JP2003023181A - GaP BASED LIGHT EMITTING DIODE AND ITS FABRICATING METHOD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for constituting a GaP based LED having a monojunction or heterojunction light emitting part exhibiting a current block function, and a technology for constituting a current block function structure utilizing a boron phosphate based semiconductor layer where conductivity can be controlled easily. SOLUTION: In a GaP based light emitting diode, a first III-V compound layer containing boron is provided in the projection area of a surface electrode in junction with one compositional layer of light emitting part, and a second III-V compound layer containing boron is provided in junction with the first III-V compound layer containing boron. Furthermore, a pn junction structure comprising the first III-V compound layer containing boron and one compositional layer of light emitting part is provided in that projection area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a group III-V compound semiconductor light emitting device having a laminated structure which realizes a function of blocking current or constricting current by utilizing a pn junction of a boron phosphide-based semiconductor layer. Technology.

[0002]

2. Description of the Related Art Gallium phosphide (GaP) system III-V
For example, gallium phosphide (GaP) green band light emitting diode (LED) is known as a light emitting device using a group compound semiconductor as a light emitting layer (Iwao Teramoto, "Introduction to Semiconductor Devices" (Baifukan Co., Ltd., March 1995). See the first edition issued on March 30th, pp. 118 to 121. As another example of the III-V group compound semiconductor light emitting device, gallium arsenide phosphide (GaAs _1-X P _X : 0 ≦ X ≦ 1) yellow band LED is used. Known ("Introduction to Semiconductor Devices", 114-116, above).
See page). Recently, gallium nitride phosphide mixed crystal (GaN _1-X P _X : 0 ≦
Blue-violet band gallium nitride LED with X ≦ 1) as light emitting layer
Is being developed (Proceedings of the 48th Joint Lecture Meeting on Applied Physics in Spring 2001), No.
1, pp. 425, 31a-M-2).

Conventionally, for example, a GaPLED is mainly constructed by using a thick film of about several micrometers (μm) or several tens of μm formed by liquid phase epitaxial (LPE) means (GB. STRINGFELL
OW et al., “High Brightness Li”
ght Emitting Diodes "(ACAD
EMIC PRESS (San Diego, US).
A. , 1997), pp. 6-7). In addition, conventional Ga
As _1-X P _X (0 ≦ X ≦ 1) LEDs are hydride (hy
(dride) It is configured by using a thick film of several μm to several tens of μm formed by vapor phase growth means (see “Hi” above).
gh Brightness LightEmitti
ng Diodes ", pp. 47-48). In these conventional GaP LEDs, a thick film is arranged between the light emitting layer and the surface electrode provided above the surface of the light emitting portion to supply the LED drive current. The configuration is as follows:
Due to the arrangement of the thick film, the distance between the surface electrode and the light emitting layer is greatly separated. Therefore, the drive current is laterally diffused inside the thick film before reaching the light emitting layer, so that the drive current can be conveniently dispersed in the light emitting region.

On the other hand, metalorganic pyrolysis vapor deposition (MOC)
In an LED using a thin film formed by VD) means, the distance between the surface electrode and the light emitting region is generally not as large as that of a GaP LED. Therefore, the LED drive current is short-circuited into the light emitting region immediately below the surface electrode (so-called shadow region of the surface electrode) rather than being diffused in the lateral direction, so that the light emitting region is sufficiently expanded. Cannot be achieved. Conventionally, as one means for achieving high brightness, a technical means for circulating an LED drive current through a light emitting region (aperture light emitting region) opened in the external visual field direction (the above "High Brightness Light" is known.
t Emitting Diodes ", 178-18
(See page 0). The object of this method is achieved by arranging a current blocking layer having a function of preferentially and intensively circulating the LED drive current in a limited region, that is, the aperture light emitting region.

In the LED, the current blocking layer is a pedestal (p) provided on the light emitting portion for supplying a device driving current.
It is usually laid under a surface electrode such as an ad) electrode. For example, aluminum phosphide / gallium / indium mixed crystal ((Al _X Ga _1-X ) _Y In _1-Y P: 0 ≦ X ≦ 1,
In a 0 <Y <1) LED, a current block (blo
The current blocking layer, which is also referred to as a ck) layer, is generally arranged in a projection region of the surface electrode to the light emitting portion (corresponding to an element region other than the above-mentioned aperture light emitting region) (App.
l. Phys. Lett. , 61 (15) (199
2) pp. 1775-1777).

The current blocking layer is, for example, a clad (barrier).
P with the constituent layer of the light emitting portion having a junction structure of the layer and the light emitting layer
Conventionally configured with an n-junction structure.
High Brightness Light Emi
tting Diodes ", pp. 178-180). For example, conventional _{(Al 1-X Ga X)} Y In 1-Y P (0
In the case of ≦ X ≦ 1, 0 <Y <1 type LED, an n-type (Al _0.60 Ga _0.40 ) _0.50 In _0.50 in which a current blocking layer is bonded to a p-type (Al _0.49 Ga _0.51 ) _0.50 In _0.50 P light-emitting layer There is an example of a pn junction structure formed by ion-implanting magnesium (Mg) into the P clad layer (JP-A-7-
326793). In addition, a p-type (Al _0.7 G) which is a constituent layer of the light emitting portion of the double heterojunction (DH) structure is used.
a _0.3 ) _0.5 In _0.5 P upper clad layer and n
Type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P with a block layer
A current blocking function layer is composed of the junction structure (see Appl. Phys. Lett., 61 (1992) above).

On the other hand, also in the conventional III-V group compound semiconductor laser diode (LD), the current constriction layer is used as a functional layer having a function similar to that of the current blocking layer of the LED (see the above " Introduction to Semiconductor Devices ", 12
6-127). Recently, a technology example in which the current constriction layer is made of boron phosphide (BP) has been disclosed (see Japanese Patent Application Laid-Open No. 10-242569). The room temperature bandgap of boron phosphide has conventionally been 2 electron volts (e
The value of V is valid ("Introduction to Semiconductor Devices", page 28, RCA Review, 25 (196).
4) 159-167, and Z. anorg. al
lg. chem. , 349 (1967), 151-15
(See page 7). The current confinement layer is also made of boron phosphide having a bandgap of 2.0 eV at room temperature (JP-A-2-275682, JP-A-10-).
247760 and Japanese Patent Application Laid-Open No. 10-247761).

Boron phosphide has a low Phillips ionic bond value of 0.006 (Phillips, "Semiconductor Coupling Theory" (Yoshioka Shoten Co., Ltd., Issued July 25, 1985, third edition), 49). (See page 51). Further, for example, boron arsenide (BAs) has a smaller ionic bond degree of 0.002 (see "Semiconductor Coupling Theory", pages 49 to 51). Therefore, the arsenic phosphide (BP) group III-V group compound semiconductor has a feature that a pn junction structure forming a current blocking layer can be easily obtained.

[0009]

The GaP LED has a homo (homo) junction type structure of semiconductor layers made of the same material. Career "confinement"
Effect (above "Introduction to Semiconductor Devices", 124-125
A GaP-based LED having a heterojunction structure, which is expected to improve the emission intensity due to the above (see page), has not been put to practical use. Furthermore, for example, a technology for obtaining a GaP-based LED having a current blocking function structure configured by utilizing the characteristics of the boron phosphide-based semiconductor layer is not disclosed at present. GaP-based LE, which is more excellent in emission intensity than the conventional homojunction GaP-based LED
In order to obtain D, it is important to take technical measures to construct the light emitting portion with a heterojunction structure or to construct a functional structure effective for exhibiting a current blocking action.

Further, the band gap of the boron phosphide-based semiconductor layer conventionally used to form the current blocking layer is 2 eV.
Since it is low, it is opaque to short-wavelength visible light in the green band and the like, so that there is a disadvantage that the loss of emission intensity due to absorption becomes large (see Japanese Patent Laid-Open No. 2-288388). For example, in an LD having a structure in which laser light is oscillated in the horizontal direction without passing through a current constriction portion, absorption by the current confinement layer does not have a significant effect on the intensity of the oscillated light. On the other hand, unlike a LD, a general LED structure has a structure in which light emission is transmitted through a constituent layer of a functional portion having a current blocking action and is extracted in the external visual field direction. Therefore, when the current blocking layer is composed of the semiconductor layer having such a low bandgap, the emitted light is absorbed, and there is a problem that it is inconvenient to obtain an LED having high emission intensity.

Conventionally, for example, the bandgap width is 2.7 eV.
As described above, there is no semiconductor material that satisfies the conditions that the conductivity type (pn) control is sufficiently large, which is convenient for constructing a pn junction structure that performs a current blocking function, and that the crystal quality is good. (The above-mentioned Japanese Patent Laid-Open No. 10-
247760). Therefore, in the conventional structure, a superlattice structure of boron phosphide having a bandgap of 2 eV and an aluminum nitride (AlN) -based mixed crystal is manufactured to have a room temperature bandgap of 2 eV or more. Is disclosed (see the above-mentioned JP-A-2-275682).
However, this conventional technique has a complicated problem that requires the formation of a superlattice structure.

The present invention has been made in order to overcome the above-mentioned drawbacks of the prior art. (A) A G having a homojunction type or a heterojunction type light emitting portion exhibiting a current blocking function.
Technology for constructing an aP-based LED, (a) Technology for constructing a current blocking function structure using a boron phosphide-based semiconductor layer capable of easily controlling conductivity, and (c)
The main purpose of the present invention is to provide a technique for providing a boron phosphide-based semiconductor layer having a large forbidden band width that works favorably for transmitting light in the short wavelength visible wavelength region.

Further, the present invention is a GaP-based LED having a current blocking function structure constructed based on the above-mentioned technique.
The present invention also provides a lamp using the GaP LED and a light source using the lamp. In addition, the present invention particularly provides a manufacturing method for easily forming a boron phosphide-based semiconductor layer having a large forbidden band width that conveniently transmits visible light in the green band or the yellow band, and the above-described GaP. A manufacturing method for forming a system LED, a lamp, and a light source is provided.

[0014]

That is, the present invention provides a conductive crystal substrate having a back surface electrode on the back surface thereof, a light emitting portion including a light emitting layer made of a GaP-based semiconductor laminated on the substrate, and a light emitting portion. In a GaP-based light emitting LED having a surface electrode on the top, the following 1. Through 19. GaP having the characteristics described in 1.
A system LED is provided. In particular, the following 1. ~
4. The invention described in (3) provides a constituent means and an arrangement means of a current blocking function unit suitable for a GaP LED. 1. A conductive crystal substrate having a back surface electrode on the back surface, a light emitting portion including a light emitting layer made of a gallium phosphide (GaP) semiconductor stacked on the substrate, and a GaP light emitting portion having a surface electrode on the light emitting portion. In the diode, the first boron-containing II is bonded to the projecting region of the surface electrode by bonding to one constituent layer of the light emitting portion.
A group IV compound semiconductor layer is provided to form a first boron-containing compound II.
The second boron-containing compound II is bonded to the group I-V compound semiconductor layer II.
A GaP-based light-emitting diode comprising an IV compound semiconductor layer. 2. The second boron-containing III-V group compound semiconductor layer is the first
1. The boron-containing III-V compound semiconductor layer of No. 1, and a conductive layer of the opposite conductivity type. GaP light emitting diode described in. 3. A pn junction structure composed of a first boron-containing III-V group compound semiconductor layer and a component layer of a light-emitting portion bonded to the first boron-containing III-V group compound semiconductor layer is provided in the projection region. 1. The above-mentioned 1. Or 2. GaP light emitting diode described in. 4. A surface of the first boron-containing III-V group compound semiconductor layer present in the projection area and a surface of a constituent layer of the light emitting portion exposed in the element area other than the projection area;
1. The boron-containing III-V group compound semiconductor layer according to 1. above is provided. Through 3. GaP light emitting diode described in.

The GaP light emitting diode of the present invention is
The above 1. Through 4. In addition to the basic configuration described in 5. It is characterized in that the second boron-containing III-V group compound semiconductor layer is a conductive layer having the same conductivity type as a constituent layer of the light emitting portion forming a junction. The above invention is based on the second boron-containing III.
By using the group-V compound semiconductor layer as a heterojunction layer that heterojunctions with the constituent layer of the light emitting portion, Ga having a heterojunction structure is formed.
A P-type LED is provided.

Further, the GaP light emitting diode of the present invention comprises: Through 5. 5. In addition to the configuration of the invention described in 6. The plane area of the second boron-containing III-V compound semiconductor layer is larger than the plane area of the first boron-containing III-V compound semiconductor layer. The above invention comprises a second boron-containing III-V group compound semiconductor layer as a heterojunction layer with the light emitting part constituting layer, and spreads a driving current supplied from the surface electrode over a wide range to the aperture light emitting region. Provided is a GaP-based LED used as a layer. In addition, the present invention suppresses the unnecessary reduction of the aperture light emitting region without enlarging the installation region of the current blocking function region, and therefore 7. The plane area (S: cm ² ) of the first boron-containing III-V compound semiconductor layer is the maximum plane area (S ₀ : c) of the surface electrode.
m ² ), GaP according to the above 6, characterized in that the range is expressed by the relational expression 0.7 ≦ S / S ₀ ≦ 1.5.
A system light emitting diode is provided.

In addition, the following 8. And 9. The invention described in
The present invention relates to a GaP-based LED that utilizes a technical means of forming a heterojunction layer from a boron-containing III-V group compound semiconductor layer that is lattice-matched to one constituent layer of a light emitting section. 8. The first boron-containing III-V group compound semiconductor layer is composed of a lattice matching layer having the same lattice constant as that of a constituent layer of the light emitting section to be bonded.
Through 7. 2. The GaP light emitting diode according to any one of 1. 9. The second boron-containing III-V group compound semiconductor layer is composed of a lattice matching layer having the same lattice constant as that of the constituent layer of the light emitting section to be bonded.
Through 8. 2. The GaP light emitting diode according to any one of 1.

In addition, the above 1. Through 9. 10. In addition to the configuration of the invention described in 10. In a GaP light emitting diode, wherein the first and second boron-containing III-V group compound semiconductor layers are composed of an amorphous layer or a polycrystalline layer, a light emitting portion in which thermal alteration is avoided GaP-based LEDs are provided.

In the present invention, the boron-containing III-V group compound semiconductor layer is composed of a boron phosphide-based semiconductor layer. Through 15. A GaP-based LED according to the above item is provided. In particular, 14. And 15. In the section (1), there is provided a GaP-based LED including a boron phosphide-based semiconductor layer having a large bandgap that can be conveniently used as a barrier layer. That is, the present invention relates to 11. 1. The first boron-containing III-V group compound semiconductor layer is composed of a boron phosphide (BP) -based semiconductor layer. Through 10. G according to any one of
aP light emitting diode. 12. 1. The second boron-containing III-V group compound semiconductor layer is composed of a boron phosphide (BP) -based semiconductor layer. Through 11. G according to any one of
aP light emitting diode. 13. 1. The first and second boron-containing III-V group compound semiconductor layers are composed of the same boron phosphide (BP) -based semiconductor layer. Through 12. 2. The GaP light emitting diode according to any one of 1. 14. The first or second boron-containing III-V compound semiconductor layer is composed of boron phosphide as a base material having a bandgap of 3.0 ± 0.2 eV at room temperature. 1. Through 13. 2. The GaP light emitting diode according to any one of 1. 15. The first or second boron-containing III-V compound semiconductor layer is composed of a monomer boron phosphide layer having a bandgap of 3.0 ± 0.2 eV at room temperature. To 1. Through 14. 2. The GaP light emitting diode according to any one of 1. Is.

In the present invention, the above 1. Through 15. In addition to the configuration of the invention described in the above item, the following 16. And 19. Provided is a GaP-based LED having a light-emitting layer made of the specified GaP-based semiconductor material according to the item. That is, the present invention relates to 16. 1. The light-emitting layer provided in the light-emitting portion is composed of gallium arsenide phosphide (GaAs _1-X P _X : 0 ≦ X ≦ 1). Through 15. 2. The GaP light emitting diode according to any one of 1. 17. Gallium arsenide phosphide (GaAs _1-X
16. P _X : 0 ≦ X ≦ 1), wherein nitrogen (N) is added. GaP light emitting diode described in. 18. 1. The light-emitting layer provided in the light-emitting portion is composed of gallium nitride phosphide (GaN _1-X P _X : 0 ≦ X ≦ 1). Through 15. 2. The GaP light emitting diode according to any one of 1. 19. 16. The second boron-containing III-V compound semiconductor layer is provided as a barrier layer that is joined to the light emitting layer. Through 18. The GaP-based light-emitting diode according to any one of 1.

The present invention also relates to the above 1. ~ 19. The following 20. using the GaP light emitting diode according to the above item. And 21. The lamp or the light source described in the item. 20. The above 1. Through 19. GaP according to any one of 1.
A lamp using a light emitting diode. 21. 20. A light source manufactured from a lamp using the GaP light emitting diode described in 1.

In the present invention, the above 1. Through 19. In order to manufacture the GaP-based light emitting diode described in the above item, the following 22. To 26. A method for manufacturing a GaP light emitting diode according to item 1 is provided. That is, the present invention relates to 22. A first component is formed on a constituent layer of the light emitting portion on the conductive crystal substrate.
Of the boron-containing III-V compound semiconductor layer, and after removing the first boron-containing III-V compound semiconductor layer in the element region other than the projecting region of the surface electrode provided on the light emitting portion, the projecting region is formed. A second boron-containing III-V group compound semiconductor layer that covers the surface of the first boron-containing III-V group compound semiconductor layer left on the substrate and the surface of the constituent layer of the light-emitting portion exposed in the device region. 1. The above-mentioned 1. Through 1
9. The method for manufacturing the GaP light emitting diode according to any one of 1. 23. 22. After forming the light emitting portion on the conductive crystal substrate, the first boron-containing III-V compound semiconductor layer is formed at a temperature lower than that of the constituent layer of the light emitting portion. 7. A method for manufacturing a GaP light emitting diode according to item 1. 24. A light-emitting portion and a first boron-containing layer on a conductive crystal substrate III
22. After forming the group-V compound semiconductor layer, the second boron-containing III-V group compound semiconductor layer is formed at a temperature lower than that of the constituent layer of the light emitting portion. Or 23. 7. A method for manufacturing a GaP light emitting diode according to item 1. 25. 22. The first and second boron-containing III-V compound semiconductor layers are formed at the same temperature.
To 24. The method for manufacturing the GaP light emitting diode according to any one of 1. 26. 22. The first and second boron-containing III-V group compound semiconductor layers are formed at a temperature of 250 ° C. or higher and 750 ° C. or lower. To 25. The method for manufacturing the GaP light emitting diode according to any one of 1. Is.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A GaP light emitting diode according to the present invention comprises a laminated structure laminated on a substrate as a base material. A semiconductor single crystal can be preferably used as the substrate material. For example, a group IV semiconductor single crystal such as silicon single crystal (silicon: Si) or silicon carbide (SiC) can be used as the substrate. Further, gallium arsenide (GaAs), gallium phosphide (GaP) or boron phosphide (BP) (J.E.
retrochem. Soc. , 120 (197
3), p. p. 802-806. Or a group III-V compound semiconductor single crystal such as gallium nitride (GaN). In particular, from the viewpoint of lattice matching, Ga
Ga having an As _1-X P _X (0 ≦ X ≦ 1) layer as a light emitting layer
GaAs single crystal is a suitable substrate for P-based LEDs.
Similarly, a GaP-based LED having a GaP layer as a light emitting layer is
The aP single crystal can be suitably configured as the substrate. Further, sapphire (α-Al ₂ O ₃ single crystal), oxide single crystal such as zinc oxide (ZnO), or refractory metal such as molybdenum (Mo) can be used as the substrate. The thickness, plane orientation, etc. of the single crystal to be formed with the substrate can be appropriately selected in consideration of the lattice constant with the constituent layers of the laminated structure for LED.

On the substrate, for example, a light emitting portion having a light emitting layer via a buffer layer made of a III-V compound semiconductor is formed. The buffer layer can be composed of, for example, an amorphous layer or a polycrystalline layer grown at a low temperature. Further, for example, it can be composed of a superlattice structure layer. In particular, when the substrate material and the constituent layers of the laminated structure have a lattice mismatch,
The buffer layer having a strained superlattice structure can contribute to provide a laminated structure constituting layer that relaxes lattice mismatching and has excellent crystallinity. Further, the buffer layer composed of a composition gradient layer having a composition gradient in the layer thickness direction also effectively acts to alleviate the lattice mismatch. In the case of the structure in which the light emitting portion is directly bonded to the buffer layer, if the buffer layer is made of a material having a large forbidden band that can sufficiently transmit the light emitted from the light emitting portion,
Ga of high brightness, which can improve the extraction efficiency of emitted light to the outside.
This is advantageous for obtaining a P-type LED. Semiconductor multi-layered film reflecting mirror formed by stacking semiconductor layers that reflect light emitted on the buffer layer (Iga and Koyama, "Surface emitting laser")
(See Ohmsha Co., Ltd., September 25, 1990, 1st edition, 1st printing), pages 181-184).

The light emitting portion is a functional portion for emitting light emission and is a light emitting layer, or a light emitting layer and a barrier (clad) layer in a single hetero (SH) junction structure type, or a double hetero (D).
H) The junction structure is composed of a light emitting layer, an upper clad layer and a lower clad layer. The light emitting layer is composed of a p-type or n-type conductive layer. In the SH junction structure, the cladding layer is composed of a conductive layer having a conductivity type opposite to that of the light emitting layer. In the DH junction structure, a light emitting layer is sandwiched between a p-type clad layer and an n-type clad layer to form a light emitting section. GaP LED according to the present invention
The light emitting layer is composed of a GaP crystal that gives a transition energy corresponding to a desired emission wavelength. Further, it is composed of GaAs _1-X P _X having a band gap corresponding to the emission wavelength.

The light emitting layer is a quantum well.
11) It can also be constructed from the structure. For example, it can be composed of a single quantum well (SQW) structure or a multiple quantum well (MQW). Further, for example, a junction body of a strained superlattice structure and a quantum well structure can be used as a light emitting layer.

In the present invention, boron-containing III-V is provided on the light emitting portion.
A pn junction structure including a group compound semiconductor layer is provided. The boron-containing group III-V compound semiconductor, for example, general formula _{B α Al β Ga γ In 1-} α - β - γ P 1- δ As δ (0
<Α ≦ 1, 0 ≦ β <1, 0 ≦ γ <1, 0 <α + β + γ ≦
There are III-V group compound semiconductors represented by 1, 0 ≦ δ ≦ 1). In addition, for example, the general formula B _α Al _β Ga _γ In
_{1- α - β - γ} P _{1- δ} N _δ (0 <α ≦ 1, 0 ≦ β <1, 0 ≦
There is a III-V group compound semiconductor containing nitrogen represented by γ <1, 0 <α + β + γ ≦ 1, 0 <δ ≦ 1). Specifically, an aluminum phosphide / boron mixed crystal (B _α Al _β P:
0 <α ≦ 1, α + β = 1), boron phosphide / gallium mixed crystal (B _α Ga _γ P: 0 <α ≦ 1, α + γ = 1) or boron phosphide / indium mixed crystal (B _α In _{1- α} P: 0 <α ≦
1) can be exemplified. Further, for example, boron nitride phosphide (B
An example is a compound V group III nitride semiconductor having a plurality of group V elements such as P _1-X N _X : 0 <X <1).

As described above, boron phosphide (BP) or boron arsenide (BAs) has low ionic bondability (see "Semiconductor Coupling Theory", pages 49 to 51). In addition, its crystalline form is a zinc sulfide ore type (sparelite) (see the above "Semiconductor Coupling Theory", pages 14 to 15) and possesses a valence band contraction structure peculiar to cubic crystals (Hideaki Ikoma). , Toshiaki Ikoma, "Introduction to Basic Physical Properties of Compound Semiconductors" (see Baifukan Co., Ltd., first edition issued September 10, 1991), p. 17). Therefore, there is an advantage that a conductive layer, particularly a p-type conductive layer can be easily obtained. Therefore, from the boron-containing III-V group compound semiconductor layer containing boron and phosphorus (P) or arsenic (As) as constituent elements, a functional site (pn junction type current blocking layer) that conveniently exhibits a current blocking action is provided. Can be configured.

In the first embodiment of the present invention, the current blocking layer is formed by joining the first and second boron-containing III-V group compound semiconductor layers. Here, the layer bonded to the constituent layer of the light emitting portion is tentatively referred to as a first boron-containing III-V group compound semiconductor layer. For example, a high-resistance first boron-containing III-V group compound semiconductor layer is bonded onto the constituent layer of the light emitting portion. next,
A conductive second boron-containing III-V compound semiconductor layer is bonded to the first boron-containing III-V compound semiconductor layer.
The high-resistance first boron-containing III-V group compound semiconductor layer is
It exerts an effect of preventing short-circuiting of the LED drive current from the surface electrode provided above to the light emitting portion immediately below the surface electrode. The conductive second boron-containing III-V compound semiconductor layer causes the drive current blocked by the action of the high-resistance first boron-containing III-V compound semiconductor layer to be applied to a region other than immediately below the surface electrode. It has the effect of being dispersed and distributed. That is, by joining the high resistance layer and the boron-containing group III-V compound semiconductor layer of the conductive layer, a structure exhibiting a current blocking function can be formed.

