JP2937692B2 - Semiconductor light emitting device and method of manufacturing the same - Google Patents

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 device capable of effectively extracting light emitted from an LED (light emitting diode) having a short wavelength in an orange to green band or an emission wavelength in an infrared to red band, and a semiconductor light emitting device therefor. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, LEDs have been spotlighted as display devices installed indoors and outdoors. In particular, with the increase in brightness, it is expected that the outdoor display market will rapidly increase in the coming years, and it is expected to grow in the future as a display medium replacing neon signs. As such a high-brightness LED, an AlGaAs DH (double hetero) type high-brightness red LED has been realized for several years,
Recently, AlGaInP-based DH type high-brightness LEDs have been studied even in the orange to green band.

FIG. 16A shows a green band AlGaInP LED as an example of a high-brightness LED. In this figure, the broken lines indicate the flow of current. This LED is nG
An n-GaAs buffer layer 39 having a thickness of 0.1 μm and n- (Al _0.7 Ga _0.3 ) _0.5 I having a thickness of 1.5 μm are formed on the aAs substrate 31 by MOCVD (metal organic chemical vapor deposition).
n _0.5 P carrier confinement layer (cladding layer) 33, 0.7 μm thick non-doped (Al _0.45 Ga _0.55 ) _0.5 In
_0.5 P active layer 34, 1.5 μm thick p- (Al _0.7 Ga
_0.3 ) _0.5 In _0.5 P window layer (cladding layer) 35, thickness 5μ
_{m p-Al 0.7 Ga 0. 3} As current spreading layer 40 and the p-
A GaAs ohmic contact layer 38 is formed. Further, a lower electrode 10 is formed on the substrate side, and an upper electrode 11 is formed on the semiconductor layer growth side. The periphery of the ohmic contact layer 38 and the electrode 11 is removed by etching except for a size (about 100 μm) where a lead bond can be formed.

[0006] In this LED, as shown in FIG. 16 (a), a current injected from the upper electrode 11 is applied to the current diffusion layer 40.
And is injected into the entire active layer 34 to emit light.

[0005]

In the above-mentioned conventional LED, current is injected into the entire active layer 34, but a considerable portion of the current is concentrated immediately below the upper electrode 11, so that light emission in this portion is caused. The amount increases. However, this LE
In FIG. 16D, as shown in FIG. 16B, light (I to C) emitted immediately below the upper electrode 11 and reflected upward is reflected by the upper electrode 11 and does not go outside, and the upper electrode 11 If the incident angle on the element surface is greater than or equal to the critical angle, the light (d) directed toward the unformed portion is reflected there and cannot exit the element. For this reason, the efficiency of extracting light to the outside deteriorates, and a considerable portion of the injected current is used for generating light that cannot be extracted to the outside.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor light emitting device and a method for manufacturing the same, which can enhance the luminous efficiency inside the device and efficiently extract light to the outside of the device. The purpose is to provide.

[0007]

According to the present invention, there is provided a semiconductor light emitting device of the first conductivity type having a (111) B plane as a main surface.
On the surface of the substrate, a protrusion having an upper surface and side surfaces is formed with the upper surface being a (111) B surface, and a second conductive type opposite to the first conductivity type is formed on the substrate excluding the upper surface of the protrusion. A two-conductivity-type GaAs layer or a second-conductivity-type AlGaAs layer is formed, and G is formed over the second-conductivity-type GaAs layer or the second-conductivity-type AlGaAs layer and the upper surface of the protrusion.
An active layer made of an aInP or AlGaInP layer includes an AlGaInP layer of a first conductivity type and an AlGaIP layer of a second conductivity type.
The light emitting laminated portion sandwiched between the nP layer and the nP layer is formed, thereby achieving the above object.

Electrodes are respectively formed on the light emitting laminated portion forming side of the substrate and on the side opposite to the light emitting laminated portion forming side, and a portion above the protruding portion of the active layer is a light emitting portion. It is preferable that the electrodes formed on the light emitting portion are formed mainly except on the light emitting portion.

[0009] It is preferable that the light emitting laminated portion is formed in a convex shape at a portion including a portion above the projecting portion.

