JPH031582A - Semiconductor light emitting diode - Google Patents

Abstract

PURPOSE:To externally radiate an incoherent light with sufficiently high intensity by forming a plurality of regions sequentially connected from a light emitting end face side longitudinally of a semiconductor laminate and oppositely to the end face side of a mixed crystallized region in which a superlattice layer is mixedly crystallized, and incorporating sequentially small mixed crystallinities in the crystallized regions. CONSTITUTION:A region 3a as a region to be excited oppositely to electrode layers 15, 16 of a semiconductor crystalline layer 3 has a plurality of n pieces of regions. The first,..., n-th regions are formed of first,... n-th mixed crystallized regions Q1,..., Qn in which superlattice layers are mixedly crystallized to sequentially small first,..., n-th mixed crystallinities. Accordingly, first,..., n-th energy band gaps of the first,..., n-th regions are sequentially widened reversely to the sequence, and the first,..., n-th regions have absorption end wavelengths sequentially lowered reversely to the sequence. Accordingly, an incoherent light L can be externally radiated with sufficiently high intensity.

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, a semiconductor light emitting diode described below with reference to FIGS. 4 and 5 has been proposed. That is, for example, a semiconductor crystal substrate 1 having an n-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 having the same n-type as the semiconductor crystal layer 2. A semiconductor crystal layer 3 is formed in contact with the semiconductor crystal layer 3 and has a narrower energy band gap and a higher refractive index than the semiconductor crystal layer 2; has a bandgap and a low refractive index, and
Semiconductor crystal I14 having p-type opposite to that of semiconductor crystal layer 1
and a semiconductor crystal layer 5 formed on and in contact with the semiconductor crystal layer 4 and having the same p-type as the semiconductor crystal layer 4. In this case, the semiconductor laminate 10 has an end face extending perpendicularly to the thickness direction of the semiconductor laminate 10 at one end in the longitudinal direction as a light emitting end face 11; ．． An antireflection film 12 is applied thereon. Further, the semiconductor stack 10 has a semiconductor crystal layer 5 on the other end side opposite to the light emitting end surface 11 side in the longitudinal direction.
．． The end faces of 4 and 3 are located on an inclined surface 14 extending obliquely to a vertical plane in the thickness direction of the semiconductor stack 10. 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, in the semiconductor crystal layer 3, neither the n-type impurity nor the n-type impurity is intentionally introduced, or even if it is introduced, it is only introduced at a significantly lower concentration than in the semiconductor crystal layers 2 and 4. For example, it is made of InGaASP type. Further, the semiconductor crystal 114 is made of, for example, InP. Further, the semiconductor layer 5 is made of, for example, an InGaAsP system into which n-type impurities are introduced at a higher concentration than that of 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.
The electrode 1! extends also onto the semiconductor crystal layers 7L and 7R on the light emitting end surface 11 side in the longitudinal direction of the electrode 1! ! i15 is attached to the ohmic. Moreover, the above-mentioned main surface 10a of the above-mentioned semiconductor stack 10
Another electrode layer 16 is formed on the other main surface 10b facing the main surface 10b of the semiconductor stack 10, that is, on the surface of the semiconductor crystal substrate 1 opposite to the semiconductor crystal layer 2 side. It is arranged in ohmic contact with the layer 15. 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 positive side facing the electrode layer 15 is connected between the electrode layers 15 and 16, the current from the power source is transferred to the semiconductor light emitting diode. It flows into the semiconductor crystal substrate 1 and the semiconductor crystal layers 2, 3, 4 and 5 of the stack 10 in the opposite order through the electrode layers 15 and 16. In this case, the current flowing through the semiconductor crystal layer 3 of the semiconductor stack 10 mainly flows through the electrodes! 115 and 16 flow into region 3a as an excitation region where they are facing each other. Therefore, in each part of the region 3a of the semiconductor crystal layer 3, InGaAS constituting the semiconductor crystal layer 3 is mainly
Wavelength λ8 according to energy bandgap Eg8 of P system
Light La having a wavelength band of, for example, 1.5 μm centered on is generated. A part of the light La is confined in the region 3a by the semiconductor crystal layers 2 and 4 and propagates toward the light emitting end face 11, and the other part of the light La is transmitted to the electrode layers 15 and 16 of the semiconductor crystal layer 3. Similarly, the region 3b, which is a non-excited region that is not facing each other, is confined by the semiconductor crystal layers 2 and 4 and propagates toward the inclined surface 14. In this way, the negative part of the light L propagating through the region 3a of the semiconductor crystal layer 3 toward the light emitting end face 11 is prevented from being emitted because the antireflection film 12 is formed on the light emitting end face 11. The anti-reflection film 1 is coated without reflection on the end surface 11.
