JPH09139347A - Semiconductor hetero-structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a hetero-structure having a flat interface without any composition denatured layer by inserting a semiconductor film layer contg. atoms of a III or II group just before growth of an InGaAsP or ZnGdSSe layer. SOLUTION: A laser diode LD is produced by the gas source MBE method such that a strainless InGaAs well layer 6 is grown, feeding of As and Ga is stopped, then In of one-atom layer molecules is supplied to form an InAs layer 7 with remaining As, and As and P to grow an InGaAs barrier layer 8 of 1.2 microns are supplied throughout 20-70sec. until their pressures are stable. During waiting for this growth, the layer 7 takes in P atoms to form an InAs(P) protective layer 7 as thin as one molecule layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor heterostructure used for a semiconductor device.

[0002]

2. Description of the Related Art A semiconductor laser having a quantum well structure as an active layer changes its oscillation wavelength due to a quantum effect and its gain spectrum becomes steep, so that the oscillation wavelength is shortened, the oscillation threshold current is reduced, and modulation is performed. It is possible to improve characteristics such as speeding up, and is used as a high performance light source in, for example, an optical disk or optical communication.

Further, in order to enhance the confinement of light,
Separate confinement heterostructure that separates light and carriers (light is in the waveguide layer and carriers are in the quantum well layer)
By adopting the SCH structure, the characteristics of the semiconductor laser have been greatly improved.

Normally, a semiconductor mixed crystal layer containing two kinds of V group such as InGaAsP, which can freely change the band gap, is used as an optical confinement layer of a semiconductor laser used in optical communication, optical measurement and the like. .

Further, a semiconductor mixed crystal layer containing two kinds of group VI such as ZnCdSSe is also used as an optical confinement layer of a group II-VI semiconductor laser expected as a light source for the next generation optical disk. In this way, two kinds of V group or
Crystal growth of a semiconductor mixed crystal itself containing a group VI is important for application to a semiconductor light emitting device such as a semiconductor laser.

These semiconductor lasers are mainly used for MBE.
(Molecular beam epitaxy) method, gas source MBE method, M
It is manufactured by using a vapor phase growth method such as an OVPE (organic metal vapor phase epitaxial) method.

However, the vapor pressures of the V and VI raw materials are generally high, and it is difficult to precisely control the supply amounts of the V and VI raw materials in these growth methods.

For example, when the group V element is supplied into the growth chamber of the MBE growth apparatus or the like, the pressure of the group V in the growth chamber is significantly increased and remains in the growth chamber even after the supply is stopped to form a background pressure. To do. When the background pressure is high, the group V atoms supplied from the background to the substrate surface cannot be ignored.

Therefore, in order to grow a semiconductor layer having a steep hetero interface having a different group V composition, it is necessary to sufficiently reduce the residual group V pressure at the hetero interface.

On the other hand, in the gas source MBE method, AsH ₃ which is a hydride of As and P is used instead of the solid raw material of As and P.
And PH ₃ are used, it is possible to control the flow rate of the group V raw material with relatively high responsiveness.

However, the group V atom and the group V gas raw material remain in the growth chamber to form the background pressure.

Since the characteristics of an optical device using a quantum effect such as a semiconductor laser having a quantum well structure are greatly influenced by the quality of the interface, the abrupt control of the hetero interface of semiconductors having different V group compositions requires the optical device. This is an important technique for manufacturing.

Reference ⁽¹⁾ (Autumn 1992, 53rd)
Proceedings of the Second Joint Lecture on Applied Physics, 245,
17p-ZF-13, "GSMBE grown InGaAs /
For precise control of the InP hetero interface "), InGaAs /
InGaAs at the interface when growing an InP heterostructure
If P is supplied to the surface and waits, InGaP is formed at the interface and the surface becomes rough. To prevent this, after inserting one In atomic layer at the interface, supply P and wait for a few seconds. It has been reported that a steep hetero interface can be obtained by growing InP.

The fact that the In atomic layer surface is exposed and switched to indicates that the residual group V pressure can be sufficiently reduced. In addition, it takes a few seconds for P to start up.
This is because the In atomic layer functions to protect the InGaAs layer from P irradiation during the irradiation waiting time.

Recently, a strained quantum well structure is used in many semiconductor lasers. By using the strained quantum well structure, the confinement of electrons in the quantum well layer is strengthened, and the hole mass is reduced, so that holes are uniformly injected into the multiple quantum well (MQW) layer. Therefore, a semiconductor laser with a long wavelength, a high output, and a low threshold can be realized.

In order to improve the characteristics of the semiconductor laser, it is expected that the strained quantum well structure has a multiple quantum well structure, and as a result, the strain amount of the strained quantum well layer increases to just before the critical film thickness. doing.

As a III-V semiconductor laser, for example, reference ⁽²⁾ (RU Martinin et al., "Temperature depende"
nce of 2 μm strained-quantum-well InGaAs / InGaAsP / I
nP diode lasers ", ELECTRONICS LETTERS, Vol. 30, No. 4, 324
Page, 1994), an InGaAs well / InGa with an oscillation wavelength of 2 μm, which was manufactured by using the MOVPE method.
The characteristics of a semiconductor laser having an AsP barrier / InP clad structure have been reported. In the InGaAs well layer of this semiconductor laser diode (hereinafter referred to as "LD"),
A strong compression strain of 1.5% is applied.

Further, as the II-VI group semiconductor laser, for example, refer to ⁽³⁾ (Satoshi Itoh et al., “ZnCdSe / ZnSSe / Zn
MgSSe SCH Laser Diode with a GaAs Buffer Layer ”,
Japanese Journal of Applied Physics, Volume 33, 7
No. A, pages L938 to L940, 1994), with an oscillation wavelength of 50
9 nm ZnCdSe well / ZnSSe barrier / Z
Room temperature continuous oscillation of an LD having an nMgSSe clad structure has been reported. In the ZnCdSe well layer of this LD,
A strong compression strain of 1.5 to 2% is applied.

As described above, an optical device having a highly strained heterostructure is expected, but there is an upper limit on the critical film thickness that can be grown while maintaining the quality of the strained layer.

[0020]

DISCLOSURE OF THE INVENTION The present invention, as will be further clarified in the following description, is a strain-free semiconductor layer and a strained semiconductor layer, and InGa having a stable V group composition.
A heterostructure layer having good crystal quality, comprising a semiconductor layer containing two or more kinds of group V atoms such as AsP or a semiconductor layer containing two or more kinds of group VI atoms such as a ZnCdSSe layer having a stable group VI composition. An object of the present invention is to provide a semiconductor light emitting device having the same.

For example, specifically, it is to improve the crystal quality of a semiconductor heterostructure including a semiconductor layer having two or more kinds of V group composition such as a hetero interface between a strained InGaAs well layer and an InGaAsP barrier layer.

The quaternary mixed crystal of InGaAsP is V of AsP.
The lattice constant and the band gap greatly change depending on the composition ratio of group atoms. In addition, if there is a lattice mismatch, InGa
The optical crystal quality of AsP bulk is easily degraded.

