JPH0335567A - Semiconductor light emitting diode - Google Patents

Abstract

PURPOSE:To obtain incoherant beams at relatively high brightness over a wide band by making a second semiconductor crystalline layer have a plurality of semiconductor crystalline layer parts as active layers which have energy band gaps different from each other. CONSTITUTION:A semiconductor crystalline layer 3 has the two semiconductor crystalline layer parts 3a and 3b as active layers respectively having energy band gaps Eg3a and Zg3b different from each other. Accordingly, they respectively generate lights L which have bands centering on the wave lengths respectively according to those energy band gaps Eg3a and Eg3b, and those are emitted as incoherant light L to the outside from the light emitting end face 11. If selecting them beforehand to the values at which large differences can be obtained respectively, between the energy band gaps of neighboring semiconductor crystalline layer parts, the coherent light L, which is obtained being emitted from the light emitting end face 11 to the outside, can be obtained having one band which has band width broader exceptionally than the conventional one.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a semiconductor light emitting diode that is obtained by emitting incoherent light to the outside.

[Conventional technology]

Conventionally, semiconductor light emitting diodes described below with reference to FIGS. 12 to 15 have been proposed. That is, for example, a semiconductor crystal substrate 1 having a ■ type, a semiconductor crystal layer 2 formed on the semiconductor crystal substrate 1 in contact with it and having the same n type as the semiconductor crystal substrate 1, and a semiconductor crystal layer 2 formed on the semiconductor crystal layer 2 in contact with it and having the same n type as the semiconductor crystal substrate 1. A semiconductor crystal layer 3 is formed on and in contact with the semiconductor crystal layer 3, such as a semiconductor crystal layer 3 which is formed in contact with the semiconductor crystal layer 3 and has a narrower energy band gap (generally 1g3) and a higher refractive index than the energy band gap 2g2 of the semiconductor crystal layer 2. and a semiconductor crystal layer 4 having a wider energy band gap 1g4 and a lower refractive index than the energy band gap 1g3 of the semiconductor crystal layer 2, and having a p-type opposite to that of the semiconductor crystal layer 1; It has a semiconductor stack 10 having a semiconductor crystal layer 5 formed above and in contact with it and having the same p-type as the semiconductor crystal layer 4. In this case, as particularly shown in FIG. 14, the semiconductor laminate 10 is arranged in the longitudinal direction of the semiconductor laminate 10 in a direction parallel to the plane of the paper in FIG. 13 and a direction perpendicular to the plane of the paper in FIG. When viewed in cross section on a plane, it has a mesa-like shape rising from the semiconductor crystal layer 2 or the semiconductor crystal substrate 1 (in the figure, it rises from the semiconductor crystal layer 2), and the mesa A semiconductor crystal layer 2 is placed on both left and right sides of the
Alternatively, on the semiconductor crystal substrate 1 side, semiconductor crystal layers 6L and 6R are formed in contact with the semiconductor crystal layers 2 and 3 and the lower half of the semiconductor crystal layer 4, respectively, and are p-type and made of, for example, InPr, and On the semiconductor crystal layers 6L and 6R, there are semiconductor crystal layers 7L and 7R, which are formed in contact with the upper half of the semiconductor crystal layer 4 and the semiconductor crystal layer 5, have n-type, and are made of, for example, InP, respectively. Further, the semiconductor stack 10 has an end face extending perpendicularly to the thickness direction of the semiconductor stack 10 on one end side in the longitudinal direction as a light emitting end face 11 , and on the other hand, the charging 18 end face 11 An anti-reflection WA12 is attached on top. Furthermore, the semiconductor stack 10 has a charging and discharging OJ in its longitudinal direction.
08 On the other end side opposite to the surface 11 side, the end surfaces of the semiconductor crystal layers 5.4 and 3 are placed on an inclined surface 14 extending obliquely to the vertical plane in the thickness direction of the semiconductor stack 10. It is made to exist. Further, in the semiconductor stacked body 10 described above, the semiconductor crystal substrate 1 has a main surface formed of a (100) plane and is made of, for example, InP. Further, semiconductor crystal layers 2.3.4 and 5 are formed on the main surface of such semiconductor crystal substrate 1 by a liquid phase epitaxial growth method, a vapor phase epitaxial growth method, a molecular beam epitaxial growth method, etc., and The semiconductor crystal layer 2 is made of, for example, InP. Further, although the semiconductor crystal layer 3 has only one semiconductor crystal layer portion 3a, and the semiconductor crystal layer portion 3a generally has the above-mentioned energy band gap 1g3, the semiconductor crystal layers 2 and 3 have only one semiconductor crystal layer portion 3a. energy bandgap 2g
2 and Eg4, and 3. and a high refractive index, such as InGaAs.
It consists of P system. Furthermore, the semiconductor crystal layer 4 is made of, for example, InP. Further, the semiconductor layer 5 is made of, for example, InGaAsP, into which p-type impurities are introduced at a degree of 1 − a compared to the semiconductor crystal layer 4 . Further, one main surface 10a of the semiconductor stack 10 described above
The semiconductor stack 1 is placed on the upper surface of the semiconductor crystal layer 5.