2 and radiates to the outside. Further, as described above, the other part of the light L8 propagating through the region 143b of the semiconductor crystal layer 3 toward the inclined surface 14 reaches the inclined surface 14 while being absorbed in the region 3b during the propagation process. , and the reflected light hardly enters the region 3b of the semiconductor crystal layer 3 again. From the above, according to the conventional semiconductor light emitting diode shown in FIGS. 4 and 5, the semiconductor crystal layer 3 of the semiconductor laminate 10 is made of InGaAs having a τ structure over its entire area.
Wavelength λ corresponding to the energy bandgap Eg8 of P system
Light La having a wavelength band centered around 8 is obtained by being emitted as incoherent light from the light emitting end face 11 through the antireflection film 12 to the outside. Moreover, in this case, semiconductor 8! The current from the power supply continues to flow through the IU body 10, so that the current from the power supply is
Since it is continuously injected into the region 3a of the semiconductor crystal layer 3, the incoherent light emitted from the light emitting end face 11 to the outside causes a current flowing in the region 3a of the semiconductor crystal layer 3 of the semiconductor stack 10. Depending on the value of □, relatively high brightness can be obtained. 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.
emitted at a relatively narrow radiation angle depending on the thickness of the Therefore, according to the semiconductor light emitting diode shown in FIGS. 4 and 5, incoherent light is emitted to the outside with a relatively high brightness and a relatively narrow radiation angle.

[Problem to be solved by the invention]

However, in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the semiconductor crystal 113 in the semiconductor stack 10 has a region 3a serving as an excitation region where the electrode layers 15 and 16 face each other, and an electrode layers 15 and 16
In the entire region including region 3b as a non-excited region where the
It has a configuration in which it has only one region having an AsP-based energy bandgap Eg8. Therefore, when a part of the light L8 propagates through the region 3b, electrons are accumulated in the region 3b based on a part of the light L8,
Due to the band filling effect in which the energy bandgap of the region 3b becomes wider than the original width, the region 3b has an effectively wider energy bandgap than the region 3a. Therefore, region 3b is the area where light propagates. It becomes difficult to absorb a part of the light, and most of the light reaches the inclined surface 14 and is reflected there. Therefore, in the above, the electrode layer 1 of the semiconductor crystal layer 3
Region 3a as an excitation region where 5 and 16 are facing each other
When a part of the light (-a) generated in the semiconductor crystal layer 3 propagates toward the inclined surface 14 through the non-excited region 3b where the electrode layers 15 and 16 are not facing each other, the light La In the process of propagating to the region 3b, a part of the light reaches the inclined surface 14 while being absorbed in the region 3b, and is reflected at the inclined surface 14, and the reflected light almost never re-enters the region 3b. However, the reflected light reflected on the inclined surface 14 is scattered and re-enters the area 3b in a non-negligible amount.For this reason, in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the light It has a drawback that the incoherent light obtained by radiating outward from the radiation end surface 11 cannot be obtained with a high degree of incoherence.Furthermore, the conventional method described above in FIGS. In the case of a semiconductor light emitting diode, the semiconductor stack 10 has a light emitting end face 11.
This has the disadvantage that the inclined surface 14 must be machined on the end surface side opposite to the end surface. Furthermore, in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the electrode layer 1 in the semiconductor stack 10
Region 3 as an excitation region where 5 and 16- are facing each other
a has a composition similar to that of each part, together with a region 3b as a non-excited region where the electrode layers 15 and 16 do not face each other.
Since it consists of one region having the energy band gap Eg of the nGaASP system, the light emitted to the outside has a wavelength λ8 corresponding to the energy band gap Eg8.
It has a relatively narrow wavelength bandwidth of, for example, 200 people in terms of half-width. For this reason, in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the degree of incoherence, which is expressed as a value proportional to the wavelength bandwidth of the light emitted to the outside, is relatively low. It had drawbacks. Further, in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the electrode layer 15 in the semiconductor stack 10
The region 3a serving as the excitation region where the and 16 face each other has a different composition as described above, and therefore each part has an energy band gap corresponding to the light emitted in the region 3a. Therefore, there is a non-negligible risk that the light emitted at a position far from the light emitting end surface 11 side of the region M3a will be absorbed in the process of propagating to the light emitting end surface 11 side. Therefore, the conventional semiconductor light emitting diode described above with reference to FIGS. 4 and 5 has a drawback in that incoherent light emitted to the outside cannot be obtained with sufficiently high brightness. Therefore, the present invention seeks to propose a novel semiconductor light emitting diode that does not have the above-mentioned drawbacks.