In particular, when the multi-quantum well structure is grown while the vapor phase ratio, which is the ratio of the supply amount of group V, is not stable during the growth, the interface is roughened and the quality deterioration of the quaternary mixed crystal becomes remarkable. . Therefore, stable control of the group V composition such as AsP is important.

When actually growing an InGaAsP layer containing two kinds of V group atoms of As and P, AsH ₃ and P are grown.
It is necessary to control the supply ratio of H ₃ gas phase raw material with high accuracy.

In the gas source MBE method, especially A
Since s is less likely to be taken in about 5 times as much as P, the flow rate of AsH ₃ is small and a high flow rate controllability is required.

Further, the group V raw materials such as N, As, P and Sb have a high vapor pressure, and even if the cracked group V raw material is introduced into the growth chamber, it reaches several tens of times before the set supply amount is reached. It takes seconds.

Further, depending on the growth apparatus, the rising manner of the supply amount of As and P may greatly differ due to the cracking effect of As and P, the difference in vapor pressure, mutual reaction, and the like. In such a case, it is not uncommon for the V group composition to take about 1 minute to stabilize.

Therefore, it is necessary to suspend the growth before irradiating InGaAsP, irradiate AsP and wait. If this waiting time is not sufficient, the group V composition of InGaAsP grows unstable and an InGaAsP metamorphic layer is formed at the interface.

When the underlying layer is a strained layer, I is affected by the strained layer.
There is a problem that the quality of the nGaAsP layer deteriorates and the quality of the strained quantum well structure that is the active layer deteriorates. MOVP
Also in the E method, since the group V raw material having a high vapor pressure remains, it is difficult to grow a semiconductor layer having a steep hetero interface having a different group V composition.

In the MBE method, As the group V raw material, As,
Solid materials such as P and Sb, and group VI materials include S, Se,
A solid raw material such as Te or a compound raw material containing them is used. According to the MBE method, it is difficult to grow a semiconductor layer having a steep hetero interface having a different V group composition.
Since the vapor pressure is higher than that of the group III raw material, it is very difficult to grow a semiconductor layer having a steep hetero interface having a different group VI composition.

In the II-VI group semiconductor laser manufactured by the MBE method, ZnCdS having two or more VI group elements is used.
Since the Se layer is used as the quantum well active layer, it has a great influence on the characteristics of the laser.

Further, since the II-VI group semiconductor material is relatively soft, the strained layer has a great influence on the ZnCdSSe layer. Based on the current II-VI group material supply control technology, Z
There is room for improvement in the composition stability of the group VI element in the semiconductor layer containing two or more kinds of group VI atoms such as the nCdSSe layer.

As described above, I having a stable group V composition
It is an important task to grow a semiconductor layer containing two or more kinds of group V atoms such as nGaAsP or a semiconductor layer containing two or more kinds of group VI atoms such as a ZnCdSSe layer having a stable group VI composition.

InGaA, a single group V semiconductor
In order to control the hetero interface between the s layer and the InP layer, in the above-mentioned conventional example, the steepness of the hetero interface is realized by growing an In layer of one atomic layer on InGaAs.
The In layer of one atomic layer at the interface has a layer thickness that is too small to withstand the interface standby for several seconds, but to withstand the interface standby for several tens of seconds or 1 minute long before the growth of InGaAsP.

Therefore, this method is suitable for growing a semiconductor heterostructure including semiconductor layers having two or more kinds of V group compositions.
It cannot be applied as is.

Further, the above conventional example is an example of a semiconductor layer lattice-matched to the substrate.

In the growth of the strained semiconductor layer and the semiconductor layer containing two or more kinds of group V atoms such as InGaAsP, InG
If the waiting time at the interface is taken long enough to stabilize aAsP, not only the interface will be roughened by the irradiated AsP, but also
In the case of a strongly strained layer, there is a problem that the strained layer easily becomes a three-dimensional island just by waiting.

Therefore, in the above-mentioned conventional method, even if one atomic layer of In is inserted into the surface of the strongly strained layer and the growth is suspended, the surface roughness of the strained layer cannot be prevented.

After all, In which is lattice-matched with the InP substrate
In the case of a GaAs layer, a steep hetero interface can be obtained by the method of inserting one In atomic layer at the interface, but in the case of an InGaAsP layer in which the interface waiting time is several tens of seconds, or InGaA
InGaAs that is not lattice-matched with the sP layer and the InP substrate
In the case of layers, the conventional method cannot avoid the problem that the hetero interface deteriorates due to the strain metamorphic layer formed during standby.

In order to improve such a hetero interface, the composition of group V or group VI stabilizes at a set value,
Further, there is a need for a method for easily optimizing the waiting time so that the group V or VI atom irradiated during the waiting time is not taken in from the surface to form a metamorphic layer. Therefore, the present invention has been made in view of such problems,
Its purpose is as described above.

[0041]

In order to achieve the above object, the semiconductor heterostructure of the present invention has a sufficient waiting time immediately before the growth of the InGaAsP layer or ZnCdSSe layer and supplies the growth layer surface during the waiting time. In order to protect the surface of the growth layer from the group V atoms or group VI atoms that are generated,
It is characterized in that one kind of group III atom or a semiconductor thin film layer containing group II atom is inserted immediately before the growth of the GaAsP layer or the ZnCdSSe layer. The present invention is characterized in that a lattice matching layer having the same V group or VI group composition as the strained layer is inserted between the strained layer and the InGaAsP layer or between the strained layer and the ZnCdSSe layer. Also, V group or
The present invention provides a semiconductor heterostructure characterized by separating an interface between a strained layer and a non-strained layer having a common VI group composition and an interface between lattice matching layers having different V group compositions or VI group compositions.

That is, the present invention provides a strain-free first III-V group compound semiconductor layer having substantially the same lattice constant as the substrate,
A layer structure in which a second semiconductor layer having a thickness of 1 to 5 molecular layers containing only one kind of group III atom (element) and a third semiconductor layer containing two or more kinds of group V atom (element) are epitaxially grown in order. There is provided a semiconductor heterostructure comprising:

Further, according to the present invention, the strained semiconductor layer of the first III-V group compound having a lattice constant different from that of the substrate, and the unstrained second semiconductor layer having the same group V composition as the first strained semiconductor layer. And a semiconductor heterostructure having a layer structure obtained by sequentially epitaxially growing a third semiconductor layer containing only one type of group III atom and a fourth semiconductor layer containing two or more types of group V atoms. To do.

Furthermore, the present invention provides the first semiconductor heterostructure described above, which has a lattice constant different from that of the substrate.
As a strained semiconductor layer of a III-V group compound, a plurality of strained semiconductor layers having a common V group composition and different strain amounts are used.

Furthermore, the present invention is characterized in that In is used as the group III atom of the semiconductor layer containing only one type of group III atom in the semiconductor heterostructure described above.

