting portion in which an N-type clad layer, an active layer and a P-type clad layer are formed in this order, the ambient temperature Since the major factor that changes the brightness characteristics is the behavior of carriers in the P-type carrier-rich region in the active layer region, the active layer region near the P-type clad layer, specifically, 1/3 of the total thickness of the active layer. In terms of thickness, the region closer to the P-type clad layer is defined as the P-type active layer region, and the concentration of the P-type dopant in the P-type active layer region is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm. In order to reduce the concentration to 3 or less and to prevent excessive diffusion into the active layer, the concentration profile gradually decreases from the P-type clad layer side to the N-type clad layer side toward the active layer during epitaxial growth. It has been found that by doping the active layer with a P-type dopant impurity, it is possible to produce a light emitting device having good characteristics of both brightness characteristics and lifetime characteristics with respect to environmental temperature, and further studies have been carried out to complete the present invention.
 以下、本発明について、実施形態について図を参照しながら更に詳細に説明するが、本発明はこれに限定されるものではない。
 (第一実施形態)
 本発明の発光素子の第一実施形態を図1に示す。図1に示すように第一実施形態の発光素子110はGaAs出発基板100上に厚さ0.1~1.0μmのGaAsバッファ層、例えば厚さ1.0μmのAlInPエッチストップ層102、例えば厚さ1.0μmのN型AlGaInPクラッド層103、例えば厚さ0.9μmのAlGaInP活性層104、例えば厚さ1.0μmのP型AlGaInPクラッド層105、電流伝播層との格子不整を緩和するP型InGaP緩衝層106、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ5.0μmのP型GaP電流伝播層107を有する。
 GaAsバッファ層は特になくてもよい。なお、図1においては発光素子の電極等は省略されている。
Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.
(First Embodiment)
The first embodiment of the light emitting device of the present invention is shown in FIG. As shown in FIG. 1, the light emitting device 110 of the first embodiment has a GaAs buffer layer having a thickness of 0.1 to 1.0 μm, for example, an AlInP etch stop layer 102 having a thickness of 1.0 μm, for example, a thickness on the GaAs starting substrate 100. An N-type AlGaInP clad layer 103 having a thickness of 1.0 μm, for example, an AlGaInP active layer 104 having a thickness of 0.9 μm, for example, a P-type AlGaInP clad layer 105 having a thickness of 1.0 μm, and a P-type that alleviates lattice irregularities with a current propagation layer. The InGaP buffer layer 106 has, for example, a P-type GaP current propagation layer 107 having a thickness of 5.0 μm, which propagates and diffuses the current applied to the device and has a function of extracting light.
The GaAs buffer layer may not be particularly provided. In FIG. 1, the electrodes of the light emitting element and the like are omitted.
 ここでN型ドーパントとしてSi、S、Seのうち、1種類以上がN型クラッド層103にドーピングされ、P型ドーパントとしてはZn、Mg、Teのうち、1種類以上がP型クラッド層105及びP型緩衝層106及びにP型電流伝播層107にドーピングされる。 Here, one or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 103, and one or more of Zn, Mg, and Te as P-type dopants are the P-type clad layer 105 and The P-type buffer layer 106 and the P-type current propagation layer 107 are doped.
 N型クラッド層103は、1層以上の組成及びドーピング水準のエピタキシャル層で構成され、P型クラッド層105は、1層以上の組成及びドーピング水準のエピタキシャル層で構成される。 The N-type clad layer 103 is composed of one or more layers of epitaxial layers having a composition and a doping level, and the P-type clad layer 105 is composed of an epitaxial layer having one or more layers and a doping level.
 活性層104は均一組成のバルク型活性層から成る。
 活性層104にはP型クラッド層105からN型クラッド層103に向かって、例えばなだらかに又は階段状に、濃度が漸減するP型ドーパントがドープされている(傾斜ドープ)。以下にP型ドーパントとしてZnとMgの2種がドープされている例を示すが、本発明はこれに限定されず、例えばZnのみドープすることもできるし、3種以上ドープすることもできる。
 また、本発明が特に好適な例として、発光部(N型クラッド層、活性層、P型クラッド層)がAlGaInP系の化合物半導体からなるものを挙げて説明するが、これに限定されない。
The active layer 104 is composed of a bulk type active layer having a uniform composition.
The active layer 104 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 105 toward the N-type clad layer 103, for example, in a gentle or stepwise manner (gradient doping). The following shows an example in which two types of Zn and Mg are doped as P-type dopants, but the present invention is not limited to this, and for example, only Zn can be doped, or three or more types can be doped.
Further, as a particularly preferable example of the present invention, an example in which the light emitting portion (N-type clad layer, active layer, P-type clad layer) is made of an AlGaInP-based compound semiconductor will be described, but the present invention is not limited thereto.
 図2に活性層中の平均のP型ドーパントの濃度の説明図を示す。
 ここで、P型クラッド層105からN型クラッド層103へ向かう方向を活性層104の深さ方向と定義し、活性層104とP型クラッド層105との界面を深さ位置の基準とする。上記傾斜ドープの濃度プロファイルは、P型クラッド層105から深さ1/3の位置までの領域(すなわち、P型クラッド層105から活性層104の1/3の厚さ分の位置までの領域)の平均P型ドーパント濃度が1.0×1016atoms/cm以上3×1017atoms/cm以下となっている。具体的にはP型ドーパントとして、Znの平均濃度が例えば5×1016atoms/cm、Mgの平均濃度が例えば1×1016atoms/cmに設計される(平均濃度の合計値:6×1016atoms/cm)。
 なお、上記深さ1/3の位置までの領域において、ドープされているP型ドーパントの種類が1種であればその1種自体の平均濃度が上記濃度範囲に収まっていれば良く、また、2種以上であれば、各々の平均濃度を足した合計値が上記濃度範囲に収まっていれば良い。
FIG. 2 shows an explanatory diagram of the average concentration of P-type dopant in the active layer.
Here, the direction from the P-type clad layer 105 to the N-type clad layer 103 is defined as the depth direction of the active layer 104, and the interface between the active layer 104 and the P-type clad layer 105 is used as a reference for the depth position. The concentration profile of the gradient dope is a region from the P-type clad layer 105 to the position of 1/3 of the depth (that is, a region from the P-type clad layer 105 to the position of 1/3 of the thickness of the active layer 104). The average P-type dopant concentration in the above is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm 3 or less. Specifically, as the P-type dopant, the average concentration of Zn is designed to be, for example, 5 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 1 × 10 16 atoms / cm 3 (total average concentration: 6). × 10 16 atoms / cm 3 ).
If there is only one type of P-type dopant doped in the region up to the position of 1/3 of the depth, it is sufficient that the average concentration of the one type is within the above concentration range. If there are two or more types, the total value obtained by adding the average concentrations of each may be within the above concentration range.