[Means for Solving the Problems] The semiconductor light emitting diode according to the first invention of the present application has the following features as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5: (1) a first semiconductor crystal layer formed on the semiconductor crystal substrate and having a first conductivity type; (2) a first semiconductor crystal layer formed on the first semiconductor crystal layer in contact with it; a second semiconductor crystal layer having a narrower energy bandgap and higher refractive index than the first semiconductor crystal layer; a semiconductor stack having a third semiconductor crystal layer having a wider energy bandgap and lower refractive index than the third semiconductor crystal layer and having a second conductivity type opposite to the first conductivity type;
and (b) the first and second opposing parts of the semiconductor laminate.
First and second electrode layers facing each other are disposed on the main surface of the semiconductor stack, and (c) the end face of the semiconductor laminate is used as a light emitting end face. However, in the semiconductor light emitting diode according to the first invention of the present application, in the semiconductor light emitting diode having such a configuration, (d) the second semiconductor crystal layer is such that the first and second electrode layers are opposed to each other; In a region serving as an excitation region, a plurality of n first, second, and ......has an n-th area portion, and (e) a plurality of n first and second......
The n-th region portion is the first, second, etc. n-th mixed crystal region portion Q1, Q2, where the superlattice layer is mixed crystal.
......Qn, respectively, and (to) the first, second......n-th mixed crystal region portions Q, Q2... . . . Qn has a first, a second, . Further, the semiconductor light emitting diode according to the second invention of the present application is the semiconductor light emitting diode according to the first invention of the present application, in which: (g) the second semiconductor crystal layer is located on the light emitting end face side of the region serving as the excitation region; has a region as a non-excitation region on the opposite side; m pieces (where m is an integer greater than or equal to 1) of first, second...
. . . has an n-th region, and the m first, second, . . . n-th region,
First, second, etc. in which the superlattice layer is mixed crystal
... n-th mixed crystal region portion M, M3, ......
M, respectively, and (nu) the first, second...
......n-th mixed crystal region M1M3,...
. . . M, both have a smaller degree of mixed crystallinity than the n-th mixed crystal region Qn in the region serving as the excitation region, but the first, second, and・・・
...has an n-th mixed crystallinity. [Operations and Effects] According to the semiconductor light emitting diode according to the first invention of the present application, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, the first and second electrodes If a required power source is connected between the layers and a current from the power source is passed through the semiconductor layered body, the second layer of the semiconductor layered body a plurality of n first, second, . . . regions as excitation regions in which first and second electrode layers of the semiconductor crystal layer face each other;
...In the n-th area, these first, second,
......First and second of the n-th area part...
...a plurality of n first and second bands each having a band centered on a wavelength corresponding to the n-th energy bandgap.
......Nth light is generated respectively. Then, these first, second, etc. n-th lights reach the region serving as the excitation region where the first and second electrode layers of the second semiconductor crystal layer are facing each other. The light is hardly absorbed in that region, and is confined by the first and second semiconductor crystal layers and propagates toward the light emitting end face. Therefore, in the case of the semiconductor light emitting diodes according to the first invention of the present application and the second invention of the present application, incoherent light is It is obtained by emitting light to the outside from the light emitting end face. In addition, in this case, the current from the power source continues to flow through the semiconductor stack as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, and therefore, the current from the power source Since the first and second electrode layers of the second semiconductor crystal layer of the semiconductor stack are continuously injected into the region serving as the excitation region facing each other, the injected radiation is emitted to the outside from the light emitting end surface. As in the case of the conventional semiconductor light emitting diode described above in FIG. 4 and FIG.