Further, the present invention provides a strain-free first II-VI group compound semiconductor layer having substantially the same lattice constant as that of the substrate, and a second layer having a thickness of 1 to 5 molecular layers containing only one kind of group II atom. There is provided a semiconductor heterostructure having a layer structure in which a semiconductor layer and a third semiconductor layer containing two or more kinds of group VI atoms are sequentially epitaxially grown.

The present invention also provides a strained semiconductor layer of the first II-VI group compound having a lattice constant different from that of the substrate, and a strain-free second semiconductor layer having the same VI group composition as the first strained semiconductor layer. ,
A semiconductor heterostructure having a layer structure in which a third semiconductor layer containing only one type II group atom and a fourth semiconductor layer containing two or more types VI group atoms are sequentially epitaxially grown. .

Furthermore, the present invention provides the first semiconductor heterostructure described above, which has a lattice constant different from that of the substrate.
As the strained semiconductor layer of the II-VI group compound, a plurality of strained semiconductor layers having a common VI group composition and different strain amounts are used.

[0049]

The principle and operation of the present invention will be described below. InG
The growth is interrupted immediately before the growth of the aAsP layer or ZnCdSSe layer, and irradiation with AsP or SSe is performed and the waiting time is set to the time until the pressure occupied by the growth chamber of AsP or SSe reaches a steady state, thereby stabilizing the stability. InGaAsP layer with stable V group composition or stable VI
A ZnCdSSe layer having a group composition can be grown.

In the semiconductor heterostructure according to the present invention as defined in claim 1 or claim 5, before the growth of the InGaAsP layer or the ZnCdSSe layer, a 1 to 5 molecular layer containing only group III or group II atoms is formed. Growing a semiconductor layer. For example, as a semiconductor layer containing only a group III atom, I
nP or InAs is used, and CdSe or CdS is used as the semiconductor layer containing only Group II atoms.

InGaAsP layer or ZnCdSSe
AsP atoms or SSe atoms supplied to the growth surface during the interface waiting time immediately before the layer growth is absorbed by these semiconductor layers, so that an InAsP layer or CdSSe layer having a thickness of 1 to 5 molecular layers is formed.

Under the normal growth condition, the interface waiting time is about 20 to 80 seconds, and the group V atom or the group VI atom supplied to the growth surface during the interface waiting time is II.
In order to prevent the diffusion of the semiconductor layer containing only group I or group II atoms into the quantum well layer to form a metamorphic layer, the layer thickness of the semiconductor layer containing group III or group II atoms is 1 to 5 molecules. The layer thickness is appropriate.

The semiconductor heterostructure according to the present invention is a semiconductor layer in which an InAsP layer or CdSSe layer having a thickness of 1 to 5 molecular layers is lattice-matched with an InGaAsP layer or ZnCd.
The semiconductor layer and the InGaAsP layer or ZnCdSS which are lattice-matched due to the feature inserted between the SSe layers.
A high-quality semiconductor heterostructure is obtained which does not contain compositionally modified metamorphic layers in both semiconductor layers of the e-layer.

In the semiconductor heterostructure according to the second aspect of the present invention, when the strained semiconductor layer is a strained InGaAs layer, a strained InGaAs layer and an InGaAsP layer are formed between the strained InGaAs layer and the InGaAsP layer.
Lattice-matched In having the same V group composition as the strained InGaAs layer
By inserting the GaAs layer, the interface between the strained InGaAs layer and the unstrained InGaAs layer having the same group V composition and the unstrained InGaAs layer and InGaAsP having different group V compositions
Since the surface of the strained InGaAs layer can be separated from the interface of the layer, it is possible to avoid surface roughness due to standby for growth interruption.

Furthermore, the surface of the strain-free InGaAs layer is
By covering with an InAs layer of a molecular layer or a protective layer of an InP layer having a thickness of 1 to 3 nm, deterioration of the surface during standby can be prevented.

When P is directly supplied to the surface of InGaAs, Ga atoms are more likely to bond with P than As.
InGaP having a lattice constant smaller than that of the substrate is formed,
After several tens of seconds, the surface becomes rough and the InGaAsP layer grown on it deteriorates. However, InG
By covering the aAs surface with an InAs layer or an InP layer, which is a semiconductor layer containing only In, the change in the lattice constant is small even if As and P are taken into the surface, so that surface roughness can be prevented.

The protective layer of the InP layer having a thickness of 1 to 3 nm can withstand the irradiation of AsP for several tens of seconds to 1 minute, and since it is on the InGaAs lattice matching insertion layer, the time until the group V composition stabilizes, It is possible to sufficiently wait for group V irradiation while maintaining the surface flatness. In addition, R at the interface standby and during growth
By observing the HEED image, it is relatively easy to optimize the layer thickness of the protective layer and the insertion layer in the range where the surface is not deteriorated.

The semiconductor heterostructure according to the present invention is strained InG.
When applied to a semiconductor heterostructure of an aAs layer and an InGaAsP layer, the strained InGaAs insertion layer and the InAsP protective layer are characterized by being inserted between the strained InGaAs layer and the InGaAsP layer. It is possible to obtain a high-quality semiconductor heterostructure having a flat interface which does not include a metamorphic layer whose composition has changed in the semiconductor layers of the insertion layer and the InGaAsP layer.

Also in the II-VI group compound semiconductor heterostructure according to the present invention as defined in claim 6, the III-structure in claim 2
A high-quality semiconductor having a flat interface, which does not include a metamorphic layer having a composition change in the strained ZnCdSe semiconductor layer, the non-strained ZnCdSe insertion layer, and the ZnCdSSe layer that form the heterostructure because it has the same effect as the group V semiconductor heterostructure A heterostructure is obtained.

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] As a first embodiment of the present invention, a heterostructure characterized by having an InAs (P) layer of one molecular layer thickness between a strain-free InGaAs well layer and an InGaAsP layer. Laser diode (L
D) will be described below. FIG. 1 shows a sectional layer structure of an LD according to the first embodiment of the present invention.

Referring to FIG. 1, the LD according to the present embodiment.
Is an n-InP clad layer 3 on the n-InP substrate 2, and
N-InGaA having a layer thickness of 150 nm and a wavelength of 1.2 μm
sP light confinement layer 4 and a layer thickness of 50 nm and a wavelength of 1.2 μm
InGaAsP barrier layer 5 having a composition, strain-free InGaAs well layer 6 having a layer thickness of 6 nm, and InAs having a monolayer thickness.
(P) I having a protective layer 7 and a layer thickness of 4 nm and a wavelength of 1.2 μm
A multiple quantum well active layer formed by alternately stacking four periods of nGaAsP barrier layers 8 and a wavelength of 1.2 μm at a layer thickness of 50 nm.
InGaAsP barrier layer 5 of m composition and layer thickness 150 nm
And a p-InGaAsP optical confinement layer 9 having a wavelength of 1.2 μm, a p-InP clad layer 10 having a thickness of 1.5 μm,
A p-InGaAs contact layer 11 having a thickness of 0.2 μm,
It is composed of a p-electrode 12 and an n-electrode 1. The n-type and p-type doping concentrations are about 7 × 10 ¹⁷ cm ⁻³ .

