JP2833604B2 - Semiconductor laminated structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laminated structure having an improved layer for preventing a reactive current and used for a semiconductor light emitting device such as a semiconductor laser and a light emitting diode.

[0002]

2. Description of the Related Art Heretofore, semiconductor light emitting devices have
Such as overflow current and leak current that escape from the optical layer
Improvement of characteristics by reducing current that does not contribute to light emission
It is planned. For example, the first of JP-A-4-218994
In the embodiment, a quantum well laser manufactured on an InP substrate is used.
In this case, an n-type InP substrate having a (100) main surface is formed on an n-type InP substrate.
InP buffer layer, InGaAs / InGaAsP multi layer
Quantum well layer, 25 nm thick carrier overflow
Prevention layer, 100 nm thick In_0.77Ga_0.23As _0.5P
_0.5A structure in which optical waveguide layers are sequentially laminated has been reported.

According to this report, in the above structure,
The band discontinuity is about 0.3182e in the conduction band
Since V is large and the film thickness is 25 nm, tunneling of electrons hardly occurs, so that leakage of electrons from the light emitting layer to the optical waveguide layer is suppressed, and in the valence band, the amount of band discontinuity is almost zero. Therefore, it is described that injection of holes into the light emitting layer is not hindered.

[0004]

However, such a semiconductor laminated structure has the following problems. First, when considering a material system in which a band discontinuity exists only in the conduction band and no discontinuity exists in the valence band, it can be seen that generally only a very limited number of materials can be used. Incidentally, in the above report, In _x Al _y
By setting the mixed crystal composition ratio x and y of Ga _1-xy As to specific values, a desired band structure is realized for the InGaAsP optical waveguide layer. However, as described in the above report, it is generally difficult to completely match the peaks of the valence band, and depending on the value of the peak of the valence band of the carrier overflow prevention layer, holes to the light emitting layer may not be formed. There is a problem that injection is hindered and holes that do not contribute to light emission are distributed.

In the above conventional example, a mixed crystal containing Al is used for the carrier overflow prevention layer adjacent to the light emitting layer. However, in a material system containing Al, the problem of non-radiative recombination is generally large, and the growth of the laminated structure is large. It is not usually used in a long-wave structure on an InP substrate having a low temperature.

Further, the composition of the carrier overflow prevention layer needs to be designed according to the wavelength of the semiconductor light emitting device. To realize devices having different wavelengths, the layer structure used for each wavelength is required. It is necessary to individually design and realize material systems and compositions based on

For the above reasons, in order to realize a carrier overflow prevention layer adjacent to the light-emitting layer such that the band discontinuity has a specific relationship between the optical waveguide layer and the light-emitting layer, strict composition control is required. However, there are problems such as design for each wavelength, crystal quality, and the like, and in the true sense, improvement in characteristics by reducing reactive current has not been sufficiently realized.

The object of the present invention is not to reduce the reactive current only by designing such a one-dimensional band structure in the stacking direction, but to generate the electrons and holes in the semiconductor due to the quantum mechanical properties. It is an object of the present invention to provide a semiconductor laminated structure in which the transmission of only electrons is restricted and the transmission of holes is not restricted by realizing a three-dimensional band structure by utilizing wave characteristics.

[0009]

The present invention comprises an n-type first semiconductor layer, a p-type second semiconductor layer, and a light-emitting layer sandwiched between the first and second semiconductor layers. In the semiconductor laminated structure, a region that restricts passage of electrons from the light emitting layer to the p-type second semiconductor layer (hereinafter, referred to as an electron passage restricting region) between the p-type second semiconductor layer and the light emitting layer. And a plurality of such regions are provided so that the distance between the regions is equal to or less than the de Broglie wavelength of electrons in the semiconductor and equal to or greater than the de Broglie wavelength of holes in the semiconductor.

In the structure of the present invention, electrons are injected from the n-type first semiconductor layer into the light-emitting layer, while holes are injected from the p-type second semiconductor layer into the light-emitting layer. Bonding occurs.