 上記のようにP型ドーパントの傾斜ドープ、かつ、深さ1/3の位置までの領域の平均濃度が3.0×1017atoms/cm以下であれば、寿命特性の悪化の抑制が可能である。しかも、深さ1/3の位置までの領域の平均濃度が1.0×1016atoms/cm以上であるので、光出力を向上させることができるし、環境温度に対する輝度特性を向上させることができる。このように、活性層104においてP型ドーパントの濃度プロファイルが上記条件を満たしている場合、従来品では成し得なかった、環境温度に対する輝度特性の向上および寿命特性の悪化の抑制を両立することができる。 As described above, if the P-type dopant is gradient-doped and the average concentration of the region up to the depth of 1/3 is 3.0 × 10 17 atoms / cm 3 or less, deterioration of the lifetime characteristics can be suppressed. Is. Moreover, since the average density of the region up to the depth 1/3 position is 1.0 × 10 16 atoms / cm 3 or more, the light output can be improved and the luminance characteristic with respect to the ambient temperature can be improved. Can be done. As described above, when the concentration profile of the P-type dopant in the active layer 104 satisfies the above conditions, it is possible to achieve both improvement of luminance characteristics with respect to environmental temperature and suppression of deterioration of life characteristics, which could not be achieved by conventional products. Can be done.
 上記本発明の効果について調査した実験について以下に説明する。
(実験)
 [001]方向に15度傾斜したGaAs基板上に有機金属気相成長法(MOVPE)法にて、1.0μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなるエッチストップ層、1.0μm厚のN型クラッド層、0.9μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる活性層、(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる1.0μm厚のP型クラッド層、GaIn1-yP(0.0≦y≦1.0)から成る中間組成層(緩衝層)、0.5μm以上の厚さを有するGaP電流拡散層(電流伝播層)を順次積層した発光素子用ウェーハを形成した。さらに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。
The experiment investigated for the effect of the present invention will be described below.
(Experiment)
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers). Further, electrodes were formed, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
 なお、活性層は均一組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成る。
 また活性層にはP型クラッド層からN型クラッド層へ向かって濃度が漸減するようにP型ドーパントをドープした。この際、活性層のP型クラッド層から深さ1/3の位置までの領域の平均濃度を変えることにより、該領域の平均濃度が異なる複数の発光素子を製造した。
 そして、各発光素子において、0℃と60℃での相対光出力比、及び寿命特性について実験を行った。その結果を表1に示す。
The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having a uniform composition.
The active layer was doped with a P-type dopant so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. At this time, by changing the average concentration of the region from the P-type clad layer of the active layer to the position of 1/3 of the depth, a plurality of light emitting devices having different average concentrations in the region were manufactured.
Then, in each light emitting element, an experiment was conducted on the relative light output ratio at 0 ° C. and 60 ° C. and the life characteristics. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
 表1に示すように傾斜ドープした活性層において、P型クラッド層から深さ1/3の位置までの領域の平均濃度が1.0×1016atoms/cm以上であれば、相対光出力比が0.86以上であり、該比が1により一層近く、環境温度に対する出力の変化を少なくすることができることが判る。また、3.0×1017atoms/cm以下であれば寿命特性を81%以上とすることができ、その悪化を抑制できることが判る。
 これらの結果から、良好な環境温度に対する輝度特性および良好な寿命特性を両立するには、傾斜ドープの活性層の上記領域において1.0×1016atoms/cm以上3.0×1017atoms/cm以下の濃度範囲とする必要があることが分かる。
As shown in Table 1, if the average concentration of the region from the P-type clad layer to the position of 1/3 of the depth is 1.0 × 10 16 atoms / cm 3 or more in the gradient-doped active layer, the relative light output It can be seen that the ratio is 0.86 or more, the ratio is closer to 1, and the change in output with respect to the ambient temperature can be reduced. Further, it can be seen that if the life characteristic is 3.0 × 10 17 atoms / cm 3 or less, the life characteristic can be 81% or more, and its deterioration can be suppressed.
From these results, in order to achieve both brightness characteristics for good environmental temperature and good lifetime characteristics, 1.0 × 10 16 atoms / cm 3 or more and 3.0 × 10 17 atoms in the above region of the gradient-doped active layer. / cm 3 it can be seen that it is necessary to make the following concentration range.
 また、図1の第一実施形態において、更にP型クラッド層105から深さ1/3の位置から深さ2/3の位置の領域(すなわち、P型クラッド層105から活性層104の1/3の厚さ分の位置から2/3の厚さ分の位置までの領域)の平均P型ドーパント濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下であるものが好ましい。具体的にはZnの平均濃度が例えば2×1016atoms/cm、Mgの平均濃度が例えば0.5×1016atoms/cmに設計される(平均濃度の合計値:2.5×1016atoms/cm)。
 上記のような濃度範囲であれば、より確実に寿命特性の悪化を抑制できる。
Further, in the first embodiment of FIG. 1, a region from the P-type clad layer 105 to a depth of 1/3 to a depth of 2/3 (that is, from the P-type clad layer 105 to 1 / of the active layer 104). The average P-type dopant concentration in the region from the position of 3 thickness to the position of 2/3 thickness) is 0.3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less. Is preferable. Specifically, the average concentration of Zn is designed to be, for example, 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 0.5 × 10 16 atoms / cm 3 (total average concentration: 2.5 ×). 10 16 averages / cm 3 ).
Within the concentration range as described above, deterioration of life characteristics can be suppressed more reliably.
 また更に、P型クラッド層105から深さ2/3の位置からN型クラッド層103の側の領域(すなわち、P型クラッド層105から活性層104の2/3の厚さ分の位置からN型クラッド層103までの領域)の平均P型ドーパント濃度(具体的には、ZnとMgの平均濃度の合計値)が0.3×1016atoms/cm以下のものであるものが好ましい。なお下限値は特に限定されないが、例えば0atoms/cm以上とすることができる。
 上記のような濃度範囲であれば、より一層確実に寿命特性の悪化を抑制できる。
Furthermore, from the position of 2/3 of the depth from the P-type clad layer 105 to the region on the side of the N-type clad layer 103 (that is, from the position of 2/3 of the thickness of the P-type clad layer 105 to the active layer 104, N It is preferable that the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) of the region up to the mold clad layer 103 is 0.3 × 10 16 atoms / cm 3 . The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
Within the concentration range as described above, deterioration of life characteristics can be suppressed even more reliably.
(第二実施形態)
 本発明の発光素子の第二実施形態を図3に示す。図3に示すように第二実施形態の発光素子210は、GaAs出発基板200上に例えば厚さ0.5μmのGaAsバッファ層、例えば厚さ1.0μmのAlInPエッチストップ層202、例えば厚さ1.0μmのN型AlGaInPクラッド層203、例えば厚さ0.48μmのAlGaInP活性層204、例えば厚さ1.0μmのP型AlGaInPクラッド層205、電流伝播層との格子不整を緩和するP型InGaP緩衝層206、素子に印加された電流を伝播かつ拡散し、光取り出しの機能を有する例えば厚さ5.0μmP型GaP電流伝播層207を有する。
 GaAsバッファ層は特になくてもよい。なお、図3においては発光素子の電極等は省略されている。
(Second Embodiment)
A second embodiment of the light emitting device of the present invention is shown in FIG. As shown in FIG. 3, the light emitting element 210 of the second embodiment has a GaAs buffer layer having a thickness of 0.5 μm, for example, an AlInP etch stop layer 202 having a thickness of 1.0 μm, for example, a thickness of 1 on the GaAs starting substrate 200. 0.0 μm N-type AlGaInP clad layer 203, for example 0.48 μm thick AlGaInP active layer 204, for example 1.0 μm thick P-type AlGaInP clad layer 205, P-type InGaP buffer that alleviates lattice irregularities with the current propagation layer The layer 206 has, for example, a 5.0 μm P-type GaP current propagation layer 207 having a function of propagating and diffusing the current applied to the element and extracting light.