For example, when this LD is manufactured by the gas source MBE method, the strain-free InGaAs well layer 6 is grown, the supply of As and Ga is stopped, and In of one atomic layer is supplied to leave the residual As. After forming the InAs layer 7 with In, 1.
As and P for growing the InGaAsP barrier layer 8 having a composition of 2 μm are continuously supplied for about 20 to 70 seconds until their pressures are stabilized.

While waiting for this growth interruption, the InAs layer 7 is exposed to P
InAs (P) protective layer 7 that incorporates atoms and has a thickness of one molecular layer
To form

In the LD according to this embodiment, the layer thickness of each layer, the composition of the InGaAsP layer, the number of quantum wells, or the doping concentration is not limited to the above values. By appropriately changing those elements, an LD having different characteristics such as oscillation wavelength can be obtained.

[Second Embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment of the present invention, instead of the InAs (P) protective layer 7 having a monolayer thickness of the LD according to the first embodiment described with reference to FIG. 1, InP having a bilayer thickness is used. (As) An LD having a heterostructure having a protective layer. Other than this, the structure is similar to that of the first embodiment. However, since the InP layer is a lattice matching layer and does not cause crystal deterioration even if the layer thickness is increased, the layer thickness of the InP (As) protective layer 7 is limited to a bimolecular layer in the LD of this embodiment. First, an InP (As) protective layer having an appropriate layer thickness is formed according to the magnitude of the waiting time.

For example, when this LD is produced by the gas source MBE method, the strain-free InGaAs well layer 6 is grown, the supply of As, Ga and In is stopped, P is introduced, and In for two atomic layers is obtained. After supplying and forming an InP layer, 1.2
As and P for growing the InGaAsP barrier layer 8 having a composition of μm are kept at 20 until the beam intensity of them is stabilized.
Continue to supply for about 70 seconds from the second. During this growth interruption standby, the InP layer takes in As atoms and forms the InP (As) protective layer 7.

The LD of this embodiment is a strain-free InGaAs
Between the well layer 6 and the InGaAsP layer 8 InP (A
The layer thickness of each layer, the composition of the InGaAsP layer, the number of quantum wells, and the doping concentration, which are the other elements, are not particularly limited. By changing those elements, an LD having different characteristics such as oscillation wavelength can be obtained.

The waiting time at the hetero interface immediately before the growth of the semiconductor layer containing two or more types of V group atoms and the standby state while supplying only two or more types of V groups atoms, and The thickness of the semiconductor layer containing only group III atoms is
Quadrupole mass spectrometer and reflection high energy electron diffraction (RHE
The method of optimization using the ED) device will be described in detail.

In the MBE apparatus, a semiconductor layer such as InGaAsP containing two or more kinds of V group atoms used for LD is grown, and the As introduced into the growth chamber is read in the quadrupole mass spectrometer.
And P the quadrupole mass spectrometer is used to measure the time change of the measured signal intensity.

The group V composition stabilization time from the introduction of As and P into the growth chamber until the measured signal intensity of As and P reaches a steady state is measured. Usually, the group V composition stabilization time is 2
The time is from 0 second to 70 seconds. However, the experiment is performed with the substrate temperature kept constant.

Next, before the growth of InGaAsP, the lattice-matched InGaAs was grown, and then I of one molecular layer was formed.
An nAs protective layer or an InP protective layer having a thickness of several nm is grown, growth is interrupted on the InAs or InP surface, AsP is supplied to the surface, and irradiation is awaited. InAs or I
Observation of the nP surface with a RHEED machine reveals a RHEED pattern suggesting a 2 × 4 Group V stabilized surface.

The group V irradiation waiting time is determined with reference to the group V composition stabilization time obtained above. And a predetermined V
After the group irradiation waiting time has elapsed, the InGaAsP layer is grown.

When the RHEED pattern starts to change from the streak pattern to the Potty pattern showing three-dimensional growth, InGaAsP growth is stopped and InP is grown to restore the interface.

When the intensity of the RHEED specular beam is observed and RHEED oscillation is obtained, two-dimensional growth has been realized, which is a guideline for recovery of the growth surface. After the growth surface is recovered, lattice-matched InGaAs is grown again and the above experiment is repeated. In this way, RHEE
V that D pattern maintains streak pattern
Find the irradiation waiting time for the group.

The group V irradiation waiting time thus obtained is determined by the growth of the growth starting surface becoming three-dimensional during the waiting time
This is the time when the GaAsP layer does not grow three-dimensionally.

When the optimum group V irradiation waiting time is not required, the layer thickness of the InP protective layer is changed to find the optimum group V irradiation waiting time. The layer thickness of the strain-free InGaAs insertion layer, which will be described in the following embodiments, is similarly optimized.

Also, in the case of hetero-growth of a II-VI group semiconductor layer containing two or more kinds of VI group atoms, the waiting time can be similarly optimized.

[Embodiment 3] FIG. 2 is a view showing a sectional layer structure of an LD according to a third embodiment of the present invention. The present embodiment has a hetero structure characterized by having a strain-free InGaAs well layer and an InAs (P) layer having a monolayer thickness between a strained InGaAs well layer and an InGaAsP barrier layer, Oscillation wavelength 1.8 to 2.1 μm
It is the LD of the belt.

Referring to FIG. 2, the LD according to the present embodiment.
Is an n-InP clad layer 23 on the n-InP substrate 22.
And n-InG having a layer thickness of 150 nm and a wavelength of 1.3 μm
The aAsP optical confinement layer 24 and the wavelength of 1.
InGaAsP barrier layer 25 having a composition of 3 μm and a layer thickness of 7 n
m InGaAs well layer 26 with 1.5% compressive strain, strain-free InGaAs spacer layer 27 with a layer thickness of 2 nm, InAs (P) protective layer 28 with a monolayer thickness, and InGaAsP with a layer thickness of 10 nm and a wavelength of 1.3 μm. A multiple quantum well active layer formed by alternately stacking three barrier layers 29 for three periods, and a layer thickness of 50
InGaAsP barrier layer 2 having a composition of wavelength 1.3 μm in nm
5 and p-In having a layer thickness of 150 nm and a wavelength of 1.3 μm
GaAsP optical confinement layer 30 and 1.8 μm thick p-I
nP clad layer 31 and 0.2 μm thick p-InGaA
s contact layer 32, p electrode 33, n electrode 21,
Consists of

For example, when this LD is manufactured by the gas source MBE method, an InGaAs well layer 26 with a compression strain of 1.5% is grown, an InGaAs spacer layer 27 without strain is grown without waiting for an interface, and As is grown. Stop the supply of Ga, 1
After supplying In for the atomic layer and forming an InAs layer with residual As and In, As and P for growing the InGaAsP barrier layer 29 having a composition of 1.3 μm are applied from 20 seconds until the pressures thereof stabilize. Continue supplying for about 70 seconds. While waiting for this growth interruption, the InAs layer takes in P atoms,
An InAs (P) protective layer 28 having a monolayer thickness is formed.

