JPH05315709A - Semiconductor light emitting device and optical apparatus using same - Google Patents

Abstract

PURPOSE:To ensure high output power while emitting light with a fine diameter in an AlGaInP semiconductor light emitting device by reducing device resistance. CONSTITUTION:There are laminated on an active layer 14 a p-AlGaInP cladding layer 15, a p-AlGaAs diffusion stopping layer 16, an n-AlGaAs current blocking layer 17, a p-AlGaAs conductor layer 18, and a p-GaAs contact layer 18, and a p-GaAs contact layer 19. Zn is diffused from the contact layer 19 to the diffusion stopping layer 16 to form a current passage region 21. A central region of the current passage region 21 reaches the diffusion stoppoing layer 16, and a surrounding region of the current passage region 21 is formed up to the conductor layer 18, and is shallower than the central region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting element and an optical device using the semiconductor light emitting element. Specifically, it relates to a semiconductor light emitting element such as a light emitting diode (LED) or a semiconductor laser element. Furthermore, an optical detection device such as a floodlight, a pointer, an optical encoder or a distance sensor,
The present invention relates to an apparatus including an optical scanner such as a laser beam printer or a bar code reader, an optical apparatus such as an optical fiber module using the semiconductor light emitting element.

[0002]

2. Description of the Related Art FIG. 1 is a cross-sectional view showing the structure of a conventional AlGaInP-based semiconductor light emitting device A in which a current confinement structure is realized by using a pn junction. In the conventional semiconductor light emitting device A, n-AlGaInP is formed on the n-GaAs substrate 1.
Lower cladding layer 2, undoped-AlGaInP active layer 3, p
-AlGaInP upper clad layer 4, n-AlGaInP
After the current blocking layer 5 and the p-GaAs contact layer 6 are sequentially epitaxially grown, a p-type current path is formed by penetrating the current blocking layer 5 and doping a p-type impurity such as Zn from the contact layer 6 to the upper cladding layer 4. Region 7 is formed. Further, a p-side electrode 8 opened above the current passage region 7 is provided on the upper surface of the contact layer 6, and an n-side electrode 9 is provided on the entire lower surface of the substrate 1.

However, when a current is injected from the p-side electrode 8, a reverse bias does not flow between the current blocking layer 5 and the upper cladding layer 4, and the current does not flow. It is injected into the active layer 3 through the passage region 7. When a current is injected into the active layer 3, the active layer 3 emits light at that portion, and the emitted light passes through the current passage region 7 and is emitted from the light emission window of the p-side electrode 8. Therefore, the semiconductor light emitting device A having the current constriction structure is realized.

[0004]

However, p-type AlGaInP is a material for which it is difficult to increase the carrier concentration, and its doping concentration rises only up to about 5 × 10 ¹⁷ cm ^-3 , and it has a low resistance. It is difficult to make it. Therefore, A
When the current confinement structure is realized in the 1GaInP-based semiconductor light emitting device A, even if a part of the current blocking layer 5 is inverted to p type by introducing a p-type impurity into the n-AlGaInP current blocking layer 5, it is inverted. It is difficult to increase the carrier concentration in the region (current passage region 7), and the element resistance increases. For this reason, if the current passage region 7 is reduced in order to obtain a small light emission diameter, the resistance of the element becomes very high, and the heat generated by the resistance causes a decrease in optical output and a decrease in reliability. There was a problem.

Further, p-GaAs between the contact layer 6 and the p-type inverted current blocking layer 5 in the current passage region 7 is formed.
In the heterojunction of / p-AlGaInP, as shown in FIG. 2, the band discontinuity value ΔEv of the valence band is 360.
Since it is so large as meV, in order to inject holes having a large effective mass from the p-GaAs contact layer 6 into the p- (Al _0.2 Ga _0.8 ) InP current blocking layer 5 over the hetero barrier ΔEv, a large voltage is applied. If it is not added, injection cannot be performed, and there are problems such as a decrease in light output and a decrease in reliability as described above.

The present invention has been made in view of the drawbacks of the above conventional examples, and in an AlGaInP-based semiconductor light emitting device such as a light emitting diode or a semiconductor laser device, the resistance of the current blocking layer in the current passage region is reduced. The main purpose of the device is to reduce the element resistance while achieving a small light emission diameter.

[0007]

A semiconductor light emitting device of the present invention has a current blocking structure having a p-type upper cladding layer, an n-type current blocking layer, and a p-type contact layer above an active layer.
In a current confinement type semiconductor light emitting device in which a current passage region penetrating a part of the n-type current blocking layer is formed by introducing a type impurity, AlG is formed in a main constituent part including the active layer.
Using an aInP-based material, AlGa is used as the n-type current blocking layer.
It is characterized by using an As-based material.

Further, the semiconductor light emitting device of the present invention has a current blocking structure having a p-type upper cladding layer, an n-type current blocking layer, and a p-type contact layer above the active layer. In a current confinement type semiconductor light emitting device having a current passage region penetrating a part of the n-type current blocking layer, the depth of impurity introduction differs between the central region and the peripheral region of the current passage region, In the region, p-type impurities are introduced to a portion deeper than the lower junction surface of the n-type current blocking layer, and in the peripheral region, deeper than the lower junction surface of the p-type contact layer and lower junction of the n-type current blocking layer. It is characterized in that the p-type impurity is introduced to a portion shallower than the surface.

Further, the semiconductor light emitting device of the present invention has a current blocking structure including a p-type upper cladding layer, an n-type current blocking layer and a p-type contact layer above the active layer. In a current confinement type semiconductor light emitting device in which a current passage region penetrating a part of the n-type current blocking layer is formed, an AlGaInP-based material is used for a main constituent part including the active layer, and the n-type current blocking layer is formed. It is characterized in that an AlGaInP-based material or an AlGaAs-based material is used and the Al composition ratio of the current blocking layer is decreased toward the p-type contact layer.

In the semiconductor light emitting device of the present invention, a first p-type AlGaAs layer may be provided between the n-type current blocking layer and the p-type contact layer.

In the semiconductor light emitting device of the present invention, the p-type contact layer and the first p-type AlGaA are used.
The valence band band discontinuity value at the heterojunction with the s layer is smaller than the valence band band discontinuity value between the p-type contact layer and the region of the n-type current blocking layer inverted to p-type, and the p-type It may be set smaller than the valence band band discontinuity between the contact layer and the p-type upper cladding layer.

Further, in the semiconductor light emitting device of the present invention, the Al composition ratio of the first p-type AlGaAs layer may be decreased toward the p-type contact layer.

Further, in the semiconductor light emitting device of the present invention, a second p-type AlGaAs layer may be provided between the n-type current blocking layer and the p-type upper cladding layer.