The GaAs buffer layer may not be particularly provided. In FIG. 3, the electrodes of the light emitting element and the like are omitted.
 N型ドーパントとしてSi、S、Seのうち、1種類以上がN型クラッド層203にドーピングされ、P型ドーパントとしてはZn、Mg、Teのうち、1種類以上がP型クラッド層205及びP型緩衝層206及びにP型電流伝播層207にドーピングされる。 One or more of Si, S, and Se as N-type dopants are doped into the N-type clad layer 203, and one or more of Zn, Mg, and Te as P-type dopants are P-type clad layer 205 and P-type. The buffer layer 206 and the P-type current propagation layer 207 are doped.
 N型クラッド層203は、1層以上の組成及びドーピング水準のエピタキシャル層で構成され、P型クラッド層205は、1層以上の組成及びドーピング水準のエピタキシャル層で構成される。 The N-type clad layer 203 is composed of one or more layers of epitaxial layers having a composition and a doping level, and the P-type clad layer 205 is composed of an epitaxial layer having one or more layers and a doping level.
 第二実施形態の発光素子210では、活性層204はAlGaInPからなる発光再結合層と発光再結合層の組成よりも大きなバンドギャップ組成を有する障壁層とが多重接合した多重接合型活性層から成る。障壁層は発光再結合層のAlGaInPより高いAl組成を有する。また、障壁層の厚さは波動関数が重なるドブロイ波長より薄い厚さに設定しても良いし、厚い厚さに設定しても良い。例えば発光再結合層の厚さを8nm、障壁層の厚さを8nmとし、30ペアの活性層構造とすることができる。 In the light emitting device 210 of the second embodiment, the active layer 204 is composed of a multi-bonded active layer in which a light-emitting recombination layer made of AlGaInP and a barrier layer having a bandgap composition larger than that of the light-emitting recombination layer are multi-bonded. .. The barrier layer has a higher Al composition than the AlGaInP of the luminescent recombination layer. Further, the thickness of the barrier layer may be set to be thinner than the de Broglie wavelength at which the wave functions overlap, or may be set to a thicker thickness. For example, the thickness of the luminescent recombination layer is 8 nm, the thickness of the barrier layer is 8 nm, and a 30-pair active layer structure can be formed.
 活性層204にはP型クラッド層205からN型クラッド層203に向かって、例えばなだらかに又は階段状に、濃度が漸減するP型ドーパントがドープされている(傾斜ドープ)。以下にP型ドーパントとしてZnとMgの2種がドープされている例を示すが、第一実施形態と同様、これに限定されない。 The active layer 204 is doped with a P-type dopant whose concentration gradually decreases from the P-type clad layer 205 to the N-type clad layer 203, for example, in a gentle or stepwise manner (gradient doping). An example in which two types of Zn and Mg are doped as the P-type dopant is shown below, but the present invention is not limited to this as in the first embodiment.
 上記傾斜ドープの濃度プロファイルは、P型クラッド層205から深さ1/3の位置までの領域の平均P型ドーパント濃度が1.0×1016atoms/cm以上3×1017atoms/cm以下となっている。具体的にはP型ドーパントとして、Znの平均濃度が例えば5×1016atoms/cm、Mgの平均濃度が例えば1×1016atoms/cmに設計される(平均濃度の合計値:6×1016atoms/cm)。
 このようなものであれば、良好な環境温度に対する輝度特性および良好な寿命特性を両立可能である。
The concentration profile of the gradient dope shows that the average P-type dopant concentration in the region from the P-type clad layer 205 to the position of 1/3 depth is 1.0 × 10 16 atoms / cm 3 or more and 3 × 10 17 atoms / cm 3 It is as follows. Specifically, as the P-type dopant, the average concentration of Zn is designed to be, for example, 5 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 1 × 10 16 atoms / cm 3 (total average concentration: 6). × 10 16 atoms / cm 3 ).
If it is such a thing, it is possible to achieve both brightness characteristics with respect to good environmental temperature and good life characteristics.
 また、P型クラッド層205から深さ1/3の位置から深さ2/3の位置の領域の平均P型ドーパント濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下であるものが好ましい。具体的にはZnの平均濃度が例えば2×1016atoms/cm、Mgの平均濃度が例えば0.5×1016atoms/cmに設計される(平均濃度の合計値:2.5×1016atoms/cm)。
 また更に、P型クラッド層205から深さ2/3の位置からN型クラッド層203の側の領域の平均P型ドーパント濃度(具体的には、ZnとMgの平均濃度の合計値)が0.3×1016atoms/cm以下のものであるものが好ましい。なお下限値は特に限定されないが、例えば0atoms/cm以上とすることができる。
 上記の各領域がこれらの濃度範囲であれば、より一層確実に寿命特性の悪化を抑制できる。
In addition, the average P-type dopant concentration in the region from the P-type clad layer 205 at a depth of 1/3 to a depth of 2/3 is 0.3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms. It is preferably 1 / cm 3 or less. Specifically, the average concentration of Zn is designed to be, for example, 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is designed to be, for example, 0.5 × 10 16 atoms / cm 3 (total average concentration: 2.5 ×). 10 16 averages / cm 3 ).
Furthermore, the average P-type dopant concentration (specifically, the total value of the average concentrations of Zn and Mg) in the region on the side of the N-type clad layer 203 from the position 2/3 of the depth from the P-type clad layer 205 is 0. .3 × 10 16 atoms / cm 3 or less is preferable. The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
If each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.
 次に、本発明の発光素子の製造方法について説明する。なお、ここでは例として図1の発光素子110を製造する場合について説明する。また、活性層へのドープ方法としてガスドープによる方法(第一の製造方法)と熱処理によるドープ方法(第二の製造方法)を例に挙げて説明するが、活性層へのドープ方法はこれらに限定されるものではない。
(第一の製造方法)
 まず、活性層へのドープをガスドープにより行う例について説明する。
 成長用基板としてGaAs出発基板100を用意し、洗浄した後、MOVPE(Metal Organic Vapor Phase Epitaxy)炉に入れ、GaAs出発基板100上に、AlInPエッチストップ層102、N型AlGaInPクラッド層103、AlGaInP活性層104、P型AlGaInPクラッド層105、P型InGaP緩衝層106をエピタキシャル成長させる。
Next, a method for manufacturing the light emitting device of the present invention will be described. Here, a case where the light emitting element 110 of FIG. 1 is manufactured will be described as an example. Further, as the doping method for the active layer, a gas doping method (first production method) and a heat treatment doping method (second production method) will be described as examples, but the doping method for the active layer is limited to these. It is not something that is done.
(First manufacturing method)
First, an example in which the active layer is doped by gas doping will be described.
A GaAs starting substrate 100 is prepared as a growth substrate, washed, and then placed in a MOVPE (MetalOrganic Vapor Phase Epitaxy) furnace. On the GaAs starting substrate 100, the AlInP etch stop layer 102, the N-type AlGaInP clad layer 103, and the AlGaInP activity The layer 104, the P-type AlGaInP clad layer 105, and the P-type InGaP buffer layer 106 are epitaxially grown.
 なお、上記各層のエピタキシャル成長は、公知のMOVPE法により行なうことができる。Al、Ga、In、Pの各成分源となる原料ガスとしては、これらに限定されるわけではないが、例えば以下のようなものを使用できる。
・Al源ガス:トリメチルアルミニウム(TMAl)、トリエチルアルミニウム(TEAl)など。
・Ga源ガス:トリメチルガリウム(TMGa)、トリエチルガリウム(TEGa)など。
・In源ガス:トリメチルインジウム(TMIn)、トリエチルインジウム(TEIn)など。
・P源ガス:トリメチルリン(TMP)、トリエチルリン(TEP)、ホスフィン(PH3)など。
The epitaxial growth of each of the above layers can be carried out by a known MOVPE method. The raw material gas that is the source of each component of Al, Ga, In, and P is not limited to these, and for example, the following can be used.
-Al source gas: trimethylaluminum (TMAl), triethylaluminum (TEAl), etc.
-Ga source gas: trimethylgallium (TMGa), triethylgallium (TEGa), etc.
-In source gas: trimethylindium (TMIn), triethylindium (TEIn), etc.
-P source gas: trimethyl phosphorus (TMP), triethyl phosphorus (TEP), phosphine (PH3), etc.