[Embodiment 4] The LD according to the fourth embodiment of the present invention is characterized by using InP (A) instead of the InAs (P) protective layer 28 having a monolayer thickness of the LD according to the third embodiment.
s) It has a heterostructure having a protective layer, and the other structure is the same as that of the third embodiment.

For example, when this LD is manufactured by the gas source MBE method, the InGaAs well layer 26 having a compression strain of 1.5% is grown, and the strain-free InGaAs spacer layer 27 is grown without waiting for the interface, and As is grown. Stop the supply of Ga, P
Is introduced to supply In for one atomic layer to form an InP layer, and then an InGaAsP barrier layer 29 having a composition of 1.3 μm is formed.
Are continuously supplied for about 20 to 70 seconds until their pressures are stabilized.

At the time of waiting for this growth interruption, the InP layer takes in As atoms and forms an InP (As) protective layer having a thickness of one molecular layer. However, since the InP layer is a lattice matching layer and does not cause crystal deterioration even if the layer thickness is increased, the layer thickness of the InP (As) protective layer in the LD of the fourth embodiment is
The InP (As) protective layer having an appropriate layer thickness is formed according to the size of the waiting time, not limited to one molecular layer.

[Fifth Embodiment] FIG. 3 is a view showing a sectional layer structure of an LD according to a fifth embodiment of the present invention. The LD according to this embodiment has a strained quantum well layer composed of an InAs layer and a strained InGaAs layer, and has a strained quantum well layer and InGa.
It has a heterostructure characterized by having a strain-free InGaAs spacer layer and an InAs (P) layer having a monolayer thickness between the AsP barrier layer and an oscillation wavelength band of 1.8 to 2.1 μm. It is the LD of.

Referring to FIG. 3, the LD according to the present embodiment.
Is an n-InP clad layer 42 on the n-InP substrate 41.
And n-InG having a layer thickness of 150 nm and a wavelength of 1.3 μm
aAsP optical confinement layer 43, and a wavelength of 1.
InGaAsP barrier layer 44 having a composition of 3 μm, strained InGaAs layer 45 having an In composition of 0.8 having a bilayer thickness, InAs well layer 46 having a thickness of 6 molecular layers, and In composition having an In composition of 0.
8 strained InGaAs layer 47 and 2 nm thick unstrained InG
aAs spacer layer 48, InAs (P) protective layer 49 having a monolayer thickness, and InG having a wavelength of 1.3 μm and a layer thickness of 10 nm.
A multiple quantum well active layer formed by alternately laminating two cycles of an aAsP barrier layer 50, an InGaAsP barrier layer 44 having a layer thickness of 50 nm and a wavelength of 1.3 μm, and a p-InGaAsP layer having a layer thickness of 150 nm and a wavelength of 1.3 μm. An optical confinement layer 51, a 2.0 μm thick p-InP clad layer 52,
A p-InGaAs contact layer 53 having a thickness of 0.2 μm,
It is composed of a p-electrode 54 and an n-electrode 40.

The method of manufacturing the LD according to this embodiment is the same as that of the LD of the third embodiment. However, In
Since As is sensitive to the growth conditions, for example, the growth rate is 1 μm / h, the growth temperature is 440 ° C. and the V / III ratio is 20.

Strained InGaAs layer 45 having an In composition of 0.8
Is a 2.5% compressive strained InAs layer and unstrained InGaAs
By relaxing the sudden change in lattice constant with
Has the effect of preventing the three-dimensional growth of

[Embodiment 6] An LD according to a sixth embodiment of the present invention is characterized by using InP (A) instead of the InAs (P) protective layer 49 having a monolayer thickness of the LD according to the fifth embodiment.
s) It has a heterostructure having a protective layer, and is otherwise the same in structure as the fifth embodiment. The LD according to this embodiment can be manufactured in the same manner as the LDs according to the fourth and fifth embodiments.

In the above, an embodiment in which the present invention is applied to a III-V group compound semiconductor laser has been described. Hereinafter, an embodiment in which the present invention is applied to a II-VI group compound semiconductor laser will be described. explain.

InGaAsP of III-V group compound semiconductor
The material of the II-VI group compound semiconductor corresponding to is CdZn.
It is SeS. In the compound semiconductor laser on the InP substrate, In constituting the III-V group compound semiconductor laser is used.
In each GaAsP-based material, In-Cd, Ga-Zn, As-Se, and P-S were replaced, respectively, to obtain a II-VI structure corresponding to the III-V compound LD.
Compound LD can be constructed.

[Embodiment 7] A seventh embodiment of the present invention is an InP substrate having a hetero structure having a CdSe (S) protective layer having a monolayer thickness between a strain-free ZnCdSe layer and a ZnCdSeS layer. It is the LD of. FIG. 4 shows a sectional layer structure of an LD according to the seventh embodiment of the present invention.

Referring to FIG. 4, the LD according to the present embodiment.
Is the n-InP buffer layer 6 on the n-InP substrate 61.
2, n-InGaAs buffer layer 63, and n-Mg
ZnCdSe clad layer 64, unstrained n-ZnCdSSe optical confinement layer 65 having a layer thickness of 50 nm, and a layer thickness of 10 nm
Strain-free n-ZnSSe barrier layer 66, a strain-free ZnCdSe well layer 67 having a layer thickness of 6 nm, and a monolayer CdS.
e (S) protective layer 68 and strain-free n-ZnCd with a layer thickness of 4 nm
A multi-quantum well active layer in which SSe barrier layers 69 are alternately laminated for four periods, and a strain-free n-ZnCdSS having a layer thickness of 10 nm.
e Barrier layer 66 and unstrained p-ZnCd with a layer thickness of 50 nm
The SSe optical confinement layer 70, the p-MgZnCdSe cladding layer 71, the 0.2 μm thick p-ZnCdSe contact layer 72, the p-electrode 73, and the n-electrode 60 are included.

The n-type and p-type doping concentrations are about 7 ×.
10 ¹⁷ cm ^-3 . Unstrained ZnCdSe well layer 67
Is a composition corresponding to a wavelength of 640 nm of Zn _0.48 Cd _0.52 Se. The composition of the unconfined ZnCdSSe optical confinement layers 65 and 70 and the barrier layers 66 and 69 is Z.
The composition corresponds to a wavelength of 590 nm of n _0.10 Cd _0.9 S _0.66 Se _0.34 . In addition, n and p type MgZnCdS
The composition of the e-cladding layers 64 and 71 is Mg _0.27 Zn _0.37
It has a composition corresponding to a wavelength of 500 nm of Cd _0.36 Se.