A relatively high brightness can be obtained depending on the current flowing through the region serving as the excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other. In addition, incoherent light emitted from the light emitting end surface to the outside is transmitted to the second semiconductor crystal on the light emitting end surface, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5. Since the light is emitted to the outside from a local area called the end face of the layer, the incoherent light obtained by being emitted to the outside from the light emitting end face is the same as the conventional semiconductor light emitting device described above in FIGS. 4 and 5. As in the case of diodes, depending on the thickness of the second semiconductor crystal layer, radiation is emitted with a relatively narrow emission angle. Therefore, in the case of the semiconductor light emitting diode according to the first invention of the present application, as in the case of the conventional semiconductor light emitting diode described above in FIG. 4 and FIG. Obtained with a narrow radiation angle. However, in the case of the semiconductor light emitting diode according to the first invention of the present application and the second invention of the present application, the excitation region where the first and second electrode layers of the second semiconductor crystal layer of the semiconductor stack are opposed to each other. The region has a plurality of n first, second, ..., nth region parts, and these first, second, ..., nth region parts First, second, etc. n-th mixed crystal region portions Q1, in which the superlattice layers are mixed crystallized to successively smaller degrees of mixed crystallinity in the region portions; Q2......Qn, so those first, second......nth
The first, second, etc. nth energy band gaps of the region portions have energy band gaps that gradually widen in the reverse order of those, and therefore, the first, second, and nth energy band gaps of The second . On the other hand, in a region serving as an excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other, a plurality of n first, second, ... The first, second, etc., nth lights generated in each region are
Since they each have wavelengths corresponding to the above-mentioned first, second, etc. n-th energy band gaps, the first, second, etc. n light is
When the light propagates toward the light emitting end face side through the excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other, the first and second electrode layers...・The nth light is hardly absorbed in the excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other, and is directed toward the light emitting end surface. propagate towards. Therefore, in the case of the semiconductor light emitting diodes according to the first invention and the second invention of the present application, the incoherent light is sufficiently higher than that of the conventional semiconductor light emitting diodes described above in FIGS. 4 and 5. Brightness can be radiated to the outside. Furthermore, in the case of the semiconductor light emitting diodes according to the first invention of the present application and the second invention of the present application, the light obtained by being radiated to the outside from the light emitting end face is the same as the above-mentioned first, second, etc.
...Since it consists of n-th light, the degree of incoherence, which is expressed as a value proportional to the wavelength bandwidth of the light obtained by radiating it to the outside, is different from that of the conventional semiconductor described above in FIGS. 4 and 5. This is higher than that for device diodes. Further, in the case of the semiconductor light emitting diode according to the second invention of the present application, there are m regions as non-excited regions in which the first and second electrode layers of the second semiconductor crystal layer of the semiconductor stack are not facing each other. (where m is an integer greater than or equal to 1)
. . . has an nth region portion, and the first and second . . . nth region portions are both a second semiconductor crystal layer. Compared to the n-th mixed crystal region Q in which the superlattice layer is mixed in the n-th region in the region serving as the excitation region where the first and second electrode layers of Small mixed crystallinity D, D2...
The first and second conditions are that the superlattice layer is mixed crystal in Dn.
......n-th mixed crystal region M1, M2...
...... Ml and L, respectively, so that the first, second... ...
...The n-th region has a narrower energy band than any other region in the excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other. has a gap, and therefore has a higher absorption edge wavelength than any region in the region serving as an excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other. ing. Moreover, the first, second, nth regions of the second semiconductor crystal layer, which are non-excited regions in which the first and second electrode layers do not face each other, have The regions have the first, second, etc. n-th mixed crystallinity degrees in order, so the first, second, etc.・・・
...The n-th regions have energy band gaps that become narrower in that order, and therefore have absorption edge wavelengths that become higher in that order. Therefore, in the region serving as the excitation region where the first and second electrode layers of the second semiconductor crystal layer face each other, the first
, second...... A part of the first, second...... n-th light generated in the n-th area, respectively,
When the first and second electrode layers of the second semiconductor crystal layer propagate through the non-excited region where they do not face each other toward the side opposite to the light emitting end surface, some of the light is transmitted to the second semiconductor crystal layer. In the non-excited region where the first and second electrode layers of the semiconductor crystal layer do not face each other, it is more effective than in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5. Absorbed. Therefore, in the case of the semiconductor light emitting diode according to the second invention of the present application, as in the case of the conventional semiconductor light emitting diode described above in FIGS. The semiconductor stack can be used as a non-excited region in which the first and second electrode layers of the second semiconductor crystal layer do not face each other without processing and providing an inclined surface on the end face side. However, in order to sufficiently absorb the light propagating therein, the first and second electrode layers of the second semiconductor crystal layer have a long length. Light propagating from a region serving as an excitation region that faces each other to a region serving as a non-excitation region where the first and second electrode layers of the second semiconductor crystal layer do not face each other is transmitted to the former region, In fact, re-incidence can be prevented. Therefore, according to the semiconductor light emitting diode according to the second invention of the present application, as in the case of the conventional semiconductor light emitting diode described above in FIGS. Also, the semiconductor laminate can be formed on the second side without processing and providing an inclined surface on the end face side of the
The light emitting end face can be formed without forming a structure having a long length so that the region serving as a non-excited region where the first and second electrode layers of the semiconductor crystal layer do not face each other has a good length. The incoherent light emitted to the outside is obtained with a higher incoherence level than in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5.