 また、各層へのドーパントのドープとしてはガスドープにより行うことができる。活性層などの各層をエピタキシャル成長しつつガスドープすることができる。ドーパントガスとしては、例えば以下のようなものを使用できる。
(P型ドーパント)
・Zn源:ジメチル亜鉛(DMZn)、ジエチル亜鉛(DEZn)など。
・Mg源:ビズ(シクロペンタジエニル)マグネシウム(CpMg)など。
・Te源:ジメチルテルル(DMTe)、ジエチルテルル(DETe)など
(N型ドーパント)
・Si源:モノシランなどのシリコン水素化物など。
・S源:硫化水素(HS)など。
・Se源:セレン化水素など。
Further, the dopant is doped into each layer by gas doping. Each layer such as the active layer can be gas-doped while epitaxially growing. As the dopant gas, for example, the following can be used.
(P-type dopant)
-Zn source: Dimethylzinc (DMZn), diethylzinc (DEZn), etc.
-Mg source: Biz (cyclopentadienyl) magnesium (Cp 2 Mg), etc.
-Te source: Dimethyl telluride (DMTe), diethyl tellurium (DETe), etc. (N-type dopant)
-Si source: Silicon hydride such as monosilane.
-S source: hydrogen sulfide (H 2 S), etc.
-Se source: hydrogen selenide, etc.
 なお、このガスドープの際、活性層104中のP型ドーパントに関して、図2に示すような傾斜ドープの濃度プロファイルとする。すなわち、活性層104において、P型クラッド層105の側からN型クラッド層103の側へP型ドーパントの濃度が漸減するように傾斜ドープする。かつ、P型クラッド層105から深さ1/3の位置までの領域の平均P型ドーパント濃度が1.0×1016atoms/cm以上3.0×1017atoms/cm以下となるようにドープする。
 例えばマスフローコントローラー等によりドーパントガスの流量を制御することにより、簡便に、上記のような濃度プロファイルでガスドープすることが可能である。
 エピタキシャル成長中の熱効果により、多少、意図した濃度プロファイルよりも熱平衡側にずれた濃度プロファイルとなり易い。この点に関しては、そのずれを考慮した上で流量等を適宜調整してガスドープし、意図した濃度プロファイルとなるようにすると良い。
 そして、活性層においてP型ドーパントがこのような濃度プロファイルであれば、前述したように、環境温度に対する輝度特性の向上および寿命特性の悪化の抑制の両立を図ることができる。
At the time of this gas doping, the concentration profile of the gradient doping as shown in FIG. 2 is used for the P-type dopant in the active layer 104. That is, in the active layer 104, gradient doping is performed from the side of the P-type clad layer 105 to the side of the N-type clad layer 103 so that the concentration of the P-type dopant gradually decreases. Moreover, the average P-type dopant concentration in the region from the P-type clad layer 105 to the position of 1/3 of the depth is 1.0 × 10 16 atoms / cm 3 or more and 3.0 × 10 17 atoms / cm 3 or less. Dope to.
For example, by controlling the flow rate of the dopant gas with a mass flow controller or the like, it is possible to easily perform gas doping with the above concentration profile.
Due to the thermal effect during epitaxial growth, the concentration profile tends to be slightly shifted to the thermal equilibrium side from the intended concentration profile. Regarding this point, it is advisable to appropriately adjust the flow rate and the like in consideration of the deviation and perform gas doping to obtain the intended concentration profile.
If the P-type dopant has such a concentration profile in the active layer, as described above, it is possible to achieve both improvement of the luminance characteristic with respect to the ambient temperature and suppression of deterioration of the lifetime characteristic.
 また、活性層104にP型ドーパントをドープするとき、活性層104において、P型クラッド層105から深さ1/3の位置から深さ2/3の位置の領域の平均P型ドーパント濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下となるようにドープするのが好ましい。
 更には、活性層104において、P型クラッド層105から深さ2/3の位置からN型クラッド層103の側の領域の平均P型ドーパント濃度が0.3×1016atoms/cm以下となるようにドープするのが好ましい。なお下限値は特に限定されないが、例えば0atoms/cm以上とすることができる。
 上記の各領域がこれらの濃度範囲であれば、より一層確実に寿命特性の悪化を抑制することができる。
Further, when the active layer 104 is doped with a P-type dopant, the average P-type dopant concentration in the region from the P-type clad layer 105 at a depth of 1/3 to a depth of 2/3 is 0 in the active layer 104. It is preferable to dope so that the content is 3 × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
Furthermore, in the active layer 104, the average P-type dopant concentration in the region on the side of the N-type clad layer 103 from the position 2/3 of the depth from the P-type clad layer 105 is 0.3 × 10 16 atoms / cm 3 or less. It is preferable to dope so as to be. The lower limit is not particularly limited, but may be, for example, 0 atoms / cm 3 or more.
When each of the above regions is within these concentration ranges, deterioration of life characteristics can be suppressed even more reliably.
 この後、P型GaP電流伝播層107をHVPE法(ハイドライド気相成長法:Hydride Vapor Phase Epitaxy法)で気相成長する。
 HVPE法は、具体的には、例えば金属Gaを所定の温度に加熱保持しながら、その金属Ga上に塩化水素を導入することにより、下記(1)式の反応によりGaClを生成させ、キャリアガスであるHガスとともに基板上に供給する。
Ga(液体)+HCl(気体)→GaCl(気体)+1/2H(気体)…(1)
 成長温度は例えば640℃以上860℃以下に設定することができる。また、V族元素であるPは、例えばPHをキャリアガスであるHと共に基板上に供給する。さらに、P型ドーパントとして例えばZnを、ジメチル亜鉛(DMZn)の形で供給して、下記(2)式のような反応によって電流伝播層107を形成することができる。
GaCl(気体)+PH(気体)
 →GaP(固体)+HCl(気体)+H(気体)…(2)
After that, the P-type GaP current propagation layer 107 is vapor-deposited by the HVPE method (Hydride Vapor Phase Epitaxy method).
Specifically, in the HVPE method, for example, by introducing hydrogen chloride onto the metal Ga while heating and holding the metal Ga at a predetermined temperature, GaCl is generated by the reaction of the following formula (1) to generate a carrier gas. It is supplied on the substrate together with the H 2 gas.
Ga (liquid) + HCl (gas) → GaCl (gas) + 1 / 2H 2 (gas) ... (1)
The growth temperature can be set to, for example, 640 ° C. or higher and 860 ° C. or lower. Further, P, which is a Group V element, supplies, for example, PH 3 on the substrate together with H 2 which is a carrier gas. Further, for example, Zn can be supplied as a P-type dopant in the form of dimethylzinc (DMZn) to form the current propagation layer 107 by a reaction as shown in the following equation (2).
GaCl (gas) + PH 3 (gas)
→ GaP (solid) + HCl (gas) + H 2 (gas) ... (2)
(第二の製造方法:熱処理によるドープ)
 次に、活性層へのドープを熱処理により行う例について説明する。
 基本的に第一の製造方法と同様にして、出発基板100の準備から緩衝層106の形成を行う。ただし、P型クラッド層105から活性層104へP型ドーパントを熱処理により拡散してドープすることを考慮して、活性層104のエピタキシャル成長時はノンドープとする。また、P型クラッド層105においては第一の製造方法の場合よりも高濃度でP型ドーパントをドープしておくと良い。
(Second manufacturing method: doping by heat treatment)
Next, an example in which the active layer is doped by heat treatment will be described.
Basically, the buffer layer 106 is formed from the preparation of the starting substrate 100 in the same manner as in the first manufacturing method. However, in consideration of diffusing and doping the P-type dopant from the P-type clad layer 105 to the active layer 104 by heat treatment, the active layer 104 is not doped during epitaxial growth. Further, it is preferable that the P-type cladding layer 105 is doped with the P-type dopant at a higher concentration than in the case of the first production method.
 より具体的には、P型クラッド層105のP型ドーパント濃度は、例えばZn、MgをP型ドーパントとした場合、Znの濃度を1.0×1016~3.0×1018atoms/cm、Mgの濃度を1.0×1016~5.0×1017atoms/cmの濃度範囲とすることができる。このような濃度範囲であれば、より確実に、次の工程である熱処理工程で図2に示すような傾斜ドープの濃度プロファイルとすることができる。 More specifically, the P-type dopant concentration of the P-type clad layer 105 is such that, when Zn and Mg are P-type dopants, the Zn concentration is 1.0 × 10 16 to 3.0 × 10 18 atoms / cm. 3. The concentration of Mg can be in the concentration range of 1.0 × 10 16 to 5.0 × 10 17 atoms / cm 3 . Within such a concentration range, the gradient dope concentration profile as shown in FIG. 2 can be more reliably obtained in the heat treatment step, which is the next step.