[0010] The method of manufacturing a semiconductor light emitting device of the present invention comprises:
Forming a protrusion having an upper surface and a side surface on the surface of the first conductivity type GaAs substrate having the (111) B surface as a main surface, the upper surface being a (111) B surface; and an upper surface of the protrusion. On the substrate except for the second conductive type, which is opposite to the first conductive type.
Forming a conductive type GaAs layer or a second conductive type AlGaAs layer; and forming a GaInP layer over the second conductive type GaAs layer or the second conductive type AlGaAs layer and the upper surface of the protrusion. Or a step of forming a light-emitting laminated portion in which an active layer made of an AlGaInP layer is sandwiched between an AlGaInP layer of a first conductivity type and an AlGaInP layer of a second conductivity type, whereby the object is achieved. You.

[0011]

According to the semiconductor light emitting device of the present invention, (11)
1) On the surface of the GaAs substrate of the first conductivity type having the B surface as the main surface, a protrusion having the (111) B surface as the upper surface is formed. Except for the upper surface of the protruding portion, the second conductive type G
An aAs layer or an AlGaAs layer of the second conductivity type is formed, and GaInP or AlG
The upper and lower surfaces of the light emitting layer composed of the aInP layer are
A light emitting laminated portion sandwiched between the lGaInP layer and the second conductivity type AlGaInP layer is formed. Therefore, the current is efficiently injected into the active layer on the protrusion.

The upper electrode formed on the light emitting laminated portion side is
When the light-emitting portion is mainly formed except for the light-emitting portion (the portion above the protruding portion of the active layer), the light from the light-emitting portion is not disturbed by the upper electrode when the light is extracted outside the element. Therefore, the efficiency of extracting light to the outside of the device can be increased. The upper electrode is
It is only necessary that a large-area portion (a region having a diameter of about 100 μm) to be subjected to lead bonding be formed except on the light emitting portion. In addition, an auxiliary electrode or the like may be formed on the light emitting unit to improve the efficiency of current injection into the light emitting unit.

When the light emitting laminated portion is formed to be convex at a portion including a portion above the projecting portion, the ratio of light incident on the device surface at a critical angle or more can be reduced. It can be even higher.

On the main surface of the GaAs substrate of the first conductivity type having the (111) B surface as the main surface, a projection having the upper surface of the (111) B surface is formed to form a GaAs layer of the second conductivity type or the second conductivity type. When a two-conductivity type AlGaAs layer is grown, the growth is selectively performed on the portion except for the (111) B plane, so that the growth can be performed on the portion except on the protrusion. Therefore, a desired current confinement structure can be easily formed.

[0015]

Embodiments of the present invention will be described below.

(Embodiment 1) FIGS. 1 (a) and 1 (b)
3A and 3B are a cross-sectional view and a plan view illustrating the semiconductor light emitting device of Example 1. In FIG. 1A, the flow of current is indicated by a broken line, and the state of light emission is indicated by a solid line. FIG. 1 (b)
In FIG. 7, the formation portion of the upper electrode 11 is indicated by oblique lines.
In the following description, the symbol “” in the Miller index (“1” 10) or the like indicates, for example, the inversion of the sign of the element 1.

In this semiconductor light emitting device, a protrusion 20 having a height difference of about 0.5 μm is formed in the [1] 10 direction on a p-type GaAs substrate 1 having a (111) B plane as a main surface. The upper surface 21 of the projecting portion 20 is a (111) B surface, and the lower portion 22 and the side surface 23 of the projecting portion 20 are buried on the substrate 1 excluding the projecting portion upper portion 21 to form the n-GaAs current confinement layer 2. Are formed, and the surface is flattened. In this state, p-type (Al _X Ga _{1 -x} ) _Y In _{1 -Y} P
Carrier confinement layer (cladding layer, for example, X = 0.7,
Y = 0.5) 3, (Al Z Ga 1-Z) W In 1-W P active layer (e.g., Z = 0.45, W = 0.5) 4, n -type (Al _U
Ga _1-U ) _V In _1-V P window layer (cladding layer, for example, U =
0.7, V = 0.5) 5 are laminated. The upper electrode 11 is formed on the n-type cladding layer 5 except for the light emitting portion 24 mainly above the protrusion 20, and the lower electrode 10 is formed on the substrate 1 side.

The cladding layers 3 and 5 are formed of a material having a larger forbidden band width than the active layer 4.
This is a light emitting laminated portion including the active layer 4 and the cladding layer 5.

This semiconductor light emitting device can be manufactured in one growth step as follows.

First, as shown in FIG.
1) A protrusion 20 having a height difference of about 0.5 μm is formed in the [“1” 10] direction on the p-type GaAs substrate 1 having the B surface by a method such as dry etching or wet etching. The upper surface of the protrusion is the (111) B surface.

Next, an n-GaAs current confinement layer 2 is formed by MOCVD. Here, the growth conditions were a growth temperature of 700 ° C. and a group V / group III ratio of 100. Under these growth conditions, the growth rate of the GaAs layer or the AlGaAs layer on the (111) B plane is almost zero. For this reason, the protrusion 2
It is difficult for the n-GaAs layer to grow on the upper surface 21 and the lower portion 22 of 0. Therefore, the growth is as shown in FIG.
It occurs laterally from the side surface 23 of the protrusion 20. In addition, 2
Since the front surfaces of the growth layers grown from the directions intersect, the side surfaces 23 and the lower portions 22 of the protrusions 20 are buried.
The current confinement layer 2 as shown in FIG.

Subsequently, a p-type cladding layer 3, an active layer 4, and an n-type cladding layer 5 are sequentially formed. At this time, A
Unlike the growth of the lGaAs and GaAs layers, the AlGaInP and GaInP layers are (11
1) An appropriate growth rate (for example, 1 μm / hou) on the B side
r). Therefore, the light-emitting lamination portion is formed as shown in FIG.
As shown in (d), it is formed on the entire surface of the substrate.

Thereafter, as shown in FIG. 2E, an upper electrode 11 is formed on the n-type cladding layer 5 by opening an upper portion of the protrusion 20, and the lower electrode 10 is formed on the entire surface of the substrate 1 side. To form Here, the upper electrode 11 was formed on the current confinement layer 2 avoiding the light-emitting portion 24, and a lead bond was performed on this portion.

Finally, the chip was divided into chips along the alternate long and short dash line 25 to obtain an LED element.

In this semiconductor light emitting device, a portion 24 above the protruding portion 20 of the active layer 4 becomes a light emitting portion. As shown in FIG. 1A, the current is injected from the upper surface 21 of the protrusion 20,
The light-emitting portion 24 above the light-emitting portion 24 can emit light efficiently. In addition, since the upper electrode 11 is formed mainly except on the light emitting portion 24, light emission is not obstructed by the upper electrode 11, and it is easy to take out light from the element surface. When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the wavelength was 555 when 20 mA was supplied.
A green band LED with a luminosity of 3 candela in nm was obtained.

(Embodiment 2) FIGS. 3 (a) and 3 (b)
FIG. 9 is a cross-sectional view and a plan view illustrating a semiconductor light emitting device of Example 2.

The semiconductor light emitting device according to the present embodiment has the structure [[1] 0
P] with the (111) B plane turned off by 2 ° in the [0] direction
GaAs substrate 1 is used. Side surface 23 of protrusion 20
A p-GaAs buffer layer 6 of the same conductivity type as the substrate 1
There is _{formed, n-Al P Ga 1-} P As current confinement layer 2 (e.g. P = 0.1) is formed on its side surface. Also, p
Al under the type carrier confinement layer (cladding layer) 3
_Q In _1-Q P (for example, Q = 0.5) and (Al _R G
a _1-R ) _S In _1-S P (for example, R = 0.5, S = 0.5)
The light reflection layer 7 is formed by alternately laminating 20 layers, and an n-type window layer (cladding layer) 5 and an upper electrode
A GaAs contact layer 8 is formed. In addition, the upper electrode 11 formed mainly except for above the protrusion 20
In addition, a small area auxiliary electrode 11 ′ is formed to facilitate current diffusion to the light emitting section 24.

In the manufacture of this semiconductor light emitting device, the growth of the contact layer 8 is performed by raising the growth temperature to 750 ° C.
The GaAs layer was grown on the (111) B plane slightly. Further, the grown GaAs layer was partially removed by etching so as not to disturb the light emission from the light emitting section 24.

In this embodiment, of the emitted light, the light directed toward the lower part of the element can be reflected upward by the light reflecting layer 7 and extracted to the outside. In addition, p-type (Al _0.5 G
a _{0.5) 0. 5} In _0.5 P cladding layer 3, an undoped Ga _0.5
In _0.5 P active layer 4, n-type _{(Al 0. 5 Ga 0.5) 0.5} In
_{By using 0.5} P clad layer 5, LED of red band
Is obtained. When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the wavelength was 650 when 20 mA was supplied.
A luminosity of 15 candela in nm was obtained.

(Embodiment 3) FIGS. 4 (a) and 4 (b)
3A and 3B are a cross-sectional view and a plan view illustrating a semiconductor light emitting device of Example 3.

The semiconductor light emitting device of this embodiment has the structure (11
1) The n-type GaAs substrate 31 having the B surface as a main surface is used. The protrusion 20 has a circular surface shape, and the current confinement layer 32, the cladding layer 33, the active layer 34, and the cladding layer 35 have the same structure as the current confinement layer 2, except that the conductivity type is reversed. The structure can be the same as that of the clad layer 3, the active layer 4, and the clad layer 5.

In the semiconductor light emitting device of this embodiment,
As in the first embodiment, the current can be efficiently injected into the light emitting unit 24 on the protrusion 20. Also, the upper electrode 11
Is formed mainly excluding the upper part of the light emitting portion 24, so that light can be efficiently extracted to the outside. When this semiconductor light-emitting device was mounted on a 5 mmφ lamp by molding, a luminous intensity of 3.2 candela at a wavelength of 563 nm was obtained at a current of 20 mA.

(Embodiment 4) FIGS. 5 (a) and 5 (b)
It is a sectional view and a plan view showing a semiconductor light emitting device of Example 4.

The semiconductor light emitting device of this embodiment has
A number of 0s are provided to make a plurality of current injection regions, and the light emitting unit is multiplied. Other configurations can be the same as in the first embodiment.

When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the current was 555 at a current of 20 mA.
A luminosity of 4 candela in nm was obtained.

Embodiment 5 FIG. 6 is a plan view showing a semiconductor light emitting device of Embodiment 5.

The semiconductor light emitting device of this embodiment has
The shape of 0 is a triangle. The active layer on the protruding portion 20 becomes a light emitting portion as in the other embodiments.

Embodiment 6 FIG. 7 is a plan view showing a semiconductor light emitting device of Embodiment 6.

The semiconductor light emitting device of this embodiment has
The shape of 0 is circular and many are provided. This protrusion 20
The upper active layer serves as a light emitting section as in the other embodiments.

(Embodiment 7) FIGS. 8A and 8B show
It is a sectional view and a plan view showing a semiconductor light emitting device of Example 7. In FIG. 8A, the flow of current is indicated by a broken line, and light emission is indicated by a solid line. Further, in FIG. 8B, the formation portion of the upper electrode 11 is indicated by oblique lines.

This semiconductor light emitting device is, like the first embodiment, a p-type GaAs substrate 1 having a (111) B plane as a main surface.
In addition, the protrusion 20 having a height difference of about 0.5 μm is [[1] 1
0] direction. The upper surface 21 of the protruding portion 20 is a (111) B surface, and the lower portion 22 and the side surface 23 of the protruding portion 20 are buried in portions other than the upper surface 21 of the protruding portion 20 so that the n-GaAs current confinement layer 2 Are formed, and the surface is flattened. A p-type (Al _X Ga _{1 -x} ) _Y In _{1 -Y} P carrier confinement layer (cladding layer, for example, X = 0.7, Y = 0.5) 3, (Al _Z
Ga _{1 -Z} ) _W In _{1 -W} P active layer (for example, Z = 0.45, W
= 0.5) 4, n-type _{(Al U Ga 1-U)} V In 1-V P window layer (cladding layer, for example, U = 0.7, V = 0.5) 5 are stacked. In the n-type cladding layer 5, a portion above the protrusion 20 serving as a light emitting region has a trapezoidal cross section, and an upper electrode 11 is formed around the trapezoidal portion. A lower electrode 10 is formed on the substrate 1 side.

The cladding layers 3 and 5 are formed of a material having a larger band gap than the active layer 4.
This is a light emitting laminated portion including the active layer 4 and the cladding layer 5.

This semiconductor light emitting device can be manufactured in one growth step as follows.

First, as in the first embodiment, (111)
On the p-type GaAs substrate 1 having the B surface, a protrusion 20 having a height difference of about 0.5 μm as shown in FIG.
0] direction.

Next, in the same manner as in the first embodiment, n-GaAs
An s current confinement layer 2 is formed. Again, the growth is shown in FIG.
As shown in FIG. 9B, the front surface of the growth layer, which occurs in the lateral direction from the side surface 23 of the protrusion 20 and grows in two directions, intersects, and the side surface 23 and the lower portion 22 of the protrusion 20 are buried. The current confinement layer 2 as shown in c) is formed.

Subsequently, the p-type cladding layer 3, the active layer 4, and the n-type cladding layer 5 are sequentially formed in the same manner as in the first embodiment. Again, the AlGaInP layer and the GaIn
The P layer grows on the (111) B plane at an appropriate growth rate. Therefore, the light emitting laminated portion is formed on the entire surface of the substrate as shown in FIG.

Thereafter, as shown in FIG. 9E, the n-type cladding layer 5 is etched by, for example, an ion milling method so that the cross-sectional shape becomes a trapezoid, and the upper electrode 11 is formed around the trapezoidal portion. Then, the lower electrode 10 is formed on the entire surface of the substrate 1. In this case, the upper electrode 11
It is mainly formed except on the light emitting section 24.

Finally, the chip was divided along the chain line 25 to obtain an LED element.

In this semiconductor light emitting device, a portion 24 above the protruding portion 20 of the active layer 4 becomes a light emitting portion. As shown in FIG. 8A, since the current is injected from the upper surface 21 of the protrusion 20,
The active layer thereon serves as the light emitting section 24, so that light can be emitted efficiently. Further, since the upper electrode 11 is formed mainly except on the light emitting portion 24, light emission is not disturbed by the upper electrode 11, and it is easy to take out light from the element surface. Further, most of the light emission is incident on the trapezoidal element surface at a critical angle or less, so that the light emission is easily extracted to the outside, and the light extraction efficiency of the LED to the outside can be increased. When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the current was 555 n
A green band LED having a luminosity of 5 candela at m was obtained.

(Embodiment 8) FIGS. 10A and 10B
9A and 9B are a cross-sectional view and a plan view illustrating a semiconductor light emitting device of Example 8.

The semiconductor light emitting device according to the present embodiment has [[1] 0
P] with the (111) B plane turned off by 2 ° in the [0] direction
GaAs substrate 1 is used. Side surface 23 of protrusion 20
A p-GaAs buffer layer 6 of the same conductivity type as the substrate 1
There is _{formed, n-Al P Ga 1-} P As current confinement layer 2 (e.g. P = 0.1) is formed on its side surface. Also, p
Al under the type carrier confinement layer (cladding layer) 3
_Q In _1-Q P (for example, Q = 0.5) and (Al _R G
a _1-R ) _S In _1-S P (for example, R = 0.5, S = 0.5)
Are alternately laminated to form a light reflection layer 7. The cross-sectional shape of the n-type cladding layer 5 is not a trapezoid but a semicircle, and an auxiliary electrode 11 ′ having a small area is formed in addition to the upper electrode 11 formed around the semicircular portion. Current diffusion to the light emitting unit 24 is facilitated.

In manufacturing the semiconductor light emitting device, the n-type cladding layer 5 was processed by ion milling while changing the tilt angle of the substrate in order to make the device surface semicircular.

In this embodiment, of the emitted light, the light directed toward the lower part of the element can be reflected upward by the light reflecting layer 7 and extracted to the outside. In this embodiment, the p-type (Al
_0.5 Ga _0.5 ) _0.5 In _0.5 P clad layer 3, non-doped G
a _0.5 In _0.5 P active layer 4, n-type (Al _0.5 Ga _0.5 ) _0.5
By forming the In _0.5 P clad layer 5, the LE of the red band
D was obtained. When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, when a current of 20 mA was supplied, a wavelength of 65 mm was obtained.
A luminous intensity of 22 candela at 0 nm was obtained.

(Embodiment 9) FIGS. 11A and 11B
9A and 9B are a cross-sectional view and a plan view showing a semiconductor light emitting device of Example 9.