Further, in the semiconductor light emitting device of the present invention, the carrier concentration of the second p-type AlGaAs layer is
The concentration may be set lower than the p-type carrier concentration in the p-type inversion region of the n-type current blocking layer.

Further, in the semiconductor light emitting device of the present invention, the carrier concentration of the second p-type AlGaAs layer is the same as that of the first p-type AlGaAs layer.
It may be set lower than the carrier concentration of the p-type AlGaAs layer.

Further, in the semiconductor light emitting device of the present invention, the band gaps of the n-type current blocking layer, the first p-type AlGaAs layer and the second p-type AlGaAs layer are all larger than the band gap of the active layer. You may.

Further, the semiconductor light emitting device of the present invention may be an edge emitting device or a top emitting device.

Further, in the semiconductor light emitting device of the present invention, the p-type contact layer portion of the current passage region may be removed or thinned by etching.

Further, the semiconductor light emitting device of the present invention can be used in an optical device together with a light receiving device, an optical scanner and the like.

[0020]

According to the present invention, in the semiconductor light-emitting device having a current confinement structure in which the main components such as the active layer and the upper and lower clad layers are made of AlGaInP type material, the n-type current blocking layer is made of AlGaAs type material. There is. Al
Since a GaAs-based material can increase the p-type carrier concentration, when the n-type current blocking layer is inverted to p-type by introducing a p-type impurity to form the current passage region, the p-type of the current blocking layer is used. A high p-type carrier concentration can be obtained in the inversion region. For this reason, it is possible to prevent the resistance of the current passage region from increasing and it is possible to reduce the resistance. In particular,
Even when the current injected into the active layer is confined to a minute region, the resistance of the current passage region can be reduced, and the light output and the reliability are not deteriorated due to heat generation, and the AlGaInP-based material with a minute light emission diameter is used. A semiconductor light emitting device made of a material can be realized.

In the semiconductor light emitting device of the present invention, the depth of impurity introduction differs between the central region and the peripheral region of the current passage region, and the central region is deeper than the lower junction surface of the n-type current blocking layer. Since the p-type impurity is introduced to the peripheral region, the p-type impurity is introduced into the peripheral region deeper than the lower junction surface of the p-type contact layer and shallower than the lower junction surface of the n-type current blocking layer. Since the peripheral region of the current passage region is diffused at least under the contact layer,
The region where holes feel the hetero barrier becomes wider and the resistance is lowered. On the other hand, since the portion of the current passage region close to the active layer is only the central region, it is possible to emit light with a minute emission diameter due to the current confinement structure.

Further, in the semiconductor light emitting device of the present invention, since the Al composition ratio of the current blocking layer is decreased toward the p-type contact layer, discontinuity in the valence band between the current blocking layer and the contact layer ( (Hetero barrier) disappears, the energy level of the valence band changes smoothly between the current blocking layer and the contact layer, holes are easily moved, and the device resistance can be reduced.

Similarly, when the first p-type AlGaAs layer is provided between the current blocking layer and the contact layer, the first
To reduce the Al composition ratio of the AlGaAs layer toward the p-type contact layer, the first p-type AlGaA
Discontinuity of the valence band between the s layer and the contact layer can be eliminated, and the device resistance can be further reduced.

Further, the p concentration in the region where the carrier concentration of the second p-type AlGaAs layer is inverted to the p-type of the n-type current blocking layer.
If the carrier concentration is set lower than the carrier concentration of the first p-type AlGaAs layer, the current does not spread again despite the current confinement, and a high current confinement effect can be achieved. Luminous efficiency can be obtained.

A first p-type AlGaAs layer is provided below the p-type contact layer, and the valence band discontinuity value at the heterojunction between the p-type contact layer and the first p-type AlGaAs layer is p-type. It is smaller than the valence band band discontinuity between the contact layer and the p-type inversion region of the n-type current blocking layer, and is between the p-type contact layer and the p-type upper cladding layer. Since it is set smaller than the discontinuity value, the p-type contact layer and the p
The hetero barrier with the AlGaAs layer can be reduced, the resistance can be reduced when the current is injected into the active layer, and the element resistance can be further reduced.

Further, a second layer provided under the n-type current blocking layer
Since the p-type AlGaAs layer has a smaller diffusion rate of impurities than the AlGaInP layer, the introduction position of the impurities can be easily controlled when the impurities are introduced, and the impurity profile of the current passage region can be controlled. it can. Particularly, in the case of the current passage region having the impurity profiles having different depths in the central region and the peripheral region, the impurity depth in the central region can be easily controlled.
As a result, the yield of the device is improved, and the reproducibility of device manufacturing is improved.

Further, an n-type current blocking layer and a first p-type Al
By making the band gaps of the GaAs layer and the second p-type AlGaAs layer both larger than the band gap of the active layer, the light generated in the active layer is absorbed by the current blocking layer and the first and second AlGaAs layers. Therefore, it is possible to prevent the luminous efficiency from decreasing.

Further, since the semiconductor light emitting device of the present invention has a small light emission diameter and can increase the light output, it can be used together with a light receiving device, an optical scanner, a lens, etc., for a projector, an optical sensor, a laser beam printer, By configuring an optical device such as a bar code reader, an optical device with good performance can be manufactured.

[0029]

EXAMPLE FIG. 3 shows AlGaIn according to an example of the present invention.
FIG. 3 is a partially cutaway perspective view showing a structure of a P-based surface-emitting light emitting diode B. This light emitting diode B will be described according to the manufacturing procedure. First, n-Ga is formed by MOCVD.
On the As substrate 11, an n-AlAs layer and n- (Al _x
Ga _1-x ) As layer [x = 0.4; only Al composition x is shown below. Multilayer reflective film layer 12 made of], n- (Al _y Ga
_1-y ) InP [y = 0.7; hereinafter, only Al composition y is shown. ] Lower clad layer 13, p-GaInP active layer 14,
p-AlGaInP [y = 0.7] upper cladding layer 15,
p-AlGaAs [x = 0.7] diffusion stop layer 16, n-
AlGaAs [x = 0.7] current blocking layer 17, p-Al
The GaAs [x = 0.5] conductive layer 18 and the p-GaAs contact layer 19 are sequentially epitaxially grown.

After that, Zn is diffused as a p-type impurity so as to reach the diffusion stop layer 16 from the contact layer 19 by penetrating a part of the current blocking layer 17 to form a current passage region 21. The current passage region 21 is deep in the central region and reaches the diffusion stop layer 16 below the lower junction surface of the current blocking layer 17, and the peripheral region is shallow and the lower junction of the contact layer 19 is formed. The conductive layer 18 below the surface is reached.