 上記のように少なくともP型クラッド層105までの各層を形成後(この例ではさらに緩衝層106まで形成済み)、MOVPE炉内で、例えばPH雰囲気下、700℃以上、3時間以上の熱処理を施す。ここでは700℃(エピタキシャル成長時と同程度の温度)で8時間の熱処理とする。このような熱処理によって、簡便に、図2に示すような傾斜ドープの濃度プロファイルとすることができる。熱処理を施すことでP型クラッド層105からドーパントが拡散式に従って活性層104内に拡散し、N型クラッド層103へ向かって漸減する濃度プロファイルを形成する。 After forming each layer up to at least the P-type clad layer 105 as described above (in this example, the buffer layer 106 has already been formed), heat treatment is performed in a MOVPE furnace, for example, in a PH 3 atmosphere at 700 ° C. or higher for 3 hours or longer. Give. Here, the heat treatment is performed at 700 ° C. (a temperature similar to that at the time of epitaxial growth) for 8 hours. By such a heat treatment, the concentration profile of the gradient dope as shown in FIG. 2 can be easily obtained. By applying the heat treatment, the dopant is diffused from the P-type clad layer 105 into the active layer 104 according to the diffusion formula, and forms a concentration profile that gradually decreases toward the N-type clad layer 103.
 なお、熱処理の温度、時間は特に限定されず、所望の傾斜ドープの濃度プロファイルが得られるよう適宜決定することができる。また上記のようにPH雰囲気で行えば、エピタキシャル層表面からのP(燐)の脱離を効果的に回避することができるので好ましい。 The temperature and time of the heat treatment are not particularly limited, and can be appropriately determined so as to obtain a desired gradient dope concentration profile. Further, it is preferable to carry out in a PH 3 atmosphere as described above because desorption of P (phosphorus) from the surface of the epitaxial layer can be effectively avoided.
 その後、第一の製造方法と同様にして、電流伝播層107をHVPE法で形成する。
 なお、上記例では緩衝層106を形成後に熱処理したが、そのタイミングで熱処理を行うのではなく、代わりに電流伝播層107を形成後に熱処理(HVPE炉でPH雰囲気下、700℃以上、3時間以上、特には、700℃で8時間)を施して、活性層104において傾斜ドープの濃度プロファイルを形成することもできる。
Then, the current propagation layer 107 is formed by the HVPE method in the same manner as in the first manufacturing method.
In the above example, the buffer layer 106 was formed and then heat-treated, but instead of being heat-treated at that timing, the current propagation layer 107 was formed and then heat-treated (in an HVPE furnace under a PH 3 atmosphere, at 700 ° C. or higher for 3 hours). As described above, in particular, the concentration profile of the gradient dope can be formed in the active layer 104 by subjecting the active layer 104 at 700 ° C. for 8 hours).
 以下、本発明の実施例及び比較例を示して本発明をより具体的に説明するが、本発明はこれらに限定されるものではない。
(実施例1)
 以下のようにして本発明の製造方法により本発明の発光素子を製造した。
 [001]方向に15度傾斜したGaAs基板上に有機金属気相成長法(MOVPE)法にて、1.0μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなるエッチストップ層、1.0μm厚のN型クラッド層、0.9μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる活性層、(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる1.0μm厚のP型クラッド層、GaIn1-yP(0.0≦y≦1.0)から成る中間組成層(緩衝層)、0.5μm以上の厚さを有するGaP電流拡散層(電流伝播層)を順次積層した発光素子用ウェーハを形成した。
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited thereto.
(Example 1)
The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
 活性層は均一組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成る。
 活性層にはP型クラッド層からN型クラッド層へ向かって濃度が漸減するようにP型ドーパント(ZnおよびMgの2種)をドープした。具体的には、活性層を形成しつつ、DEZn、CpMgを流してガスドープした。
 濃度プロファイルは、P型クラッド層との界面において、P型ドーパントとしてのZnの濃度が5×1016atoms/cm、P型ドーパントとしてのMgの濃度が1×1016atoms/cmであった。
 そして、P型クラッド層から深さ0.3μmの位置(活性層全厚0.9μmの1/3)までの領域のZn平均濃度が2×1016atoms/cm、Mg平均濃度が0.5×1016atoms/cmであった(平均濃度の合計値:2.5×1016atoms/cm)。
 また、深さ0.3μmの位置から深さ0.6μmの位置(全厚0.9μmの1/3から2/3)までの領域におけるZn平均濃度が0.5×1016atoms/cm、Mg平均濃度が0.2×1016atoms/cmであった(平均濃度の合計値:0.7×1016atoms/cm)。
 それ以降の深さ(深さ2/3の位置からN型クラッド層まで)のMg及びZnの各々の平均濃度の合計値は0.3×1016atoms/cm以下であった。
 このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。
The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having a uniform composition.
The active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. Specifically, while forming an active layer, DEZn and Cp 2 Mg were flowed and gas-doped.
The concentration profile is that the concentration of Zn as a P-type dopant is 5 × 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 × 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was.
Then, the Zn average concentration in the region from the P-type clad layer to the position of 0.3 μm in depth (1/3 of the total thickness of the active layer of 0.9 μm) is 2 × 10 16 atoms / cm 3 , and the Mg average concentration is 0. It was 5 × 10 16 atoms / cm 3 (total average concentration: 2.5 × 10 16 atoms / cm 3 ).
In addition, the average Zn concentration in the region from the position of 0.3 μm in depth to the position of 0.6 μm in depth (1/3 to 2/3 of the total thickness of 0.9 μm) is 0.5 × 10 16 atoms / cm 3 , Mg average concentration was 0.2 × 10 16 atoms / cm 3 (total value of average concentration: 0.7 × 10 16 atoms / cm 3 ).
The total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
(実施例2)
 以下のようにして本発明の製造方法により本発明の発光素子を製造した。
 [001]方向に15度傾斜したGaAs基板上に有機金属気相成長法(MOVPE)法にて、1.0μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなるエッチストップ層、1.0μm厚のN型クラッド層、0.48μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる活性層、(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる1.0μm厚のP型クラッド層、GaIn1-yP(0.0≦y≦1.0)から成る中間組成層(緩衝層)、0.5μm以上の厚さを有するGaP電流拡散層(電流伝播層)を順次積層した発光素子用ウェーハを形成した。
(Example 2)
The light emitting device of the present invention was manufactured by the manufacturing method of the present invention as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), an N-type clad layer with a thickness of 1.0 μm, and a (Al x Ga 1-x ) y In 1-y P (0 ≦) with a thickness of 0.48 μm. An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
 活性層は第一組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成る発光再結合層と、第二組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成る障壁層が交互に積層された多重障壁型活性層から構成される。
 第一組成のAl比率は第二組成のAl比率より少ない比率に設定した。
The active layer consists of a luminescent recombination layer composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) layer having the first composition, and a second composition. (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) It is composed of multiple barrier type active layers in which barrier layers are alternately laminated. Will be done.
The Al ratio of the first composition was set to be smaller than the Al ratio of the second composition.
 活性層にはP型クラッド層からN型クラッド層へ向かって濃度が漸減するようにP型ドーパント(ZnおよびMgの2種)をドープした。具体的には、活性層を形成しつつ、DEZn、CpMgを流してガスドープした。
 濃度プロファイルは、P型クラッド層との界面において、P型ドーパントとしてのZnの濃度が5×1016atoms/cm、P型ドーパントとしてのMgの濃度が1×1016atoms/cmであった。
 そして、P型クラッド層から深さ0.16μmの位置(活性層全厚0.48μmの1/3)までの領域のZnの平均濃度が2×1016atoms/cm、Mg平均濃度が0.5×1016atoms/cmであった(平均濃度の合計値:2.5×1016atoms/cm)。