In the present invention, the carrier overflow prevention layer for preventing electrons from leaking from the light-emitting layer to the second semiconductor layer is provided with a conventional band discontinuity in only one direction in the stacking direction to prevent electron leakage. Instead of preventing the injection of holes, the three-dimensional carrier wave in the semiconductor is used. That is, if the distance between the electron passage restricted region substantially restricting the passage of electrons and the electron passage restricted region is set to be equal to or less than the de Broglie wavelength of electrons in the semiconductor and equal to or greater than the de Broglie wavelength of holes in the semiconductor, the distance An electron with a large de Broglie wavelength, which is a quantum mechanical wavelength, cannot pass through. On the other hand, a hole cannot pass through the electron passage restricted region like an electron, but a hole with a small de Broglie wavelength can pass through between the electron passage restricted region and the same region.

Therefore, it is possible to prevent electrons from leaking from the light emitting layer to the p-type second semiconductor layer and not to prevent injection of holes from the p-type second semiconductor layer into the light emitting layer. With the use of the stacked structure, a light-emitting element with high luminous efficiency can be provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an electron passage restricting region is a semiconductor having a bandgap wider than a bandgap of a semiconductor constituting a surface of a light emitting layer on a second semiconductor layer side (hereinafter, a wide bandgap). This can be realized by using a thin film of a semiconductor (referred to as a semiconductor) so as to have a sufficiently small electron tunneling probability.

Here, the light emitting layer used in the present invention preferably has a quantum well structure, but is not particularly limited. Further, it may be composed of a plurality of layers.

The tunneling probability of electrons in the electron passage restricted region is preferably small in order to prevent the passage of electrons, for example, 4 × 10 ⁻² or less, preferably 2 × 10 ⁻² or less, particularly preferably 10 × 10 ⁻² or less. ^-2 or less. In order to obtain such a tunneling probability, either the film thickness is increased or the composition is adjusted so as to further increase the forbidden band width. Either method may be used, or both may be used in combination.

The distance between adjacent electron passage restriction regions is equal to or less than the de Broglie wavelength of an electron in a semiconductor and equal to or greater than the de Broglie wavelength of a hole. Is 120% or more of the de Broglie wavelength of the electron, and particularly preferably 70% of the de Broglie wavelength of the electron.
% Or less and 150% or more of the de Broglie wavelength of the hole. Further, the value slightly changes depending on the semiconductor used for the light emitting layer.

The shape of the electron passage restricted region is not limited as long as it satisfies the above-mentioned inter-region interval. For example, a stripe shape called a so-called quantum wire in which the electron passage restricted region is continuous in one direction, It can be formed in a dot shape called a quantum dot in which an electron passage restriction region exists independently. The stripe shape may be a square cross-section or a semicircular cross-section such as a semi-cylindrical shape. Further, as the dot shape, even if the cross-sectional shape is a square shape like a disk shape (short columnar shape) or a short prism, the cross-sectional shape is almost half like a hemisphere shape (or a shape where a part of a sphere is turned down). It may be circular.

In the case where the end face is not vertical, such as a semicylindrical shape or a hemispherical shape, the distance between the adjacent electron passage restricting regions means that the tunneling probability that electrons can escape to the second semiconductor layer is sufficiently small. It means the distance between portions having such a film thickness. For example, when the target is 2 × 10 ⁻² or less, which is a preferable range of the tunneling probability, a portion having a layer thickness that is equal to or less than the probability is referred to as an electron passage restriction region. However, in this case, it is necessary that the width of the region through which the holes can sufficiently pass be equal to or longer than the de Broglie wavelength of the holes.

Since the region between the electron passage restricted regions is a region through which holes pass, the efficiency is better when the tunneling probability is closer to 1, but it is not necessarily required to be 1, for example, 0.6 or more, preferably 0. If it is 0.7 or more, a light-emitting element with higher efficiency than the conventional one can be obtained. Therefore, a thin film having such a tunneling probability may be formed between the electron passage restriction regions.

Here, the area ratio between the area of the electron passage restricting region and the area through which the holes pass is determined by, for example, (electron passing restricting region Area) / (area of the area through which the hole passes) is 0.2 to 3, preferably 0.2
It is preferable to design so as to be 1.