【Example】

Next, an embodiment of a semiconductor light emitting diode according to the present invention will be described with reference to FIGS. 1 and 2. In FIGS. 1 and 2, parts corresponding to those in FIGS. 4 and 5 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. 1 and 2 has the same structure as the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, except for the following points. That is, in a region 3a serving as an excitation region where the electrode layers 15 and 16 face each other, the semiconductor crystal layer 3 of the semiconductor stack 10 is exposed to the semiconductor stack 10 from the light emitting end surface 11 side.
A plurality of n first and second...
- Has an n-th area. In addition, in the figure, the case of n-3 is shown. And the first, second... of those semiconductor crystals WA3.
. . . G in which the nth region has a thickness of, for example, 80 people
I with a semiconductor crystal layer consisting of aAs and a thickness of 20
First, second, n-th mixed crystal regions in which superlattice layers in which nGaAs-based semiconductor crystal layers are stacked repeatedly, for example, 20 times, are mixed crystal, respectively. Q
, Q3, ......Q, and these first, second, ...... nth mixed crystal regions Qn
Q2...Qn has successively smaller degrees of mixed crystallinity F, F2......Fo. Further, in the region 3b as a non-excited region where the electrode layers 15 and 16 do not face each other, the semiconductor crystal layer 3 is formed into a semiconductor 8iWJ body from the n-th mixed crystal region Qn side in the region 3a as the excitation region described above. It has m first, second, . Then, the m first, second...
. . . The n-th region portion is the first and second mixed crystal region portions M, M in which the above-mentioned superlattice layer is mixed. , 2......M A, respectively, and the first, second......nth
The mixed crystal region portions M, M2...M Mixed crystallinity degrees F1 to Fn of crystallized region Q-Q. The first, second..., n-th mixed crystallinity degrees are smaller in order than D2... ...Has DI. However, in this case, the n-th degree of mixed crystallinity DI may be substantially zero. In addition, in the figure, the nth degree of mixed crystallization of the nth mixed crystallized region portion Ml is shown. is zero. Further, on the other side of the semiconductor stack 10 opposite to the light emitting end face 11 side, the end faces of the semiconductor crystal layers 5.4 and 3 are extended with respect to the vertical plane in the thickness direction of the semiconductor stack 10. Therefore, it does not have such an inclined surface 14. In addition, the above-mentioned mixed crystal region portions Q, Q2...
. . Q , Ml, M2 . . . M, can be formed as follows, although detailed explanation will be omitted. That is, after obtaining the semiconductor laminate 10 in which the layer that will become the semiconductor crystal layer 3 is the above-mentioned superlattice layer, an insulating film made of, for example, 5ho2 is formed on its upper surface, and then the SiO2
With a GaAS wafer stacked on top, 9°C was heated at a relatively high speed of 30°C/sec in a hydrogen atmosphere.
The first heat treatment is performed to raise the temperature to a high temperature of 50°C and maintain that temperature for a relatively short period of time, such as 30 seconds. □ is obtained, and then the mixed crystal region MIIl of the insulating film is obtained.
After removing the region facing the , a heat treatment similar to the first heat treatment is performed as a second heat treatment, and then a mixed crystal region portion M (IIl-1) with a small degree of mixed crystallinity is removed. Then, by repeating the same process sequentially, the mixed crystal region portion M(Ill-1)M (+a-
2) ``''''''''' M 1 ・QnQ (low 1) ---Q1 is obtained. Note that the mixed crystal region Mi
When the degree of mixed crystallinity is zero, the above-described sequential heat treatment is started from the second heat treatment. The above is the configuration of an actual droplet example of a semiconductor light emitting diode according to the present invention. According to the semiconductor light emitting diode according to the invention shown in FIGS. 1 and 2, the electrodes H15 and 16 are similar to the case of the conventional semiconductor light emitting diode described above in FIGS.
By connecting a required power source between them and passing current from the power source through the semiconductor laminate 10, the semiconductor gI
A plurality of n first regions 3a as excitation regions where the electrode layers 15 and 16 of the semiconductor crystal layer 3 of the layer body 10 are facing each other.
, second......in the n-th area section, the first, second......n-th area section,
Second......n-th energy band gap E, 1.6g3,...Eg. The wavelengths λ, λ2, λ2, etc. corresponding to λ, respectively. A plurality of n lights having a band centered on L, L...