When the LD according to this embodiment is manufactured by the MBE method, the strain-free ZnCdSe well layer 67 is grown, and S
The supply of e and Zn was stopped, Cd for one atomic layer was supplied, and a CdSe layer was formed with residual Se and Cd.
Se and S for growing the dSSe barrier layer 69,
Continue supplying for about 30 to 90 seconds until their pressure becomes stable. While waiting for this growth interruption, the CdSe layer takes in S atoms and the CdSe (S) protective layer 68 having a thickness of one molecular layer is formed.
To form

However, in the present embodiment in which the present invention is applied to the II-VI group compound semiconductor laser or the embodiments described below, the layer thickness and composition of each semiconductor layer constituting the LD, for example, a strain-free ZnCdSSe layer. Composition or Mg
Numerical values that define the composition of the cladding layer of the ZnCdSe layer, or the number of quantum wells and the doping concentration are
It is not limited to the above numerical values. Then, by changing the numerical values defining these components, LDs of visible light such as red, orange, yellow, green, and blue can be obtained.

In the present embodiment or the embodiments described below, the optical confinement layer or barrier layer of the LD is a strain-free ZnCdSS lattice-matched to the InP substrate.
The CdSSe layer or ZnSeT is not limited to the e layer.
An e layer or a ZnCdSeTe layer may be used instead. The LD clad layer is not limited to the strain-free MgZnCdSe layer lattice-matched to the InP substrate, and the strain-free MgCdSSe layer or the strain-free MgZnCdSSe layer.
Alternatively, a layer, a MgZnSeTe layer, or a layer composed of a combination thereof may be used.

For example, Se lattice-matched to the InP substrate,
The composition of a typical ternary semiconductor layer containing S is Zn _0.48 Cd
_0.52 Se, CdS _0.83 Se _0.17 , Mg _0.9 Zn _0.1 Se,
MgS _0.08 Se _0.92 and a strain-free quaternary composition lattice-matched to the InP substrate can be obtained by combining these ternary compositions.

That is, the composition of the unstrained ZnCdSSe layer used for the optical confinement layer or barrier layer of the LD is
(Zn _0.48 Cd _0.52 Se) _X (CdS _0.83 Se _0.17 ) _1-X
And strain-free MgZ used for LD clad layer
The composition of the nCdSw layer is (Mg _0.9 Zn _0.1 Se) _x (Z
n _0.48 Cd _0.52 Se) _1-X , the composition of the MgCdSSe layer without strain is (MgS _0.08 Se _0.92 ) _X (CdS _0.83 Se
_0.17 ) _1-X , unstrained MgZnCdSSe layer composition is
(MgS _0.08 Se _0.92 ) _X (Zn _0.48 Cd _0.52 S
e) _1-X , or (Mg _0.9 Zn _0.1 Se) _X (CdS
_0.83 Se _0.17 ) _1-X .

[Embodiment 8] The LD according to the eighth embodiment of the present invention is the same as the LD according to the seventh embodiment, except that the CdSe (S) protective layer 68 having a monolayer thickness of CdS (S) is used.
e) The structure is the same as that of the seventh embodiment except that it has a heterostructure having a protective layer. However, since the CdS layer has relatively good lattice matching with the InP substrate,
In the LD of the example, the layer thickness of the CdS (Se) protective layer is not limited to one molecular layer, and may be changed depending on the waiting time.
A CdS (Se) protective layer having an appropriate layer thickness shall be formed.

When the LD according to the present embodiment is manufactured by the MBE method, a strain-free ZnCdSe well layer 67 is grown, and Z
The supply of n and Cd is stopped, Se is switched to S, Cd for one atomic layer is supplied to form a CdS layer, and then the growth is interrupted to grow a strain-free ZnCdSSe barrier layer 69 Se. 30 and S until their pressure stabilizes
Continue to supply for about 90 seconds from the second. During this growth interruption standby, the CdS layer takes in Se atoms and has a thickness of one molecular layer of Cd.
An S (Se) protective layer is formed.

Since S as a simple substance has a very high vapor pressure and is difficult to control with an ordinary Knudsen cell, for example, a raw material of a compound such as ZnS is used to lower the vapor pressure and supply it. It is not possible to supply only S without it.

Stable supply control of only S as in the present embodiment is performed by using a needle valve cracking cell filled with S solid raw material or by cracking a gas raw material such as H ₂ S to obtain only S. It can be realized by controlling the supply of.

[Ninth Embodiment] An LD according to a ninth embodiment of the present invention is a strained ZnCdSe well layer and a ZnCdSSe.
1 and a strain-free ZnCdSe spacer layer between the barrier layer and
An LD on an InP substrate having a heterostructure characterized by having a CdSe (S) layer having a molecular layer thickness. In FIG.
The cross-sectional layer structure of LD which concerns on the 9th Embodiment of this invention is shown.

Referring to FIG. 5, the LD according to the present embodiment.
Is an n-InP buffer layer 82 on the n-InP group 81.
, N-InGaAs buffer layer 83, and n-MgZ
The nCdSe clad layer 84 and a strain-free n layer having a layer thickness of 50 nm.
-ZnCdSSe optical confinement layer 85, unstrained n-ZnCdSSe barrier layer 86 having a layer thickness of 10 nm, and layer thickness of 6 nm
Of Zn _0.25 Cd _0.75 Se with 1.5% compressive strain of Zn
CdSe well layer 87 and strain-free ZnCdSe having a layer thickness of 2 nm
Spacer layer 88 and CdSe (S) protective layer 8 having a monolayer thickness
9 and a strain-free n-ZnCdSSe barrier layer 9 having a layer thickness of 5 nm
A multi-quantum well active layer formed by alternately stacking 3 periods of 0, a strain-free n-ZnCdSSe barrier layer 86 having a layer thickness of 10 nm, a strain-free p-ZnCdSSe optical confinement layer 91 having a layer thickness of 50 nm, and p. -MgZnCdSe cladding layer 92
And a p-ZnCdSe contact layer 93 having a thickness of 0.2 μm.
And a p-electrode 94 and an n-electrode 80. The n-type and p-type doping concentrations are about 7 × 10 ¹⁷ cm ⁻³ .

When the LD having the heterostructure according to this embodiment is manufactured by the MBE method, the strain ZnCd of 1.5% compression strain is obtained.
The Se well layer 87 is grown, and there is no interface waiting.
After growing the nCdSe spacer layer 88, Zn and Se
Is stopped and Cd for one atomic layer is supplied to form a CdSe layer with residual Se and Cd.
Se and S for growing the barrier layer 90 are continuously supplied for about 30 to 90 seconds until the pressures thereof stabilize.

At the time of waiting for this growth interruption, the CdSe layer takes in S atoms and the CdSe (S) protective layer 89 having a thickness of one molecular layer is formed.
Is formed.

[Embodiment 10] The LD according to the tenth embodiment of the present invention is the same as the LD according to the ninth embodiment, except that CdSe (S) protective layer 89 having a monomolecular layer thickness is used instead of CdS (S).
e) It has a heterostructure having a protective layer, and is otherwise the same in structure as the ninth embodiment. However, since the CdS layer has relatively good lattice matching with the InP substrate, the CdS (S
e) The layer thickness of the protective layer is not limited to one molecular layer, and a CdS (Se) protective layer having an appropriate layer thickness is formed according to the size of the waiting time.