Incidentally, the electron passage limiting region may be provided between the light emitting layer and the p-type second semiconductor layer.
It may be provided directly on the light-emitting layer, or may be provided on the surface of the light-emitting layer as needed, in particular, in contact with another layer which does not serve as an energy barrier.

In order to form the electron passage restricted region pattern, after forming the light emitting layer, a thin film of a wide bandgap semiconductor is formed, and then the wide bandgap semiconductor thin film is exposed to an electron beam resist, an electron beam exposure, and the like. Patterning is performed by a known method such as a patterning method by etching.
It can be formed so as to have a wavelength equal to or less than the Broy wavelength and equal to or greater than the de Broglie wavelength of the hole.

The thin film of the wide bandgap semiconductor may be formed directly on the surface after forming the light emitting layer, or may be formed on the surface after forming the other layers described above. The restriction region may be formed so as to be provided between the light emitting layer and the p-type second semiconductor layer.

After the light emitting layer is formed, a wide band gap semiconductor having a lattice constant different from that of the semiconductor exposed on the surface is used, and the wide band gap semiconductor is formed on the light emitting layer surface in a very self-forming manner. It can also be grown into fine dots. In this method, a three-dimensional structure is formed on the entire surface of the substrate, and by increasing the density, the dot interval can be set smaller than the electron de Broglie wavelength and larger than the hole de Broglie wavelength. Manufacturing becomes very easy.

At the time of this growth, a thin film of a wide band gap semiconductor is usually formed between the dots. However, since this film thickness is not more than about two molecular layers, the tunneling probability of the hole is zero. .7 or more, and hole injection is generally performed without any problem as described above.

In this self-forming manufacturing method, in particular, in an InP-based material system used for a long wavelength band light emitting device in which electron overflow is a problem, Ga _x In _{1 -x} P is used as a material having a wide band gap. Mixed crystal (where x is 0 <
It is a number that satisfies x ≦ 1. ) Can be used.
Then, it is possible to realize a band structure in which both electrons and holes do not transmit carriers without using Al which tends to be a problem in crystal growth. By adopting the above structure, the overflow of electrons is suppressed, and the holes are formed of GaInP.
It is injected into the light emitting layer through the gap between the dots.

Also, overflow is likely to be a problem.
Red light-emitting element using InGaP-based material on GaAs
As for the element, lattice mismatch with GaAs, (Al_xG
a_1-x) _yIn_1-yP mixed crystal (x is unrelated to the above)
0 <x ≦ 1, y satisfies y ≦ 0.4 or y ≧ 0.6
It is the number to do. ) To create a dot structure in a self-forming manner.
Can be manufactured.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic cross-sectional view of an example in which the present invention is applied to a semiconductor laser on an InP substrate, FIG. 2 is a schematic enlarged view of a light emitting layer portion thereof, and FIG.
(A) and (b) are AA 'cross section of FIG.
The band diagram along the section B ′ corresponds to an electron passage restricted region and a non-existent region.

First, the present structure has a plane orientation (100) by a gas source molecular beam epitaxy method (GSMBE method).
0.5 μm thick Si-doped n-type InP buffer layer 12 on a Sn-doped n-type InP substrate 11, non-doped, 50 nm thick band gap 1.18 eV (corresponding to a wavelength of 1.05 μm) and lattice matching with InP InGa
AsP light guide layers 13 are sequentially laminated.

Next, a band gap of 1.08 eV having a non-doped thickness of 20 nm (wavelength 1.
InGaAs lattice-matched to InP at 15 μm)
After laminating the P layer 14, a 7 nm thick band gap of 0.95 eV (corresponding to a wavelength of 1.3 μm) InGaAsP
Quantum well layer 15 and band gap of 10 nm thickness 1.0
A light emitting layer 17 consisting of seven repetitions of an InGaAsP barrier layer 16 lattice-matched to InP at 8 eV is formed, and a non-doped 20 nm thick band gap of 1.08 eV (corresponding to a wavelength of 1.15 μm) is formed thereon. An InGaAsP layer 18 lattice-matched is stacked.