 また、深さ0.16μmの位置から深さ0.32μmの位置(全厚0.48μmの1/3から2/3)までの領域におけるZn平均濃度が0.5×1016atoms/cm、Mg平均濃度が0.2×1016atoms/cmであった(平均濃度の合計値:0.7×1016atoms/cm)。
 それ以降の深さ(深さ2/3の位置からN型クラッド層まで)のMg及びZnの各々の平均濃度の合計値は0.3×1016atoms/cm以下であった。
 このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。
The active layer was doped with a P-type dopant (two types of Zn and Mg) so that the concentration gradually decreased from the P-type clad layer to the N-type clad layer. Specifically, while forming an active layer, DEZn and Cp 2 Mg were flowed and gas-doped.
The concentration profile is that the concentration of Zn as a P-type dopant is 5 × 10 16 atoms / cm 3 and the concentration of Mg as a P-type dopant is 1 × 10 16 atoms / cm 3 at the interface with the P-type clad layer. It was.
Then, the average concentration of Zn in the region from the P-type clad layer to the position of 0.16 μm in depth (1/3 of the total thickness of the active layer of 0.48 μm) is 2 × 10 16 atoms / cm 3 , and the average concentration of Mg is 0. It was .5 × 10 16 atoms / cm 3 (total average concentration: 2.5 × 10 16 atoms / cm 3 ).
Further, the average Zn concentration in the region from the position of 0.16 μm in depth to the position of 0.32 μm in depth (1/3 to 2/3 of the total thickness of 0.48 μm) is 0.5 × 10 16 atoms / cm 3 , Mg average concentration was 0.2 × 10 16 atoms / cm 3 (total value of average concentration: 0.7 × 10 16 atoms / cm 3 ).
The total average concentration of each of Mg and Zn at the subsequent depths (from the position of 2/3 depth to the N-type clad layer) was 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
(比較例1)
 以下のようにして発光素子を製造した。
 [001]方向に15度傾斜したGaAs基板上に有機金属気相成長法(MOVPE)法にて、1.0μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなるエッチストップ層、1.0μm厚のN型クラッド層、0.9μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる活性層、(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる1.0μm厚のP型クラッド層、GaIn1-yP(0.0≦y≦1.0)から成る中間組成層(緩衝層)、0.5μm以上の厚さを有するGaP電流拡散層(電流伝播層)を順次積層した発光素子用ウェーハを形成した。
(Comparative Example 1)
A light emitting device was manufactured as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
 活性層は均一組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成り、かつ、ガスドープ(DEZn、CpMg使用)により活性層のMg及びZnの各々の濃度の合計値は0.3×1016atoms/cm以下とした。
 このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。
The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg). The total concentration of Mg and Zn in the active layer was set to 0.3 × 10 16 atoms / cm 3 or less.
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
(比較例2)
 以下のようにして発光素子を製造した。
 [001]方向に15度傾斜したGaAs基板上に有機金属気相成長法(MOVPE)法にて、1.0μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなるエッチストップ層、1.0μm厚のN型クラッド層、0.9μm厚の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる活性層、(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)からなる1.0μm厚のP型クラッド層、GaIn1-yP(0.0≦y≦1.0)から成る中間組成層(緩衝層)、0.5μm以上の厚さを有するGaP電流拡散層(電流伝播層)を順次積層した発光素子用ウェーハを形成した。
(Comparative Example 2)
A light emitting device was manufactured as follows.
(Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦) with a thickness of 1.0 μm by the organic metal vapor phase growth method (MOVPE) method on a GaAs substrate inclined by 15 degrees in the [001] direction. An etch stop layer consisting of 1,0.4 ≦ y ≦ 0.6), a 1.0 μm thick N-type clad layer, and a 0.9 μm thick (Al x Ga 1-x ) y In 1-y P (0 ≦). An active layer consisting of x ≦ 1,0.4 ≦ y ≦ 0.6), (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) 1.0μm thick P-type clad layer made of, Ga y in 1-y P (0.0 ≦ y ≦ 1.0) consisting of the intermediate composition layer (buffer layer), GaP having the above 0.5μm thick A wafer for a light emitting element was formed by sequentially stacking current diffusion layers (current propagation layers).
 活性層は均一組成の(AlGa1-xIn1-yP(0≦x≦1,0.4≦y≦0.6)層から成り、また、ガスドープ(DEZn、CpMg使用)により活性層のZnの濃度を5×1016atoms/cm、Mgの濃度を1×1016atoms/cmで一定とした(濃度の合計値:6×1016atoms/cm)。
 このようにして製造したウェーハに電極を形成しダイシングを行い、ワイヤーボンディングを行って発光素子を製造した。
The active layer is composed of a (Al x Ga 1-x ) y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) layer having a uniform composition, and is gas-doped (DEZn, Cp 2 Mg). (Use) made the Zn concentration of the active layer constant at 5 × 10 16 atoms / cm 3 and the Mg concentration at 1 × 10 16 atoms / cm 3 (total concentration: 6 × 10 16 atoms / cm 3 ). ..
Electrodes were formed on the wafer manufactured in this manner, dicing was performed, and wire bonding was performed to manufacture a light emitting device.
 表2に実施例1、実施例2、比較例1、比較例2の発光素子について環境温度の違い(0℃vs60℃)による光出力比及び寿命特性を示す。
 表2に示すように実施例1、2に関しては、環境温度の違いによる光出力比が0.86以上であり、かつ、寿命特性は87であり、これらの両方が良好な値であった。
 一方、比較例1は活性層にドーパントがほとんど存在しないため、寿命特性は良好であるが、環境温度の違いによる光出力比は0.8となり、環境温度による輝度の変化が大きかった。また、比較例2は環境温度の違いによる光出力比は良好であったが、活性層のドーパントを漸減させず一定としたことにより、寿命特性が60%であり悪化してしまった。
Table 2 shows the light output ratio and the life characteristics of the light emitting elements of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 due to the difference in environmental temperature (0 ° C vs. 60 ° C).
As shown in Table 2, in Examples 1 and 2, the light output ratio due to the difference in environmental temperature was 0.86 or more, and the life characteristic was 87, both of which were good values.
On the other hand, in Comparative Example 1, since there was almost no dopant in the active layer, the lifetime characteristics were good, but the light output ratio was 0.8 due to the difference in the environmental temperature, and the change in brightness due to the environmental temperature was large. Further, in Comparative Example 2, the light output ratio was good due to the difference in the environmental temperature, but the lifetime characteristic was 60%, which was deteriorated by keeping the dopant of the active layer constant without gradually reducing it.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
 また、ガスドープによる実施例1、2とは別に、少なくともP型クラッド層までの各層を形成後、熱処理を施してP型ドーパントをP型クラッド層から活性層に拡散させることで、実施例1、2と同等の傾斜ドープの濃度プロファイルを有し、かつ、同等の光出力比及び寿命特性を有する発光素子を製造できることを本発明者らは確認している。 Further, apart from Examples 1 and 2 by gas doping, each layer up to at least the P-type clad layer is formed, and then heat treatment is performed to diffuse the P-type dopant from the P-type clad layer to the active layer. The present inventors have confirmed that a light emitting device having the same gradient doping concentration profile as No. 2 and having the same light output ratio and lifetime characteristics can be manufactured.
 なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。 The present invention is not limited to the above embodiment. The above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. It is included in the technical scope of the invention.