FIGS. 4A to 4E show a method for obtaining an impurity profile having different diffusion depths in the central region and the peripheral region as described above. In FIG. 4A, as described above, n
A state in which each layer from the multilayer reflective film layer 12 to the contact layer 19 is epitaxially grown on the GaAs substrate 11 (in FIG. 4, the layers from the substrate 11 to the upper cladding layer 15 are omitted) is shown. .. This contact layer 1
A SiO ₂ film 25 is formed on the entire surface of the substrate 9, and the SiO ₂ film 25 is patterned to open a window 26 having a shape corresponding to the central region of the current passage region 21, as shown in FIG. 4B.
Then, from the window 26 of the SiO ₂ film 25 to the contact layer 19
Zn-doped spin-on glass 27 is applied to the surface of the SiO 2 and SiO 2 is made to correspond to the peripheral region of the current passage region 21.
Applying a Zn-doped spin-on-glass 27 on the ₂ film 25, and regions not covered by the spin-on-glass 27 of the SiO ₂ film 25 is removed by etching or the like [FIG. 4 (c)]. After this, Z in the spin-on glass 27
When n is diffused, Zn diffuses directly from the contact layer 19 in the central portion where the SiO ₂ film 25 is not deposited, so that the diffusion rate is high and the diffusion depth is deep. In contrast, in the peripheral portion that the deposition of the SiO ₂ film 25, SiO ₂
Since Zn is diffused through the film 25, the diffusion rate of Zn becomes slower and the diffusion depth becomes shallower than that in the central portion where the SiO ₂ film 25 is not deposited [FIG. 4 (d)]. After this,
When the spin-on glass 27 and the SiO ₂ film 25 are removed, as shown in FIG. 4E, the current passage region 21 having a deep impurity profile in the central region and a shallow impurity profile in the peripheral region is formed.
Is obtained.

FIG. 5 is a diagram showing the relationship between the diffusion depth d of Zn in GaAs and the diffusion time t. The straight line α is S.
The relationship is shown in the case where Zn is directly diffused without the iO ₂ film 25 being deposited, and the straight lines β and γ indicate the thicknesses D ₁ and D ₂ (D ₁ <D ₁ <
The SiO ₂ film 25 of D ₂ ) is deposited, and the SiO ₂ film 25
The relationship when Zn diffuses through is shown. Si
In the portion where O ₂ film 25 is not deposited, to the diffusion depth d that is proportional to the diffusion time √T, it has √T sections in a portion where the SiO ₂ film 25 is deposited, SiO ₂ The diffusion depth d becomes shallower at the same diffusion time t as compared to the portion where the film 25 is not deposited. Further, the thicker the deposited SiO ₂ film 25 is, the smaller the diffusion depth d is. For example, the diffusion time t
Is t ₁ , the diffusion depth is d ₁ in the portion where the SiO ₂ film 25 is not deposited, and the SiO ₂ film having a relatively thin film thickness D ₁ is formed.
_{2 The} diffusion depth becomes d ₂ in the portion where the film 25 is deposited,
The diffusion depth is d ₃ (d ₁ > d ₂ > d ₃ ) in the portion where the SiO ₂ film 25 having a relatively large film thickness D ₂ is deposited. Therefore, by controlling the diffusion time t and the film thickness of the SiO ₂ film 25, it is possible to freely control the diffusion depth of the central region and the diffusion depth of the peripheral region of the current passage region 21, and it is possible to easily control the diffusion depth of FIG. Such an impurity profile can be obtained.

Further, since the diffusion stop layer 16 is formed below the n-AlGaAs current blocking layer 17, it is easy to control the diffusion depth of Zn in the central region.
When impurities such as Zn are introduced to the bottom of the current blocking layer 17, if the layer below the current blocking layer 17 is an AlGaInP-based material, it is very difficult to control the diffusion depth of the impurities because the diffusion coefficient is large. However, the AlGaAs layer (diffusion stop layer 1
In the case of 6), since the diffusion coefficient is small, the diffusion depth of impurities can be easily controlled. As a result, the reproducibility of the diffusion pattern in the current passage region 21 is improved, and the characteristics and reliability of the device are improved.

After the current passage region 21 is formed in this manner, in order to prevent absorption of light emitted from the active layer 14, the contact layer 19 is removed in the central region of the current passage region 21 to open the light emission window 20. Further, a p-side electrode 22 in ohmic contact is provided on the contact layer 19, and a light emitting window 23 is also opened in the p-side electrode 22. on the other hand,
An n-side electrode 24 in ohmic contact is provided on the lower surface of the substrate 11.

However, when a voltage is applied between the p-side electrode 22 and the n-side electrode, holes are injected from the p-side electrode 22 into the active layer 14 through the current passage region 21, and the active layer 14 emits light. The emitted light passes through the current passage region 21, and the light exit window 20,
It is emitted from 23 to the outside.

In such an AlGaInP-based light emitting diode B, the n-type current blocking layer 17 is made of Al in the present invention.
GaAs is used. Since AlGaAs can increase the p-type carrier concentration, the current passage region 21 in the current blocking layer 17 which is inverted to the p-type by the diffusion of Zn has a high carrier concentration and a low resistivity. As a result, the p-side electrode The element resistance between the electrode 22 and the n-side electrode can be lowered.

Furthermore, n-AlGaAs [x = 0.7]
Between the current blocking layer 17 and the p-GaAs [x = 0] contact layer 19, the p-AlGaAs [x = 0.5] conductive layer 1
8 is provided, and the valence band band discontinuity at the heterojunction between the contact layer 19 and the conductive layer 18 is
9 and the valence band band discontinuity between the region of the current blocking layer 17 inverted to p-type, and the valence band discontinuity between the contact layer 19 and the upper cladding 15 layer. 6, the hetero barrier ΔEv due to the band discontinuity between the conductive layer 18 and the contact layer 19 in the valence band can be reduced, and the hetero barrier on the lower surface of the contact layer 19 can be reduced. It is possible to facilitate the movement of holes at the junction portion and easily inject current into the active layer 14 at a low voltage. Specifically, in the conventional light emitting diode, the heterobarrier ΔEv is 360 meV as described above, whereas in the light emitting diode according to the present invention, the heterobarrier ΔEv is 25 meV.
It could be 0 meV and could be reduced by 100 meV or more.

Further, since the p-AlGaAs conductive layer 18 is doped with a relatively high concentration, holes injected from the outside of the current passage region 21 through the contact layer 19 easily move in the conductive layer 18. The conductive layer 18
Then, the holes are uniformly spread over the entire current passage region 21.

Further, since the impurity profile of the current passage region 21 is deep in the central region and relatively shallow in the peripheral region, the horizontal cross-sectional area is large above the current passage region 21 and the current diffusion region 21 is formed. Since the resistance is reduced and the horizontal cross-sectional area is small in the lower part of the current passage region 21 near the active layer 14, the current confinement structure is formed and the diameter of the minute light emission is reduced. That is, at least the contact layer 1 is provided in the peripheral region of the current passage region 21.
Since the diffusion is performed below the lower surface of 9, the region where holes feel the hetero barrier becomes wider and the resistance is lowered. By doing so, even if the contact layer 19 is removed to prevent light absorption, holes can be injected into the current passage region 21 from a wide region, so that the resistance can be further reduced.

The carrier concentration of the diffusion stop layer 16 is
It is about 5 × 10 ¹⁷ cm ⁻³ , which is set to be lower than the carrier concentration of the conductive layer 18 and the p-type carrier concentration of the current blocking layer 17 which is inverted to the p-type, so that current confinement can be performed once. Regardless, the current does not spread again, a high current constriction effect can be achieved, and high luminous efficiency can be obtained.

According to the present invention, it is possible to reduce the element resistance while achieving a minute light emission diameter by the above-mentioned constitutions. FIG. 7 is a diagram showing the relationship between the forward voltage and the diffusion area of the current passage region 21 (cross-sectional area of the current passage region) in the light emitting diode, where δ is AlGaIn in the current blocking layer 5.
A conventional example using a P layer, ε is AlGaA in the current blocking layer 17.
1 illustrates a light emitting diode of the present invention using an s layer. Here, the voltage when the forward current I _F is 10 mA is the forward voltage. In the conventional example, when the diffusion area becomes small, the forward voltage becomes 3 V as the element resistance increases.
It is very close and very high. On the other hand, in the device using AlGaAs for the current blocking layer 17 according to the present invention, the forward voltage could be suppressed to as low as about 2V.

As described above, according to the present invention, the element resistance can be reduced, and the initial heat amount associated therewith can be suppressed low. As a result, saturation of the optical output due to heat generation can be suppressed, and high output operation becomes possible. In addition, since the temperature rise of the element can be suppressed, the life can be extended. In particular, the emission area is miniaturized (for example, the emission diameter is 1
In the case of 0 μm or 5 μm), the present invention is very effective.

The n-type current blocking layer and the first p-type AlG
Since the band gaps of the aAs layer and the second p-type AlGaAs layer are both made larger than the band gap of the active layer, the light generated in the active layer is reflected by the current blocking layer and the first and second AlGaAs layers. Not absorbed, the luminous efficiency can be improved.

FIGS. 8A to 8E are sectional views showing another method for forming the impurity profiles having different diffusion depths in the central region and the peripheral region. In this method, as shown in FIG. 8A, each layer from the multilayer reflective film layer 12 to the contact layer 19 is epitaxially grown on the n-GaAs substrate 11 (in FIG. Each layer up to layer 15 is omitted.) After that, FIG.
As shown in (b), the upper surface of the contact layer 19 is etched at a portion which will be the central region of the current passage region 21 to form a recess 28 in the central portion of the contact layer 19. Then, after Zn-doped spin-on glass 27 is applied on the entire surface of the contact layer 19, the spin-on glass 27 is patterned to leave the spin-on glass 27 in a region corresponding to the current passage region 21, and the spin-on glass 2 in other regions.
7 is removed [FIG. 8 (c)]. After that, when Zn in the spin-on glass 27 is diffused, G of the contact layer 19
Since the diffusion speed is slow in aAs, the Zn contact layer transit time is short and the diffusion depth is deep in the recess 28 of the contact layer 19. On the other hand, in the peripheral portion of the concave portion 28 of the contact layer 19, since the Zn contact layer transit time is long, the diffusion depth is smaller than that in the central region [FIG.
(D)]. After that, when the spin-on glass 27 is removed, a current passage region 21 having an impurity profile deep in the central region and shallow in the peripheral region is obtained as shown in FIG. The thin portion of the concave portion 28 of the contact layer 19 may be left as it is, or may be removed thereafter to open the light emitting window 20.

FIG. 9 is a band structure diagram showing a band structure of a light emitting diode according to another embodiment of the present invention. In this embodiment, p-A in which the Al composition ratio x gradually changes in a region of the conductive layer 18 adjacent to the contact layer 19 is used.
An lGaAs [x = 0.5 to 0] grade layer 29 is formed. That is, the Al composition ratio is x = 0.5 in the region of the conductive layer 18 distant from the contact layer 19, but in the grade layer 29, the Al composition ratio is x = 0.5.
It is gradually decreasing toward x = 0.5-0. Therefore, the discontinuity of the valence band is eliminated, and the energy level of the valence band changes smoothly and continuously between the conductive layer 18 and the contact layer 19. As a result, holes easily move through the hetero barrier between the contact layer 19 and the conductive layer 18,
The element resistance can be reduced. Although the Al composition ratio of the grade layer 29 is continuously changed in this embodiment, it may be changed stepwise.

FIG. 10 is a sectional view showing still another embodiment of the light emitting diode according to the present invention. In this light emitting diode B1, the conductive layer 18 is not provided between the current blocking layer 17 and the contact layer 19, and the current blocking layer 1 is provided.
The contact layer 19 is provided directly on the surface 7. In this embodiment, p− where the Al composition ratio x gradually changes in the region of the current blocking layer 17 adjacent to the contact layer 19.
An AlGaAs [x = 0.7 to 0] grade layer 30 is formed. That is, the contact layer 1 of the current blocking layer 17
In the region away from 9, the Al composition ratio is x = 0.7, but in the grade region 30, the Al composition ratio gradually decreases toward the contact layer 19 at x = 0.7 to 0.
Therefore, as shown in FIG. 11, the energy level of the valence band changes smoothly and continuously between the current blocking layer 17 and the contact layer 19. As a result, even when the conductive layer 18 is not provided, holes easily move in the hetero barrier between the contact layer 19 and the current blocking layer 17 in the current passage region 21, and the device resistance can be reduced. In addition,
Also in this embodiment, the Al composition ratio of the grade layer 30 is continuously changed, but it may be changed stepwise. In this embodiment, the current blocking layer is n-
It may be AlGaAs or n-AlGaInP.

FIG. 12 is a perspective view showing the structure of an AlGaInP based semiconductor laser device C according to still another embodiment of the present invention. This semiconductor laser device C is an n-GaAs
On the substrate _{31, n- (Al y Ga 1} -y) InP [y =
0.7] lower cladding layer 32, undoped-GaInP active layer 33, p-AlGaInP [y = 0.7] upper cladding layer 34, p-AlGaAs [x = 0.7] diffusion stop layer 3
5, n-AlGaAs [x = 0.7] current blocking layer 36,
p-AlGaAs [x = 0.5] conductive layer 37, p-Ga
An As contact layer 38 is sequentially epitaxially grown,
A current passage region 39 is formed from end face to end face over the entire length of the epitaxial crystal substrate 31.
The current passage region 39 is formed by diffusing Zn so as to penetrate the current blocking layer 36 and reach the diffusion stop layer 35 from the contact layer 38. The current passage region 39 is deep in the central region and is deep in the current blocking layer 36. It reaches the diffusion stop layer 35 below the lower junction surface, is shallow in the peripheral region, and reaches the conductive layer 37 below the lower junction surface of the contact layer 38. In order to form such an impurity profile, the same method as shown in FIGS. 4 and 8 may be used. A p-side electrode 40 is provided on the upper surface of the contact layer 38, and an n-side electrode 41 is provided on the lower surface of the substrate 31.

In this semiconductor laser device C, when holes are injected into the active layer 33 through the current passage region 39, laser light is emitted from the end face of the active layer 33.

FIG. 13 shows AlG according to another embodiment of the present invention.
FIG. 3 is a perspective view showing a structure of an aInP-based edge emitting light emitting diode D. This light emitting diode D is n-GaAs
On the substrate _{51, n- (Al y Ga 1} -y) InP [y =
0.7] lower cladding layer 52, undoped-GaInP active layer 53, p-AlGaInP [y = 0.7] upper cladding layer 54, p-AlGaAs [x = 0.7] diffusion stop layer 5
5, n-AlGaAs [x = 0.7] current blocking layer 56,
p-AlGaAs [x = 0.5] conductive layer 57, p-Ga
An As contact layer 58 is sequentially grown epitaxially,
A current passage region 59 is partially formed so as to face one end face of this epitaxial crystal substrate 51. The current passage region 59 is formed by diffusing Zn so as to penetrate the current blocking layer 56 and reach the diffusion stop layer 55 from the contact layer 58. The current passage region 59 is deep in the central region and is deeper in the current blocking layer 56. It reaches the diffusion stop layer 55 below the lower junction surface, is shallow in the peripheral region, and reaches the conductive layer 57 below the lower junction surface of the contact layer 58. Further, the p-side electrode 60 is provided on the upper surface of the contact layer 58, and the n-side electrode 6 is provided on the lower surface of the substrate 51.
1 is provided.

Since the light emitting diode D is of an end face emission type, when a current is injected into the active layer 53 through the current passage region 59, light is emitted from the end face of the active layer 53.

Next, application examples using the above semiconductor light emitting device will be described. First, FIG. 14 (a) (b) (c)
The floodlight E shown in FIG. In this projector E, the semiconductor light emitting device 71 of the present invention is provided on one lead frame 72.
While die-bonding on the above and wire-bonding to the other lead frame 73, the resin is low-pressure cast into a predetermined shape with a sealing resin 74 such as a transparent epoxy resin for sealing.
The overall shape is a square block. On the surface of the sealing resin 74, a Fresnel type flat plate lens 75 in which a large number of annular lens units are concentrically arranged is integrally formed, and on both sides of the surface, the same height as the Fresnel type flat plate lens 75, or Fresnel. A jaw portion 76 that is slightly higher than the die plate lens 75 is provided so as to project, and the jaw portion 76 protects the Fresnel plate lens 75.

In the case of this projector E, the semiconductor light emitting device 71
Has a high light emission efficiency and has a minute light emitting region. Therefore, the Fresnel-type flat plate lens 75 narrows the directional characteristics of light, and a strong output and a thin beam can be obtained even at a long distance. For example, a Fresnel type flat lens 75 has a focal length f = 4.5 mm and a lens diameter of 3.5 m.
m, the light extraction window of the semiconductor light emitting device 71 has a diameter of 20
Beam diameter at a distance of 1 m is 4
It is about mm. However, a conventional light emitting diode (that is, the light emitting area is 3
In the case of about 50 μm square), the diameter spreads to about 70 mm, so that a great advantage can be obtained by manufacturing the projector E using the semiconductor light emitting device 71 according to the present invention.

Further, as a conventional projector, there is a can seal type in which a semiconductor laser element and a Fresnel type flat lens are attached to a heat sink protruding from a stem, and these are covered with a metal cap. Compared with such a conventional projector, the projector E of the present invention has a greatly simplified structure, and can reduce cost and bulk volume.

Although a light beam which emits parallel light rays having a narrow directivity has been described here, by changing the parameters of the Fresnel type flat plate lens 75, a light beam such as a focused beam or a deflected beam can also be projected. The applicability is self-evident.

FIG. 15 shows a handy type pointer (light projector) F for pointing the position of an image on a screen or the like. The pointer F comprises a light emitting diode (LED) 81 according to the present invention, a collimating light projecting lens 82, an operating circuit 83 and a battery 84. The light emitted from the semiconductor light emitting element 81 is collimated by the light projecting lens 82. Then, it is projected on the screen, and the designated spot is indicated by a light spot.

Most of the pointers currently used are those using a semiconductor laser element, but since laser light is used, it is harmful if the emitted laser light enters the eyes of the surrounding people. Due to this danger, problems such as laser regulation have occurred. Therefore, in order to solve such a problem, an LED pointer using a light emitting diode has been considered. However, in the case of an LED pointer that is collimated by a conventional light emitting LED (emission diameter 400 μm) and a projection lens with a focal length f = 10 mm and a lens diameter of 4 mm, the beam diameter on the screen 5 m ahead is 200 m.
It spreads so much that it is almost invisible.

On the other hand, in the case of the pointer F using the LED 81 according to the present invention, the LED 8 having an emission diameter of 10 μm is used.
1 and a similar projection lens 82 having a focal length f = 10 mm and a lens diameter of 4 mm is used, the beam diameter is as small as 5 mm even on a screen 5 m ahead, which makes it easy to see. Therefore, by improving the light output and directivity with the LED 81 of the present invention, a safe and easy-to-see pointer F can be manufactured.

FIG. 16A is a perspective view showing a transmissive optical rotary encoder G using the semiconductor light emitting device 95 according to the present invention. The rotary encoder G includes a rotary plate 92 attached to a rotary shaft 91, a fixed plate 93 facing the outer peripheral portion of the rotary plate 92, a rotary plate 92, and a light projecting lens 94 facing the fixed plate 93. It comprises a semiconductor light emitting device 95 and a light receiving device 96 according to the invention. The outer circumference of the rotary plate 92 is perforated with slits 97 at intervals of 1 mm, and the fixed plate 93 is also perforated with track A slits 98 and track B slits 99 at intervals of 1 mm.

The light emitted from the semiconductor light emitting element 95 is collimated by the light projecting lens 94, divided by the slits 98 and 99 of the fixed plate 93, passes through the slit 97 of the rotary plate 92, and passes through the light receiving element. Detected at 96. The track A slit 98 and the track B slit 99 of the fixed plate 93 are shifted in electrical phase angle by 90 °.
The scale is read by counting when both phase signals are turned on (light receiving state) as one unit (one slit) of the scale. Further, as shown in FIG. 16B, the rotation direction can be determined depending on whether the A phase is turned on or the B phase is turned on.