Then, non-doped InP having a thickness of about 8 nm is grown thereon. After this layer is grown, it is taken out from the growth apparatus, and the InP on the surface is formed into a fine line by electron beam exposure and etching, and the fine line portion and the interval thereof are both 20 mm.
Process into a line and space shape to about nm
An nP thin line portion 19 is formed. Next, G
InP with a non-doped 50 nm thick band gap of 1.18 eV (corresponding to a wavelength of 1.05 μm) using SMBE
Then, a Be-doped p-type InP cladding layer 21 with a thickness of 2 μm and a 50-nm thick Be-doped p-type InGaAs cap layer 22 with a lattice match with InP are sequentially laminated.

Thereafter, the light guide layer 20 on the front side and the InP fine line portion 19 below the light guide layer 20 are removed by ordinary photolithography and etching, leaving a ridge-like region with a width of about 5 μm. Then, electrodes 23 are formed on the upper surface of the ridge and the lower surface of the substrate, and thereafter, both end surfaces are formed by cleavage to produce a semiconductor laser structure.

In this structure, the light emitting layer 17 and the p-type InP
Between the cladding layer 21, there is a thin wire portion 19 made of InP which acts as a barrier because the band discontinuity value is positive for both electrons and holes. Here, considering a two-dimensional band in the stacking direction, the portion where InP exists has a thickness of 8 nm.
Becomes a barrier. The band diagram of this region is shown in FIG.

Here, the tunneling probability of electrons and holes having momentum due to thermal energy at room temperature in the InP fine wire portion 19 will be considered. InG for electrons and holes
The band discontinuity between the aAsP layer 18 and the InP thin wire portion 19 is estimated to be about 0.11 eV and 0.14 eV, respectively. Then, the tunneling probability with respect to the structure having the potential barrier and having a thickness of 8 nm can be obtained by a simple calculation of 9 × 10 ^{−3 for} electrons and 1 × 10 ^{−8 for} holes. Therefore, the InP fine wire portion 19 acts as a barrier to both electrons and holes, and substantially does not allow carriers to pass.

Here, in the portion where there is no InP, that is, in the region where there is no thin line portion 19 in the lamination plane, as shown in the band diagram of FIG. 3B, no barrier exists for both electrons and holes. Therefore, in this region, both electrons and holes
It is conceivable to be able to move without the influence of nP fine lines. However, in this embodiment, since the interval between the InP fine wire portions 19 is 20 nm, electrons cannot move.

That is, electrons having thermal energy at room temperature,
Considering the de Broglie wavelength of a hole, the electron is 32n
m and the hole is about 12 nm. This difference arises from the difference in effective mass. Therefore, an interval of 20 nm
Region blocks the passage of electrons with long quantum mechanical wavelengths, but cannot block the passage of holes with short wavelengths.

When the semiconductor laser having this structure is operated by current injection and its oscillation temperature dependence is evaluated, the oscillation threshold currents at room temperature and 90 ° C. are approximately 4
0 mA and about 70 mA. This corresponds to a value of about 120 K as the characteristic temperature T ₀ , which is ₆ times that of a normal long-wave laser.
The improvement is larger than about 0K. This is because the InP fine wire portion 19 according to the present invention and its surroundings are formed by electron p-type InP.
This is considered to be due to the fact that overflow to the cladding layer is suppressed and that injection of holes into the light emitting layer is not hindered.

[Embodiment 2] In this embodiment, the width of the InP fine wire portion 19 in the above-mentioned Embodiment 1 was increased to about 50 nm, and the interval between them was the same as 20 nm. The laser structure is exactly the same as that of the first embodiment, but in the structure around the light emitting layer shown in FIG. 2, only the in-plane size of the InP fine wire portion changes. Here, the basic operation is the same as that shown in the first embodiment, and the same oscillation temperature characteristics as those of the first embodiment can be obtained with respect to the laser characteristics.
However, since the in-plane density of the region through which the holes pass is reduced, the operating voltage is increased by several percent.

[Embodiment 3] In this embodiment, the thickness of 0.4 nm in the region between the InP thin wire portions 19 in the embodiment 1
There are some InP thin films 41. FIG. 4 is a cross-sectional view of the periphery of the light emitting layer of the semiconductor laser having this structure. In this structure, holes need to pass through the InP thin film 41 to reach the light emitting layer. Here, a 0.4 nm thick InP
The tunneling probability of holes in the thin film is calculated to be about 0.8. Therefore, it is predicted that the injection of holes into the light emitting layer is practically no problem. As for the operating characteristics of the semiconductor laser, the oscillation threshold current is about 40 m from room temperature to about 90 ° C., similarly to the characteristics in the first embodiment.
It became 70 mA from A.