Claims (10)

  1.  N型クラッド層と活性層とP型クラッド層がこの順序で形成された発光部を有する発光素子であって、
     前記活性層は、前記P型クラッド層側から前記N型クラッド層側へ濃度が漸減するP型ドーパントを含み、
     前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が1.0×1016atoms/cm以上3.0×1017atoms/cm以下であることを特徴とする発光素子。
    A light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
    The active layer contains a P-type dopant whose concentration gradually decreases from the P-type clad layer side to the N-type clad layer side.
    2. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. A light emitting element having a concentration of 0 × 10 17 atoms / cm 3 or less.
  2.  前記発光部は、AlGaInP系の化合物半導体からなることを特徴とする請求項1に記載の発光素子。 The light emitting device according to claim 1, wherein the light emitting unit is made of an AlGaInP-based compound semiconductor.
  3.  前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置から2/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下であることを特徴とする請求項1または請求項2に記載の発光素子。 In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. The light emitting element according to claim 1 or 2, wherein the light emitting element is x10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
  4.  前記活性層において、前記P型クラッド層から前記活性層の2/3の厚さ分の位置からN型クラッド層までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以下であることを特徴とする請求項3に記載の発光素子。 In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the active layer to the N-type clad layer is 0.3 × 10 16 atoms /. The light emitting element according to claim 3, wherein the light emitting element is cm 3 or less.
  5.  N型クラッド層と活性層とP型クラッド層をこの順序で形成した発光部を有する発光素子の製造方法であって、
     前記活性層において、前記P型クラッド層側から前記N型クラッド層側へP型ドーパントの濃度が漸減し、かつ、
     前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が1.0×1016atoms/cm以上3.0×1017atoms/cm以下となるように前記P型ドーパントをドープして製造することを特徴とする発光素子の製造方法。
    A method for manufacturing a light emitting device having a light emitting portion in which an N-type clad layer, an active layer, and a P-type clad layer are formed in this order.
    In the active layer, the concentration of the P-type dopant gradually decreases from the P-type clad layer side to the N-type clad layer side, and
    3. In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 of the thickness of the active layer is 1.0 × 10 16 atoms / cm 3 or more. A method for manufacturing a light emitting device, which comprises doping the P-type dopant so as to be 0 × 10 17 atoms / cm 3 or less.
  6.  前記発光部を、AlGaInP系の化合物半導体からなるものとすることを特徴とする請求項5に記載の発光素子の製造方法。 The method for manufacturing a light emitting device according to claim 5, wherein the light emitting unit is made of an AlGaInP-based compound semiconductor.
  7.  前記活性層に前記P型ドーパントをドープするとき、
     前記活性層において、前記P型クラッド層から前記活性層の1/3の厚さ分の位置から2/3の厚さ分の位置までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以上3.0×1016atoms/cm以下となるようにドープすることを特徴とする請求項5または請求項6に記載の発光素子の製造方法。
    When doping the active layer with the P-type dopant,
    In the active layer, the average concentration of the P-type dopant in the region from the P-type clad layer to the position of 1/3 thickness of the active layer to the position of 2/3 thickness is 0.3. The method for producing a light emitting element according to claim 5 or 6, wherein the light emitting element is doped so as to have a concentration of × 10 16 atoms / cm 3 or more and 3.0 × 10 16 atoms / cm 3 or less.
  8.  前記活性層に前記P型ドーパントをドープするとき、
     前記活性層において、前記P型クラッド層から前記活性層の2/3の厚さ分の位置からN型クラッド層までの領域の平均の前記P型ドーパントの濃度が0.3×1016atoms/cm以下となるようにドープすることを特徴とする請求項7に記載の発光素子の製造方法。
    When doping the active layer with the P-type dopant,
    In the active layer, the average concentration of the P-type dopant in the region from the position of 2/3 of the thickness of the P-type clad layer to the N-type clad layer is 0.3 × 10 16 atoms /. The method for manufacturing a light emitting element according to claim 7, wherein the light emitting element is doped so as to be cm 3 or less.
  9.  前記活性層への前記P型ドーパントのドープを、
     前記活性層を形成しつつガスドープにより行うことを特徴とする請求項5から請求項8のいずれか一項に記載の発光素子の製造方法。
    Doping the P-type dopant on the active layer,
    The method for manufacturing a light emitting device according to any one of claims 5 to 8, wherein the active layer is formed and gas-doped.
  10.  前記活性層への前記P型ドーパントのドープを、
     前記活性層を形成した後、前記P型ドーパントをドープした前記P型クラッド層を形成してから熱処理を施して、前記P型クラッド層にドープした前記P型ドーパントを前記活性層に拡散させることにより行うことを特徴とする請求項5から請求項8のいずれか一項に記載の発光素子の製造方法。
     
    Doping the P-type dopant on the active layer,
    After forming the active layer, the P-type clad layer doped with the P-type dopant is formed and then heat-treated to diffuse the P-type dopant doped in the P-type clad layer into the active layer. The method for manufacturing a light emitting element according to any one of claims 5 to 8, wherein the method is performed according to the above.
PCT/JP2020/011575 2019-04-09 2020-03-17 Light emitting element and method of manufacturing light emitting element WO2020209014A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019073865A JP2020174077A (en) 2019-04-09 2019-04-09 Light emitting element and manufacturing method thereof
JP2019-073865 2019-04-09

Publications (1)

Publication Number Publication Date
WO2020209014A1 true WO2020209014A1 (en) 2020-10-15

Family

ID=72752006

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/011575 WO2020209014A1 (en) 2019-04-09 2020-03-17 Light emitting element and method of manufacturing light emitting element

Country Status (3)

Country Link
JP (1) JP2020174077A (en)
TW (1) TW202046514A (en)
WO (1) WO2020209014A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01204489A (en) * 1988-02-10 1989-08-17 Toshiba Corp Semiconductor laser
JPH07254751A (en) * 1994-03-15 1995-10-03 Toshiba Corp Compound semiconductor element
US6720571B1 (en) * 1999-12-02 2004-04-13 United Epitaxy Company, Ltd. Quantum well device with ESD endurance and method of forming the same
JP2006019695A (en) * 2004-06-03 2006-01-19 Hitachi Cable Ltd Epitaxial wafer for semiconductor light-emitting element, and the element
JP2006269568A (en) * 2005-03-23 2006-10-05 Fuji Photo Film Co Ltd Semiconductor laser element
JP2010267776A (en) * 2009-05-14 2010-11-25 Stanley Electric Co Ltd Semiconductor light emitting device and method of manufacturing semiconductor light emitting device
JP2012129388A (en) * 2010-12-16 2012-07-05 Stanley Electric Co Ltd Semiconductor light-emitting device

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2512223B2 (en) * 1990-09-25 1996-07-03 三菱電機株式会社 Semiconductor laser and manufacturing method thereof
JP2950316B2 (en) * 1998-02-17 1999-09-20 松下電器産業株式会社 Gallium nitride based compound semiconductor light emitting device and method of manufacturing the same
JP2010199381A (en) * 2009-02-26 2010-09-09 Stanley Electric Co Ltd Method of manufacturing semiconductor light-emitting device, and semiconductor light-emitting device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01204489A (en) * 1988-02-10 1989-08-17 Toshiba Corp Semiconductor laser
JPH07254751A (en) * 1994-03-15 1995-10-03 Toshiba Corp Compound semiconductor element
US6720571B1 (en) * 1999-12-02 2004-04-13 United Epitaxy Company, Ltd. Quantum well device with ESD endurance and method of forming the same
JP2006019695A (en) * 2004-06-03 2006-01-19 Hitachi Cable Ltd Epitaxial wafer for semiconductor light-emitting element, and the element
JP2006269568A (en) * 2005-03-23 2006-10-05 Fuji Photo Film Co Ltd Semiconductor laser element
JP2010267776A (en) * 2009-05-14 2010-11-25 Stanley Electric Co Ltd Semiconductor light emitting device and method of manufacturing semiconductor light emitting device
JP2012129388A (en) * 2010-12-16 2012-07-05 Stanley Electric Co Ltd Semiconductor light-emitting device

Also Published As

Publication number Publication date
TW202046514A (en) 2020-12-16
JP2020174077A (en) 2020-10-22

Similar Documents

Publication Publication Date Title
US8829489B2 (en) Nitride semiconductor template and light-emitting diode
KR20050074274A (en) Zn semiconductor light-emitting device and method for manufacturing same
JPH08139361A (en) Compound semiconductor light emitting device
WO2019015217A1 (en) Deep uv led
WO2017185777A1 (en) Algainp light emitting diode
CN114927601A (en) Light emitting diode and preparation method thereof
JP4940670B2 (en) Method for fabricating nitride semiconductor light emitting device
US20120241753A1 (en) Semiconductor device and method for manufacturing same
JP4333426B2 (en) Compound semiconductor manufacturing method and semiconductor device manufacturing method
JP4781028B2 (en) Group III nitride semiconductor laminate and method for manufacturing group III nitride semiconductor light emitting device
JP4873381B2 (en) Light emitting device manufacturing method, compound semiconductor wafer, and light emitting device
WO2020209014A1 (en) Light emitting element and method of manufacturing light emitting element
US20160365474A1 (en) Group iii nitride semiconductor light-emitting device and production method therefor
CN113675306A (en) Compound semiconductor epitaxial wafer and method for manufacturing same
JP3301371B2 (en) Method for manufacturing compound semiconductor epitaxial wafer
JPH09107124A (en) Method for manufacturing iii-v compound semiconductor
WO2009116232A1 (en) Compound semiconductor substrate, light emitting element using compound semiconductor substrate, and method for manufacturing compound semiconductor substrate
JP2010278262A (en) Method of manufacturing epitaxial wafer for light-emitting diode
CN108258090A (en) A kind of LED epitaxial structure and preparation method thereof
WO2012120798A1 (en) Compound semiconductor substrate, method for producing compound semiconductor substrate, and light-emitting element
JP3788344B2 (en) Method for improving productivity of group 3-5 compound semiconductor
JP2010287818A (en) Method of manufacturing epitaxial wafer for semiconductor light-emitting device
JPH05343740A (en) Gallium arsenide phosphide epitaxial wafer
JP5768879B2 (en) COMPOUND SEMICONDUCTOR SUBSTRATE, ITS MANUFACTURING METHOD, AND LIGHT EMITTING DEVICE USING THE COMPOUND SEMICONDUCTOR SUBSTRATE
JP5582066B2 (en) Compound semiconductor substrate, method of manufacturing compound semiconductor substrate, and light emitting device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20786703

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20786703

Country of ref document: EP

Kind code of ref document: A1