When the LD having the heterostructure according to this embodiment is manufactured by the MBE method, the strain ZnCd of 1.5% compression strain is obtained.
The Se well layer 87 is grown, and there is no interface waiting.
The nCdSe spacer layer 88 is grown, the supply of Zn and Cd is stopped, and Se is switched to S to change the Cd for one atomic layer.
Is supplied to form a CdS layer, then the growth is interrupted, and Se for growing a strain-free ZnCdSSe barrier layer 69 is obtained.
And S are continuously supplied for about 30 to 90 seconds until their pressure becomes stable.

At the time of waiting for this growth interruption, the CdS layer takes in Se atoms and forms a CdS (Se) protective layer having a monolayer thickness.

[Embodiment 11] An LD according to an eleventh embodiment of the present invention has a strained quantum well layer composed of a CdSe layer and a strained ZnCdSe layer, and has a strained quantum well layer and an unstrained Zn layer.
An LD on an InP substrate having a heterostructure characterized by having a non-strained ZnCdSe spacer layer and a CdSe (S) protective layer having a monolayer thickness between a CdSSe barrier layer. FIG. 6 shows a sectional layer structure of an LD according to the eleventh embodiment of the present invention.

Referring to FIG. 6, the LD according to the present embodiment.
Is an n-InP buffer layer 1 on the n-InP group 101.
02, n-InGaAs buffer layer 103, n-
MgZnCdSe cladding layer 104, unstrained n-ZnCdSSe optical confinement layer 105 having a layer thickness of 50 nm, and unstrained n-ZnCdSSe barrier layer 106 having a layer thickness of 10 nm.
And 1.8% compressive strain Zn _0.2 Cd _0.8 Se of bilayer thickness
Strained ZnCdSe layer 107 and CdSe with 6 molecular layers
Zn having a well layer 108 and a bilayer thickness of 1.8% compressive strain
Strained ZnCdSe layer 109 of _0.2 Cd _0.8 Se and layer thickness 2
and a multi-quantum well active layer formed by alternately stacking a strain-free ZnCdSe spacer layer 110 having a thickness of 1 nm, a CdSe (S) protective layer 111 having a thickness of one molecular layer, and a strain-free ZnCdSSe barrier layer 112 having a thickness of 5 nm for two periods. , Unstrained n with a layer thickness of 10 nm
-ZnCdSSe barrier layer 106, p-ZnCdSSe optical confinement layer 113 with a layer thickness of 50 nm and no strain, p-M
gZnCdSe clad layer 114 and p of 0.2 μm thickness
-ZnCdSe contact layer 115 and p-electrode 116
And n-electrode 100. The n-type and p-type doping concentrations are about 7 × 10 ¹⁷ cm ⁻³ .

The manufacturing method of the LD according to this embodiment is the same as that of the LD according to the ninth embodiment. However, CdS
Since e is sensitive to growth conditions, for example, the growth rate is 1
The growth temperature is 200 to 250 ° C. and the growth rate is low VI / II. Zn _0.2 Cd with 1.8% compressive strain
_{The 0.8} Se layer 107 has an effect of preventing the three-dimensional growth of CdSe by relaxing the abrupt lattice constant change between the 2.5% compressive strain CdSe well layer and the unstrained ZnCdSe layer.

[Embodiment 12] The LD according to the twelfth embodiment of the present invention is the same as the LD according to the eleventh embodiment.
Instead of the CdSe (S) protective layer 111 having a molecular layer thickness, C
The LD has a dS (Se) protective layer, and has the same structure as the LD according to the eleventh embodiment except for the LD.
The LD according to this embodiment can be manufactured in the same manner as the LD having the heterostructure according to the tenth and eleventh embodiments.

[0115]

As described above, the semiconductor heterostructure of the present invention takes into consideration the practical limitation of the performance of the manufacturing apparatus, avoids damage to the semiconductor layer due to AsP or SSe irradiation, and makes InGaAsP Layer or Z
It has the effect that a high quality heterostructure can be provided without the compositional metamorphic layer of the nCdSSe layer.

Further, according to the present invention, the strained semiconductor layer and the In
Even in a heterostructure including a GaAsP layer or a ZnCdSSe layer, a heterostructure having a flat interface without a composition metamorphic layer can be realized.

The semiconductor heterostructure according to the present invention is provided with a lattice-matched InGaAs well layer and InGaAs.
When applied to a quantum well structure composed of a P barrier layer, a quantum well structure in which an InAsP layer having a thickness of 1 to 5 molecular layers is inserted between a strain-free InGaAs well layer and an InGaAsP barrier layer is obtained. Since the thickness is small,
It has the advantages that effective electron confinement and hole injection are possible, and that a high-quality quantum well structure that does not include a compositional metamorphic layer is obtained in both the InGaAs well layer and the InGaAsP barrier layer.

Further, the semiconductor heterostructure according to the present invention is provided with a lattice-matched ZnCdSe well layer and ZnCdSS.
When applied to a quantum well structure composed of an e-barrier layer, a quantum well structure in which a CdSSe layer having a thickness of 1 to 5 molecular layers is inserted between an unstrained ZnCdSe well layer and a ZnCdSSe barrier layer is obtained. Since the thickness is small,
It is possible to effectively confine electrons and inject holes, and obtain a high-quality quantum well structure that does not include a compositional metamorphic layer in both the ZnCdSe well layer and the ZnCdSSe barrier layer.

Furthermore, when the semiconductor heterostructure of the present invention is applied to the strained quantum well structure of the strained InGaAs well layer and the InGaAsP barrier layer, the strainless InGaAs insertion layer and the InAsP protective layer are the strained InGaAs well layer and the IAsP protective layer.
A strained quantum well structure inserted between the nGaAsP barrier layers can be obtained, but the bandgap of the unstrained InGaAs insertion layer is between the strained InGaAs well layer and the InGaAsP barrier layer, and the InAsP protective layer is small in thickness, which is effective. It is possible to confine electrons and inject holes, and a high-quality strained quantum well structure that does not include a compositional metamorphic layer in all the semiconductor layers forming the quantum well structure can be obtained.

In addition, II-according to the present invention according to claim 6
Also in the VI group semiconductor heterostructure, the same effect as that of the III-V group semiconductor heterostructure according to the present invention described in claim 2 is obtained, and as a result, a ZnCdSSe layer having a stable VI group composition is formed. A strained quantum well structure having is obtained.

As described in the above embodiment of the present invention,
When the semiconductor heterostructure according to the present invention is applied to a multiple quantum well semiconductor laser having an InGaAsP layer or a ZnCdSSe layer as a barrier layer of a quantum well layer or an optical confinement layer, it is caused by a compositional metamorphic layer or a non-flat strained interface. Since there is no non-radiative recombination of carriers, an active layer having a multiple quantum well structure with excellent optical quality can be obtained.
Therefore, there is an advantage that the threshold, output, temperature characteristics, and reliability of the semiconductor laser can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sectional layer structure of an LD according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a sectional layer structure of an LD according to a third embodiment of the present invention.