[Embodiment 4] Next, a case where a quantum dot structure obtained by a self-forming method using a lattice mismatch material will be described. FIG. 5 schematically shows a cross-sectional view near the light emitting layer of the semiconductor laser according to the present embodiment. A substrate, a buffer layer, a light emitting layer, and the like are manufactured in the same manner as in Example 1. Then, a non-doped layer having a thickness of 20 nm on the light emitting layer 17 is formed.
The InGaAsP layer 18 lattice-matched to InP is laminated with a band gap of 1.08 eV (corresponding to a wavelength of 1.15 μm). Then, a mixed crystal layer 51 of Ga _0.5 In _0.5 P is laminated thereon while observing the electron diffraction pattern on the surface. Here, after the electron diffraction pattern is changed to an object having a high spot property due to the stripe structure on the surface, Ga _0.5 I
The growth of the n _0.5 P layer is terminated. Thereafter, a band gap of 1.18 eV with a non-doped thickness of 50 nm (wavelength 1.05 eV)
An InGaAsP optical guide layer 20 lattice-matched to InP is grown (corresponding to μm), and thereafter, a semiconductor laser structure is manufactured by the same growth and process as in the first embodiment.

Here, the Ga _0.5 In _0.5 P layer has a lattice constant different from InP by about 3.7%. Due to this lattice mismatch, when growing on InP, the surface grows three-dimensionally so that the strain is relaxed after growth of a certain critical film thickness. here,
By controlling the growth film thickness of Ga _0.5 In _0.5 P, a diameter of 20 n
Ga _0.5 In _0.5 P island crystals of about m and a thickness of about 10 nm are present at intervals of about 20 nm. Here, Ga of about 1.5 molecular layers is provided between the island-shaped growth portions.
_{There is a 0.5} In _0.5 P thin film.

With respect to the semiconductor laser having this structure,
Since the laminated structure can be realized by only one growth, the manufacturing process is simplified as compared with the first embodiment. As for the characteristics, as in the case of the first embodiment, the oscillation threshold currents at room temperature and 90 ° C. are about 40 mA and about 70 mA, respectively. This is a self-forming G
It is considered that the a _0.5 In _0.5 P island structure functions as a barrier that hardly allows both electrons and holes to pass through, and a region between them functions as a barrier only to electrons, and does not hinder the injection of holes into the light emitting layer. .

Embodiment 5 In the above embodiments, InP
Although a specific example of the laser structure of the substrate has been described, in this embodiment, a semiconductor laser using GaInP as a light emitting layer on a GaAs substrate will be described. FIG. 6 is a schematic cross-sectional view of an example in which the present invention is applied to a semiconductor laser on a GaAs substrate 61, and FIG. 7 is a schematic enlarged view of the light emitting layer portion. This structure uses a gas source molecular beam epitaxy method (GS
By the MBE method, a thickness of 0.1 mm that lattice-matches with GaAs on a Si-doped n-type GaAs substrate 61 having a plane orientation of (100).
5 μm Si-doped n-type (Al _0.6 Ga _0.4 ) _0.5 In _0.5
A P buffer layer 62 is laminated, and then a Ga
(Al _0.6 Ga _0.4 ) _0.5 In _0.5 P barrier layer 64 lattice-matched to InP quantum well layer 63 and GaAs having a thickness of 4 nm.
The light emitting layer 65 is formed by repeating the above four cycles.

On the light emitting layer, (Al _0.8 Ga _0.2 )
_A layer 66 of _0.4 In _0.6 P is laminated. Here, since this layer has a larger lattice constant than GaAs,
As in the fourth embodiment, an island-like structure is formed in a self-forming manner. Here, the film thickness to be grown is controlled so that the in-plane size of the island structure is about 20 nm, the height is about 10 nm, and the interval is about 15 nm.