When the first III-V compound semiconductor layer is composed of a high-resistance layer having a resistance higher than that of the conductive second boron-containing III-V compound semiconductor layer by about 2 digits, preferably by 3 digits or more. Therefore, it is possible to configure a portion that can more effectively exhibit the current blocking function. The resistance of the high-resistance first boron-containing III-V compound semiconductor layer is preferably 100 ohm (Ω) or more, more preferably 1 kilo ohm (kΩ) or more. Further, for example, it may be composed of an insulating layer having a resistivity of 10 ³ Ω · cm or more. The resistivity (= specific resistance) can be measured, for example, by a normal Hall effect measuring means or the like. The current blocking layer can be formed by using the first boron-containing III-V compound semiconductor layer as a conductive layer and the second boron-containing III-V compound semiconductor layer as a high resistance layer or an insulating layer. However, in this joint structure, especially, the second
In the structure in which the surface electrode is provided on the boron-containing III-V group compound semiconductor layer, the contact resistance of the surface electrode increases, and the forward voltage (so-called Vf) of the LED increases, which is a preferable structure. Is hard to come by.

In the second embodiment of the present invention, the current blocking function portion is composed of a pn junction structure. The pn junction structure is
The first and second boron-containing III-V group compound semiconductor layers having different conductivity types are bonded to each other. For example, an n-type boron-containing III-V group compound semiconductor layer and a p-type boron-containing III compound layer.
A pn junction is formed from the junction structure with the group-V compound semiconductor layer. The pn junction structure is a boron-containing III-V group compound semiconductor layer having a layer thickness exceeding the depth of a depletion layer at a carrier concentration (hole concentration or electron concentration) at zero (0) bias. It is desirable to configure from. The depth of the depletion layer decreases as the carrier concentration increases, and can be calculated using the carrier concentration, the relative permittivity, and the like (see AS Groov, “Physics an”).
d Technology of Semiconductor
center Devices "(John Wiley
& Sons, Inc. , 1967, p. 159).
By the way, boron phosphide (BP) (Nature, 179 (No.
4569) (1957), p. 1075) is expected to have a relative permittivity of about 8.02 (WA Harrison,
"Solid state electronic structure and physical properties (first volume)" (Hyundai Engineering Co., 19
Issued May 30, 1987, second edition), p. 122).

The current blocking function portion is provided in the projection area immediately below the surface electrode such as a pedestal electrode for connecting the lead wire for supplying the LED drive current. The projection area refers to a projection area of the pedestal electrode in the vertical direction, and the maximum plane area of the area is equal to the maximum horizontal sectional area of the surface electrode. In the third embodiment of the present invention, a pn junction structure is formed by one constituent layer of the light emitting section and the first boron-containing III-V group compound semiconductor layer bonded to the constituent layer. For example, the pn junction structure is formed by joining the n-type first boron-containing III-V group compound semiconductor layer to the p-type cladding layer. Also, for example,
A p-type first boron-containing III-V group compound semiconductor layer is joined to the n-type GaP light emitting layer to form a pn junction structure.
The pn junction structure according to the invention described in the third embodiment of the present invention performs the same current blocking function as the pn junction structure according to the second embodiment, but the constituent elements of the pn junction structure are different. It is a thing. That is, the invention described in the third embodiment of the present invention is characterized in that a pn junction structure for current blocking is simply configured by using one constituent layer of the light emitting portion.

In forming the current blocking function portion composed of the high resistance layer or the pn junction structure, the first boron-containing III
Second boron-containing compound bonded to Group-V compound semiconductor layer III
When the -V compound semiconductor layer is provided so as to cover the surface of the surface electrode other than the projection area, there is an advantage that the LED drive current can be diffused in a wide range in the aperture light emitting area. That is, by providing the current blocking function portion, the drive current in which the short-circuited flow to the light emitting portion in the projection region is suppressed is utilized by the conductivity of the second boron-containing III-V compound semiconductor layer. Then, it can be effectively dispersed and diffused in the aperture light emitting region. Therefore, it is effective in obtaining a GaP-based LED with excellent photoelectric conversion efficiency and high brightness. Particularly, in the invention of the fourth embodiment of the present invention,
A second boron-containing III-V compound semiconductor layer is provided so as to cover the surface of the first boron-containing III-V compound semiconductor layer, and a surface electrode is provided on the second boron-containing III-V compound semiconductor layer. Is preferably provided. In such a configuration, the LED drive current can be dispersed in the horizontal direction in the second boron-containing III-V compound semiconductor layer by utilizing the conductivity of the second boron-containing III-V compound semiconductor layer, and therefore the aperture light emitting region is preferentially and It has the effect of being distributed centrally.

For example, in the case where the second boron-containing III-V compound semiconductor layer is provided in the opening region in the light-emitting portion of the pn junction type heterojunction structure of the light-emitting layer and the barrier layer, the second boron-containing III-V compound semiconductor layer is joined to the barrier layer. , A conductive layer of the same conductivity type as the barrier layer to a second layer
If the boron-containing III-V compound semiconductor layer is formed, it is possible to avoid the formation of a pn junction with the light emitting part constituting layer in the aperture light emitting region. Therefore, the element driving current can be supplied to the open light emitting region evenly through the aperture light emitting region. Therefore, in the fifth embodiment of the present invention, the second boron-containing II
A high-luminance GaP-based LED is obtained by forming the IV compound semiconductor layer from a constituent layer of a light-emitting layer that is joined to the IV-compound semiconductor layer, in particular, a conductive layer having the same conductivity type as the barrier layer. In the structure in which the second boron-containing III-V compound semiconductor layer is directly bonded to the light-emitting layer, the conductivity type of the second boron-containing III-V compound semiconductor layer is the same as or different from that of the light-emitting layer. But it doesn't matter. For example, in a GaP-based LED including a gallium phosphide (GaP) homojunction structure light-emitting portion, an n-type GaP light-emitting layer is formed on a p-type second boron-containing III-V group compound semiconductor layer. Can be joined together to form a light emitting portion.

In particular, the second boron-containing III-V compound semiconductor layer is arranged in a region larger than the plane area of the surface of the first boron-containing III-V compound semiconductor layer to be joined below. As a result, the region where the LED drive current can be dispersed can be expanded. The larger the planar area in which the second boron-containing III-V compound semiconductor layer is laid, the wider the area in which the LED drive current can be dispersed and diffused. Therefore, in the sixth embodiment of the present invention, for example, the first boron-containing II
It is preferable to lay the second boron-containing III-V compound semiconductor layer on the entire surface or substantially the entire surface of the aperture light emitting region while covering the surface of the IV compound semiconductor layer.

On the contrary, if the installation plane area of the first boron-containing III-V group compound semiconductor layer constituting the current blocking function section is made too large, the area where the flow of the LED drive current is blocked increases. Therefore, it is inconvenient to obtain a high-luminance GaP LED. The ratio (= S /) of the plane area (= S: cm ² ) of the first boron-containing III-V group compound semiconductor layer arranged immediately below to the maximum plane area (= S ₀ : cm ² ) of the surface electrode. When S ₀ ) is set to 2, for example, the area of the current blocking function portion occupying a certain element forming area becomes large, but the surface area of the aperture light emitting area is significantly reduced, so that a GaP LED with high brightness can be obtained. It will be inconvenient. Further, when S / S ₀ is, for example, 0.5 or less, the current blocking function cannot be sufficiently exhibited, and a large amount of LED drive current cannot be efficiently distributed to the aperture light emitting region, so that a GaP LED with high brightness is obtained. Will be at a disadvantage. Suitable S /
The range of S ₀ is 0.7 ≦ S / S ₀ ≦ 1.5. As an example of the seventh embodiment of the present invention, with respect to a circular surface pedestal electrode (S ₀ ≈1.1 × 10 ⁻⁴ cm ² ) having a diameter of 120 μm, the diameter is 140 μm in the projection area immediately below. First boron-containing III-V group compound semiconductor layer (S≈1.5 ×
An example of arranging 10 ⁻⁴ cm ² ; S / S ₀ ≈1.4) is given.

When the current blocking function part is formed from the first and second boron-containing III-V group compound semiconductor layers, boron-containing III which is lattice-matched to one constituent layer of the light emitting portion serving as an underlayer.
When it is made of a group-V compound semiconductor material, a first boron-containing group III-V compound semiconductor layer having particularly excellent crystallinity can be obtained. That is, in the eighth embodiment of the present invention, a misfit (misf) due to a lattice mismatch (mismatch).
It) aims to provide a good first boron-containing III-V group compound semiconductor layer while suppressing generation of crystal defects such as dislocations.

Further, in the ninth embodiment of the present invention, the second
Of the boron-containing III-V compound semiconductor layer of the first boron-containing compound I
It is made of a material that is lattice-matched to the II-V group compound semiconductor layer. If the aperture light emitting region is covered with the second boron-containing III-V group compound semiconductor layer that is lattice-matched to one component layer of the light-emitting portion to be joined, crystal defects due to lattice mismatch are introduced into the inside of the light-emitting portion. Since it can be avoided, the effect that the crystal quality of the light emitting part constituting layer can be kept good can be enhanced. Further, by forming the first and second boron-containing III-V group compound semiconductor layers from materials having a lattice matching relationship with each other, for example, a pn junction structure excellent in rectifying property capable of exhibiting good current blocking action can be obtained. It has the advantage of being configurable.

According to the invention described in the tenth embodiment of the present invention, it is possible to suppress the thermal deterioration of the crystallinity of the constituent layers of the light emitting section and the joint interface characteristics between the constituent layers, while suppressing the thermal deterioration of the first and second constituent layers. The current blocking functional portion can be formed from the boron-containing III-V group compound semiconductor layer. For example, in order to avoid thermal modification of the order of the pn junction interface of the pn junction structure, in the tenth embodiment, an amorphous or polycrystalline boron-containing III film formed at low temperature is used.
The feature is that the current blocking function portion is formed of the group-V compound semiconductor layer. For example, as an example of boron-containing III-V group compound semiconductor layer, boron arsenide (BAs) is used.
A first boron arsenide layer mainly composed of an amorphous film and a second boron arsenide layer mainly composed of an amorphous film, which are formed in a low temperature region of 0 ° C. to 750 ° C., form a current blocking function site. To do.
For example, according to the MOCVD means of an alkyl (boryl) boron compound / phosphine (PH ₃ ) raw material system, within the above-mentioned low temperature range, a boron-containing III-V group which is polycrystalline at a high temperature of about 500 ° C. is generally used. A compound semiconductor layer can be easily obtained. On the other hand, the lower the film forming temperature, the easier it is to obtain a boron-containing III-V group compound semiconductor layer mainly composed of an amorphous material. Whether the boron-containing boron phosphide-based semiconductor layer is an amorphous layer or a polycrystalline layer can be analyzed by a general X-ray diffraction method or electron beam diffraction method. Amorphous or polycrystalline boron-containing III
The group V compound semiconductor layer has a thickness of about 50 nm to about 1000 nm.
A layer thickness of the order of magnitude is suitable. The boron phosphide-based III-V group compound semiconductor layer having a layer thickness within a suitable range relaxes lattice strain caused by a difference in coefficient of thermal expansion, for example, and has an effect of maintaining good crystallinity of the light emitting layer. Also exerts.

In the MOCVD means, for example, a general film forming temperature of a gallium phosphide (GaP) layer which forms a light emitting layer is 775 ° C. to 825 ° C. (J. Crystal G.
rowth, 56 (1982), 382-388). On the other hand, according to the means for forming the current blocking function portion at a temperature lower than the film formation temperature of the constituent layer of the light emitting portion, while preventing thermal deterioration of the characteristics of the constituent layer of the light emitting portion, There is an advantage that an excellent pn junction structure can be formed. In particular, by forming the first and second boron-containing III-V group compound semiconductor layers at the same temperature, it is possible to reduce the thermal strain, etc., which the constituent layers of the light emitting section undergo with changes in the film forming temperature. Therefore, for example, there is an advantage that the current blocking function portion can be formed of a pn junction structure capable of expressing good rectifying characteristics.

In the eleventh embodiment of the present invention, the first boron-containing III-V compound semiconductor layer is formed of boron phosphide (BP).
It is assumed to be composed of a system semiconductor layer. The boron phosphide-based semiconductor is a III-V group compound semiconductor containing boron (B) and phosphorus (P) as constituent elements. Specifically, as described above, for example, aluminum phosphide / boron mixed crystal (B _α A
l _β P: 0 <α ≦ 1, α + β = 1) or a boron phosphide / gallium mixed crystal (B _α Ga _γ P: 0 <α ≦ 1, α + γ = 1). In addition, for example, boron nitride phosphide (BP _1-X N _X : 0)
<X <1) and other Group V elements containing multiple Group V elements III-
It is a Group V compound semiconductor. Boron phosphide (BP) has a low ionic bondability as described above (see “Semiconductor Coupling Theory”, 4 above).
See pages 9-51). Therefore, a conductive first boron-containing III-
There is an advantage that the group V compound semiconductor layer can be simply constructed. In addition, the BP-based semiconductor has an advantage that the first boron-containing III-V group compound semiconductor layer having high resistance can be easily formed by adding oxygen (O), for example.

In the twelfth embodiment of the present invention, the second boron-containing III-V compound semiconductor layer is composed of a boron phosphide-based semiconductor layer. As described above, the boron phosphide-based semiconductor is an I containing boron (B) and phosphorus (P) as constituent elements.
It is a II-V group compound semiconductor. Specifically, as described above, for example, an aluminum phosphide / boron mixed crystal (B _α Al _β
P: 0 <α ≦ 1, α + β = 1) or a boron phosphide / gallium mixed crystal (B _α Ga _γ P: 0 <α ≦ 1, α + γ = 1). Further, for example, boron nitride phosphide (BP _1-X N _X : 0 <
Double Group III-V containing multiple Group V elements such as X <1)
It is a group compound semiconductor. Boron phosphide (BP) is not as good as boron arsenide (BAs), but has a low ionic bondability as described above (see "Semiconductor Coupling Theory", pages 49 to 51).
Therefore, there is an advantage that the conductive second boron-containing III-V group compound semiconductor layer can be simply formed from the BP-based semiconductor using BP as a base material. Further, BP has a high melting point (> 3) as compared with boron arsenide (melting point> 1000 ° C.).
000 ° C.) (see “Introduction to Semiconductor Devices” above, page 28). Therefore, there is an advantage that a second boron-containing III-V group compound semiconductor layer that provides a pn junction structure, for example, that does not deteriorate the junction characteristics even if it is caused by heat in the film forming environment is provided. .

In the thirteenth embodiment of the present invention, the first and second boron-containing III-V group compound semiconductor layers are composed of the same boron phosphide-based semiconductor layer. That is, a pn junction structure having a current blocking function is formed from a boron phosphide-based semiconductor layer having the same lattice constant. The current blocking function portion according to this configuration avoids deterioration of crystallinity due to lattice mismatching and is composed of a boron phosphide-based semiconductor layer having excellent crystallinity, and thus has a good current blocking function. Demonstrate. For example, each of the first and second boron phosphide-based semiconductor layers is a monomer boron phosphide (boron monopho).
The current blocking function portion is configured as a sphere. Three
Binary crystals are generally easier to form than ternary semiconductors composed of four constituent elements or quaternary semiconductor mixed crystals composed of four constituent elements (see "Introduction to Semiconductor Devices", page 24). Therefore, if the boron phosphide (BP) binary crystal layer is used, there is an advantage that the current blocking function portion can be easily configured.

The boron phosphide-based semiconductor layer according to the present invention is
For example, the MOCVD method (Inst. Phys. Con)
f. Ser. , No. 129 (IOP Publish
ingLTd. , 1993), pp. 157-162.
B), molecular beam epitaxy (MBE) method (J. Sol
id State Chem. , 133 (1997),
Pp. 269-272), the halide method
("Journal of the Crystal Growth Society of Japan", Vol. 24, No. 2
(1997), page 150 and J. Appl. Phy
s. , 42 (1) (1971), pp. 420-424.
Gas phase, such as illuminating) and hydride method
The film can be formed depending on the growth means. By these growth means
When forming a film, increase the supply of growth raw materials, especially the boron source.
If it is decreased, the film formation rate can be adjusted. Also, the layer thickness is
You can adjust and control the time. For example, for MOCVD means
Therefore, to form a boron phosphide-based semiconductor layer,
Ruboron ((C ₂H_Five)₃B) / Borane (BH₃) / Phosphy
(PH₃) System or triethylboron / diborane (B₂
H₆) / Phosphine-based, or triethylboron and tar
Tert.-butyl phosphine
Normal pressure (approx. Atmospheric pressure) of systems containing organic phosphorus compounds such as nitrogen
Alternatively, a vacuum growth reaction system can be used.

The boron phosphide-based semiconductor layer can be composed of an undoped layer in which impurities are not intentionally added. Further, when a boron phosphide-based semiconductor layer is formed, if a n-type or p-type impurity is added, a boron phosphide-based semiconductor layer having a desired resistance can be obtained. For example, II
If zinc (Zn) or magnesium (Mg) belonging to the group is added, a p-type boron phosphide-based semiconductor layer can be obtained. Also,
By adding a Group IV element such as silicon (Si) or tin (Sn), an n-type boron phosphide-based semiconductor layer can be obtained. The n-type boron phosphide-based semiconductor layer can also be obtained by adding sulfur (S) or selenium (Se). Although it is a Group VI element, when oxygen (O) is doped, a high resistance oxygen-containing boron phosphide-based semiconductor layer can be formed. In order to obtain a single-crystal oxygen-containing boron phosphide-based semiconductor layer, it is desirable that the film formation temperature be higher than 700 ° C. However, when the temperature is higher than 1200 ° C., the generation of multimers such as B ₁₃ P ₂ becomes remarkable (J. Amer. Ceramic Soc., 47).
(1964) p. p. 44-46. However, it is difficult to obtain a uniform boron phosphide-based semiconductor layer, which is not preferable.

It is also possible to add these impurities from the surface of the formed boron phosphide-based semiconductor layer by ion implantation. The above vapor phase growth means is characterized in that a polycrystalline boron phosphide layer is easily formed due to the presence of oxygen (see Japanese Patent Laid-Open No. 2000-351692).
The ion implantation method for implanting impurities into the formed boron phosphide-based semiconductor layer once and recovering the damage caused by the implantation by subsequent annealing and electrically activating the implanted ions is a semiconductor layer. It is convenient that oxygen can be added without accelerating the polycrystallization. Regardless of the means for adding impurities such as doping or ion implantation, excessive addition of elements will impair the crystallinity of the boron phosphide-based semiconductor layer. It is desirable to keep it at 5 × 10 ¹⁹ cm ⁻³ or less. The impurity concentration in the boron phosphide-based semiconductor layer can be quantified by an analytical means such as general secondary ion mass spectrometry (SIMS).

In the fourteenth embodiment of the present invention, a boron-containing III-V compound semiconductor layer composed of a boron phosphide base material having a bandgap at room temperature of 2.8 eV or more and 3.2 eV or less is used as a current source. Configure blocking function site. Particularly, in the fifteenth embodiment of the present invention, the forbidden band width at room temperature is 2.8e.
A boron-containing III-V compound semiconductor layer is formed from a boron phosphide layer of a monomer having a voltage of V or more and 3.2 eV or less. The band gap is obtained, for example, from the wavelength dependence of the imaginary part (= ε ₂ ) of the complex permittivity. Imaginary part of complex permittivity (ε ₂ = 2 ・ η
・ K) is an ellipsometer
Refractive index (= η) measured by ellipsometer such as r)
And the extinction coefficient (= k) (see "III-V Group Compound Semiconductor" (Baifukan Co., Ltd., May 20, 1994, first edition, pages 170-171)).

Boron phosphide (BP), which has a bandgap of 3.0 ± 0.2 eV or less at room temperature, is formed by setting both the growth rate and the supply ratio of the raw materials within prescribed ranges. It is possible (see Japanese Patent Application No. 2001-158288). The growth rate is preferably 20Å or more per minute and 30
It is set to 0 Å or less (see Japanese Patent Application No. 2001-158288 mentioned above). When the growth rate is slower than 20 Å / min, the phosphorus (P) constituent element or its compound cannot be sufficiently desorbed and volatilized from the surface of the growth layer, and the film formation may not be achieved. If the growth rate is set higher than 300 Å / min, the obtained bandgap value becomes unstable, which is not preferable. Further, if the growth rate is excessively increased, a polycrystalline crystal layer tends to be formed, which is inconvenient for obtaining a single crystal layer.

Further, together with the growth rate, the supply ratio of the raw material is preferably defined in the range of 15 or more and 60 or less. B
In the case of forming the P layer, the supply ratio of the raw material means phosphorus (P) with respect to the supply amount of the boron (B) source to the growth reaction system.
It is the ratio of source supply. Further, in the case of forming a BP-based mixed crystal, it is the ratio of the total supply amount of the group V source containing phosphorus (P) to the total supply amount of the group III source containing boron (B). Boron phosphide / indium (B _α In _1-
α P: 0 <α ≦ 1) Taking the case of forming a mixed crystal as an example,
It is the ratio of the supply amount of the phosphorus (P) source to the total amount of the gallium (Ga) source and the indium (In) source supplied to the growth reaction system. That is, the so-called V / III ratio. V / I
When the II ratio is as small as less than 15, the surface of the growth layer becomes disordered, which is not desirable. Further, if the V / III ratio is made extremely large exceeding 60, stoichiometrically, it becomes easy to form a growth layer in which phosphorus (P) is rich. Excessive phosphorus (P) enters the position where boron (B) should occupy in the crystal lattice and acts as a donor (Katsufusa Shono, “Semiconductor Technology 100 in the VLSI era (5)”). (Ohm Co., Ltd., issued May 1, 1984,
Electronic magazine Electronics Vol. 29, No. 5, May 1984, Appendix, p. 121). If the stoichiometric composition shifts to the rich side of phosphorus (P), it is disadvantageous because it hinders the formation of a p-type crystal layer having a low resistance.

The boron phosphide-based semiconductor layer constituting the current blocking function portion according to the present invention has a band gap of 3.0 ± 0.2.
It is constructed by using the above boron phosphide having eV. For example, gallium phosphide (G) having a bandgap of about 2.3 eV
aP) (“III-V group compound semiconductor” described above, 150
Page) and boron phosphide (BP) with a bandgap of 3.1 eV, a boron phosphide-gallium mixed crystal (B _0.62 Ga _0.38 P) with a bandgap of about 2.8 eV at room temperature is used. ) Can be formed. By the way, if the conventional BP having a bandgap of 2.0 eV is used, B _α Ga _{1- α} P with a low bandgap of less than 2.3 eV, which is the bandgap of GaP at the maximum, is used.
(0 <α ≦ 1) Only mixed crystals can be formed.

In the sixteenth embodiment of the present invention, a GaP LED is constructed by using gallium arsenide phosphide (GaAs _1-X P _X : 0 ≦ X ≦ 1) in the light emitting layer. The light emitting layer can be formed from a GaAs _1-X P _X (0 ≦ X ≦ 1) layer of either p-type or n-type conductivity. For example, silicon (Si) or tellurium (T
It can be composed of an n-type GaAs _0.8 P _0.2 layer doped with e). Further, it can be composed of a p-type GaP layer doped with zinc (Zn) and oxygen (O). GaAs _1-X P _X
The (0 ≦ X ≦ 1) layer can be formed by liquid phase epitaxial (LPE) means in addition to the above vapor phase growth means.

Particularly, in the seventeenth embodiment of the present invention, a GaP-based LED is constructed by using a GaAs _1-X P _X (0 ≦ X ≦ 1) layer doped with nitrogen (N) as a light emitting layer. In particular,
Nitrogen (N) isotope trap (isoelectroc)
The GaAs _1-X P _X layer added as a nic trap) can be effectively used as a light emitting layer resulting in high intensity light emission. The nitrogen-added GaAs _1-X P _X light-emitting layer is formed by using a vapor phase growth (VPE) method such as a liquid phase epitaxial (LPE) method, a halide method, or a hydride method to form ammonia (NH ₃ ) at the time of film formation. It can be obtained by adding nitrogen to the above as a nitrogen source. In addition, at the time of film formation by the metalorganic pyrolysis vapor deposition (MOCVD) method,
It can be obtained by adding nitrogen using a nitrogen compound such as ammonia (NH ₃ ) or hydrazine (N ₂ H ₄ ) as a nitrogen source. G
aAs _1-X P _X (0 ≦ X ≦ 1) The atomic concentration of nitrogen contained in the light emitting layer is 5 × 10 ¹⁷ cm ⁻³ or more and 5 × 10 ¹⁹ c.
It is desirable to set it in the range of m ^-3 . The atomic concentration of nitrogen can be quantified by an analytical means such as general secondary ion mass spectrometry (SIMS).

In the eighteenth embodiment of the present invention, the light emitting layer is composed of gallium nitride phosphide (GaN _1-X P _X : 0 ≦ X ≦ 1). For example, cubic n-type GaN _0.97 P _0.03 (lattice constant = 4.5) with a nitrogen composition ratio of 3% (= 0.03).
38Å), a light emitting layer lattice-matched to the boron phosphide (lattice constant = 4.538Å) layer constituting the current blocking function site can be formed. When the light emitting layer is made of a material lattice-matched with the boron-containing III-V group compound semiconductor layer forming the current blocking function portion, it is possible to prevent the crystallinity of the light emitting layer from being deteriorated due to the influence of the lattice strain caused by the lattice mismatch. . Therefore, there is an advantage that a GaP-based LED having excellent emission intensity can be constructed.

In the nineteenth embodiment of the present invention, the second boron-containing III-V compound semiconductor layer is provided as a barrier layer to be joined to the light emitting layer to form a GaP LED. In particular, the boron phosphide-based semiconductor crystal according to the present invention having a bandgap of 3.0 ± 0.2 eV produces a BP-based mixed crystal having a high bandgap which is not present in conventional BP-based mixed crystals. From such a BP-based mixed crystal layer, for example, a second boron-containing III-V group compound semiconductor layer that can also serve as a barrier layer for a light emitting layer provided for emitting short wavelength light can be formed. For example, B _0.90 Al _0.10 with a boron composition ratio of 0.90 based on boron phosphide having a bandgap of 3.0 eV
The bandgap of P mixed crystal at room temperature is about 2.9 eV. This band gap has a band gap (= 2.77) in the Γ band of GaP.
eV; “Solid electronic structure and physical properties, first volume” above, 269
(See page). Therefore, B _0.90 Al _0.10
A second boron-containing III-V group compound semiconductor layer can be formed from the P mixed crystal layer, and GaAs _1-X P _X (0 ≦ X ≦
1) A clad layer for the light emitting layer can be formed. In addition, the boron phosphide layer having a band gap of about 3.1 eV is GaN.
_A second boron-containing III-V group compound semiconductor layer having a cladding effect on the _0.90 P _0.10 light emitting layer can be formed.

If the second boron-containing III-V group compound semiconductor layer is made of a material having a high band gap that can function as a barrier (cladding) layer for the light emitting layer, G can be easily formed.
An aP LED can be constructed. For example, a first boron-containing III-V compound semiconductor layer is deposited on the light-emitting layer, and the first boron-containing III- compound is formed only in a region corresponding to the plane area of the surface electrode.
After leaving the group V compound semiconductor layer, the second boron-containing compound III layer is formed so as to cover the surface of the remaining first boron-containing compound III-V compound semiconductor layer and the light emitting part constituting layer exposed to the open light emitting region. Deposit a group V compound semiconductor layer. With such a layered structure, the second boron-containing III-V compound semiconductor layer can function as a barrier layer, so that it is possible to easily emit light having a heterojunction structure without having to rejoin the cladding layer to the light emitting layer. There is an advantage that the parts can be configured.

As described above, the boron phosphide (BP) or BP-based mixed crystal is a zinc-blende type crystal, and its band structure in the valence band (above-mentioned "Introduction to Basic Physical Properties of Compound Semiconductors").
It is easy to obtain the p-type layer from the reference). Therefore, for example, unlike the case of hexagonal gallium nitride (h-GaN), a p-type low-resistance clad layer can be easily formed. The cubic Ga _0.75 In _0.25 N light emitting layer emits blue-violet near-ultraviolet light having an emission wavelength of about 443 nm, so that the p-type B _0.90 Al _0.10 P mixed crystal and the n-type Ga _0.75 In are mixed.
If a heterojunction structure composed of _0.25 N is used, a pn-junction type light emitting section that produces blue band emission can be formed. Also,
As another example, B _0.90 Al _0.10 P mixed crystal and Ga _{0. 75} an In
It has the same lattice constant (= 4.628Å) as _0.25 N (the lattice constant of cubic indium nitride (InN) is 4.
Calculated as 98Å: see "III-V compound semiconductors," above, page 330). That is, as in the present invention, BP
If the barrier layer is made of a mixed crystal, a cladding layer that lattice-matches the light-emitting layer can be formed, so that a lattice-matched heterojunction light-emitting portion can be formed. The crystal layers having a lattice matching relationship with each other have few crystal defects due to the lattice mismatch and are of good quality. Therefore, high-intensity light emission is emitted from the lattice-matching light-emitting portion, which can contribute to providing a high-luminance boron phosphide-based semiconductor light-emitting element.

Further, the present invention is a high-brightness LED lamp manufactured by using the above GaP LED. For example, as illustrated in FIG. 8, an LE including a boron-containing III-V group compound semiconductor semiconductor layer 12 according to the present invention on a substrate 11
The D10 is fixed to the central portion of the bowl body 16 plated with a metal such as silver (Ag) or aluminum (Al) on the pedestal 15 with the metal bowl body 16 and a conductive bonding material. As a result, the unipolar back electrode 14 provided on the bottom surface of the substrate 11 is electrically connected to the one terminal 17 attached to the pedestal 15. Further, the electrode 13 installed on the heterojunction structure 12 is connected to the other terminal 18 attached to the pedestal 15. An LED lamp can be constructed by encapsulating the bowl body 16 with a general epoxy resin 19 for encapsulating a semiconductor. Further, according to the present invention, a small LED lamp having a size of about 200 μm to about 300 μm square can be formed. Therefore, a small light emitting diode lamp suitable for an indicator or the like having a small installation volume can be formed. The front and back electrodes 13 and 14 of the LED 10 can be made of a material that makes ohmic contact with a formation layer that forms them. For example, the back surface electrode provided on the back surface of the p-type Si single crystal substrate can be made of aluminum (Al), gold (Au), or the like. Further, as the back electrode material of the n-type gallium phosphide (GaP) single crystal substrate, a gold-germanium (Au.Ge) alloy or the like can be exemplified. Also, p
A p-type ohmic electrode made of, for example, a gold-zinc (Au.Zn) alloy is provided on the boron-phosphide (BP) barrier layer to form an LED.

The present invention is also a light source made of a lamp having a GaP LED. For example, a light source can be configured by collecting LED chips or resin-sealed diode lamps. For example, a plurality of LEDs can be electrically connected in parallel to form, for example, a constant voltage drive type light source. Further, a constant current type light source can be configured by electrically connecting diode lamps in series. Unlike conventional incandescent lamp light sources, light sources using these LEDs do not radiate much heat when turned on, and thus can be particularly usefully used as cold light sources. For example, it can be used as a light source for displaying frozen foods. Further, for example, a light source suitably used for an outdoor display, a traffic light for presenting a traffic signal, a direction indicator, a lighting device, or the like can be configured.

[0059]

[Function] The first electrode provided in the projection area of the surface electrode of the present invention.
And a second junction structure composed of the second boron-containing III-V group compound semiconductor layer has a current blocking action of preventing the LED driving current supplied from the surface electrode from short-circuiting to the light emitting portion in the projection region. Exert. In addition, in addition, L is preferentially applied to the aperture light emitting area other than the projection area opened to the outside.
It has a function of dispersing and diffusing the ED drive current.

A pn formed of first and second boron-containing III-V group compound semiconductor layers whose conductivity types are opposite to each other according to the present invention.
The junction has a function of providing a current blocking function portion composed of a pn junction in the projection area of the front surface electrode and preventing short-circuiting of the LED drive current to the light emitting portion in the projection area of the front surface electrode.

A second boron-containing II compound provided so as to cover the first boron-containing III-V group compound semiconductor layer of the present invention and one constituent layer of the light-emitting portion exposed on the surface of the aperture light-emitting region.
The IV group compound semiconductor layer constitutes a part that exhibits a current blocking function together with the first boron-containing III-V group compound semiconductor layer, and exhibits the action of preventing the flow of the LED drive current into the projective flow region. In addition, over a wide range of the aperture light emitting area,
It has a function of diffusing the drive current.

The second boron-containing III-V group compound semiconductor layer made of a conductive layer having the same conductivity type as the constituent layer of the light emitting section to be joined is pn-junction with the constituent layer of the light emitting section in the aperture light emitting region. To avoid the formation of
It has a function of diffusing the ED drive current.

The second boron-containing III-V compound semiconductor layer having a plane area exceeding the first boron-containing III-V compound semiconductor layer is bonded to the first boron-containing III-V compound semiconductor layer. The LED drive current, which has been blocked from flowing in the projection area by the section, is surely flowed in the aperture light emitting area.

Current blocking consisting of a first boron-containing III-V compound semiconductor layer and a second boron-containing III-V compound semiconductor layer having a plane area defined with respect to the maximum horizontal cross-sectional area of the surface electrode. The functional portion has an effect of allowing the LED drive current to efficiently flow through the aperture emission region without reducing the surface area of the aperture emission region.

The first boron-containing III-V group compound semiconductor layer that is lattice-matched to the constituent layer of the light-emitting portion to be joined avoids the introduction of lattice strain, crystal defects, etc. into the light-emitting portion due to the lattice mismatch. Thus, it has an effect of providing a current blocking functional portion that exhibits good bonding characteristics.

The second boron-containing III-V group compound semiconductor layer that is lattice-matched to one constituent layer of the light-emitting portion to be joined has a lattice strain to the light-emitting portion due to lattice mismatch in the aperture light-emitting region. This has the effect of avoiding the introduction of crystal defects and the like and maintaining the crystallinity of the constituent layers forming the light emitting portion in a good condition.

First and second amorphous or polycrystalline
Since the boron-containing III-V group compound semiconductor layer can be formed at a relatively low temperature, it has a function of providing a current blocking function portion while preventing thermal alteration of the constituent layer of the light emitting portion due to thermal strain or the like.

The first boron-containing III-V group compound semiconductor layer made of a boron phosphide (BP) -based semiconductor layer has a pn junction exhibiting a current blocking action, a low ionic bondability and a cubic zinc blende crystal. Depending on the band structure of the valence band of the mold, it is easily brought.

In particular, the first boron-containing III-V group compound semiconductor layer made of monomeric boron phosphide (BP) has excellent crystallinity due to lattice matching, and therefore exhibits an excellent current blocking characteristic. It has a function of providing a current blocking function site.

A boron phosphide (BP) -based semiconductor layer having a bandgap of 3.0 ± 0.2 eV or a boron-containing group III-V compound semiconductor layer made of monomeric boron phosphide is It functions as a constituent layer that forms a current blocking function portion, and also functions as a barrier layer that constitutes a heterojunction light emitting portion.

[0071]

EXAMPLE A GaP-based LE provided with a current blocking function portion composed of first and second boron-containing III-V group compound semiconductor layers.
D was constructed from the following basic laminated construction. Substrate 101, Light-Emitting Layer 10 Made of Single Crystal, Especially Conductive Single Crystal
2, the first boron-containing III-V group compound semiconductor layer 103,
A second boron-containing III-V compound semiconductor layer 104, a front surface electrode 106 provided above the current blocking function portion 105, and an ohmic back surface electrode 107 provided on the back surface of the single crystal substrate 101. Hereinafter, the present invention will be specifically described with reference to the first to fourth embodiments.

(First Embodiment) GaP according to the first embodiment
A schematic cross-sectional view of the system LED 1A is shown in FIG. Further, FIG. 2 shows a schematic plan view of the LED 1A. In the following first to fourth embodiments, the same constituent elements are
The same reference numerals are attached.

In the first embodiment, silicon (Si) -doped n
Form (100) -gallium phosphide (GaP) single crystal was used as the substrate 101. The light emitting layer 102 was composed of a silicon (Si) -doped n-type GaP layer formed at 950 ° C. to 980 ° C. by a general liquid phase epitaxial (LPE) means. The carrier concentration of the light emitting layer 102 was about 2 × 10 ¹⁸ cm ⁻³ , and the layer thickness was about 30 μm. In addition, the light emitting layer 102 also has an atomic concentration of about 6 × 10 ¹⁸ atoms / cm ^3.
Nitrogen (N) of the
onic trap). On the light emitting layer 102, 800 ° C. is also formed by the liquid phase epitaxial means.
A zinc (Zn) -doped p-type GaP layer 111 was deposited at ˜900 ° C. The carrier concentration of the p-type GaP layer 111 is about 1 ×
The layer thickness was 10 ¹⁸ cm ⁻³ and the layer thickness was about 15 μm.

The first boron-containing III-V group compound semiconductor layer 103 is formed by a triethylboron ((C ₂ H ₅ ) ₃ B) / phosphine (PH ₃ ) / hydrogen (H ₂ ) system atmospheric pressure MOCVD method at 800. It was composed of single crystal boron phosphide (BP: lattice constant ≈4.538Å) of a monomer grown at ℃. First
Since the boron-containing III-V group compound semiconductor layer 103 of No. 1 was formed while adding oxygen (O), the resistance was about 2.5 kΩ.
And became a high resistance layer. High resistance first boron-containing III
The layer thickness of the group-V compound semiconductor layer was set to about 0.4 μm. Under the first boron-containing III-V compound semiconductor layer 103, GaP (lattice constant≈5.
In order to relax the lattice mismatch with 450 Å) and obtain the first boron-containing III-V group compound semiconductor layer having excellent crystallinity, the film was formed at a low temperature of 350 ° C. by the above MOCVD means. A low temperature buffer layer 108 made of boron phosphide (BP) was interposed. The low temperature buffer layer 108 is an undoped layer.
of n-type layer, and the layer thickness is about 5 nm.

After the growth of the first boron-containing III-V compound semiconductor layer 103 was completed, the first boron-containing III-V compound semiconductor layer 103 was left only in the projected region 109 of the surface electrode 106. . The first boron-containing III-V group compound semiconductor layer 103 in the aperture light emitting region 110 occupying the element forming region other than the projecting region 109 is formed by using a selective patterning means using a known photolithography technique. Was removed by etching. The plane shape of the remaining first boron-containing III-V group compound semiconductor layer 103 was a circle similar to the horizontal cross-sectional shape of the surface electrode 106. Its diameter was 130 μm (hence the plane area S≈1.1 × 10 ⁻⁴ cm ² ). First boron-containing III-V
In addition to removing the group compound semiconductor layer 103 by etching, the low temperature buffer layer 108 in the open light emitting region was also removed by etching. The low-temperature buffer layer 108 was left in the same plane shape as that of the first boron-containing III-V compound semiconductor layer 103. In order to remove the unnecessary first boron-containing III-V group compound semiconductor layer 103 and the low temperature buffer layer 108, a plasma etching means using a mixed gas of argon (Ar) / methane (CH ₄ ) / hydrogen (H ₂ ). Was used.

The surface of the first boron-containing III-V compound semiconductor layer 103 with the first boron-containing III-V compound semiconductor layer 103 and the low-temperature buffer layer 108 limited to the projection region 109 and left. And the surface of the light emitting layer 102 exposed to the aperture light emitting region 110 was covered with the second boron-containing III-V compound semiconductor layer 104. In the first embodiment, the second boron-containing III-V compound semiconductor layer 104 is composed of a monomeric boron phosphide (BP) having a bandgap of about 3.0 eV at room temperature. P-type GaP layer 11 forming a light emitting portion
In order to obtain a p-type conductive layer similar to that of No. 1, the second boron-containing compound I
The II-V group compound semiconductor layer 103 is formed by the MOCVD described above.
Means was used to dope zinc (Zn) to form a film. The carrier concentration of the second boron-containing III-V compound semiconductor layer 104 is about 6 × 10 ¹⁸ cm ⁻³ , and the layer thickness is about 0.
It was 5 μm.

The first boron-containing III-V group compound semiconductor layer 10 left only in the projected region 109 of the surface electrode 106.
3 and the second boron-containing III-V group compound semiconductor layer 104 bonded to the surface thereof constituted the current blocking functional portion 105. In the first embodiment, the first boron-containing III-
Since the V-group compound semiconductor layer 103 has a high resistance, it has a function of preventing the LED drive current supplied from the surface electrode 106 from short-circuiting to the light-emitting layer 102 in the projection region 109. . In addition, the second boron-containing III-
The V-group compound semiconductor layer 104 has a function of diffusing the drive current, which is blocked by the first boron-containing III-V group compound semiconductor layer 103 from flowing into the projection region 109, to the aperture light emitting region 110.

The surface electrode 106 is located above the projection region 109 and is a p-type second boron-containing III-V compound semiconductor layer 1.
It was provided in contact with 04. The center of the circular projected area 109 and the center of the surface electrode 106 are substantially aligned with each other. In the first embodiment, the surface electrode 106 has a circular shape with a diameter of 120 μm, and the gold / zinc (Au / Zn) alloy /
It was composed of a vacuum deposition film in which three metal layers of nickel (Ni) / gold (Au) were overlaid. The horizontal cross-sectional area (= S ₀ ) of the surface electrode 106 was about 1.1 × 10 ⁻⁴ cm ² , and the ratio (= S / S ₀ ) to the plane area (= S) of the projection area was 1.
The back surface electrode 1 is formed on substantially the entire back surface of the n-type single crystal substrate 101.
07 is provided. In the first embodiment, the ohmic back electrode 107 is formed of a vacuum deposition film of gold (Au).

The front electrode 106 is connected as a pedestal electrode, and a drive current is passed in the forward direction between the front electrode 106 and the back electrode 107 of the LED 1A to obtain a GaP LED having the light emitting characteristics shown in Table 1. It was Table 1 also shows characteristic values of conventional GaP LEDs. Conventional G
The aP-based LED has the same configuration as that of the first embodiment except that it does not include the current blocking function portion 105 including the first and second boron-containing III-V group compound semiconductor layers 103 and 104. It is an LED. In particular, the GaP-based LED according to the present invention provided high-intensity light emission, which was about 1.5 times the conventional emission intensity. Moreover, according to the observation of the near-field light emission pattern (J. Crystal Growth,
221 (2000), 652-656), the light emission from the aperture light emitting region 110 of the GaP LED 1A of the first example was uniform. These good emission characteristics are
GaP system having a function of diffusing the drive current of the second boron-containing III-V compound semiconductor layer into the aperture light-emitting region in combination with the current blocking function of the boron-containing III-V compound semiconductor layer. This is a light emission characteristic characteristically associated with an LED.

Further, since the ratio of the plane area between the installation region of the current blocking function portion 105 (projection region of the surface electrode 106) and the aperture light emitting region 110 (the above ratio S / S ₀ ) is set to be suitable, the forward voltage ( An excessive increase in Vf was avoided (Table 1
reference). The reverse voltage was also good (see Table 1). From the junction structure of the first or second boron-containing III-V group compound semiconductor layer, a GaP system having a current blocking function portion having good junction characteristics without causing disorder of the junction interface with the light emitting portion is obtained. An LED could be constructed.

Table 1 below shows characteristic values of emission wavelength, luminance and forward voltage when the forward current was 20 mA, and
The reverse voltage value when the reverse current value is set to 10 μA will be described by comparing the LED according to the present embodiment (abbreviated as “present invention” in Table 1) and the conventional LED.

[0082]

[Table 1]

(Second Embodiment) The present invention will be described in detail by taking as an example the case of constructing a GaP LED with a laminated structure different from that of the first embodiment. GaP according to the second embodiment
A cross-sectional structure of the system LED 2A is schematically shown in FIG.

The GaP LED 2A is basically composed of the following elements. n-type GaP single crystal substrate 101, n-type Ga
P light emitting layer 102, first boron-containing III-V group compound semiconductor layer 103, second boron-containing III-V group compound semiconductor layer 104, surface electrode 106 provided above the current blocking function portion 105, single crystal substrate Ohmic backside electrode 107 provided on the backside of 101.

In the second embodiment, the first boron-containing III-
The group V compound semiconductor layer 103 was composed of magnesium (Mg) -doped p-type boron phosphide (BP). Further, the p-type first boron-containing III-V compound semiconductor layer 103 is
This is different from the first embodiment in that it is directly bonded to the surface of the GaP light emitting layer 102. First boron-containing III-
The V-group compound semiconductor layer 103 was composed of a BP crystal layer having a bandgap of about 3.1 eV. First boron-containing III-V
The carrier concentration of the p-type BP layer forming the group compound semiconductor layer 103 was about 1 × 10 ¹⁸ cm ⁻³ , and the layer thickness was about 0.1 μm.

After the film formation of the first boron-containing III-V compound semiconductor layer 103 is completed, the projection area 109 immediately below the surface electrode 106 is formed only by the etching means as described in the first embodiment. The boron-containing III-V compound semiconductor layer 103 of No. 1 was left. In addition, the surface of the GaP light emitting layer 102 was exposed in the aperture light emitting region 110. Therefore, the n-type GaP light emitting layer 10 is limited to the projection region 109.
2 and p-type first boron-containing III-V group compound semiconductor layer 1
The current blocking function site 105 was constructed from the pn junction structure with 03.

After forming the current blocking function portion 105, the same MOCVD means as in the first embodiment was used to form the first boron-containing III-V group compound semiconductor layer 103, and the same as that described in the first embodiment. Of the second boron-containing III-V group compound semiconductor layer 104 of FIG.
It was provided so as to cover 10. On the second boron-containing III-V compound semiconductor layer 104, the same planar shape and cross-sectional area (= S ₀ ) as those described in the first embodiment are provided, and the projection area 109 is formed.
A surface electrode 106 having a ratio (= S / S ₀ ) to the cross-sectional area (= S) of 1 was installed. In addition, the n-type single crystal substrate 101
A back surface electrode 107 made of the same material as that of the first embodiment is arranged on the back surface of the above to form the LED 2A.

From the LED 2A thus constructed, the center wavelength is about 560 n when the forward current is 20 mA.
Yellow-green light of m was emitted. LED according to this embodiment
2A, in the aperture light emitting region 110, the p-type second boron-containing III-V group compound semiconductor layer 104 and the n-type GaP are formed.
Since the light emitting portion having a pn junction type single hetero (SH) structure with the light emitting layer 102 is configured, a high light emission intensity of about 15 millicandelas (mcd), which is about twice as high as that of the conventional GaP LED, is obtained. It will be brought. Further, the second boron-containing III-V group compound semiconductor layer 104 having a high forbidden band width exceeding the transition energy corresponding to the emission wavelength exhibits the function as a window layer which also functions as a barrier layer and can transmit light emission. It was possible to provide a GaP LED 2A having higher brightness than the GaP LED 1A of the first embodiment. Furthermore, in the LED 2A of the present example, the thyristor behavior sometimes observed in the conventional pn junction type homojunction structure LED made of GaP using the GaP layer was not observed. In the second embodiment, the second boron-containing III-V group compound semiconductor layer 104 to be bonded onto the liquid phase epitaxial growth layer (the n-type GaP light emitting layer 102 in this embodiment).
The meltback that induces thyristor (melt b
ack; "LIGHT EMITTING DIODE
S "(Prentice-Hall Int. (UK,
1987), see pages 50-51).
Since the technical means for forming a pn junction structure by forming a film by means is adopted, it is possible to provide a GaP-based LED without thyristor behavior.

(Third Embodiment) Gallium Nitride Phosphate (Ga)
N _1-X P _X : GaP provided with a light emitting layer of 0 ≦ X ≦ 1)
The present invention will be specifically described by taking a case of forming a system LED as an example.

FIG. 4 is a GaP system LE according to the third embodiment.
It is a plane schematic diagram of D3A. Further, FIG. 5 is a schematic cross-sectional view taken along the broken line XX ′ shown in FIG.

The GaP LED 3A is basically composed of the following elements. n-type Si single crystal substrate 101, n-type GaN
_0.97 P _0.03 light emitting layer 102, p-type first boron-containing III-
Group V compound semiconductor layer 103, n-type second boron-containing III
Group-V compound semiconductor layer 104, current blocking function portion 105
A front surface electrode 106 provided on the upper side of the substrate and an ohmic back surface electrode 107 provided on the back surface of the single crystal substrate 101. LE
In D3A, the GaP system L described in the first and second embodiments is used.
Unlike the ED1A and 2A, the single crystal substrate 101 is GaP
Was replaced with silicon (Si single crystal), and the light emitting layer 102 was composed of GaN _0.97 P _0.03 instead of GaP.

The n-type GaN _0.97 P _0.03 light-emitting layer 102 was provided with a buffer layer made of boron phosphide (BP) provided on the antimony (Sb) -doped n-type Si single crystal substrate 101 interposed therebetween. The buffer layer is a low temperature buffer layer 108 made of amorphous boron phosphide (BP) (layer thickness = 5 nm) formed at a low temperature of 350 ° C., and a Si-doped layer overlaid on the low temperature buffer layer 108 at 850 ° C. High temperature buffer layer 11 made of n-type single crystal BP (layer thickness = 0.4 μm, carrier concentration = 9 × 10 ¹⁷ cm ⁻³ ).
2 and (see US Pat. No. 6,069,021).
No.). By disposing the BP low temperature buffer layer 108, the lattice mismatch with the Si single crystal substrate 101 is relaxed and the light emitting layer 102 having excellent crystallinity is provided (US-6, above).
069,021). The low-temperature buffer layer 108 and the high-temperature buffer layer 112 are (C ₂ H ₅ ) ₃ B / PH ₃ / H ₂ system atmospheric pressure MO.
Although grown by the CVD means, other growth means such as boron trichloride (BCl ₃ ) / phosphorus trichloride (PCl ₃ ) /
The H ₂ reaction-based halogen vapor phase growth means (see Journal of Japan Society for Crystal Growth, Vol. 25, No. 3 (1998), page A28) can also be used to form the above-mentioned multilayer buffer layer. The n-type GaN _0.97 P _0.03 light emitting layer 102 was provided on the high temperature buffer layer 112 made of the above boron phosphide (BP).

On the light emitting layer 102 made of n-type cubic GaN _0.97 P _0.03 (lattice constant≈4.538Å), the light emitting layer 1 is formed.
No. 02, Mg-doped p-type boron phosphide layer (layer thickness = 0.2 μm, carrier concentration = 3 × 10 ¹⁸ c)
m ⁻³ ) was laminated as a barrier (cladding) layer 113. N-type BP (lattice constant ≈4.538Å) high temperature buffer layer 1
12, n-type GaN _0.97 P _0.03 light emitting layer 102 and p-type BP
(Lattice constant≈4.538Å) A light emitting portion having a lattice matching type pn junction double hetero (DH) structure was constructed with the barrier layer 113.

On the p-type BP barrier layer 113, the n-type first
The boron-containing III-V group compound semiconductor layer 103 was provided.
The first boron-containing III-V compound semiconductor layer 103 is made of S.
It was composed of i-doped n-type boron phosphide (layer thickness = 0.2 μm, carrier concentration = 2 × 10 ¹⁸ cm ⁻³ ). First and second
The first boron-containing III-V group compound semiconductor layer 103 is subjected to the etching removal treatment as described in the above example, and only the projecting region 109 of the surface electrode 106 is formed.
The group V compound semiconductor layer 103 was left. On the other hand, in the aperture light emitting region 110, the surface of the p-type BP barrier layer 113 was exposed. Therefore, the p-type BP barrier layer 1 is limited to the projection area.
A current blocking function portion 105 having a pn junction structure composed of 13 and the n-type first boron-containing III-V group compound semiconductor layer 103 was formed. Also, Si-doped GaN _0.97 P _0.03
(Layer thickness = 0.2 μm, carrier concentration = 3 × 10 ¹⁷ c
While the m ⁻³ ) light emitting layer 102 and the p-type BP barrier layer 113 were formed at 950 ° C. by the above MOCVD means containing ammonia (NH ₃ ) as a nitrogen (N) source.
The first boron-containing III-V compound semiconductor layer 103 was formed at a lower temperature of 850 ° C. That is, the first boron-containing II
The group IV compound semiconductor layer 103 is used as the constituent layer 11 of the light emitting portion.
It is formed of a semiconductor material that lattice-matches 2, 102, and 113, and is formed at a temperature lower than that of the light-emitting portion forming layers 112, 102, and 113 to avoid introduction of lattice strain or thermal strain into the light-emitting layer 102. Adopted technical means.

First boron-containing III-V compound semiconductor layer
The first boron-containing element 103 is formed on the 103 and the aperture light emitting region 110.
At the same 850 ° C. as the III-V compound semiconductor layer 103
Formed Mg-doped p-type boron phosphide (layer thickness = 0.2μ
m, carrier concentration = 2 × 10¹⁸cm^-3) Consisting of a second
A boron-containing III-V compound semiconductor layer 104 was provided. B
P high temperature buffer layer 112, BP barrier layer 113 and first boron-containing layer
Like the element III-V compound semiconductor layer 103, the second
The boron-containing III-V group compound semiconductor layer 104 has the above M content.
The film formation rate was set to 25 nm / min by the OCVD means, and V /
III ratio (= PH ₃/ (CH₃)₃Ga supply ratio)
The film was formed as 50. Select film formation conditions in this way
The layers 112, 113, 103, 104 described above.
Is a BP crystal with a bandgap of about 3.1 eV at room temperature?
It was composed of

On the surface of the second boron-containing III-V compound semiconductor layer 104, which is located above the projected region 109,
The planar surface electrode 106 shown in FIG. 4 was laid. The front surface electrode 106 is orthogonal to the circular center electrode (diameter = 120 μm) 106a for connection (bonding) at its center, and two strip electrodes (width = 30 μm, which extend on the diagonal line of the aperture light emitting region 110). Length = 300μm) 106b
And consisted of Therefore, the total plane area of the surface electrodes 106a and 106b was about 1.8 × 10 ⁻⁴ cm ² .
The projection area 109 of the third embodiment has the same planar shape and plane area as the surface electrode 106. The surface electrode 106 is composed of a gold-zinc (Au 95 wt% Zn 5 wt%) alloy film. On the other hand, an n-type ohmic back surface electrode 107 made of aluminum (Al) is formed on almost the entire back surface of the n-type Si single crystal substrate 101, and the GaP LED 3 is formed.
It was A.

The LED 3A according to the third embodiment is 20
When a forward current of mA was applied, blue-violet light having an emission center wavelength of about 420 nm was emitted. Further, the LED has a substantially uniform emission intensity in the aperture emission region 110. This is because the pn junction structure is formed from the upper barrier layer 113 having a high forbidden band width on the light emitting layer 102 and the first boron-containing III-V group compound semiconductor layer 103 having a wide band gap as well, and thus has a current blocking function. This is because it is configured to be efficiently achieved and to preferentially diffuse the forward current over a wide range of the aperture light emitting region 110. Furthermore, the emission intensity measured by a general radiation integrating sphere was as high as about 18 microwatts (μW). This is because the upper barrier layer 113 and the second boron-containing III-V group compound semiconductor layer 104 are composed of boron phosphide (BP) having a high bandgap capable of sufficiently transmitting the emission of the blue-violet band. Therefore, the efficiency of taking out emitted light to the outside (for example, it can be represented by the photoelectric conversion efficiency of the supplied power and the emission intensity) is improved. That is,
According to the present invention, (a) the light emitting portion is composed of a lattice-matching DH structure, and (b) the first and second boron-containing III.
The group-V compound semiconductor layer is made of a semiconductor material that is lattice-matched to the light-emitting section constituent layer, and (c) the first and second boron-containing III-V group compound semiconductor layers are formed at a lower temperature than the light-emitting section constituent layer. And (d) the first and second boron-containing III-V group compound semiconductor layers are composed of a high forbidden band width monomeric boron phosphide (BP) layer together with the upper barrier layer 113. Reflecting the characteristics of the technical means, it was possible to provide a GaP-based LED that is excellent in the efficiency of extracting light emitted to the outside.

(Fourth Embodiment) First and second boron-containing II
The group IV compound semiconductor layer is formed of boron arsenide phosphide (BAs _{1- X
P X: 0 ≦ X ≦ 1} ) and then, the light emitting layer of gallium phosphide nitride _{(GaN 1-X P X:} 0 ≦ X ≦ 1) configured GaP as
The present invention will be specifically described by taking a system LED as an example.

FIG. 6 is a GaP system LE according to the fourth embodiment.
It is a plane schematic diagram of D4A. 7 is a schematic cross-sectional view taken along the broken line YY 'shown in FIG.

The GaP LED 4A is basically composed of the following elements. p-type zinc-doped gallium arsenide (GaA)
s) Single crystal substrate 101, p-type GaAs _1-X P _X light emitting layer 10
2, p-type first boron-containing III-V group compound semiconductor layer 1
03, an n-type second boron-containing III-V compound semiconductor layer 104, a front surface electrode 106 provided above the current blocking function portion 105, and an ohmic back surface electrode 107 provided on the back surface of the single crystal substrate 101. . The LED 4A includes a substrate material different from the LEDs 1A to 3A described in the first to third embodiments, and the first and second boron-containing group III nitride semiconductor layers 10.
It is configured by utilizing the No. 3, 104.

In the laminated structure for LED4A shown in FIG. 7, a general gallium (Ga) / arsine (AsH ₃ ) / PH ₃ reaction system hydride vapor phase epitaxy (VPE) is formed on a p-type GaAs single crystal substrate 101. Means (“III-V” above
Group Compound Semiconductors ”, pp. 262-263).
From the surface of the aAs substrate 101, arsenic (A
s) Providing a GaAs _1-X P _X composition gradient layer 114 with a composition gradient that linearly decreases the composition (= 1-X) and linearly increases the phosphorus composition ratio (= X). It was The compositional gradient of arsenic (As) was set to 1.0 at the junction interface with the GaAs single crystal substrate 101, was uniformly reduced until the layer thickness reached 6 μm, and finally decreased to 0.5. While decreasing the supply amount of AsH ₃ with respect to PH ₃ to the growth system over time to give a composition gradient, zinc (Zn) was added to add p.
The composition gradient layer 114 has a shape. Carrier concentration is about 1
It was set to × 10 ¹⁸ cm ^-3 .

On the GaAs _1-X P _X composition gradient layer 114,
Similarly, the p-type GaAs _0.5 P _0.5 light emitting layer 102 doped with zinc (Zn) and oxygen (O) having a constant arsenic composition ratio of 0.5 was laminated by the above hydride VPE means. The arsenic composition ratio of the light emitting layer 102 is set to the composition gradient layer 11
By setting the same arsenic composition ratio on the surface of No. 4, the degree of lattice mismatch was reduced, and a high-quality light emitting layer 102 was obtained. GaAs _1-X P _X composition gradient layer 114 and light emitting layer 102
Both films were formed at 750 ° C. The thickness of the light emitting layer 102 is about 4 μm.
m, and nitrogen was added as an isoelectronic impurity to the region of about 1 μm thickness on the surface side. The atomic concentration of nitrogen atoms in the surface area was set to about 6 × 10 ¹⁸ cm ⁻³ . The carrier concentration of the light emitting layer 102 is about 4 × 10 ¹⁷ cm ^−3.
And

[0103] On the p-type GaAs _0.5 P _0.5 emitting layer 102 is a laminate of a first boron-containing group III-V compound semiconductor layer 103 made of n-type arsenide boron phosphide (BAs _0.1 P _{0 .9)} layer . First boron-containing III-V compound semiconductor layer 10
3 is (C ₂ H ₅ ) ₃ B / AsH ₃ / PH ₃ / H ₂ system atmospheric pressure MO
Si-doped n-type layer (layer thickness = 0.1 μm, carrier concentration = 8 × 10 ¹⁷ c during film formation by CVD means)
m ^-3 ). The first boron-containing III-V compound semiconductor layer 103 has a temperature lower than the film formation temperature of the light emitting layer 102 by 350.
An amorphous layer was formed at a temperature of ℃.
In this way, the technical means for avoiding the introduction of lattice strain or thermal strain into the light emitting layer 102 is adopted.

As described in the first to third embodiments, the etching removal treatment is applied to the first boron-containing Group IIIV compound semiconductor layer 103, and the projection area 1 of the surface electrode 106 described later is obtained.
09 only the first boron-containing III-V group compound semiconductor layer 1
03 was left behind. On the other hand, in the aperture light emitting region 110, p
The surface of the GaAs _0.5 P _0.5 light emitting layer 102 was exposed.

On the first boron-containing III-V group compound semiconductor layer 103 and the opening light emitting region 110, Mg-doped p formed at 350 ° C. which is the same as the first boron-containing III-V group compound semiconductor layer 103. Boron phosphide type (layer thickness = 0.2μ
The second boron-containing III-V group compound semiconductor layer 104 having m and carrier concentration = 2 × 10 ¹⁸ cm ⁻³ ) was provided. Amorphous second boron-containing III-V compound semiconductor layer 104
Is a film formation rate of 15 n / min by the MOCVD means described above.
and the V / III ratio (= PH ₃ / (CH ₃ ) ₃ Ga supply ratio) was about 30 to form a film. By selecting the film forming conditions in this manner, the second III-V compound semiconductor layer 104 was made of a BP crystal having a bandgap of about 3.0 eV.

On the surface of the second boron-containing III-V compound semiconductor layer 104, which is located above the projected area 109,
As shown in FIG. 6, two surface electrodes 106 were laid diagonally in the element formation region. The surface electrode 106 is formed of a right-angled isosceles triangular Au / Zn alloy film in which two equal sides are arranged parallel to the end surface of the LED 4A. The length of each equilateral side of the triangular surface electrode 106 is 120 μm, and therefore the total plane area (= S ₀ ) of the surface electrode 106 is about 1.
It became 4 × 10 ⁻⁴ cm ² . On the other hand, the projection area 109 of the fourth embodiment has an isosceles right triangle shape similar to the surface electrode 106, with the length of the equilateral side being 130 μm. The projected areas 109 were arranged at two positions directly below the surface electrode 106 with their apexes of the planar shape aligned. Two projected areas 10
The total plane area (= S) of 9 is about 1.7 × 10 ⁻⁴ cm ² , and the ratio (= S) of the plane area (= S) of the projection region 109 to the cross-sectional area (= S ₀ ) of the surface electrode 106. / S ₀ ) was about 1.2. On the other hand, an n-type ohmic back electrode 107 made of an aluminum (Al) -antimony (Sb) alloy vacuum deposited film is formed on substantially the entire back surface of the n-type Si single crystal substrate 101 to form the GaP LED 4A. did.

From the LED 4A according to the fourth embodiment,
When a forward current of 20 mA was applied, red light having an emission center wavelength of about 650 nm was emitted. First above
To the LEDs 1A to 3A described in the third embodiment,
The LED has a substantially uniform emission intensity in the aperture emission region 110. This is the first boron-containing III-V group compound semiconductor layer 1 having a wide band gap with the light emitting layer 102.
This is because the pn junction structure is formed from No. 03 and No. 03, so that the current blocking function can be efficiently achieved, and the forward current can be preferentially diffused in the wide range of the aperture light emitting region 110. Furthermore, the emission intensity measured by a general radiation integrating sphere was as high as about 10 microwatts (μW). This is because the first and second boron-containing III-V group compound semiconductor layers 103 and 104 are formed at a temperature lower than that of the light emitting layer 102, so that the crystallinity of the light emitting layer 102 due to heat is generated. This is because a good heterojunction interface could be formed while suppressing thermal denaturation and preventing disorder. Further, since the second III-V group compound semiconductor 104 composed of the BP-based mixed crystal layer having a high forbidden band width sufficient for transmitting red light emission is provided on the aperture light emitting region 110, the light emission to the outside can be prevented. This is because the extraction efficiency is improved.

[0108]

According to the present invention, for example, a high resistance first
And a boron-containing III-V compound semiconductor layer of
The current blocking function portion constituted by the junction with the boron-containing III-V group compound semiconductor layer is arranged in the projection region immediately below the surface electrode, and the second III-V compound semiconductor layer is arranged in the external view direction. Since it is arranged to be installed on substantially the entire surface of the opened light emitting area (aperture light emitting area), the high resistance of the first III
Since the LED drive current, the flow of which is blocked by the group V compound semiconductor layer, can be concentratedly passed through the aperture light emitting region at a high density, gallium phosphide (GaP) -based L having high emission intensity is obtained.
ED can be provided.

Further, according to the present invention, the current blocking function portion is formed by a junction with the first and second III-V group compound semiconductor layers whose conduction types are opposite to each other, that is, a pn junction. In addition, since the conductive second III-V compound semiconductor layer is provided on substantially the entire surface of the aperture light emitting region, the LED drive current can be prevented from flowing to the projection region, and the drive current can be prevented. Because it can be distributed preferentially to
A GaP-based LED with high emission intensity can be provided.

In particular, in the present invention, since the pn junction is formed with the first boron-containing III-V group compound semiconductor layer by utilizing one constituent layer forming the light emitting portion, the current blocking function is achieved. Since the site that can be exhibited can be easily configured, it is possible to easily provide a GaP-based LED that has excellent photoelectric conversion efficiency and high emission intensity.

In particular, according to the present invention, the second boron-containing compound I
Since the II-V group compound semiconductor layer is made of a semiconductor layer having the same conductivity type as that of the constituent layer of the light emitting portion for joining the same, it is possible to avoid the formation of the pn junction in the aperture light emitting region. Therefore, since the LED drive current can be effectively passed through the aperture light emitting region, it is possible to provide a GaP LED with high emission intensity.

According to the present invention, the first and second boron-containing compounds I
Since the horizontal cross-sectional area of the current blocking function portion composed of the II-V compound semiconductor layer is set within the range of the ratio defined with respect to the horizontal cross-sectional area of the surface electrode, the LED driving current can be diffused to the aperture light emitting region. It is possible to provide a GaP LED having a low forward voltage and a high emission intensity. In addition, in particular, the current blocking function portion composed of the III-V group compound semiconductor layer having a large forbidden band has a GaP excellent in reverse breakdown voltage.
It is effective in providing a system LED.

According to the present invention, the first and second boron-containing compounds I
Since the II-V group compound semiconductor layer is composed of a boron phosphide-based semiconductor layer having a high band gap, particularly boron phosphide, it is convenient for transmitting the light emission along with the current blocking function site. It is possible to provide a GaP-based LED having a high emission intensity and having a function as a window layer that transmits light emission. In particular,
First and second boron-containing III-V group compound semiconductors are formed on a light emitting layer made of gallium nitride phosphide capable of emitting high-intensity short-wavelength visible light or gallium arsenide phosphide containing nitrogen as an isoelectronic trapping center. It is possible to provide a high-luminance GaP-based LED by providing a portion having both a current blocking function and a light emission transmitting function, which is composed of layers.

According to the present invention, the first and second boron-containing II
Since the group IV compound semiconductor layer is formed of an amorphous layer or a polycrystalline layer that can be formed at a lower temperature than the constituent layer of the light emitting section, thermal strain applied to the constituent layer of the light emitting section such as the light emitting layer is reduced. Since it can be suppressed and the crystallinity of the light emitting layer and the like can be favorably maintained,
A GaP-based LED with high emission intensity can be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an LED described in a first embodiment.

FIG. 2 is a schematic plan view of the LED described in the first embodiment.

FIG. 3 is a schematic sectional view of an LED described in a second embodiment.

FIG. 4 is a schematic plan view of an LED described in a third embodiment.

FIG. 5 is a schematic sectional view of an LED described in a third embodiment.

FIG. 6 is a schematic plan view of an LED described in a fourth embodiment.

FIG. 7 is a schematic sectional view of an LED described in a fourth example.

FIG. 8 is a schematic sectional view of an LED lamp according to the present invention.

[Explanation of symbols]

1A, 2A, 3A, 4A, 10 GaP LED 11 board 12 Boron-containing III-V group compound semiconductor layer 13 Surface electrode 14 Back electrode 15 pedestal 16 bowl 17, 18 terminals 19 Epoxy resin 101 single crystal substrate 102 GaP light emitting layer 103 First boron-containing III-V group compound semiconductor layer 104 Second boron-containing III-V group compound semiconductor layer 105 Current blocking function part 106 surface electrode 106a center electrode 106b strip electrode 107 Back electrode 108 low temperature buffer layer 109 Projection area of surface electrode 110 Aperture emission region of element formation region 111 p-type GaP layer 112 High temperature buffer layer 113 Barrier layer 114 composition gradient layer

Claims (26)

[Claims] 1. A conductive crystal substrate having a back surface electrode on the back surface, a light emitting portion including a light emitting layer made of a gallium phosphide (GaP) -based semiconductor laminated on the substrate, and a front surface electrode on the light emitting portion. In the provided GaP light emitting diode, a first boron-containing III-V group compound semiconductor layer is provided in the projection region of the surface electrode so as to be bonded to one component layer of the light-emitting portion. A GaP-based light-emitting diode comprising a second boron-containing III-V compound semiconductor layer bonded to the -V compound semiconductor layer. 2. The second boron-containing III-V compound semiconductor layer is formed of a conductive layer having a conductivity type opposite to that of the first boron-containing III-V compound semiconductor layer. Item 1. A GaP light emitting diode according to item 1. 3. A first boron-containing III-on the projection area.
2. A pn junction structure comprising a group V compound semiconductor layer and a constituent layer of a light emitting portion which is bonded to the first boron-containing III-V group compound semiconductor layer. 2. The GaP light emitting diode according to item 2. 4. A first boron-containing III present in the projected area III.
A second boron-containing III-V compound semiconductor layer is provided, which covers the surface of the -V compound semiconductor layer and the surface of the constituent layer of the light-emitting portion exposed in the element region other than the projection region. The GaP light emitting diode according to claim 1, wherein the GaP light emitting diode is a light emitting diode. 5. The second boron-containing III-V compound semiconductor layer is formed of a conductive layer having the same conductivity type as that of a constituent layer of the light emitting portion forming a junction. Four
2. The GaP light emitting diode according to any one of 1. 6. The plane area of the second boron-containing III-V compound semiconductor layer is larger than the plane area of the first boron-containing III-V compound semiconductor layer. The GaP light emitting diode according to any one of 1 to 5. 7. A relational expression 0.7 ≦ with respect to the maximum plane area (S ₀ : cm ² ) of the surface electrode of the plane area (S: cm ² ) of the first boron-containing III-V compound semiconductor layer. S / S ₀ ≦ 1.
7. The GaP light emitting diode according to claim 6, wherein the range is set to 5. 8. The first boron-containing III-V compound semiconductor layer is composed of a lattice matching layer having the same lattice constant as that of a constituent layer of the light emitting section to be bonded. 7. The GaP light emitting diode according to any one of items 1 to 7. 9. The second boron-containing III-V compound semiconductor layer is composed of a lattice matching layer having the same lattice constant as one constituent layer of the light emitting section to be joined. 9. The GaP light emitting diode according to any one of items 1 to 8. 10. The first and second boron-containing III-V group compound semiconductor layers are composed of an amorphous layer or a polycrystalline layer. GaP light emitting diode described in. 11. The boron-containing III-V group compound semiconductor layer according to claim 1, wherein the first boron-containing group III-V compound semiconductor layer is composed of a boron phosphide (BP) -based semiconductor layer. GaP light emitting diode. 12. The boron-containing III-V group compound semiconductor layer according to claim 1, wherein the second boron-containing III-V group compound semiconductor layer is composed of a boron phosphide (BP) based semiconductor layer. GaP light emitting diode. 13. The first and second boron-containing III-V group compound semiconductor layers are composed of the same boron phosphide (BP) -based semiconductor layer. 2. A GaP light emitting diode according to item 1. 14. The first or second boron-containing III-V compound semiconductor layer comprises boron phosphide (BP) having a bandgap of 3.0 ± 0.2 electron volts (eV) at room temperature. The GaP light emitting diode according to any one of claims 1 to 13, wherein the GaP light emitting diode is configured as a base material. 15. A monomeric boron phosphide having a band gap of 3.0 ± 0.2 electron volts (eV) at room temperature as the first or second boron-containing III-V compound semiconductor layer. The GaP light emitting diode according to any one of claims 1 to 14, wherein the GaP light emitting diode is composed of a (BP) layer. 16. The light emitting layer provided in the light emitting portion is composed of gallium arsenide phosphide (GaAs _1-X P _X : 0 ≦ X ≦ 1). The GaP light emitting diode according to any one of items. 17. A gallium arsenide phosphide (G) used as a light emitting layer.
The GaP light emitting diode according to claim 16, wherein nitrogen (N) is added to aAs _1-X P _X : 0 ≦ X ≦ 1). 18. The light-emitting layer provided in the light-emitting portion is nitrided.
Gallium phosphide (GaN _1-XP_X: 0 ≦ X ≦ 1)
16. The method according to any one of claims 1 to 15, characterized in that
The GaP light emitting diode according to item 1. 19. The GaP according to claim 16, wherein the second boron-containing III-V group compound semiconductor layer is provided as a barrier layer that is in contact with the light emitting layer. System light emitting diode. 20. A lamp using the GaP light emitting diode according to any one of claims 1 to 19. 21. A light source manufactured from a lamp using the GaP light emitting diode according to claim 20. 22. A device region other than a projection region of a surface electrode formed on a light emitting portion by forming a first boron-containing III-V compound semiconductor layer on a constituent layer of the light emitting portion on a conductive crystal substrate. And removing the first boron-containing III-V compound semiconductor layer in the first boron-containing compound III-V compound semiconductor layer left in the projection region.
-Second boron-containing compound that covers the surface of the group V compound semiconductor layer and the surface of the constituent layer of the light emitting portion exposed in the element region III-
The method for manufacturing a GaP light emitting diode according to claim 1, wherein a group V compound semiconductor layer is formed. 23. After forming the light emitting portion on the conductive crystal substrate, the first boron-containing III-
The method for manufacturing a GaP light emitting diode according to claim 22, wherein a group V compound semiconductor layer is formed. 24. After forming a light emitting portion and a first boron-containing III-V group compound semiconductor layer on a conductive crystal substrate, a second boron-containing III-V group compound is formed at a temperature lower than that of the constituent layer of the light emitting portion. The semiconductor layer is formed, 22 or 2 characterized by the above-mentioned.
4. A method for manufacturing a GaP light emitting diode according to item 3. 25. The GaP light emitting diode according to claim 22, wherein the first and second boron-containing III-V group compound semiconductor layers are formed at the same temperature. Production method. 26. The first and second boron-containing III-V compound semiconductor layers are formed at a temperature of 250 ° C. or higher and 750 ° C. or lower. 1. A method for manufacturing a GaP light emitting diode according to claim 1.