The semiconductor light emitting device of this embodiment has the structure (11
1) The n-type GaAs substrate 31 having the B surface as a main surface is used. The protrusion 20 has a circular surface shape, and the current confinement layer 32, the cladding layer 33, the active layer 34, and the cladding layer 35 have the same structure as the current confinement layer 2, except that the conductivity type is reversed. The structure can be the same as that of the clad layer 3, the active layer 4, and the clad layer 5. Also, the upper electrode 1
Numeral 1 is formed around a circular dome-shaped portion which is a light emitting region, and a p-type
A type GaAs contact layer 38 is formed.

The manufacture of the semiconductor light emitting device can be performed as follows.

First, as shown in FIG.
1) A circular protrusion 20 having a height difference of about 0.7 μm is formed on an n-type GaAs substrate 31 having a surface B by a method such as dry etching or wet etching.

Next, a p-GaAs current confinement layer 32 is formed by MOCVD. Here, the growth conditions were a growth temperature of 680 ° C. and a group V / III ratio of 150. Under this growth condition, the p-GaAs layer is unlikely to grow on the upper surface 21 and the lower portion 22 of the protruding portion 20 as in the first embodiment. Therefore,
The growth occurs laterally from the side surface 23 of the protrusion 20 and 2
Since the front surfaces of the growth layers grown from the directions intersect, the side surfaces 23 and the lower portions 22 of the protrusions 20 are buried.
The current confinement layer 2 as shown in FIG.

Subsequently, an n-type cladding layer 33 and an active layer 34 are sequentially formed. The growth conditions at this time were a growth temperature of 680 ° C. and a group V / III ratio of 400. Thereafter, the growth temperature is lowered to 550 ° C., and the growth portion on the protrusion 20 is selectively irradiated with KrF excimer laser light (248 nm) to form the p-type cladding layer 35. Here, if the intensity distribution of the irradiation light is made strong at the central portion of the irradiated portion and weakened at the peripheral portion, a circular dome-shaped p-type clad layer 35 as shown in FIG. it can. Such growth is possible because the temperature of the light-irradiated portion increases according to the light intensity distribution, and the AlGaInP
This is because the crystal growth rate of the layer increases.

Thereafter, as shown in FIG. 12D, a KrF excimer laser beam is selectively irradiated to the growth portion on the current confinement layer 32 to form a p-type GaAs contact layer 38. By performing this irradiation, a GaAs layer can be formed also on the (111) B plane, although the growth rate is low. The p-type GaAs contact layer 38 is formed around the dome-shaped portion of the p-type cladding layer 35.

Further, the upper electrode 11 is formed on the p-type contact layer 38, and the lower electrode 10 is formed on the entire surface of the substrate 1 side. As a result, the upper electrode 11 is formed around the dome-shaped portion of the p-type cladding layer 35 in a state excluding the light-emitting portion.

Finally, the chip was divided into chips along the alternate long and short dash line 25 to obtain an LED element.

In the semiconductor light emitting device of this embodiment,
As in the seventh embodiment, the active layer on the protrusion 20 is
Thus, current can be injected efficiently. In addition, since the upper electrode 11 is mainly formed except for a portion above the light emitting portion 24, light can be efficiently extracted to the outside. Further, since the light emitting region is formed in a dome shape, most of the light emission enters the element surface at a critical angle or less, and the light emission is easily extracted to the outside. When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, a luminous intensity of 6 candela at a wavelength of 563 nm was obtained at a current of 20 mA.

(Embodiment 10) FIGS. 13A and 13B
14A and 14B are a cross-sectional view and a plan view illustrating a semiconductor light emitting device of Example 10.

In the semiconductor light emitting device of this embodiment, the n-GaAs contact layer 8 is formed on the n-type cladding layer 5, and the light emitting region has a truncated cone shape. Further, when processing the light emitting region into a convex shape, not only the n-type cladding layer 5 is processed but also the front of the processing extends to the p-type cladding layer 3. In addition, the upper electrode 11 is formed on a truncated cone, not on a convex periphery.

In the manufacture of this semiconductor light emitting device, the GaAs layer can be grown slightly on the (111) B plane by increasing the growth temperature to 760 ° C.
A GaAs contact layer 8 is formed. Further, the formation of the truncated cone serving as the light emitting region can be performed by etching the light emitting laminated portion by an ion milling method or the like.