Thereafter, the Be-doped p-type (Al
_{A 0.6} Ga _0.4 ) _0.5 In _0.5 P clad layer 67 and a Be-doped p-type GaAs cap layer 68 are grown. Thereafter, a ridge-shaped region having a width of about 5 μm is formed by ordinary photolithography and etching, electrodes 69 are formed on the upper surface and the lower surface of the substrate, and then both end surfaces are formed by cleavage to produce a semiconductor laser structure. .

[0047] In this structure, between the light-emitting layer 65 and the p-type cladding layer _{67, (Al 0.8 Ga 0 .2} ) 0.4 In 0.6 consisting P layer 66 are laminated, and has an island-like structure. Therefore, as shown in the fourth embodiment, (Al _0.8 Ga _0.2 ) _0.4 In has a larger band gap than GaInP.
_{The 0.6} P island structure acts as a barrier to both electrons and holes. In the thin film region between the island-shaped structures, the tunneling probability of both electrons and holes is large because the film thickness is about 0.4 nm, but electrons are narrow in the narrow region between the island-shaped structures due to their wave nature. Can not pass through.

The semiconductor laser having this structure is operated by current injection, and the operating temperature dependence of the oscillation is evaluated. Then, the oscillation threshold current changes from about 50 mA to 77 mA from room temperature to about 90 ° C. This corresponds to a characteristic temperature of 160K. This is because (Al
_According to the fact that the island-shaped structure portion made of _0.8 Ga _0.2 ) _0.4 In _0.6 P and the thin film region around the island structure suppress the overflow of electrons into the p-type cladding layer and do not inhibit the injection of holes into the light emitting layer. Conceivable.

As described above, in Examples 1 to 5, InP or Ga
Although a semiconductor laser formed on an As substrate has been described, the material system is not limited to those on these substrates, but may be other III-V semiconductors or II-V semiconductors.
A VI group semiconductor or the like may be used.

The semiconductor laminated structure according to the present invention can be applied not only to a semiconductor laser but also to a light emitting device such as a light emitting diode.

[0051]

According to the present invention, a semiconductor laminated structure in which the transmission of only electrons is restricted and the transmission of holes is not restricted by utilizing the wave property generated by the quantum mechanical properties of electrons and holes in a semiconductor. Can be provided. Therefore, a semiconductor light emitting device such as a semiconductor laser or a light emitting diode having a laminated structure of the present invention exhibits high current efficiency.

The present invention also provides a method for manufacturing the above-mentioned semiconductor multilayer structure. In particular, according to a self-forming manufacturing method utilizing lattice mismatch, design and manufacture can be performed very easily.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view when the present invention is applied to the semiconductor laser on an InP substrate shown in Example 1.

FIG. 2 is a schematic enlarged view of a light emitting layer portion of the semiconductor laser according to the first embodiment.

FIGS. 3 (a) and 3 (b) respectively show A-
The band diagram along the A ′ section and the vicinity of the BB ′ section corresponds to the electron passage restricted region and the non-existent region.

FIG. 4 is a schematic enlarged view of a light emitting layer portion of a semiconductor laser according to a fourth embodiment.

FIG. 5 is a schematic enlarged view of a light emitting layer portion of a semiconductor laser according to a fifth embodiment.

FIG. 6 is a schematic sectional view of a semiconductor laser according to a sixth embodiment.

FIG. 7 is a schematic enlarged view of a light emitting layer portion of a semiconductor laser according to a sixth embodiment.

[Explanation of symbols]