...L° is generated respectively. Then, these lights L1L2...Lo are hardly absorbed in the region 3a, which is the excitation region where the electrode layers 15 and 16 of the semiconductor crystal layer 3 are facing each other, and the semiconductor The light is confined by the crystal layers 2 and 4 and propagates toward the light emitting end face 11 side. Therefore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 and 2, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 3 and 4, incoherent light is It is obtained by radiating outward from the end face 11. Furthermore, in this case, the current from the power source continues to flow through the semiconductor stack 10, as in the case of the conventional semiconductor light emitting diode described above in FIGS. , since the electrode layers 15 and 16 of the semiconductor crystal layer 3 of the semiconductor stack 10 are continuously injected into the region 3a serving as an excitation region facing each other, incoherent light emitted from the light emitting end face 11 to the outside is As in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, this light causes a current flowing in the region 3a as an excitation region where the electrode layers 15 and 16 of the semiconductor crystal layer 3 face each other. Depending on the brightness, relatively high brightness can be obtained. Furthermore, incoherent light emitted from the light emitting end surface 11 to the outside is transmitted to the semiconductor crystal layer on the light emitting end surface 11, as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5. Since the light is emitted to the outside from a local area called the end face of 3, the light emitting end face 11
Depending on the thickness of the semiconductor crystal layer 3, the incoherent light emitted from the semiconductor crystal layer 3 can be
It 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 and 2, as well as in the case of the conventional semiconductor light emitting diode described above in FIGS. 4 and 5, relatively incoherent light is produced. 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 and 2, there are a plurality of regions 3a as excitation regions where the electrodes 1115 and 16 of the semiconductor crystal 13 of the semiconductor stack 10 are facing each other. [9th 1st, 2nd,
......has an nth area part, and those! 1, 2nd...... nth region portion has sequentially smaller first, second...... nth mixed crystallinity degrees F, F2. ...Town...F. The superlattice layer is mixed crystal in the first, second, etc.
Since the mixed crystal region portions Q, Q2...Qn are respectively formed, the first and second......
1st, 2nd, etc., nth energy band gap EE of the nth region section EE...E
gll g2 gn are sequentially wider in the reverse order, and therefore, the first, second, etc. nth regions are sequentially lower in the reverse order. They each have absorption edge wavelengths of On the other hand, the electrode layers 15 and 16 of the semiconductor crystal layer 3 are arranged in a plurality of n first, second, . The first, second, etc., nth light L1 generated in
L2...Lo is the first, second, and
......nth energy band gap Ea1
, E ...... Wavelength λ , λ corresponding to E
・・・・・・g2 gn
1 2...λ. Therefore, the first, second......n-th light L2......Lo is transmitted to the electrode layer 15 and the semiconductor crystal layer 3, respectively. 16 propagates toward the light emitting end face 11 side through the region IIIt3a as an excitation region facing each other, the first, second, ... nth light, L
2...Lo is the electrode layer 1 of the semiconductor crystal layer 3
Region 3a as an excitation region where 5 and 16 are facing each other
In this case, the light propagates toward the light emitting end face 11 side without being absorbed. Therefore, in the case of the semiconductor light emitting diode according to the invention shown in FIGS. 1 and 2, incoherent light can be
It is possible to emit light to the outside with sufficiently higher luminance than in the case of the conventional semiconductor light emitting diode described above with reference to FIGS. Furthermore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS.
...consisting of the n-th light L1, L2...L, the degree of incoherence, which is expressed as a value proportional to the wavelength bandwidth of the light obtained by radiating it to the outside, is the fourth This is higher than that of the conventional semiconductor light emitting diode described above in FIGS. Further, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 and 2, the semiconductor crystal layer 3 of the semiconductor stack 10
The region 3b where the electrode layers 15 and 16 are not facing each other is
m (however, m is an integer greater than or equal to 1) first, second...
. . . has an nth region portion, and the first, second, . . . nth region portions are both electrode layers 15 and 16 of the semiconductor crystal layer 3. The superlattice layer of the n-th region in region 3a as an excitation region where the two are opposed to each other is mixed crystallized with a smaller degree of mixing compared to the n-th mixed crystallized region Qn, in which the superlattice layer is mixed crystallized. The first, second...
......n-th mixed crystal region portions M1, M2...
. . . M, respectively, so that the first, second, . . . , n
has a narrower energy bandgap than any region in the region 3a as an excitation region where the electrode layers 15 and 16 of the semiconductor crystal layer 3 face each other, and therefore the semiconductor crystal The region serving as the excitation region where the electrode layers 15 and 16 of the layer 3 face each other has a higher absorption edge wavelength than any region in the region [3a]. Moreover, the first, second, . . . . . . , the first, second...... nth mixed crystallization degree D 1D2...... Do is smaller in that order, so the first, second... The second...n-th region has an energy band gap that becomes narrower in that order, and therefore has an absorption edge wavelength that becomes higher in that order. Therefore, in the region 3a serving as the excitation region where the electrode' layers 15 and 16 of the semiconductor crystal layer 3 face each other, the first
The first, second, n-th lights L1, L2, respectively generated in the second, n-th area.
..... A part of Lo propagates through region 3b as a non-excited region where electrode layers 15 and 16 of semiconductor crystal layer 3 do not face each other to the side opposite to light emitting end surface 11 side. At this time, a part of these lights L 2 , L 2 . . . . . . . It is absorbed more effectively than in the case of the conventional semiconductor light emitting diode described above in FIG. Therefore, in the case of the semiconductor light emitting diode according to the present invention shown in FIGS. 1 and 2, as in the case of the conventional semiconductor light emitting diode described above in FIGS. Without processing and providing the inclined surface 14 on the end surface side opposite to the side 11,
Semiconductor 8! The i-layer body 10 is connected to the electrode layer 15 of the semiconductor crystal layer 3.
and region 3 as a non-excited region where 16 are not facing each other.
The electrode layers 15 and 16 of the semiconductor crystal layer 3 face each other without being configured to have a long length so that b has a long length to sufficiently absorb the light propagating there. The light propagating from the region 3a as an excitation region to the region 3a as a non-excitation region where the electrode layers 15 and 16 of the semiconductor crystal layer 3 are not facing each other is substantially re-injected into the former region 3a. It can be eliminated. Therefore, according to the semiconductor light emitting diode according to the invention shown in FIGS. 1 and 2, as in the case of the conventional semiconductor light emitting diode described above in FIGS. The semiconductor laminate 10 can be manufactured without processing and providing the inclined surface 14 on the end surface side opposite to the end surface 11 side, and the semiconductor stack 10 can be formed into a non-contact structure in which the electrode layers 15 and 16 of the semiconductor crystal layer 3 are not facing each other. Region 3b as excitation region
The incoherent light obtained by radiating outward from the light emitting end surface 11 without configuring the light emitting end face 11 to have a long length is shown in FIGS. 4 and 5.
A higher degree of incoherence is obtained than in the case of the conventional semiconductor light emitting diode described above in the figure. Incidentally, in the above description, only one embodiment of the semiconductor light emitting diode according to the present invention has been shown, and a detailed explanation of the drawings will be omitted. It is also possible to omit the region where the electrode layers 15 and 16 do not face each other, so that the structure does not include the region 3b of the semiconductor crystal layer 3. In this case, the mixed crystal region Q of the n-th region in region 3b
. The degree of mixed crystallinity may be zero. Furthermore, in the configuration described above in FIGS. 1 and 2, the third
As shown in the figure, one of the electrode layers 15 and 16, in the figure, the electrode layer 15 is the first in the region 3a.
, a plurality of n first, second, nth areas facing the nth area, respectively.
The structure is divided into electrode parts G, SG2......Go, and the first, second,..., nth electrode parts 01 to G, By using the required number of electrode parts counting from the electrode part as effective electrode parts, light having different degrees of coherence can be obtained, and the area under the other electrodes of the semiconductor stack 10 can be used as a non-excited area. It can also be used as a region. Furthermore, in the semiconductor light emitting diode according to the present invention shown in FIG. electrode parts H1, H2...