When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the current was 555 at a current of 20 mA.
A luminosity of 7 candela in nm was obtained.

(Embodiment 11) FIGS. 14A and 14B
14A and 14B are a cross-sectional view and a plan view illustrating a semiconductor light emitting device of Example 11.

In the semiconductor light emitting device of this embodiment, the light emitting region is formed in a circular dome shape, and a plurality of light emitting portions are provided. Other configurations can be the same as in the first embodiment.

When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the current was 557 at a current of 20 mA.
A luminosity of 8 candela in nm was obtained.

(Embodiment 12) FIGS. 15A and 15B
9A is a sectional view and a plan view showing a semiconductor light emitting device of Example 5. FIG.

In the semiconductor light emitting device of this embodiment, the V-groove is formed concentrically in the p-type cladding layer 5, and the light emitting region has a truncated cone shape. On the p-type cladding layer 5 around the V groove, an n-GaAs contact layer 8 and an upper electrode 11 are formed.

When this semiconductor light emitting device was mounted on a 5 mmφ lamp by molding, the current was 559
A luminosity of 8 candela in nm was obtained.

In the semiconductor light emitting device of the present invention, the conductivity type of the substrate may be either p or n type, and the conductivity type of the growth layer may be determined to be p or n type according to the substrate. The emission wavelength can be in any wavelength band from red to green by appropriately selecting the composition of the AlGaInP or GaInP active layer. The active layer does not necessarily have to be undoped;
It may be of type or n-type. The mixed crystal ratio of the growth layer can be appropriately selected. The current confinement layer may be either a GaAs layer or an AlGaAs layer. The GaAs substrate is (1
11) If the main surface is the B surface, it is not necessary to be in the just direction, and the ['1'00] direction or [0'1']
It may be turned off several times in the '1'] direction. The upper electrode is
It is sufficient that a large-area portion where lead bonding is performed is formed except for the upper part of the light-emitting part, and a small-area auxiliary electrode may be formed above the light-emitting part. The protruding shape of the light emitting laminated portion is not limited to the one shown in the above embodiment, but may be various shapes such as a triangular pyramid and a quadrangular pyramid.

In manufacturing the semiconductor light emitting device of the present invention,
The current confinement layer may be grown while leaving the resist mask or the insulating mask used for forming the protruding portion, and the mask may be removed before forming the light emitting laminated portion. The growth method is
Although MOCVD is preferred, other vapor phase growth methods such as MBE (molecular beam epitaxy), ALE (atomic layer epitaxy), and CBE (chemical beam epitaxy) may be used.

[0076]

As is apparent from the above description, according to the present invention, since the current confinement layer is formed in a portion other than the surface of the protrusion formed on the substrate, the active layer on the protrusion is formed. The current is efficiently injected into the portion (light emitting portion), and the luminous efficiency can be increased. Further, since the upper electrode is formed mainly except on the light emitting portion, the efficiency of extracting light to the upper portion can be increased. Further, since the light emitting laminated portion is formed in a convex shape at a portion including the upper part (light emitting region), the ratio of light incident on the element surface at a critical angle or more out of emitted light is reduced. Therefore, the efficiency of taking out light to the upper part can be increased.

The method for manufacturing a semiconductor light emitting device of the present invention
Since a projection having a (111) B surface as an upper surface is formed on a first conductivity type GaAs substrate having a (111) B surface as a main surface, and a second conductivity type GaAs layer or an AlGaAs layer is grown on the side surface thereof. In addition, it is possible to selectively grow a portion other than the upper portion of the protrusion, and a desired current confinement structure can be easily formed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a semiconductor light emitting device of Example 1.
(A) is a sectional view, and (b) is a plan view.

2 (a) to 2 (e) are views showing a manufacturing process of the semiconductor light emitting device of Example 1. FIG.

FIG. 3 is a view showing a semiconductor light emitting device of Example 2.
(A) is a sectional view, and (b) is a plan view.

FIG. 4 is a diagram showing a semiconductor light emitting device of Example 3;
(A) is a sectional view, and (b) is a plan view.

FIG. 5 is a view showing a semiconductor light emitting device of Example 4.
(A) is a sectional view, and (b) is a plan view.

FIG. 6 is a plan view showing a semiconductor light emitting device of Example 5.

FIG. 7 is a plan view showing a semiconductor light emitting device of Example 6.

FIG. 8 is a view showing a semiconductor light emitting device of Example 7;
(A) is a sectional view, and (b) is a plan view.

FIGS. 9A to 9E are diagrams illustrating a manufacturing process of the semiconductor light emitting device of Example 7.

FIG. 10 is a view showing a semiconductor light emitting device of Example 8;
(A) is a sectional view, and (b) is a plan view.

FIG. 11 is a view showing a semiconductor light emitting device of Example 9;
(A) is a sectional view, and (b) is a plan view.

FIGS. 12A to 12E are diagrams illustrating a manufacturing process of the semiconductor light emitting device of Example 9;

FIGS. 13A and 13B are views showing a semiconductor light emitting device of Example 10, wherein FIG. 13A is a cross-sectional view and FIG. 13B is a plan view.

14A and 14B are diagrams showing a semiconductor light emitting device of Example 11, wherein FIG. 14A is a cross-sectional view and FIG. 14B is a plan view.

FIGS. 15A and 15B are diagrams showing a semiconductor light emitting device of Example 12, wherein FIG. 15A is a sectional view and FIG. 15B is a plan view.

FIG. 16 is a view showing a conventional semiconductor light emitting device;
(A) is a sectional view, and (b) is a plan view.

[Explanation of symbols]

Reference Signs List 1 p-type GaAs substrate 2 n-GaAs or n-AlGaAs current confinement layer 3 p-type AlGaInP carrier confinement layer (cladding layer) 4, 34 AlGaInP or GaInP active layer 5 n-type AlGaInP window layer (cladding layer) 6 p-GaAs buffer Layer 7 Light reflecting layer 8 n-GaAs contact layer 10 Lower electrode 11 Upper electrode 11 'Upper electrode (auxiliary electrode) 20 Projecting portion 21 Projecting upper portion 22 Projecting lower portion 23 Projecting portion side surface 24 Light emitting portion 31 n-type GaAs substrate 32 p -GaAs current confinement layer 33 n-type AlGaInP carrier confinement layer (cladding layer) 35 p-type AlGaInP window layer (cladding layer) 38 p-GaAs contact layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 33/00 H01S 3/18

Claims (4)

(57) [Claims] 1. A protrusion having an upper surface and side surfaces is formed on a surface of a first conductivity type GaAs substrate having a (111) B surface as a main surface, and the upper surface is formed as a (111) B surface. A second conductivity type GaAs layer or a second conductivity type AlGaAs which is a conductivity type opposite to the first conductivity type
s layer is formed, and the GaAs layer of the second conductivity type or the second
An active layer made of a GaInP or AlGaInP layer is formed on the AlGaAs layer of the conductivity type and the upper surface of the protruding portion by an AlGaInP layer of the first conductivity type and an AGaInP layer of the second conductivity type.
A semiconductor light emitting device in which a light emitting laminated portion sandwiched between an lGaInP layer is formed. 2. An electrode is formed on a side of the substrate on which the light emitting laminated portion is formed and on a side opposite to the side of the light emitting laminated portion, and a portion above the protruding portion of the active layer is a light emitting portion. 2. The semiconductor light emitting device according to claim 1, wherein the electrode formed on the side is formed mainly except on the light emitting portion. 3. The semiconductor light-emitting device according to claim 1, wherein the light-emitting laminated portion is formed in a convex shape at a portion including on the protruding portion. 4. A step of forming a projection having an upper surface and a side surface on the surface of a GaAs substrate of the first conductivity type having a (111) B surface as a main surface, the upper surface being a (111) B surface; Forming a second conductivity type GaAs layer or a second conductivity type AlGaAs layer having a conductivity type opposite to the first conductivity type on the substrate except for an upper surface of the protrusion; Layer or AlGa of the second conductivity type
GaInP over the As layer and the upper surface of the protrusion.
Or a step of forming a light emitting laminated portion in which an active layer made of an AlGaInP layer is sandwiched between an AlGaInP layer of a first conductivity type and an AlGaInP layer of a second conductivity type.