On the light emitting end surface 11 side in the longitudinal direction of 0, an electrode layer 15 extending also onto the semiconductor crystal layer 7 [and 7R is arranged in an ohmic manner. Moreover, the above-mentioned main surface 10a of the above-mentioned semiconductor stack 10
On the other main surface 10b facing the main surface 10b, that is, on the surface of the semiconductor crystal substrate 1 opposite to the semiconductor crystal layer 2 side, another electrode B16 is formed on the electrode layer on the main surface 10a of the semiconductor stack 10. 15 and is arranged in an ohmic manner. In this case, the electrode layer 16 may extend onto a region on the main surface 10a that does not face the electrode layer 15, as shown in the figure. The above is the structure of the conventionally proposed semiconductor light emitting diode. According to the semiconductor light emitting diode having such a configuration, if a required power source (not shown) with the electrode layer 15 side positive is connected between the electrode layers 15 and 16, the driving current from the power source is It flows into the semiconductor crystal substrate 1 and the semiconductor crystal layers 2, 3, 4 and 5 of the semiconductor stack 10 in the opposite order through the electrode layers 15 and 16. However, the drive from the power source! The tlI current flows through electrode layer 1
5 extends over the semiconductor crystal layers 7L and 7R of the semiconductor stack 10, the power supply in this case does not provide a reverse bias to the pn junction between the semiconductor crystal layers 7L and 6L and between 7R and 6a. Since the liquid has a polarity that is opposite to the semiconductor crystal layer 3, it does not flow to the semiconductor crystal layers 7L and 6L, and 7R and 6R, bypassing the semiconductor crystal layer 3. Therefore, the driving current from the power supply is applied to the semiconductor crystal li! of the semiconductor stack 10! 3, it narrows and flows. Moreover, in this way, the semiconductor crystal layer 3 of the semiconductor stack 10
The driving current flows constrictedly in the region 1ii!, where the electrode layers 15 and 16 face each other. Flows to 3'. Therefore, in each part of the region 3' of the semiconductor crystal layer 3, the energy band gap 93. A light '3a having a wavelength band of, for example, 1.45 μm centered on the wavelength S3a corresponding to the wavelength is generated. Then, a part of those lights L3a covers the area hA3',
It is confined by the semiconductor crystal layers 2 and 4 and propagates toward the light emitting end face 11, and the other part of the light '3a is transmitted to the semiconductor crystal 1!
Region 3″ where the electrode layers 15 and 16 of No. 13 are not facing each other
Similarly, it is confined by the semiconductor crystal layers 2 and 4 and propagates toward the inclined surface 14 side. In this way, a part of the light '3a propagating through the region 3' of the semiconductor crystal layer 3 toward the charging QJ end face 11 is transmitted by the anti-reflection film 12 formed on the light emitting end face 11.
The powder passes through the anti-brocade film 12 to the outside without being reflected on the charging/discharging fA end face 11. Furthermore, as described above, the region 3'' of the semiconductor crystal layer 3 is
The other part of the light '3a propagating toward the inclined surface 14 reaches the inclined surface 14 while being absorbed in the region 3'' during the propagation process, and is reflected at the inclined surface 14, and the reflected light is Almost no light re-enters the OiI region 3'' of the semiconductor crystal layer 3. From the above, according to the conventional semiconductor light emitting diode shown in FIGS. 12 to 15, the InGaASP-based semiconductor crystal layer portion 3a of the semiconductor crystal layer 3 of the semiconductor stack 10 is The energy band gap E of
3a corresponding to the wavelength λ3a is released outside as incoherent light from the light emitting end face 11 through the antireflection film 12, and is obtained. Further, in this case, the drive current from the power supply continues to flow through the semiconductor stack 10, and

[Since the driving current from the power source is continuously injected into the region 3' of the semiconductor crystal layer 3, incoherent light emitted from the light emitting end surface 11 to the outside is transmitted to the semiconductor stack 10. Depending on the value of the current flowing in the region 3' of the semiconductor crystal layer 3, a relatively high luminance of 1q is produced. Furthermore, since the incoherent light obtained by being radiated to the outside from the light emitting end face 11 is light radiated to the outside from a local region of the end face of the semiconductor crystal layer 3 on the light emitting end face 11, the light emitted Incoherent light emitted from the end surface 11 to the outside is transmitted to the semiconductor crystal layer 3.
is emitted with a relatively narrow radiation angle, depending on the thickness of the Therefore, according to the semiconductor light emitting diodes shown in FIGS. 12 to 15, incoherent light is emitted to the outside with relatively high brightness and a relatively narrow radiation angle. [Problems to be Solved by the Invention] However, in the case of the conventional semiconductor light emitting diode shown in FIGS. 3a has only one semiconductor crystal layer portion 3a, so the incoherent light emitted from the light emitting end face 11 to the outside is generated as described above. L n Q a A constituting one half-body crystal layer portion 3 a of the semiconductor crystal layer 3
It has a band centered on the wavelength λ3°3a corresponding to the energy bandgap E of the sP system, but its bandwidth W3a is relatively narrow. For example, when the semiconductor crystal layer portion 3a of the semiconductor crystal layer 3 has an InGaAsP composition having an energy band gap Eg3a such that the center wavelength λ3a of the light L3a is 1.45 μm, the bandwidth W3a
However, the characteristic of the brightness of the incoherent light emitted to the outside with respect to its wavelength is half 1 (0.