H1 is provided (in this case, the electrode layer 16 needs to be opposed to the electrode parts H, H2...H. as shown in the figure), and the semiconductor stack 10 is made into a mixed crystal. It is also possible to use the regions facing the required number of mixed crystalline regions counted from the first mixed crystalline region in the regions M to Mffi as the excitation region. In addition, although the above description describes an embodiment in which the present invention is applied to a basic semiconductor light emitting diode, the main point is (a) ■ the semiconductor crystal described above in FIGS. a semiconductor crystal substrate having a first conductivity type corresponding to the substrate 1; and (2) a semiconductor crystal layer 2 formed on the semiconductor crystal substrate and having the first conductivity type described in FIGS. 1 and 2; (1) formed on and in contact with the first semiconductor crystal layer and having a narrower energy bandgap and higher refractive index than the first semiconductor crystal layer; This corresponds to the semiconductor crystal layer 3 described above in FIGS. 1 and 2! A semiconductor crystal layer of ¥2,
(2) A second semiconductor crystal layer formed on and in contact with the second semiconductor crystal layer, which has a wider energy band gap and lower refractive index than the second semiconductor crystal layer, and has a conductivity type opposite to that of the first semiconductor crystal layer. a third semiconductor crystal layer corresponding to the semiconductor crystal layer 4 described above in FIGS. 1 and 2 and having a conductivity type of On the first and second main surfaces facing each other,
The first and second electrode layers corresponding to the electrode layers 15 and 16 described above in FIG. 1 and FIG. It is clear that the present invention can be applied to any semiconductor light emitting diode in which one end face in the direction is a light emitting end face, even if it is a buried type. Furthermore, in the semiconductor light-emitting diode according to the present invention described above, it is also possible to have a configuration in which "n-type" is read as "p-type" and "p-type" is read as "n-type", or in other ways that depart from the spirit of the present invention. Various modifications and changes may be made without further modification.

[Brief explanation of drawings]

1 and 2 are a schematic perspective view and a vertical cross-sectional view showing an embodiment of a semiconductor light emitting diode according to the present invention. 4 and 5 are a linear perspective view and a vertical cross-sectional view showing a conventional semiconductor light emitting diode. 1・・・・・・・・・・・・・・・・・・Semiconductor crystal substrate 2.3.4.5 ・・・・・・・・・・・・・・・・・・Semiconductor crystal layer 3
a, 3b...Fr4 region 10 of semiconductor crystal m3
...... Semiconductor laminate 11
・・・・・・・・・・・・・・・・Light emitting end surface 12
・・・・・・・・・・・・・・・・・・Anti-reflection film 14
・・・・・・・・・・・・・・・・・・Slope 15.1
6... Electrode layer Q, Q......Q.・・・・・・・・・・・・・・・ Semiconductor crystal layer 3
Mixed crystal region portions M1 to M of the region portion 3a, . . . region 3 of the semiconductor crystal layer 3
Mixed crystal region portion G −G of b, H1 to Hm n

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 first semiconductor crystal layer and having a narrower energy bandgap and a higher refractive index than the first semiconductor crystal layer; 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 refractive index than the second semiconductor crystal layer, and has a conductivity type opposite to that of the first semiconductor crystal layer. a semiconductor stacked body having a third semiconductor crystal layer having a conductivity type; In the semiconductor light emitting diode, in which two electrode layers are arranged and one end surface of the semiconductor laminate is used as a light emitting end surface, the second semiconductor crystal layer is arranged such that the first and second electrode layers are opposite to each other. In the region serving as the excitation region, a plurality of n first, second, . . .・・・・・・Nth
The plurality of n first, second, . . .
. . . The n-th region is the first and second mixed crystal regions Q in which the superlattice layer is mixed.
_1, Q_2......Q_n, respectively, and the above-mentioned first, second......n-th mixed crystal region portions Q_1, Q_2... A semiconductor light-emitting diode characterized in that Q_n has a first, second, etc. n-th degree of mixed crystallinity that is sequentially smaller in that order. 2. The semiconductor light emitting diode according to claim 1, wherein the second semiconductor crystal layer is arranged on a side opposite to the light emitting end face side of the region serving as the excitation region,
a region serving as a non-exciting region, and in the region serving as the non-exciting region, a plurality of strips are sequentially connected in the longitudinal direction of the semiconductor laminate from the side of the region serving as the excitation region and in a direction opposite to the light emitting end surface. m (however, m is an integer greater than or equal to 1) first and second
. . . has an m-th region, and the m-th first, second, m-th region has a superlattice layer in which the superlattice layer is a mixed crystal. The first and second...
... m-th mixed crystal region M_1, M_2, ...
...M_m respectively, and the first, second, m-th mixed crystal region portions M_1, M_2, ...M_m are both The degree of mixed crystallinity is smaller than that of the n-th mixed crystal region Q_n in the region serving as the excitation region, but the first, second, m-th mixed crystals, etc. have a smaller mixed crystallinity in that order. A semiconductor light emitting diode characterized by having a crystallinity. 3. The semiconductor light emitting diode according to claim 1 or 2, wherein the first and second electrode layers are arranged in a plurality of regions, each of which faces a plurality of n regions in the region serving as the excitation region. A semiconductor light emitting diode characterized in that it is divided into n electrode parts.