FIG. 3 is a diagram showing a sectional layer structure of an LD according to a fifth embodiment of the present invention.

FIG. 4 is a diagram showing a sectional layer structure of an LD according to a seventh embodiment of the present invention.

FIG. 5 is a diagram showing a cross-sectional layer structure of an LD according to a ninth embodiment of the present invention.

FIG. 6 is a diagram showing a sectional layer structure of an LD according to an eleventh embodiment of the present invention.

[Explanation of symbols]

 1, 21, 40, 60, 80, 100 n-electrode 2, 22, 41, 61 n-InP substrate 3, 23, 42 n-InP clad layer 4 n-InGaAsP optical confinement layer 5 InGaAsP barrier layer 6 InGaAs well layer 7 InAs (P) protective layer 8 InGaAsP barrier layer 9 p-InGaAsP optical confinement layer 10 p-InP clad layer 11 p-InGaAs contact layer 12, 33, 54, 73, 94, 116 p electrode 24 n-InGaAsP optical confinement layer 25 InGaAsP barrier layer 26 Strained InGaAs well layer 27 Unstrained InGaAs spacer layer 28 InAs (P) protective layer 29 InGaAsP barrier layer 30 p-InGaAsP optical confinement layer 31, 52 p-InP clad layer 32 p-InGaAs contact layer 43 n- In GaAsP optical confinement layer 44 InGaAsP barrier layer 45 strained InGaAs layer 46 InAs well layer 47 strained InGaAs layer 48 unstrained InGaAs spacer layer 49 InAs (P) protective layer 50 InGaAsP barrier layer 51 p-InGaAsP optical confinement layer 53 p-InGaAs contact Layer 62 n-InP buffer layer 63 InGaAs buffer layer 64 n-MgZnCdSe cladding layer 65 Unstrained n-ZnCdSSe optical confinement layer 66 n-ZnSSe barrier layer 67 Unstrained ZnCdSe well layer 68 CdSe (S) protective layer 69 Unstrained N-ZnCdSSe barrier layer 70 Unstrained p-ZnCdSSe optical confinement layer 71 p-MgZnCdSe clad layer 72 p-ZnCdSe contact layer 81 n-InP group 82 n-InP Buffer layer 83 n-InGaAs buffer layer 84 n-MgZnCdSe clad layer 85 n-ZnCdSSe optical confinement layer 86 n-ZnCdSSe barrier layer 87 strained ZnCdSe well layer 88 strain-free ZnCdSe spacer layer 89 CdSe (P) protective layer 90 n-ZnCdSSe barrier Layer 91 p-ZnCdSSe optical confinement layer 92 p-MgZnCdSe clad layer 93 p-ZnCdSe contact layer 101 n-InP group 102 n-InP buffer layer 103 n-InGaAs buffer layer 104 n-MgZnCdSe clad layer 105 n-ZnSSe optical confinement layer 106 n-ZnCdSSe barrier layer 107 Strained ZnCdSe layer 108 CdSe well layer 109 Strained ZnCdSe layer 110 Unstrained ZnCdSe spacer layer 111 C Se (S) protective layer 112 ZnCdSSe barrier layer 113 p-ZnCdSSe light confining layer 114 p-MgZnCdSe cladding layer 115 p-ZnCdSe contact layer

Claims (13)

[Claims] 1. A strain-free II having substantially the same lattice constant as the substrate.
A first semiconductor layer of a group IV compound and a second semiconductor layer of a predetermined molecular layer containing one type of group III element (atom)
And a third semiconductor layer containing a plurality of types of V-group elements in this order, a semiconductor heterostructure having a layered structure. 2. A first strained semiconductor layer of a III-V group compound having a lattice constant different from that of the substrate, and a non-strained second semiconductor layer having the same V group composition as the first strained semiconductor layer. A semiconductor heterostructure having a layer structure in which a third semiconductor layer containing one type of group III element (atom) and a fourth semiconductor layer containing a plurality of types of group V element are sequentially formed. Construction. 3. The semiconductor heterostructure according to claim 2, wherein the first strained semiconductor layer comprises a plurality of strained semiconductor layers having a common V group composition and different strain amounts. 4. The third semiconductor layer comprises I as a group III element.
4. The semiconductor heterostructure according to any one of claims 1 to 3, comprising n. 5. A strain-free II having substantially the same lattice constant as the substrate.
-A first semiconductor layer of a group VI compound and a second semiconductor layer of a predetermined molecular layer containing one type of group III element (atom)
And a third semiconductor layer containing plural kinds of VI group elements in this order, a semiconductor heterostructure having a layered structure. 6. A first strained semiconductor layer of II-VI group compound having a lattice constant different from that of the substrate, and a strain-free second semiconductor layer having the same VI group composition as the first strained semiconductor layer, A semiconductor heterostructure having a layer structure in which a third semiconductor layer containing one kind of group II element (atom) and a fourth semiconductor layer containing a plurality of kinds of group VI element are sequentially formed. Construction. 7. The semiconductor heterostructure according to claim 6, wherein the first strained semiconductor layer comprises a plurality of strained semiconductor layers having a common VI group composition and different strain amounts. 8. The third semiconductor layer comprises Cd as a group II element.
8. The semiconductor heterostructure according to claim 5, comprising: 9. The semiconductor heterostructure according to claim 1, wherein the predetermined molecular layer thickness is a molecular layer thickness of 1 to 5. 10. Strain-free InG provided on an InP substrate.
Between the aAs layer and the InGaAs barrier layer, the strain-free In
A layer containing at least In having a predetermined thickness formed on the GaAs layer is used for forming the InGaAs barrier layer.
And / or a protective layer having P incorporated therein, a heterostructure of a semiconductor laser. 11. A strain-free ZnC provided on an InP substrate.
Between the dSe layer and the ZnCdSSe barrier layer, at least C having a predetermined layer thickness formed on the unstrained ZnCdSe layer.
A heterostructure of a semiconductor laser, wherein the layer containing d includes a protective layer incorporating Se and / or S for forming the ZnCdSSe barrier layer. 12. Strained InGa provided on an InP substrate.
The strained InG is formed between the As layer and the InGaAs barrier layer.
An unstrained InGaAs layer having the same V group (As) composition as the aAs layer is inserted, and a layer containing at least In having a predetermined layer thickness formed on the unstrained InGaAs layer is an As layer for forming the InGaAs barrier layer. And / or a protective layer having P incorporated therein, a heterostructure of a semiconductor laser. 13. A strained ZnCd formed on an InP substrate.
Between the Se layer and the ZnCdSSe barrier layer, the strained Zn
A strain-free ZnCdSe layer having the same VI group composition as the CdSe layer is inserted, and a layer containing at least Cd having a predetermined layer thickness formed on the strain-free ZnCdSe layer is Se and / or for forming the ZnCdSSe barrier layer. Alternatively, a heterostructure of a semiconductor laser including a protective layer containing S.