The deviation is only about 0.065 to 0.075 μm. For this reason, in the case of the conventional semiconductor light emitting diode shown in FIGS. 12 to 15, the incoherent light that is externally divided by tli and iq has a degree of incoherence that is proportional to its bandwidth W3a, The disadvantage was that it could only be obtained at relatively low values. The present invention aims to propose a novel semiconductor light emitting diode that does not have the above-mentioned drawbacks.

[Means for Solving the Problems 1] A semiconductor light emitting diode according to the present invention is shown in FIGS.
As in the case of the conventional semiconductor light emitting diode described above in FIG. (1) a second semiconductor crystal layer formed on and in contact with the semiconductor crystal layer and having a narrower energy bandgap and higher refractive index than the first semiconductor crystal layer;
a semiconductor crystal layer formed on and in contact with the second semiconductor crystal layer, having a wider energy band gap and lower refractive index than the second semiconductor crystal layer, and having a first conductivity type; a third having a second conductivity type opposite to
(b) The second semiconductor crystal layer has no impurity intentionally introduced therein, or even if impurities that impart a conductivity type are introduced therein, the second semiconductor crystal layer has no impurity. (c) The first and second semiconductor crystal layers are introduced at a much lower concentration than the first and third semiconductor crystal layers; The second electrode layers are arranged to face each other, and (d) one end face in the longitudinal direction of the semiconductor laminate is used as a light emitting end face. However, the semiconductor light emitting diode according to the present invention
In a semiconductor light emitting diode having such a configuration, (e) the second semiconductor crystal layer has a plurality of semiconductor crystal layer portions as active layers having mutually different energy band gaps, and (f) The plurality of semiconductor crystal layer portions as active layers are
They are sequentially laminated with or without a semiconductor crystal layer serving as a barrier layer having an energy band gap wider than those but narrower than the first and third semiconductor crystal layers. In this case, (1) the energy band gap of the first semiconductor crystal layer and the active layer of the second semiconductor crystal layer are located between the second semiconductor crystal layer and the first semiconductor crystal layer; a fourth semiconductor crystal layer having an energy band gap between that of the semiconductor crystal layer portion having the widest energy band gap among the plurality of semiconductor crystal layer portions; between the second semiconductor crystal layer and the third semiconductor crystal layer, the energy band gap of the third semiconductor crystal layer and the second semiconductor crystal layer are
A fifth semiconductor crystal layer having an energy band gap between the energy band gap of the semiconductor crystal layer portion having the widest energy band gap among the semiconductor crystal layer portions having the number fM as an active layer of the semiconductor crystal layer of may be inserted. [Operations/Effects] According to the semiconductor light emitting diode according to the present invention, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15, a required power source can be connected between the first and second electrode layers. However, when a driving current from the power source is passed through the semiconductor stack, the first and second electrode layers of the plurality of semiconductor crystal layer sections serving as active layers of the second semiconductor crystal layer of the semiconductor stack are activated. In the opposing regions, a plurality of lights each having a band centered on a wavelength corresponding to the energy band gap of the plurality of semiconductor crystal layer portions serving as the active layer are generated. The plurality of lights generated in the regions where the first and second electrode layers of the plurality of semiconductor crystal layer parts as active layers are opposed to each other are transmitted to the first and second electrode layers of the second semiconductor crystal layer.
The region where the electrode layers face each other is confined by the first and third semiconductor crystal layers and propagates toward the light emitting end surface. Therefore, the semiconductor light emitting diode according to the present invention is based on a plurality of lights respectively generated in the plurality of semiconductor crystal layer parts as the active layer described above, but it is different from the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. As in the case of , incoherent light is obtained by radiating outward from the light emitting end face. In addition, in this case, the semiconductor laminate includes FIGS. 12 to 15.
As in the case of the conventional semiconductor light emitting diode described above in the figure, the drive current from the power supply continues to flow, and therefore the drive current from the power supply is applied to the first and second semiconductor crystal layers of the semiconductor stack. The second electrode layer is continuously injected into the opposing regions.

[As in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15, the incoherent light emitted from the light emitting end surface
1 with relatively high brightness depending on the drive current flowing in the region where the first and second electrode layers of the semiconductor crystal layer face each other.
I'm getting beaten up. Furthermore, the incoherent light obtained by controlling the tli to the outside from the light emitting end face is transmitted to the second semiconductor on the light emitting end face, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. Since the light is emitted to the outside from a local region called the end face of the crystal layer, the incoherent light obtained by being emitted to the outside from the charging and discharging tA end face is different from the conventional method described above in FIGS. 12 to 15. As in the case of semiconductor light-emitting diodes, depending on the thickness of the second semiconductor crystal layer, radiation is emitted with a relatively narrow firing angle. Therefore, also in the case of the semiconductor light emitting diode according to the present defense,
As with the conventional semiconductor light emitting diodes described above in FIGS. 12-15, incoherent light is obtained at a relatively high brightness and at a relatively narrow emission angle. However, in the case of the semiconductor light emitting diode according to the present invention, the second semiconductor crystal layer has a plurality of semiconductor crystal layer parts as active layers having mutually different energy band gaps, and In the fM number of semiconductor crystal layers, light is generated in bands centered on wavelengths corresponding to their mutually different energy band gaps, and these lights are emitted from the light emitting end face to the outside. Emit as incoherent light. For this reason, when the mutually different energy band gaps of a plurality of semiconductor crystal layer parts as active layers are arranged in order of increasing or decreasing, the mutually different energy band gaps are Within the range in which a plurality of light bands generated in each of the semiconductor crystal layer portions overlap partially in sequence, there is a large difference of 1q between the energy band gaps of adjacent semiconductor crystal layer portions as successive active layers. If C is pre-selected to a value that will This can be achieved by having one band with a wide bandwidth. Therefore, according to the semiconductor light emitting diode according to the present invention, the incoherent light emitted from the charging/discharging fA end face to the outside (q) increases its degree of incoherence and becomes the first
As shown in FIGS. 2 to 15, much higher values can be obtained than in the case of the conventional semiconductor light emitting diode described above. Further, according to the semiconductor light emitting diode according to the present invention, the plurality of semiconductor crystal layer portions serving as active layers of the second semiconductor crystal layer of the semiconductor stack are sequentially laminated via the semiconductor crystal layer portion serving as a barrier layer. In this case, the semiconductor crystal layer serving as the barrier layer allows the drive current to be applied to the plurality of semiconductor crystal layers serving as the active layer, so that the effect of chirelia can be maintained without having a large difference in quantity. Therefore, a plurality of lights emitted to the outside from a plurality of semiconductor crystal layer portions serving as active layers can be illuminated without having a large difference in brightness. Therefore, if the incoherent light obtained by radiating outward from the light emitting end face is obtained in one wide band as described above, the incoherent light has a relatively high Obtained by brightness. In general, in the case of the semiconductor light emitting diode according to the present invention, a fourth semiconductor crystal layer is provided between the second semiconductor crystal layer and the first semiconductor crystal layer, and between the second semiconductor crystal layer and the third semiconductor crystal layer.
and a fifth semiconductor crystal layer are respectively inserted,
The fourth and fifth semiconductor crystal layers cooperate with the first and third semiconductor crystal layers to form a plurality of semiconductor crystal layer portions as active layers of the second semiconductor crystal layer, respectively. Since the plurality of lights obtained by emitting light can be effectively confined in the second semiconductor crystal layer and propagated toward the light emitting end surface, incoherent light can be efficiently obtained. [Embodiment 1] Next, a first embodiment of the semiconductor light emitting diode according to the present invention will be described with reference to FIGS. 1 to 4. In FIGS. 1 to 4, corresponding parts to those in FIGS. 12 to 15 are denoted by the same reference numerals, and detailed description thereof will be omitted. The semiconductor light emitting diode according to the present invention shown in FIGS. M1 to 4 has the same structure as the conventional semiconductor light emitting diode described above in FIGS. 12 to 15, except for the following points. That is, the semiconductor crystal layer 3 of the semiconductor stack 10 is made of In
In place of the case of FIGS. 12 to 15, which have the configuration of having only one semiconductor crystal layer portion 3a having an energy band gap E g3a of the GaAsP system, other than the semiconductor crystal layer portion 3a, Due to its narrowness, the energy band gap E (E
For example one a3b with <E )
g3a a3a has the semiconductor crystal layer portion 3b, therefore l nQaAsP
The system has two 3b semiconductor crystal layer portions 3a and 3b as active layers having energy band gaps Eg3a and E, respectively, and conductor crystal layer portions 3a and 3b as semi-active layers have energy band gaps Eg3a and E, respectively. In the InGa3ab ASP system, the energy band gap E is wider than the gaps E, 38 and E of the semiconductor crystal layer 2, but narrower than the energy band gap E of the semiconductor crystal layer 2 and the energy band gap of the semiconductor crystal layer 4. Semiconductor crystal layer portion 3ab as a barrier layer
are sequentially laminated through the . Further, between the semiconductor crystal layer 3 and the semiconductor crystal layer 2, In
Another semiconductor crystal layer 22 made of GaASP type is inserted,
In addition, there is also In between the semiconductor crystal layer 3 and the semiconductor crystal layer 4.
Another semiconductor crystal layer 24 made of GaASP type is interposed. In this case, the semiconductor crystal layer 4 is a semiconductor having the energy band gap E, 2 of the semiconductor crystal layer 2 and the highest energy band gap among the plurality of semiconductor crystal layer parts 3a and 3b as active layers of the semiconductor crystal layer 3. Crystal layer part 3
The energy band gap Eg22 between the energy band gap E of b and the energy band gap Eg22 of the energy band 3b is set. In addition, the semiconductor crystal layer 24
is the energy band gap Eg4 of the semiconductor crystal layer 4 and the energy band gear rough of the semiconductor crystal layer portion 3b having the highest energy band gap among the plurality of semiconductor crystal layer portions 3a and 3b as active layers of the semiconductor crystal layer 3. Let the energy band gap E between 1g3b be 24. Note that the energy band gap E of the semiconductor crystal layer 22
The energy band gap E of Q22 and the semiconductor crystal layer 24 may be equal to the energy band gap E of the semiconductor crystal layer portion 3ab as a barrier layer to which the semiconductor crystal layer 2 is located on the right 22, and the energy band gap Eg22 of the semiconductor crystal layer 2 may be equal to Although 24 and E are shown as being equal in FIG. 5, they do not have to be equal. The above is the configuration of the first embodiment of the semiconductor light emitting diode according to the present invention. According to the semiconductor light emitting diode according to the present invention having such a configuration, except for the above-mentioned matters, FIGS.
Since it has the same structure as the conventional semiconductor light emitting diode described above with reference to FIG. 5, a detailed explanation will be omitted. If a required power source (not shown) is connected between the terminals 16 and 16, and a driving current from the power source is passed through the semiconductor laminate 10, it will be possible to generate a semiconductor light emitting diode in the same manner as in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. The semiconductor stack 10
Semiconductor crystal layer portion 3a as an active layer of semiconductor crystal 13 of
and region 3 where electrode layers 15 and 16 of 3b are facing each other
', semiconductor crystal layer portions 3a and 3 as active layers
The energy band gaps E and E (in this case, E > 2g3a g3b
wavelength λ according to the relationship g3a g3b)
Light '3a and '3b having bands respectively centered at 3a and λ3b (in this case, the relationship λ3a<λ3b) is generated. The light L and '3b generated in the regions 3' of the semiconductor crystal layer parts 3a and 3b as active layers, respectively, penetrate the region 3' where the electrode layers 1a 5 and 16 of the semiconductor crystal layer 3 are facing each other. , are confined by the semiconductor crystal layers 2 and 22, and 4 and 24, and propagate to the light emitting end face 1111Ill. Therefore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, based on the above-mentioned lights '3a and L3b, it is different from the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. Similarly, incoherent light is obtained by radiating outward from the light emitting end face 11. Further, in this case, the drive current from the power supply continues to flow through the semiconductor stack 10, as in the case of the conventional semiconductor device diode described above in FIGS. 12 to 15, and therefore,
Since the driving current from the power source is continuously injected into the region 3' of the semiconductor crystal layer 3 of the semiconductor stack 10 where the electrode layers 15 and 16 face each other, the driving current is emitted to the outside from the light emitting end face 11. As in the case of the conventional semiconductor light emitting diode described above with reference to FIGS. 12 to 15, the incoherent light generated by Accordingly, relatively high fi1 degrees are obtained. In addition, the incoherent light IJ obtained by radiating outward from the light emitting end face 11, the semiconductor crystal layer on the light emitting end face 11, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. Since the light is emitted to the outside from the local fold of the end face of 3, the incoherent light obtained by being emitted to the outside from the light emitting end face 11 is the same as that of the conventional semiconductor described above in FIGS. 12 to 15. As in the case of light-emitting diodes, depending on the thickness of the semiconductor crystal layer 3, the radiation is emitted at a relatively narrow radiation angle. Therefore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15, relatively incoherent light is generated. High brightness and relatively narrow radiation angles are obtained. However, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, the semiconductor crystal layer 3 has two semiconductor crystal layer parts as active layers each having a mutually different energy band gap 1g3a and E(13b). 3
a and 3b, in the semiconductor crystal layer portions 3a and 3b as active layers, waves 3a and 3b corresponding to the energy band gaps E and EQ3b, respectively, are generated. and light L3a having a multiplication and subtraction centered on λ3b.
and '3b are generated, respectively, and these lights and '3b are emitted from the light emitting end face 11 to the outside a as incoherent light. Therefore, the energy band gaps 1g3a and E93. When arranged in order of increasing or decreasing energy band gaps E (J3a and E) are generated in the plurality of semiconductor crystal layers 3a and 3b as active layers, respectively. multiple lights L
The values are selected in advance so that a large difference can be obtained between the energy band gaps of adjacent semiconductor crystal layer portions as successive active layers within a range where bands W3a and W3b of 3a and '3b partially overlap in sequence. If you do this, the light emitting end face 1
The incoherent light emitted from 1 to the outside has one band with a much wider bandwidth than that of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15. can get. Therefore, according to the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, the incoherent light obtained by radiating outward from the light emitting end face 11 increases its degree of incoherence. ~A much higher value can be obtained than in the case of the conventional semiconductor light emitting diode described above in FIG. Further, according to the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, the semiconductor crystal layer 3 of the semiconductor stack 10 has a plurality of semiconductor crystal layer portions 3a as active layers.
and 3b are sequentially stacked through the semiconductor crystal layer section 3ab as a barrier layer, so that the semiconductor crystal layer section 3ab as a barrier layer allows the plurality of semiconductor crystal layer sections 3a and 3b as active layers to Since carriers are effectively accumulated in the drive current without having a large difference in quantity, carriers can be obtained by being radiated to the outside from the plurality of semiconductor crystal layer parts 3a and 3b as active layers. A plurality of lights L1 and L3b can be obtained without having a large difference in brightness from each other. Therefore, when the incoherent light emitted from the light emitting end face 11 to the outside has one wide band as described above, the incoherent light has a relatively high Obtained by brightness. Furthermore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, between the semiconductor crystal layer 3 and the semiconductor crystal layer 2, and between the semiconductor crystal layer 3 and the semiconductor crystal layer 4,
Since the semiconductor crystal layers 22 and 24 are interposed, the semiconductor crystal layers 22 and 24 work together with the semiconductor crystal layers 2 and 4 to combine the active layers of the semiconductor crystal layer 3. The plurality of semiconductor crystal layer parts 3a and 3b respectively emit light, and the resulting plurality of lights '3a and '3b are effectively confined in the semiconductor crystal layer 3 and propagated to the light emitting end face 11 side. Therefore, incoherent light can be obtained efficiently. Incidentally, in the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4, the semiconductor crystal layer 2 has a thickness of 1.0 μm.
(1) The semiconductor crystal layer 22 is made of InGaASP system, and the energy band gap E of the semiconductor crystal layer has a value corresponding to a wavelength of 1.30 μm. It has a composition of
It is made of GaASP system, has a composition in which the energy band X and the tube E of the semiconductor crystal layer portion 3a have a wavelength of 1.53 μm, and has a thickness of 5 C) nm. In addition, the semiconductor crystal layer portion 3ab as a barrier layer of the semiconductor crystal layer 3 has +t4
The aAsP system has a composition in which the energy bandgap E of the semiconductor crystal layer 3ab has a value corresponding to a wavelength of 1.30 μm, and has a thickness of 5 Q nm, and , (2) The active layer of the semiconductor crystal layer 3 [semiconductor crystal layer portion 3b]
The energy band gap E of the semiconductor crystal layer portion 3b is 1.45 due to the InGaAsP system that constitutes it.
41 with a composition having a value corresponding to a wavelength of μm3b, and 5
The semiconductor crystal layer 24 has a thickness of 0 nm, and the semiconductor crystal layer 24 is made of InGaAsP, and the energy band Eg24 of the semiconductor crystal layer has a value corresponding to a wavelength of 1.30 μm. and has a composition of 110
It has a thickness of 0n, and furthermore, the semiconductor crystal layer 4 has a thickness of 1°0
In the case where the light emitting end face 11 has a thickness of μm,
When we measured the relationship between the luminance (arbitrary scale) and the wavelength λ (μm) of the light emitted from the outside, we found that when the drive current was 225 mA, 300 mA, 350 mA, and 400 mA, respectively, Fig. 5 A, B, The results shown in C and D were obtained. This result also shows that in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. It is clear that it can be obtained with a high degree of incoherence because it has one band with a wide bandwidth of about .15 μm. In the case of a semiconductor light-emitting diode, similar measurements were performed using the same specific example as described above, and the light emission was 0.7 to 0.8 μm.
This could only be achieved by having a band with only a moderate bandwidth. [Embodiment 2] Next, a second embodiment of the semiconductor light emitting diode according to the present invention will be described with reference to FIGS. 6 and 7. In FIGS. 6 and 7, corresponding parts to those in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed explanation thereof will be omitted. The semiconductor light emitting diode according to the present invention shown in FIGS. 6 and 7 is the same as the semiconductor light emitting diode according to the present invention described above in FIGS. 1 to 4, except that the semiconductor crystal layers 22 and 2.1 are omitted. It has a similar configuration to a diode. The above is the configuration of the second embodiment of the semiconductor light emitting diode according to the present invention. According to the semiconductor light emitting diode according to the present invention having the configuration as shown in FIG. 1, the semiconductor light emitting diode according to the present invention described above in FIGS. , and even if the semiconductor crystal layers 22 and 24 are omitted, it has the semiconductor crystal layers 2 and 4, and they are as shown in FIGS.
As is clear from the above description of the conventional semiconductor light emitting diode shown in FIG. 15, the light generated in the semiconductor crystal layer 3 is confined and propagated within the semiconductor crystal layer 3, so a detailed explanation will be omitted. , as in the case of the semiconductor light emitting diode according to the invention described above in FIGS. 1 to 4, the lights L3a and L3b1 . In the case of the conventional semiconductor light-emitting diode described above in FIGS. 12 to 15, incoherent light is emitted from the light emitting surface 11 to the outside with high brightness and a narrow radiation angle. can be obtained by emitting radiation with a higher degree of incoherence than that of . Embodiment 3 Next, a third embodiment of the semiconductor light emitting diode according to the present invention will be described with reference to FIGS. 8 and 9. In FIGS. 8 and 9, parts corresponding to those in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description thereof will be omitted. In the semiconductor light emitting diode according to the present invention shown in FIGS. 8 and 9, the semiconductor crystal layer 3 is arranged in the first part, except that the semiconductor crystal layer part 3ab as a barrier layer on the right side is omitted.
It has the same structure as the semiconductor light emitting diode according to the present invention described above with reference to FIGS. The above is the configuration of the third embodiment of the semiconductor light emitting diode according to the present invention. According to the semiconductor light emitting diode according to the present invention having such a configuration, the semiconductor crystal layer portion 3ab as a barrier layer included in the semiconductor crystal layer 3 is omitted, but the structure described above in FIGS. Even if the semiconductor crystal layer portion 3ab is omitted, a drive current is applied to the semiconductor crystal layer portions 3a and 3b as active layers of the semiconductor crystal layer 3. The carriers are quantitatively distributed in the semiconductor crystal layer portion 3ab.
Even if there is a large disparity compared to the case of the semiconductor light emitting diode according to the present invention described above in FIGS. As in the case of the semiconductor light emitting diode according to the present invention described above with reference to FIGS. 1 to 4, incoherent light a L based on light L and It can be obtained by emitting radiation at a narrow radiation angle and with a higher degree of incoherence than in the case of the conventional semiconductor light emitting diode described above in FIGS. 12 to 15.

Embodiment 4 Next, a fourth embodiment of the semiconductor light emitting diode according to the present invention will be described with reference to FIGS. 10 and 11. In FIGS. 10 and 11, parts corresponding to those in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description thereof will be omitted. The semiconductor light-emitting diode according to the present invention shown in FIGS. 10 and 11 has the exception that the semiconductor crystal layers 22 and 24 and the semiconductor crystal layer portion 3ab as a barrier layer included in the semiconductor crystal layer 3 are omitted. , has the same structure as the semiconductor light emitting diode according to the present invention described above in FIGS. 1 to 4. The above is the configuration of the fourth embodiment of the semiconductor light emitting diode according to the present invention. According to the semiconductor light emitting diode according to the present invention having such a configuration, the semiconductor crystal layers 22 and 24 and the semiconductor crystal layer portion 3ab as a barrier layer included in the semiconductor crystal layer 3
It has the same structure as the semiconductor light emitting diode according to the present invention described above in FIGS. 1 to 4, except that As mentioned above in Example 2, there are no particular problems,
Further, even if the semiconductor crystal layer portion 3ab as a barrier layer included in the semiconductor crystal layer 3 is omitted, there is no particular problem as described above in Example 3, so a detailed explanation will be omitted.
Figures 1 to 4: As in the case of the semiconductor light emitting diode according to the present invention described above, incoherent light based on L3ba and L3ba emits high brightness to the outside from the light emitting end surface 11. It is obtained by emitting radiation with a narrow radiation angle and with a higher degree of incoherence than in the case of the conventional semiconductor light emitting diode described above in FIGS. 12-15. Note that in the above description, a case has been described in which the semiconductor crystal layer 3 has two semiconductor crystal layer portions as active layers;
It is also possible to use three or more and obtain light emitted to the outside with a higher degree of incoherence than in the above case. Furthermore, although the above description describes an embodiment in which the present invention is applied to a so-called embedded type semiconductor light emitting diode, the magazine also describes an embodiment in which the present invention is applied to the semiconductor crystal substrate 1 described above in FIGS. 1 to 4. Corresponding (a) ■ A semiconductor crystal substrate having a first conductivity type, and ■ The semiconductor crystal layer described above in FIGS. 1 to 4 formed on the semiconductor crystal substrate and having the first conductivity type. (2) a first semiconductor crystal layer corresponding to the above first semiconductor crystal layer; a second semiconductor crystal layer corresponding to the semiconductor crystal layer 3 described above in FIGS. 1 to 4;
A second semiconductor crystal layer is formed on and in contact with the second semiconductor crystal layer, has a wider energy band gap and a lower +fT index than the second semiconductor crystal layer, and has a conductivity type opposite to the first semiconductor crystal layer. a third semiconductor crystal layer corresponding to the semiconductor crystal layer 4 described above in FIGS. 1 to 4 and having a conductivity type of The crystal layer is not intentionally introduced with an impurity that imparts a conductivity type, or even if it is introduced, it is introduced only at a significantly lower concentration than in the first and third semiconductor crystal layers, and (c) Also, on the first and second main surfaces facing each other of the semiconductor laminate, first and second electrode layers corresponding to the electrode layers 15 and 16 described above in FIGS. 1 to 4 are provided. It is obvious that the present invention can also be applied to a semiconductor light emitting diode in which two electrode layers are arranged facing each other, and (d) one end surface in the longitudinal direction of the semiconductor laminate is used as a light emitting end surface. Probably. Furthermore, in the above description, in terms of a semiconductor light emitting diode that can be applied to the present invention, the first and second electrodes of the second semiconductor crystal layer extending linearly in a stripe shape of the semiconductor stack A portion of the light generated in the region where the layers face each other is reflected at the region where the first and second electrode layers of the second semiconductor crystal layer do not face each other, and the light is reflected in a straight line of the semiconductor stack. In order to prevent the first and second electrode layers of the second semiconductor crystal layer extending in a stripe shape from re-injecting into the region facing each other, the semiconductor stack is
The second semiconductor crystal layer has a relatively long length such that a region where the first and second electrode layers do not face each other has a relatively long length to sufficiently absorb light therein. The present invention is applied to a semiconductor light-emitting diode in which the semiconductor stack is formed with an inclined surface on the end face side opposite to the light emitting end face side so that light is not reflected there. Although an embodiment has been described, for the above-mentioned purpose, the semiconductor stack is constructed such that the ft region in which the first and second electrode layers of the second semiconductor crystal layer are not facing each other is the second semiconductor layer. A semiconductor light emitting diode, a semiconductor stack, in which the first and second electrode layers of the crystal layer are configured to curve and extend from opposing regions; A semiconductor stack, such as a semiconductor light emitting diode, in which a groove having an inner surface extending diagonally across a region where the first and second electrode layers do not face each other is bored from above. It will also be clear that the present invention can be applied to various semiconductor light emitting diodes configured to achieve the above objectives. Furthermore, in the semiconductor light emitting diode according to the present invention described above, "n-type" may be read as "p-type" and "p-type" may be read as "n-type", and in other ways, the spirit of the present invention may be replaced. You will be able to make various changes to your eating habits without losing weight.

[Brief explanation of drawings]

1, 2, 3, and 4 are a linear plan view showing a first embodiment of a semiconductor light emitting diode according to the present invention, a cross-sectional view along the line ■-■, and a cross-sectional view along the line ■-■. FIG. 2 is a cross-sectional view of FIG. FIGS. 5A to 5D show wavelengths 2 of light obtained by radiating the light to the outside from the light emitting end surface, with drive current as a parameter, for explaining the semiconductor light emitting diode according to the present invention shown in FIGS. 1 to 4. FIG. 3 is a diagram showing the characteristics of brightness (arbitrary scale) versus (μm). FIGS. 6 and 7 are a sectional view showing a second embodiment of a semiconductor light emitting diode according to the present invention, and FIG. C showing an energy band structure of the main part. FIGS. 8 and 9 are a cross-sectional view showing a third embodiment of the semiconductor light emitting diode according to the present invention, and a diagram showing the energy band structure of the main part. FIGS. 10 and 11 are a cross-sectional view showing a fourth embodiment of the semiconductor light emitting diode according to the present invention, and a diagram showing the energy band structure of the main part. 12, 13, 14, and 15 are line plan views showing conventional semiconductor light emitting diodes, and their xm
They are a cross-sectional view along the -xm line, a cross-sectional view along the XIVXIV line, and a diagram showing important parts in an energy band structure. 1・・・・・・・・・・・・・・・・・・Semiconductor crystal heavy plate 2.3.4.5 ・・・・・・・・・・・・・・・・・・Semiconductor Crystal layer 3 r , 3 n...Region 3 of semiconductor crystal layer 3
a, 3b... Semiconductor crystal layer section 3ab as active layer... Semiconductor crystal layer section 10 as barrier layer...・・・・・・・・・Semiconductor v4
Layer body 11......Light emitting end face 12......Anti-reflection coating 14... ......... Slanted surface 15.16... Electrode layer 22.24... Semiconductor crystal layer 1st hole ■ Figure 3 Figure 1 Ring 4 Flash Figure 5 A Figure 5 Mark λCptt) Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 14 Figure 1 Figure 15

Claims (1)

[Claims] 1. A semiconductor crystal substrate having a first conductivity type, and a first semiconductor crystal substrate formed on the semiconductor crystal substrate and having the first conductivity type.
a second semiconductor crystal layer formed on and in contact with the semiconductor crystal layer and having a narrower energy bandgap and higher refractive index than the first semiconductor crystal layer; The first semiconductor crystal layer is formed on and in contact with the second semiconductor crystal layer, and has a wider energy band gap and lower refractive index than the second semiconductor crystal layer.
a third semiconductor crystal layer having a second conductivity type opposite to that of the second semiconductor crystal layer, wherein the second semiconductor crystal layer is intentionally introduced with an impurity imparting a conductivity type. If not, or even if it is introduced, it is only introduced at a much lower concentration than in the first and third semiconductor crystal layers, and the first and second principal surfaces of the semiconductor stack are opposed to each other. In a semiconductor light emitting diode, a first and a second electrode layer are disposed facing each other thereon, and one end face in the longitudinal direction of the semiconductor laminate is a light emitting end face, wherein the second semiconductor crystal layer is It has a plurality of semiconductor crystal layer parts as active layers having mutually different energy band gaps, and the plurality of semiconductor crystal layer parts as active layers are wider than the first and third semiconductor crystal layers. 1. A semiconductor light emitting diode characterized in that the semiconductor light emitting diode is sequentially stacked with or without a semiconductor crystal layer serving as a barrier layer having an energy band gap narrower than that of the semiconductor light emitting diode. 2. The semiconductor light emitting diode according to claim 1, wherein an energy band gap between the first semiconductor crystal layer and the second semiconductor crystal layer is provided between the second semiconductor crystal layer and the first semiconductor crystal layer. A fourth semiconductor crystal layer having an energy band gap between the energy band gap of the semiconductor crystal layer portion having the widest energy band gap among the plurality of semiconductor crystal layer portions serving as an active layer of the semiconductor crystal layer is interposed. and between the second semiconductor crystal layer and the third semiconductor crystal layer, an energy band gap of the third semiconductor crystal layer and a plurality of semiconductors as active layers that the second semiconductor crystal layer has. 1. A semiconductor light-emitting diode, characterized in that a fifth semiconductor crystal layer is interposed, the fifth semiconductor crystal layer having an energy band gap between the energy band gap of the semiconductor crystal layer portion having the widest energy band gap among the crystal layer portions.