In this rotary encoder, for example, a conventional full-face emission type semiconductor light emitting device (emission diameter 400 μm) is used.
m) and collimating with a projection lens having a focal length f = 10 mm and a lens diameter of 4 mm, the beam diameter on the rotating plate spreads to the slit width of the fixed plate + about 40 μm due to the poor collimating property. .. Therefore, 6
With a scale of 00 DPI (40 μm pitch) or more, the beam spreads beyond the slit width, the scale cannot be read, and high resolution cannot be achieved.

On the other hand, in the rotary encoder G using the semiconductor light emitting device 95 according to the present invention, the light emitting diameter of the semiconductor light emitting device 95 can be reduced to about 10 μm, so that the focal length f = 10 mm and the lens diameter 4 mm. Even if the same light projecting lens 94 is used for collimation, the beam diameter on the rotating plate 92 can be suppressed to the slit width of the fixed plate 93 + about 0.5 μm. Therefore, higher resolution is possible and 600 DPI (4
It is also possible to read a scale of 0 μm pitch or more. Therefore, by using the semiconductor light emitting device 95 according to the present invention for the rotary encoder G, the resolution of the rotary encoder G can be improved without using a special optical system.

Although the rotary encoder has been described in the above embodiment, the same effect can be obtained by using the semiconductor light emitting device according to the present invention in the linear encoder head.

FIG. 17 shows a semiconductor light emitting device 10 according to the present invention.
3 is an explanatory diagram showing a configuration of an optical distance sensor H using 1. The distance sensor H includes a light projecting portion including a semiconductor light emitting element 101 and a collimator lens 102 according to the present invention,
The light receiving section includes a light receiving lens 103 and a position detecting element 104.

FIG. 17 shows a case where the step d of the unevenness of the object 105 is measured by the distance sensor H. The light emitted from the semiconductor light emitting element 101 is collimated by the collimator lens 102, and then irradiated onto the object 105 to generate beam spots SP ₁ and SP ₂ , and the beam spots SP ₁ and SP ₂ are reflected. An image is formed on the position detection element 104. These image forming positions can be detected by the signal ratio obtained by the signal lines 106 and 107 of the position detecting element 104, and the step q is calculated from the amount of positional deviation using the principle of triangulation.

Since the semiconductor light emitting device 101 according to the present invention has a high output and a limited light emitting region and has a minute light emitting window, the semiconductor light emitting device 101 according to the present invention is used for such a distance sensor H. Thus, long-distance detection is possible, the beam spot diameter is small, and the resolution can be improved.

FIG. 18 shows the measurement result of the step q by the distance sensor H. This is 10c from the distance sensor H
2 mm and 5 mm in height and 2 at a position separated by m
It is a measurement result when an object having concave portions of mm and 5 mm is positioned, and a characteristic curve 108 corresponding to the step q is obtained. In the characteristic curve 108, a is 2 mm.
The convex part of B, the convex part of B is 5 mm, the concave part of C is 2 mm, and D is 5
This is a portion corresponding to a recess of mm.

FIG. 19 shows a semiconductor laser device 1 according to the present invention.
11 is a perspective view showing a laser beam printer J using No. 11. This is a semiconductor laser element 111, a light projecting side collimator lens 112, and a rotary polygon mirror (polygon mirror) 11.
3, a scanner motor 114 for rotating the rotary polygon mirror 113 in a constant direction at a constant speed, a scanner controller 11
5, a condenser lens 116, a photosensitive drum 117, a horizontal synchronization light receiving sensor 118, and the like.

Thus, the light emitted from the semiconductor laser element 111 passes through the light projecting side collimator lens 112 to become collimated light, which is reflected by the rotary polygon mirror 113 and is scanned in the horizontal direction, and is exposed by the condenser lens 116. The latent image is formed on the photoconductor drum 117 by being condensed on the body drum 117.

In such a laser beam printer, for example, a conventional LED of the whole surface emission type (emission diameter 400 μm) is used.
15) with a condenser lens with a focal length f = 15 mm.
If the light is focused on the photosensitive drum 0 mm ahead, the beam diameter on the photosensitive drum is 4.
It became as large as 8 mm and could not satisfy the print density specification of 400DP1.

On the other hand, in the laser beam printer J using the semiconductor laser device 111 according to the present invention,
Since the emission diameter can be reduced to about 5 μm, the beam diameter can be reduced to 60 μm or less even when the light is condensed under the same conditions, and the specifications of 400 DPI can be sufficiently satisfied.

FIG. 20A is a perspective view showing a bar code reader K using the semiconductor light emitting device 121 according to the present invention. This bar code reader K includes a semiconductor light emitting device 12
1, a light projecting side condenser lens 122, a rotary polygon mirror 123, a scanner motor 124 for rotating the rotary polygon mirror 123 in a constant direction at a constant speed, a constant velocity scanning lens 125, a light receiving side condenser lens 126, and a light receiving element 127. Has been done.

Thus, the light emitted from the semiconductor light emitting element 121 passes through the light projecting side condenser lens 122, is reflected by the rotary polygon mirror 123 and is scanned in the horizontal direction, and is made uniform in speed by the constant speed scanning lens 125. After being bar coded 12
8 is focused and scanned on the barcode 128. Further, the reflected light from the bar code 128 is condensed and detected on the light receiving element 127 by the light receiving side condensing lens 126, and the bar code signal BS is obtained. In this bar code reader K, since the scanning speed of the light beam is made uniform by the constant speed scanning lens 125, when the horizontal axis represents time and the vertical axis represents the detection signal (bar code signal BS),
As shown in FIG. 20B, the signal BS corresponding to the barcode
Is obtained.

In such a bar code reader, for example, a conventional LED of full surface emission type (emission diameter 400 μm) is used, and a focusing lens of focal length f = 15 mm is 250 mm.
If the beam was focused on the bar code above, the beam diameter on the bar code would be as large as about 6.7 mm due to its poor light converging property, and the beam code would generally have a minimum line width of 0.2 mm.
mm) cannot be read at all.

On the other hand, in the bar code reader K using the semiconductor light emitting device 121 according to the present invention, the light emitting diameter can be made as small as about 10 μm. The beam diameter on the code 128 can be narrowed down to the minimum line width of the bar code 128 (less than 0.2 mm), and the bar code 128 can be read.

21 (a) to 21 (g) are schematic views showing optical fiber modules L1 to L7 each comprising a semiconductor light emitting device 131 and an optical fiber 132 according to the present invention. In FIG. 21A, the end surface of the optical fiber 132 faces the light emitting region of the semiconductor light emitting element 131, and the light emitted from the semiconductor light emitting element 131 is reflected by the optical fiber 132.
Is a direct coupling type optical fiber module L1 which is incident on the core from the end face and is transmitted through the optical fiber 132. Further, in FIG. 21B, the semiconductor light emitting device 131 and the end face of the optical fiber 132 are brought close to each other,
This is a direct coupling type optical fiber module L2 in which an optical resin 133 is filled between the semiconductor light emitting device 131 and the end face of the optical fiber 132. Also, FIG. 21 (c) (d)
(E) is a semiconductor light emitting device 131 and an optical fiber 132
The focusing optical system is placed between the end face of the
FIG. 21 (c) shows the individual lens coupling type optical fiber modules L3 to L5 in which the light emitted from the optical fiber 31 is focused by the focusing optical system to efficiently enter the optical fiber 132. 21D) uses the focusing rod lens 134, and the optical fiber module L4 of FIG.
21 (e), the focusing rod lens 1 is used in the optical fiber module L5 of FIG.
34 and a spherical lens 136 are used. In addition, FIG.
The optical fiber modules L6 and L7 of (f) and (g) are
An optical fiber (front spherical fiber) 132 having a spherical portion 137 having a lens function at its tip is used as a semiconductor light emitting device 131.
It is of a fiber lens coupling type that is opposed to.

In such an optical fiber module, the coupling efficiency between the semiconductor light emitting device and the optical fiber is
It strongly depends on the emission diameter of the semiconductor light emitting device. FIG. 22 is a diagram showing the theoretical limit value αc of the coupling efficiency in several types of optical fiber modules of the direct coupling type and the lens coupling type (written by Hiroo Yonezu in the optical book “Optical Communication Device Engineering”).
As shown in this figure, it is generally known that the smaller the emission diameter D of the semiconductor light emitting element, the higher the coupling efficiency. Therefore, in order to increase the coupling efficiency of the optical fiber module, it is very effective to reduce the emission diameter of the semiconductor light emitting device.

However, in the conventional semiconductor light emitting element such as LED, when the emission diameter is reduced, the element resistance rises and the heat generation becomes intense, so that a large light output cannot be obtained.

On the other hand, in the semiconductor light emitting device (particularly, LED) 131 having a small light emitting diameter according to the present invention, the increase in the element resistance can be suppressed to a low level even if the light emitting diameter is made small. Can be made smaller. Therefore, it is possible to obtain high coupling efficiency without lowering the optical output. In particular, since the semiconductor light emitting device 131 of the present invention uses the AlGaInP-based material for the active layer, it is possible to obtain a high light emission efficiency even at around 660 nm where the transmission loss of the plastic fiber is minimized, and the plastic fiber is used. It is possible to configure a system with low loss and high SN ratio in an optical fiber communication system.

FIG. 23A is a schematic view showing an optical fiber type sensor M using the semiconductor light emitting device 141 according to the present invention. The optical fiber type sensor M includes a semiconductor light emitting element 141, a light projecting optical fiber 142, a light receiving optical fiber 143, a light receiving element 144, and a processing circuit 145.

Thus, the light emitted from the semiconductor light emitting element 141 is sent through the light projecting optical fiber 142 with low loss, and is emitted from the end face of the optical fiber 142 toward the object 146. The light reflected by the object 146 enters the light receiving optical fiber 143 and is detected by the light receiving element 144. In this way, the output of the received light signal detected by the light receiving element 144 changes as shown in FIG. 23B depending on the distance S between the end faces of the light projecting / receiving optical fibers 142 and 143 and the object 146. Distance to
Can know. In such a sensor, the distance when the received light signal falls to a detectable level is the detectable distance. Therefore, when the semiconductor light emitting device 141 according to the present invention is used, it is possible to emit light having a small light emission diameter, so that the coupling efficiency with the light projecting optical fiber 142 is increased and the light entering the light projecting optical fiber 142 is prevented. Even if the distance S to the detection object 145 is increased to increase the detection signal, a sufficient detection signal can be obtained and the detectable distance can be increased.

[0081]

According to the present invention, the n-type current blocking layer is made of Al.
By forming the GaAs-based material, the resistance of the current passage region can be reduced. In particular, even when trying to confine the current injected into the active layer to a minute region, the resistance of the current passage region can be reduced, and the light output and the reliability are not deteriorated due to heat generation, and AlGa
A semiconductor light emitting device made of an InP-based material can be realized.

The current passage area is deep in the central area,
By making it shallower in the peripheral region, the region where holes feel the hetero barrier becomes wider and the device resistance can be reduced. on the other hand,
Since the lower part of the current passage region close to the active layer is only the central region, it is possible to emit light with a minute light emission diameter due to the current confinement structure.

The current blocking layer (or the first Al layer
Since the Al composition ratio of the GaAs layer) is decreased toward the p-type contact layer, holes can easily move from the contact layer to the current blocking layer (or the first AlGaAs layer), and the device resistance can be reduced. Can be reduced.

Further, the carrier concentration of the second p-type AlGaAs layer is p in the region where the carrier concentration of the n-type current blocking layer is inverted to p-type.
If the carrier concentration is set lower than the carrier concentration of the first p-type AlGaAs layer, the current does not spread again despite the current confinement, and a high current confinement effect can be achieved. Luminous efficiency can be obtained.

Further, since the first p-type AlGaAs layer is provided below the p-type contact layer, the hetero barrier between the p-type contact layer and the p-type AlGaAs layer below it can be reduced, and the active layer can be formed. When injecting a current into the device, the resistance can be reduced, and the element resistance can be further reduced.

Further, a second layer provided under the n-type current blocking layer
Since the p-type AlGaAs layer has a smaller diffusion rate of impurities than the AlGaInP layer, the introduction position of the impurities can be easily controlled when the impurities are introduced, and the impurity profile of the current passage region can be controlled. it can. Particularly, in the case of the current passage region having the impurity profiles having different depths in the central region and the peripheral region, the impurity depth in the central region can be easily controlled.
As a result, the yield of the device is improved, and the reproducibility of device manufacturing is improved.

Further, the n-type current blocking layer and the first p-type Al
By making the band gaps of the GaAs layer and the second p-type AlGaAs layer both larger than the band gap of the active layer, the light generated in the active layer is absorbed by the current blocking layer and the first and second AlGaAs layers. Therefore, it is possible to prevent the luminous efficiency from decreasing.

Further, since the semiconductor light emitting device of the present invention has a small emission diameter and can increase the light output, it can be used together with a light receiving device, an optical scanner, a lens, etc., for a projector, an optical sensor, a laser beam printer, By configuring an optical device such as a bar code reader, an optical device with good performance can be manufactured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an AlGaInP-based semiconductor light emitting device having a conventional current constriction structure.

FIG. 2 is a band structure diagram showing a band structure in a contact layer and a current blocking layer of the above semiconductor light emitting device.

FIG. 3 is a partially cutaway perspective view showing a surface emitting light emitting diode according to an embodiment of the present invention.

4 (a), (b), (c), (d), and (e) are cross-sectional views showing a process for forming a current passage region in the above light emitting diode.

FIG. 5 is a diagram showing the relationship between the diffusion depth of Zn in GaAs and the diffusion time.

FIG. 6 is a band structure diagram showing a band structure between a conductive layer and a contact layer.

FIG. 7 is a diagram showing a relationship between a forward voltage and a diffusion area.

8A, 8B, 8C, 8D, and 8E are cross-sectional views showing another process for forming a current passage region.

FIG. 9 is a band structure diagram showing a band structure of a light emitting diode according to another embodiment of the present invention.

FIG. 10 is a sectional view showing still another embodiment of the present invention.

FIG. 11 is a band structure diagram showing a band structure of the same.

FIG. 12 is a perspective view showing a semiconductor laser device according to still another embodiment of the present invention.

FIG. 13 is a perspective view showing an edge emitting light emitting diode according to still another embodiment of the present invention.

14 (a), (b) and (c) are a perspective view, a horizontal sectional view and a side sectional view showing a projector according to the present invention.

FIG. 15 is a sectional view showing a pointer according to the present invention.

16A is a perspective view showing a rotary encoder according to the present invention, and FIG. 16B is a phase A signal and B of the encoder.
It is a wave form diagram which shows a phase signal.

FIG. 17 is a schematic diagram showing a configuration of a distance sensor according to the present invention.

FIG. 18 is a diagram showing an example of measurement results obtained by the above distance sensor.

FIG. 19 is a perspective view showing a laser beam printer according to the present invention.

20A is a perspective view showing a barcode reader according to the present invention, and FIG. 20B is a diagram showing a detection signal by the barcode reader.

21 (a) (b) (c) (d) (e) (f)
(G) is a schematic diagram showing various optical fiber modules by the present invention, respectively.

FIG. 22 is a diagram showing a theoretical limit value of coupling efficiency in a direct coupling type and a lens coupling type optical fiber module.

FIG. 23 (a) is a schematic diagram showing the configuration of an optical fiber type sensor, and FIG. 23 (b) is a diagram showing changes in the received light output depending on the distance to the object.

[Explanation of symbols]

 14 Active Layer 15 Upper Clad Layer 16 Diffusion Stop Layer 17 Current Blocking Layer 18 Conductive Layer 19 Contact Layer 21 Current Passage Region 29 Grade Layer 30 Grade Layer

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location H01L 33/00 B 8934-4M L 8934-4M

Claims (16)

[Claims] 1. A current blocking structure having a p-type upper cladding layer, an n-type current blocking layer, and a p-type contact layer above an active layer, wherein one of the n-type current blocking layers is formed by introducing a p-type impurity. In a current confinement type semiconductor light emitting device in which a current passage region penetrating the portion is formed, an AlGaInP-based material is used for a main constituent part including the active layer, and an AlGaAs-based material is used for the n-type current blocking layer. A characteristic semiconductor light emitting device. 2. A current blocking structure having a p-type upper cladding layer, an n-type current blocking layer, and a p-type contact layer above the active layer, wherein one of the n-type current blocking layers is formed by introducing a p-type impurity. In a current confinement type semiconductor light emitting device in which a current passage region penetrating a portion is formed, the depth of impurity introduction differs between the central region and the peripheral region of the current passage region, and the n-type current blocking layer of the n-type current blocking layer is formed in the central region. P-type impurities are introduced to a portion deeper than the lower junction surface, and in the peripheral region, p-type impurities are deeper than the lower junction surface of the p-type contact layer and shallower than the lower junction surface of the n-type current blocking layer. A semiconductor light-emitting device having impurities introduced therein. 3. A current blocking structure having a p-type upper cladding layer, an n-type current blocking layer, and a p-type contact layer above an active layer, wherein one of the n-type current blocking layers is formed by introducing a p-type impurity. In a current confinement type semiconductor light emitting device in which a current passage region penetrating a portion is formed, an AlGaInP-based material is used for a main constituent part including the active layer, and an AlGaInP-based material or A is used for the n-type current blocking layer.
lGaAs-based material is used and Al of the current blocking layer is used.
A semiconductor light emitting device having a composition ratio reduced toward the p-type contact layer. 4. The semiconductor light emitting device according to claim 1, wherein a first p-type AlGaAs layer is provided between the n-type current blocking layer and the p-type contact layer. 5. A region in which a valence band band discontinuity value in a heterojunction between the p-type contact layer and the first p-type AlGaAs layer is inverted to p-type in the p-type contact layer and the n-type current blocking layer. Is smaller than the valence band band discontinuity between the p-type contact layer and the p-type upper cladding layer. 4. The semiconductor light emitting device according to item 4. 6. The semiconductor light emitting device according to claim 4, wherein the Al composition ratio of the first p-type AlGaAs layer decreases toward the p-type contact layer. 7. A second p-type AlGaAs layer is provided between the n-type current blocking layer and the p-type upper cladding layer, 1, 2, 3, 4, 5 or 6. The semiconductor light emitting device according to 6. 8. The carrier concentration of the second p-type AlGaAs layer is set to be lower than the p-type carrier concentration of a region of the n-type current blocking layer which is inverted to p-type. 7. The semiconductor light emitting device according to 7. 9. The carrier concentration of the second p-type AlGaAs layer is set lower than the carrier concentration of the first p-type AlGaAs layer.
The semiconductor light emitting device according to. 10. The n-type current blocking layer, first p-type Al
The band gaps of the GaAs layer and the second p-type AlGaAs layer are both larger than the band gap of the active layer.
8. The semiconductor light emitting device according to 8 or 9. 11. An end face emission type device in which the current passage region formed by introducing a p-type impurity is formed to face an end face of the current blocking structure, and an ohmic contact electrode is formed on substantially the entire upper surface of the p-type contact layer. It is an element, Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10
The semiconductor light emitting device according to. 12. The current passage region formed by introducing a p-type impurity is formed in a part of the current blocking structure, and an ohmic contact electrode is formed on substantially the entire upper surface of the p-type contact layer except a region corresponding to the current passage region. The device is a top emission type element that is formed.
The semiconductor light emitting device according to 5, 6, 7, 8, 9 or 10. 13. The semiconductor light emitting device according to claim 12, wherein the p-type contact layer portion of the current passage region is removed or thinned by etching. 14. Claims 1, 2, 3, 4, 5, 6, 7,
An optical device comprising the semiconductor light emitting element according to 8, 9, 10, 11, 12, or 13. 15. Claims 1, 2, 3, 4, 5, 6, 7,
An optical device comprising the semiconductor light emitting element according to 8, 9, 10, 11, 12 or 13 and a light receiving element. 16. Claims 1, 2, 3, 4, 5, 6, 7,
An optical device comprising the semiconductor light emitting element according to 8, 9, 10, 11, 12 or 13 and an optical scanner for scanning the light emitted from the semiconductor light emitting element.