11 Plane orientation (100) Sn-doped n-type InP substrate 12 Si-doped n-type InP buffer layer 13 InGaAsP with band gap 1.18 eV
Light guide layer 14 InGaAsP with bandgap of 1.08 eV
Layer 15 InGaAsP quantum well layer 16 InGaAsP with bandgap of 1.08 eV
Barrier layer 17 light-emitting layer 18 InGaAsP with band gap of 1.08 eV
Layer 19 InP thin line section 20 InGaAsP with band gap of 1.18 eV
Optical guiding layer 21 Be-doped p-type InP cladding layer 22 Be-doped p-type InGaAs cap layer 23 electrode 41 thickness 0.4nm approximately InP film 51 Ga _0.5 In _0.5 mixed crystal layer 61 by P Si-doped n-type GaAs substrate 62 Si Doped n-type (Al _0.6 Ga _0.4 ) _0.5 In _0.5
P buffer layer 63 GaInP quantum well layer 6 nm thick 64 Lattice-matched to GaAs 4 nm thick (Al
_0.6 Ga _0.4 ) _0.5 In _0.5 P barrier layer 65 Light emitting layer 66 (Al _0.8 Ga _0.2 ) _0.4 In _0.6 P layer 67 Be-doped p-type (Al _0.6 Ga _0.4 ) _0.5 In _0.5
P cladding layer 68 Be-doped p-type GaAs cap layer 69 Electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-215032 (JP, A) JP-A-5-62896 (JP, A) JP-A-9-270508 (JP, A) JP-A 9- 214047 (JP, A) JP-A-9-260779 (JP, A) JP-A-5-283793 (JP, A) Appl. Phys. Lett. 63 (1993) p. 3203 (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/18 H01L 33/00

Claims (10)

(57) [Claims] In a semiconductor laminated structure having an n-type first semiconductor layer, a p-type second semiconductor layer, and a light emitting layer sandwiched between the first and second semiconductor layers, a p-type A region that restricts the passage of electrons from the light emitting layer to the p-type second semiconductor layer (hereinafter, referred to as an electron passage restricting region) is provided between the second semiconductor layer and the light emitting layer. Wherein a plurality of semiconductor layers are provided so as to have a wavelength equal to or less than the de Broglie wavelength of electrons in the semiconductor and equal to or greater than the de Broglie wavelength of holes in the semiconductor. 2. The semiconductor device according to claim 1, wherein the electron passage restricting region is formed of a thin film of a semiconductor having a bandgap wider than a bandgap of a semiconductor constituting the light emitting layer (hereinafter referred to as a wide bandgap semiconductor). The semiconductor multilayer structure according to claim 1. 3. The semiconductor multilayer structure according to claim 2, wherein the thickness of the thin film of the wide bandgap semiconductor is such that the electron tunneling probability is 2 × 10 ⁻² or less. 4. The region according to claim 3, wherein a region between the electron passage restriction region and the electron passage restriction region is a region through which holes can pass, and a tunneling probability of the holes is 0.6 or more. Semiconductor laminated structure. 5. The semiconductor multilayer structure according to claim 1, wherein said electron passage restricting region is formed in a stripe shape. 6. The semiconductor multilayer structure according to claim 1, wherein said electron passage restricting regions are formed in independent dot shapes. 7. A method of manufacturing a semiconductor multilayer structure including an n-type first semiconductor layer, a p-type second semiconductor layer, and a light emitting layer sandwiched between the first and second semiconductor layers. After forming this light emitting layer, a wide band gap semiconductor thin film is formed, and then the wide band gap semiconductor thin film is patterned. A method for producing a semiconductor multilayer structure, comprising a step of forming a layer so as to have a wavelength equal to or less than a Broy wavelength and equal to or greater than a de Broglie wavelength of a hole. 8. A method of manufacturing a semiconductor multilayer structure including an n-type first semiconductor layer, a p-type second semiconductor layer, and a light emitting layer sandwiched between the first and second semiconductor layers. Forming a light-emitting layer, and using a wide bandgap semiconductor having a lattice constant different from that of the semiconductor exposed on the surface, growing the light-emitting layer in a dot-like manner on the surface of the light-emitting layer. Manufacturing method. 9. An n-type first semiconductor layer and a p-type second semiconductor layer.
Are all InP, and the wide bandgap semiconductor is a Ga _x In _1-x P mixed crystal (where x is a number satisfying 0 <x ≦ 1). Claim 8
The manufacturing method of the semiconductor laminated structure of Claim. 10. The n-type first semiconductor layer and the p-type second semiconductor layer are both semiconductors lattice-matched to GaAs, and the wide bandgap semiconductor is (Al _x Ga _{1 -x} ) _y In _1-y
P mixed crystal (where x is 0 <x ≦ 1, irrespective of the above, y
Is a number satisfying y ≦ 0.4 or y ≧ 0.6. )
9. The method for manufacturing a semiconductor multilayer structure according to claim 8, wherein: