JP3164482B2 - Crystal growth method and semiconductor device manufacturing method using the crystal growth method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a Zn _1-Y Mg _Y S _Z Se
_1-Z (hereinafter abbreviated as “ZnMgSSe”) single crystal thin film,
A method for growing a ZnS _x Se _1-x (hereinafter abbreviated as “ZnSSe”) single crystal thin film and a Zn _{1- W} Cd _W Se (hereinafter abbreviated as “ZnCdSe”) single crystal thin film, and a semiconductor using this growth method The present invention relates to a device manufacturing method.

[0002]

2. Description of the Related Art ZnMgSSe, ZnSSe and ZnC
dSe has attracted attention as a material for II-V semiconductor lasers that emit blue-green light. Single-crystal semiconductor thin films made of these materials are manufactured by molecular beam epitaxy (hereinafter, “MBE”).
). FIG. 1 shows a schematic configuration of the MBE apparatus. For crystal growth by this MBE apparatus, metal Zn, metal Cd, metal Mg, metal Se, metal
Te, a ZnS compound, a ZnCl ₂ compound, and N ₂ gas are used as raw materials.

[0003] When a ZnMgSSe single crystal thin film is grown by MBE, according to the prior art, metal Zn, metal Mg,
After four kinds of raw materials of metal Se and a ZnS compound (or simple substance of S) are filled in four independent heating evaporation sources, four kinds of molecular beams are simultaneously irradiated on the substrate from each heating evaporation source. Although not shown, the MBE device includes an exhaust device,
A substrate heating mechanism, a plurality of heating evaporation sources and a plasma cell are provided. Such a method of growing a single crystal thin film is described, for example, in H. Okuyama et al. Journal of Crystal Growt.
h Vol. 117, pp. 139-143. and S. Ito
et al. Japanese Journal of Applied Physics
Vol. 32, pp. L1530-L1532, 1993.

[0004] When a ZnSSe single crystal thin film is grown by the MBE method, three layers of metal Zn, metal Se and a ZnS compound are used.
After filling the three types into independent heating evaporation sources, the substrate is simultaneously irradiated with three types of molecular beams from each heating evaporation source. Such a single crystal thin film growth method is described, for example, in W. Xie et a
l. Applied Physics Letters Vol.60, pp.199
9-2001, 1992.

When a ZnCdSe single crystal thin film forming a quantum well is grown by MBE, metal Zn, metal Se,
After filling three types of metal Cd into three independent heating evaporation sources, the substrate is simultaneously irradiated with three types of molecular beams from each heating evaporation source. Such a single crystal thin film growth method is, for example,
W.Xie et al. Applied Physics Letters Vol.6
0, pp. 463-465, 1992.

[0006]

In the conventional MBE method, the number of evaporation sources used during crystal growth is large. This means that in order to obtain a single crystal thin film with excellent crystallinity, it is necessary to control the molecular beam intensity of each constituent element of the thin film independently of the other molecular beam intensities and determine the optimal intensity ratio. Because there is. The rate at which molecular beam molecules adhere to the substrate and contribute to crystal growth is
Since the intensity is different for each constituent element, it is necessary to adjust the intensity for each molecular beam. For example, when trying to obtain a GaAs single crystal thin film having excellent crystallinity by the MBE method, the ratio of the intensity of the As molecular beam to the intensity of the Ga molecular beam (V / III ratio) is in the range of about 10 to 20. It is preferred that there be. According to the conventional MBE method, there is a problem that the composition and the carrier density change in the plane of the thin film and / or in the depth direction, and change in each thin film growth process. Therefore, it is difficult to obtain a single crystal thin film having a uniform composition and carrier density with high reproducibility. These problems hinder low-cost and high-reproducibility manufacture of a device including a ZnMgSSe single-crystal thin film, a ZnSSe single-crystal thin film, or a ZnCdSe single-crystal thin film as a component.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a crystal growth method capable of forming a single crystal thin film having a uniform composition and carrier density with high reproducibility. An object of the present invention is to provide a method for manufacturing a semiconductor device using the crystal growth method.

[0008]

According to the present invention, there is provided a crystal growth method comprising the steps of separately heating a material selected from the group consisting of metallic Mg, MgS compound and MgSe compound, a ZnSe compound and a ZnS compound. The step of filling the evaporation sources, and controlling the temperature and molecular beam intensity of the heating evaporation source to form Zn _1-Y Mg _Y S on the heated substrate.
A step of crystal-growing a _Z Se _1-Z (0 <Y <1 and 0 <Z <1) single crystal thin film, whereby the object is achieved.

[0009] Another crystal growth method of the present invention is a method of growing metal Mg,
Any one material selected from the group consisting of MgS compounds and MgSe compounds, and ZnS _{X ′} Se _{1-X ′} (0 <X ′ <
1) a step of filling each the mixed crystal to separate heating evaporation sources, by controlling the temperature and the molecular beam intensity of the heating evaporation sources, Zn _1-Y on a heated substrate Mg _Y S _Z Se
_1-Z (0 <Y <1 and 0 <Z <1) a step of growing a single crystal thin film, whereby the above object is achieved.

[0010] Another crystal growth method of the present invention is a method for growing Zn _{1-Y '} M
g _{Y ′ SZ ′} Se _{1 -Z ′} (0 <Y ′ <1 and 0 <Z ′ <1) Mixed crystal filling step and controlling the temperature and molecular beam intensity of the heating evaporation source By doing so, Zn on the heated substrate
_1-Y Mg _Y S _Z Se _1-Z (0 <Y <1 and 0 <Z <1) a step of crystal-growing a single-crystal thin film, whereby the object is achieved.

[0011] _{Preferably, Zn 1-Y 'Mg Y} ' S Z 'Se 1-Z'
(0.02 ≦ Y a mixed crystal of '≦ 0.08 and 0.30 ≦ Z' ≦ 0.60 was charged into the heating evaporation _{source, Zn 1-Y Mg Y S} Z Se 1-Z
(0.05 ≦ Y ≦ 0.15 and 0.10 ≦ Z ≦ 0.25) A single crystal thin film is grown.

[0012] Another crystal growth method of the present invention comprises a step of filling a ZnSe compound and a ZnS compound into separate heating evaporation sources, and controlling the temperature and molecular beam intensity of the heating evaporation sources to form a film on a heated substrate. To ZnS _X Se _1-X (0 <X
<1) a step of crystal-growing a single-crystal thin film, whereby the above object is achieved.

[0013] Another crystal growth method of the present invention is a method of growing ZnS _{X '} S
e _{1 -X ′} (0 <X ′ <1) A step of filling a mixed crystal into a heating evaporation source, and controlling the temperature and molecular beam intensity of the heating evaporation source so that ZnS _X Se _{1 -X} (0 <X <
1) a step of crystal-growing a single-crystal thin film, whereby the above object is achieved.

Preferably, ZnS _{X ′} Se _{1-X ′} (0.08
≦ X ′ ≦ 0.40) The mixed crystal is filled in a heating evaporation source, and a ZnS _X Se _1-X (0.03 ≦ X ≦ 0.10) single crystal thin film is grown on the heated substrate.

Another crystal growth method of the present invention is a method for growing a metal Cd,
A step of filling any one of the materials selected from the group consisting of CdSe compounds and a ZnSe compound into separate heating evaporation sources, and controlling the temperature and molecular beam intensity of the heating evaporation source to thereby heat the heated substrate. Zn _1-W Cd _W S on top
e (0 <W <1) to grow a single-crystal thin film in crystal, whereby the above object is achieved.

A step of filling a mixed crystal of Zn _{1-W ′} Cd _{W ′} Se (0 <W ′ <1) into a heating evaporation source and heating by controlling the temperature and molecular beam intensity of the heating evaporation source. Z on the substrate
and a step of growing a single-crystal thin film of n _{1 -W} Cd _W Se (0 <W <1), whereby the object is achieved.

Preferably, the temperature of the heated substrate is 1
The temperature is set in the range of 00 ° C to 400 ° C.

A method for manufacturing a semiconductor device according to the present invention includes a step of forming a single-crystal thin film using the above-described crystal growth method.

According to another method of manufacturing a semiconductor device of the present invention, Zn _{1 -W} Cd _W Se (0 <W <
1) A quantum well layer made of a single crystal thin film is formed, and a barrier layer made of a ZnS _x Se _1-x (0 <X <1) single crystal thin film is formed by using the above-described crystal growth method. An active layer is formed.

[0020]

When the ZnMgSSe single crystal thin film is grown by the MBE method, the present invention employs any of the following combinations of raw materials (1) to (3).

(1) Metallic Mg, MgS compound and MgS
e, one selected from the group consisting of
Three types of Se compounds and ZnS compounds.

(2) Metallic Mg, MgS compound and MgS
Any one selected from the group consisting of e-compounds and two types of ZnSSe mixed crystals.

(3) ZnMgSSe mixed crystal.

In the conventional MBE growth method, four types (Zn,
Although it was considered that a raw material of Se, Mg, ZnS or S) was necessary, in the present invention, one to three kinds of raw materials are used. Conventionally, it has been considered that it is necessary to fill a separate heating evaporation source with a number of raw materials close to the number of constituent elements contained in a single crystal thin film to be grown, and to individually adjust the molecular beam intensity of each raw material. However, according to the crystal growth method of the present invention, excellent crystallinity can be obtained even when a compound of a constituent element is used as a raw material for a molecular beam. The reason is ZnMgS
Se and ZnSSe and ZnCdSe described later are Ga
This is because, unlike As or the like, even if the ratio between the molecular beam intensity of the group II element and the molecular beam intensity of the group VI element does not largely differ, it has the property of growing into a thin film having excellent crystallinity. The present invention has been completed based on such new findings by the present inventors.

According to the present invention, as a result of reducing the number of raw materials to be filled in each heating evaporation source of the MBE apparatus, the obtained single crystal thin film is excellent in composition reproducibility. That is, the in-plane uniformity of the grown single crystal thin film, the uniformity in the thickness direction, and the reproducibility for each lot are excellent. In addition, due to the small number of raw materials and the use of II-VI group compounds in many of the raw materials, the VI / II ratio is spatially and temporally 1 (in the case of using metallic Mg, 1 or more). (Small value). As a result, the reproducibility of the n-type or p-type carrier density is improved. When metallic Mg is used as a raw material for Mg, oxidation of metallic Mg becomes a problem.
By using the Se compound as a raw material, such a problem of oxidation can be reduced.

In growing the ZnSSe single crystal thin film, any one of the following combinations of raw materials (1) and (2) is employed in the present invention.

(1) ZnSe compound and ZnS compound 2
type.

(2) Only ZnSSe Mixed Crystal Conventionally, it was thought that three types of raw materials (Zn, Se, ZnS) were required, but in the present invention, one or two types of raw materials are used.

The present invention has excellent composition reproducibility because the number of raw materials is smaller than in the prior art. Because the number of raw materials is small and all raw materials use II-VI group compounds, VI / II
The ratio is fixed at 1 spatially and temporally, improving the reproducibility of the n-type or p-type carrier density. In growing a ZnCdSe single crystal thin film, the present invention provides the following (1) and
Either of the combinations of raw materials shown in (2) is adopted.

(1) One of metal Cd or CdSe compound and two of ZnSe compound.

(2) Only ZnCdSe mixed crystal.

Conventionally, it has been considered that three types of materials (Zn, Se, ZnS) are required.
Two types of raw materials are used. The present invention is excellent in composition reproducibility because the number of raw materials is smaller than in the past.

[0033]

FIG. 2 shows a schematic configuration of an MBE apparatus used for forming a semiconductor thin film according to the present invention. MB in FIG.
In the E apparatus, as raw materials, ZnSe compound, CdSe compound, metallic Mg, ZnTe compound, ZnS compound, ZnC compound
An l ₂ compound and N ₂ gas are used. Raw materials other than the N ₂ gas are charged into separate heating evaporation sources 1 to 6 provided in the MBE apparatus. The nitrogen gas is supplied from a cylinder 81 and is used to generate active nitrogen for p-type doping.
Activated nitrogen is obtained by discharging nitrogen gas with the plasma cell 8 (for example, K. Ohkawa et al. Japa
nese Journal of Applied Physics Vol. 30, p
p.L152-L155, 1991.). In the MBE device,
A substrate heating mechanism 9 for heating and maintaining the substrate 10 at a predetermined temperature is provided. Back pressure of the MBE apparatus, the vacuum pump, but becomes ^{1 0} Torr table ^{10-8 over,}
During p-type doping, the degree of vacuum in the MBE apparatus is 1 × 10 ⁻⁵ To
rr to 1 × 10 ⁻⁸ Torr.

For the sake of simplicity, the basic mechanism of crystal growth according to the present invention will be described first, taking the growth of a ZnSe single crystal thin film as an example.

In the crystal growth method of the present invention, a ZnSe compound is used as a raw material to grow a ZnSe single crystal thin film. Therefore, the molecular beam intensity of _Zn (J _Zn ; the number of Zn atoms flying to 1 cm ² per second) and the molecular beam intensity of _Se (J _Se ; 1 cm ² per ^second)
Ratio of the number of Se atoms flying to the surface (J _Se / J _Zn ; Flux Rati
o) is fixed to 1. On the other hand, if the metal Zn and the metal Se are filled in separate heating evaporation sources so that the intensity of each molecular beam can be adjusted arbitrarily, the molecular beam intensity of Zn and S
The ratio of the molecular beam intensity of e (J _Se / J _Zn ) can be set to an arbitrary value.

FIG. 9 shows that when the metal Zn and the metal Se are charged into separate heating evaporation sources, the crystallinity of the thin film is reduced.
It shows how it changes with J _Se / J _Zn and the substrate temperature. The graph in FIG. 9 is based on K. Menda et al. Jap
anese Journal of Applied Physics Vol. 26, L
1326, 1987.

In FIG. 9, the mark ○ indicates Reflection High.
-Energy Electron Diffraction (RHEED) pattern is c
A condition of (2 × 2) is indicated, and a black circle indicates a condition of the RHEED pattern being (1 × 2). In the regions I and III, the RHEED pattern becomes streak-like, and in the region II, the RHEED pattern becomes streak-like at the initial stage of growth, but becomes spotty as the growth is continued. The spotty or V-shaped pattern means that the growing surface has irregularities. When the molecular beam intensity ratio is 1 and the substrate temperature is 150
In the region from ℃ to 320 ℃, c (2x2) spotty
This indicates that a RHEED pattern can be obtained. In such a region, only a rough surface with the group II stabilizing surface can be obtained. A device structure such as a laser structure requires a single crystal flat thin film. From the viewpoint of lowering the resistivity of the P-type, it is preferable to grow the substrate at a relatively low substrate temperature (R. Park, Journal of Vacuum Science and Technology).
A Vol. 10, pp. 701-704, 1992).

From the above, it is understood that the growth under the condition of the region I is preferable. In order to realize the growth under the condition of the region I, it is necessary to set the ratio (J _Se / J _Zn ) to be larger than 1 and to set the substrate temperature in a range from 200 ° C. to 400 ° C. Based on the graph of FIG. 9, it is predicted that it is not preferable to grow a ZnSe single crystal thin film using a ZnSe compound as a raw material. This is because when a ZnSe compound is used as a raw material, the molecular beam intensity ratio J _Se / J _Zn is fixed at 1. Conventionally, based on such a prediction, the raw material for the thin film is charged into separate heating evaporation sources for each constituent element, the intensity of each molecular beam is adjusted, and the intensity ratio is set within the above range. Has been done. However, according to the experiment of the present inventor, even when the ZnSe compound was used, a streak (2 × 1) RHEED pattern was observed, and it was found that flat crystal growth was realized on the group VI stabilized surface. FIG. 10 shows the outline of the experimental result. Thus, when the ZnSe compound is used, a streak RHEED pattern of (2 × 1) is observed at a substrate temperature of 150 ° C. to 100 ° C., even though the molecular beam intensity ratio J _Se / J _Zn is fixed at 1. Was done. From experiments, it has been found that the growth temperature in the method of the present invention is suitably in the range of 100 ° C. to 400 ° C. where no spotty or V-shaped pattern is observed.

The reason why an experimental result deviated from the conventional prediction was obtained is considered as follows. However, the growth mechanism according to the present invention has not been elucidated yet.

In the conventional method, at 196 ° C., which is around the temperature usually used, the molecular beam component from metal Se is Se ₆ : Se ₅ : Se ₇ : Se ₂ : Se ₈ = 1: 0.66: 0.2
8: 0.11: 0.04. This can be seen, for example, in H. Cheng et al. Journal of Vacuu.
m Science Technology B Vol.8, pp.181-18
6, 1990.

However, when a polycrystalline compound AB containing a group VI element B is used as a raw material for MBE, this compound sublimates as shown in the following formula to form a molecular beam.

AB → A + 1 / 2B ₂ (1) where A = Zn, Cd, Mg, Hg (Group II element), B
= S, Se, Te (Group VI element). This is, for example, the case of T. Yao, Researches of the Electrotechnical L.
aboratory No. 854, 1985, p.23. Therefore, according to the crystal growth method of the present invention, the group VI element is a diatomic molecule. The group VI element molecule used in the present invention is a small molecule as compared with a conventional molecular beam molecule, and thus has higher reactivity. Therefore, even if the molecular beam intensity ratio is 1, FIG.
It is considered that a Se-stabilized surface such as 0 was observed.

When the metal Se is used as a raw material, the metal Se
When the temperature of the heating evaporation source is raised to 600 ° C., the molecular beam components are in the descending order of Se ₅ , Se ₂ , Se ₆ , Se ₇ and S 5.
the e ₃ (for example H.Cheng et al. Journal of
Vacuum Science Technology B Vol.8, pp.181
-186, 1990). However, as in the case where a ZnSe compound is used as a raw material, Se ₂ does not become a main component. When ZnSe is grown by heating the evaporation source at a high temperature for both metal Zn and metal Se, the growth temperature can be reduced to 100 ° C. (eg, M. Ohishi et al. Journ).
al of Crystal Growth Vol.117, pp.125-1
28, 1992.), and the method of the present invention using a compound as a raw material has made it possible to further lower the temperature to about 50 ° C. It is considered that the use temperature of the compound polycrystal is several hundred degrees higher than the metal raw material, and the group VI element contained in the molecular beam is mainly composed of diatomic molecules.

Since the composition and carrier density of the single crystal semiconductor thin film are sensitive to the fluctuation of the molecular beam intensity, if the molecular beam intensity changes even in one of the plurality of evaporation sources, the composition changes corresponding to the fluctuation. Would. Further, S and S which are group VI elements
The fluctuation of the ratio between the molecular beam intensity of e and the molecular beam intensity of the group II elements Zn and Mg (VI / II ratio) affects the incorporation of the donor or acceptor impurity element and changes the carrier density. There is a problem that it is. Therefore, the smaller the number of evaporation sources, the higher the reproducibility of the composition and carrier density, the better the yield, and the lower the device manufacturing cost.

In the conventional method, since many heating evaporation sources are required, there is also a problem that the MBE apparatus becomes huge and the cost becomes high. If the number of heating evaporation sources can be reduced,
A simple and small MBE apparatus can be used, and the manufacturing cost can be further reduced.

Hereinafter, a ZnMgSSe single crystal thin film, ZnS
An example of a crystal growth method of a Se single crystal thin film and a ZnCdSe single crystal thin film will be described in detail. In the following embodiment, FIG.
Each single-crystal thin film was grown on a GaAs (100) substrate by using the MBE apparatus. A typical substrate temperature during crystal growth was 280 ° C.

Example 1 An n-type ZnMgSSe single crystal thin film was grown from a ZnSe compound, a ZnS compound and metallic Mg as raw materials. As the n-type dopant, chlorine from a ZnCl ₂ raw material was used (for example, K. Ohkawa et al. Jou
rnal of Applied Physics Vol.62, pp.3216
-3221, 1987.).

FIG. 3 shows the n-type ZnMgS thus obtained.
4 shows a photoluminescence (PL) spectrum measured from a Se single crystal thin film. Measurements were taken at 12K. In the PL measurement at 12K, a strong band edge emission at 420 nm was observed. The origin of the emission is believed to be exciton emission (I ₂ ) constrained by a neutral chlorine donor. The bandgap energy of the ZnMgSSe thin film shown in FIG. 3 is 2.95 eV at 12 K and about 2.85 eV at room temperature.
V. In the present specification, the band gap energy of the ZnMgSSe mixed crystal is defined by the photon energy of band edge emission.

[0049] Zn _1-Y Mg Y S lattice constant of _Z Se _1-Z thin film is matched to the lattice constant of GaAs, Okuyama et graph (H.Okuyama et al. Journal of Crystal Grow
The composition obtained from FIG. 1 and FIG. 3 in th Vol. 117, pp. 139-143, (1992) is Y = 0.07 and Z = 0.18. Zn _1-Y Mg _Y S _Z Se of this composition
_In order to obtain a _1-Z thin film at a growth temperature of 280 ° C., the molecular beam intensity was set to P (ZnSe) = 1.75 × 10 ⁻⁶ Torr and P (Z
nS) = 9.0 × 10 ⁻⁷ Torr, P (Mg) = 2.5 × 10
^-8 Torr. This molecular beam intensity is a value measured by a flux gauge. During the growth of the ZnMgSSe thin film, the temperature of the evaporation source was controlled so that the intensity of each molecular beam became constant. Under the conditions of this example, the growth rate of the ZnMgSSe thin film was 0.63 μm / h.

The RHEED pattern during growth is (2 × 1) and c
(2 × 2) and 1 μm thick from the beginning of growth
Until the end of growth, it had a beautiful streak. The streak RHEED indicates the flatness of the surface, confirming that the thin film had a mirror surface. A single crystal ZnMgSSe thin film has a growth temperature of 100 ° C. to 400 ° C.
It was possible in the range of ° C. In addition, it was necessary to lower the growth rate for a low substrate compared to a case of a high substrate temperature.

Example 2 In this example, a ZnSe compound, a ZnS compound and a MgS compound were used as raw materials,
_{n 1-Y Mg Y S Z} Se 1-Z grown single crystal thin film.

[0052] The obtained _{Zn 1-Y Mg Y S Z} Se 1-Z lattice constant of the single crystal thin film is 0.12% greater relative to GaAs,
As for the crystallinity, the full width at half maximum (FWHM) in the double crystal X-ray diffraction method was as good as 64 seconds. The band gap of the single crystal thin film was 2.98 eV at 12K. Its composition is Y =
0.10 and Z = 0.20. The molecular beam intensity for obtaining this composition at a growth temperature of 280 ° C. is P (ZnSe) =
1.25 × 10 ⁻⁶ Torr, P (ZnS) = 9.4 × 10 ⁻⁷
Torr, P (MgS) = 2.8 × 10 ⁻⁸ Torr, and the growth rate was 0.40 μm / h.

The RHEED pattern during growth is (2 × 1) and c
(2 × 2) and a beautiful streak pattern mixed. The thin film surface had a mirror surface. In addition, the working temperature (1240) of the MgS raw material for obtaining the above molecular beam intensity.
° C) is about 1 compared to the working temperature of metal Mg (250 ° C).
000 ° C high temperature. For this reason, when the temperature of the heating evaporation source is changed, the molecular beam intensity also quickly changes. Therefore, by changing both the molecular beam intensity of ZnS and MgS, it becomes possible to realize a Grin structure in which the band gap is gradually changed while lattice-matching with GaAs.

When using a metal Mg which is easily oxidized,
Surface oxidation of metallic Mg occurs due to moisture and the like remaining even in a vacuum, which may cause problems such as difficulty in obtaining a molecular beam. However, in the case of the present embodiment, such a problem does not occur because the MgS compound is used instead of the metallic Mg.

Example 3 In this example, a ZnSe compound, a ZnS compound and a MgSe compound were used as raw materials,
_{n 1-Y Mg Y S Z} Se 1-Z grown single crystal thin film.

[0056] The obtained _{Zn 1-Y Mg Y S Z} Se 1-Z lattice constant of the single crystal thin film is matched to the lattice constant of GaAs, was also favorable crystallinity. The band gap energy is 1
It was 2.96 eV at 2K. The composition of the thin film was Y = 0.08 and Z = 0.19. This composition is grown at 280 ° C.
The intensity of the molecular beam to be obtained by P (ZnSe) = 1.55 ×
10 ⁻⁶ Torr, P (ZnS) = 9.0 × 10 ⁻⁷ Torr
r, P (MgSe) = 2.5 × 10 ⁻⁸ Torr, and the growth rate was 0.50 μm / h.

The RHEED pattern during growth is (2 × 1) and c
(2 × 2) and a beautiful streak pattern mixed. The thin film surface had a mirror surface.

Operating temperature of MgSe raw material (1100 ° C.)
Is about 850 compared to the operating temperature (250 ° C.) of metallic Mg.
Since the temperature is high by ° C., if the temperature of the heating evaporation source is changed, the molecular beam intensity also changes quickly. Therefore ZnS and M
By changing the molecular beam intensity of gSe together, Ga
It is possible to fabricate a Grin structure in which the band gap energy gradually changes while lattice-matching As.

Any one of the source flows of Mg selected from the group consisting of metallic Mg, MgS compounds and MgSe compounds
By increasing the molecular beam intensity for Zn _1-Y M
g _Y S _Z Se _1-Z could be a composition Y single-crystal thin film is increased. In addition, the composition Z could be increased by increasing the molecular beam intensity of ZnS. Therefore, M
The composition of g and S could be changed in the range of 0 <Y <1, 0 <Z <1.

Further, by fixing the temperature of each heating and evaporating source containing the respective raw materials of the ZnS compound, metallic Mg, MgS compound and MgSe compound, it was possible to make each molecular beam intensity constant. However, since the molecular beam intensity did not become constant at a constant temperature when the temperature of the heating evaporation source containing ZnSe was increased, the molecular beam intensity was kept constant by increasing the temperature of the heating evaporation source at a gradient of 0.01 ° C./min. Kept.

Example 4 In this example, a mixed crystal of metal Mg and ZnS _{X ′} Se _{1-X ′} (X ′ = 0.50) was used as a raw material.
_{Zn 1-Y Mg Y S Z} Se 1-Z grown single crystal thin film.

The lattice constant matched that of GaAs, and the crystallinity was good. And the band gap is 2.
It was 94 eV. Its composition is Y = 0.065 and Z = 0.1
7 The molecular beam intensity for obtaining this composition at a growth temperature of 280 ° C. is P (ZnSSe) = 2.50 × 10 ⁻⁶ Torr.
r, P (Mg) = 2.3 × 10 ⁻⁸ Torr, and the growth rate was 0.55 μm / h. The RHEED pattern during the growth was a clear streak with a mixture of (2 × 1) and c (2 × 2). The thin film surface had a mirror surface. Obtained Zn
The composition Y of the _1-Y Mg _{YS Z} Se _1-Z single crystal thin film is represented by the growth temperature and the molecular beam intensity ratio P (Mg) / (P (ZnSSe) + P
(Mg)). Therefore, it is difficult to stipulate it.
The composition Y can be increased by employing a high growth temperature or a high molecular beam intensity ratio. In order to reduce the composition Y, the growth temperature may be set low or the molecular beam intensity ratio may be reduced. Furthermore, the composition Z of the obtained Zn _1-Y Mg _Y S _Z Se _1-Z single crystal thin film is the growth temperature and the composition of the ZnS _{X ′} Se _{1-X ′} mixed crystal raw material.
Depends on X '. Therefore, it is difficult to define the composition Z in general, but it is possible to increase the composition Z by using a mixed crystal material having a low growth temperature or a large composition X ′. Composition Z
In order to reduce the value, the growth temperature may be set higher or the material composition X ′ may be reduced. By changing the way the composition X of the growth temperature and the molecular beam intensity ratio and the mixed crystal material ', resulting _{Zn 1-Y Mg Y S Z} Se 1 -Z single-crystal thin film of the composition Y, Z is 0 <Y It is possible to control the range of <1, 0 <Z <1.

Further, the metal Mg raw material of the above embodiment was replaced with a MgS compound or a MgSe compound, and ZnS _{X ′} Se
_{1-X '(0 <X} '<1) are possible _{Zn 1-Y Mg Y S Z} Se 1-Z single-crystalline thin film growth by combining a mixed crystal material. The compositions Y and Z can be adjusted to 0 <Y <1, 0 <Z <by changing the growth temperature, the molecular beam intensity ratio, and the composition X ′ of the mixed crystal raw material.
It is possible to control in the range of 1.

(Embodiment 5) In this embodiment, Zn _{1-Y ′} Mg
_{Y 'S Z' Se 1-} Z a '(0 <Y'<1 and 0 <Z '<1) mixed crystal as a starting _{material, Zn 1-Y Mg Y S} Z Se 1-Z (0 <Y <1 and 0 <Z <1)
A single crystal thin film can be manufactured.

Since the compositions Y and Z depend on the substrate temperature, it is difficult to unconditionally define them. However, the relations of Y> Y ′ and Z <Z ′ are satisfied. At a substrate temperature of 100 ° C. to 400 ° C., the adhesion coefficient of Mg is higher than that of Zn, and the adhesion coefficient of S is S
This is because it is smaller than e. Zn _{1-Y '} Mg _Y' S _{Z '} Se
_{1-Z '} (0.02≤Y'≤0.08 and 0.30≤Z'≤0.6
0) Mixed crystal is used as a raw material, and 200 ° C to 350 ° C
Grown on the heated substrate. Zn _1-Y Mg _Y S _Z Se
_Since the composition of the _1-Z single crystal thin film depends on the substrate temperature, it is difficult to define the composition, but 0.05 ≦ Y ≦ 0.15 and 0.10 ≦ Z ≦
It is in the range of 0.25. The ZnMgSSe thin film of this composition has a band gap at 77K of 2.85 eV to 3.10 eV.
And the resistance can be reduced by adding impurities. Further, the lattice constant of the obtained film is GaAs or ZnSe.
And excellent crystallinity. Therefore, Z of this composition
The nMgSSe thin film is extremely important as a device constituent material. Further, in the present invention, a ZnMgSSe mixed crystal thin film can be produced from one raw material, so that the method is extremely reproducible and simple.

Example 6 In this example, a ZnSe single crystal thin film was grown by using a ZnSe compound and a ZnS compound. FIG. 4 is a photoluminescence (PL) spectrum measured from an undoped ZnSSe single crystal thin film. In PL measurements at 12K, I ₂ emission is observed in the free exciton emission (E _X) and 437.3nm to 436.5nm. It E _X emission is dominant, resulting Zn
This means that the SSe thin film and the raw materials of the ZnSe compound and the ZnS compound have high purity.

The composition of the obtained ZnS _X Se _{1 -X} thin film is represented by X =
0.065, and one growth condition for obtaining this composition is that the substrate temperature is 280 ° C. and the molecular beam intensity is P (ZnSe).
= 1.75 × 10 ⁻⁶ Torr and P (ZnS) = 3.5 × 10
^-7 Torr. The composition X is based on the substrate temperature and the molecular beam intensity ratio P (ZnS) / (P (ZnSe) + P (Zn
S)). As the substrate temperature increases, the composition X decreases. The composition X increases as the molecular beam intensity ratio increases. That is, at a growth temperature lower than 280 ° C., it is necessary to further reduce P (ZnS) in the molecular beam intensity example. By doping the growing ZnSSe with chlorine or nitrogen, n-type or p-type conduction can be controlled.

(Embodiment 7) In this embodiment, ZnS _{X '} Se
_{Using 1-X '} (0 <X'<1) mixed crystal as a raw material, ZnS _X S
An e _1-X (0 <X <1) single crystal thin film was grown.

Since the composition X depends on the substrate temperature, it is difficult to define the composition X in a straightforward manner, but the relation X <X ′ is satisfied. Substrate temperature 100
This is because the adhesion coefficient of S is smaller than that of Se in the range of from 400C to 400C.

(Embodiment 8) In this embodiment, ZnS _{X ′} Se
_{1-X ′} (0.08 ≦ X ′ ≦ 0.40) mixed crystal is used as a raw material,
And molecular beam intensity P (ZnSSe) = 2.0 × 10 ⁻⁶ Torr
r on the substrate heated from 200 ° C. to 350 ° C.
ZnSe _X Se obtained by growing an _X Se _1-X single crystal thin film
_Although the composition of the _1-X single crystal thin film depends on the substrate temperature, it is difficult to unconditionally define it. However, in this embodiment, 0.03 ≦ X ≦ 0.10
Was in the range. Since the lattice constant of the ZnSSe thin film having this composition is close to the lattice constant of GaAs and has excellent crystallinity, it is extremely important as a device constituent material. According to the present embodiment, the ZnSSe mixed crystal thin film can be manufactured from one raw material, so that reproducibility is extremely high and simple.

(Embodiment 9) In this embodiment, ZnMgSS
e clad layer (thickness: 1 μm), ZnSSe light guide layer (thickness: 0.1 μm), ZnCdSe active layer (thickness: about 20 nm or less), ZnSSe light guide layer (thickness: 0.1 μm)
μm) and a ZnMgSSe cladding layer (thickness: 1 μm).
m) was continuously grown to form a laser structure.

The obtained ZnSSe thin film and ZnMgSS
e thin film is lattice-matched to the GaAs substrate, but ZnCd
The Se active layer has a larger lattice constant than GaAs,
No lattice matching with the As substrate. The thickness of the ZnCdSe thin film is set so thin that defects are not introduced into the ZnCdSe thin film. The thickness of the Zn _1-W Cd _W Se thin film in which no defect is present depends on the composition W and is difficult to define all together, but is about 20 nm or less.

The composition W and the room-temperature band gap (Eg) of the ZnCdSe thin film are defined by the following equation.

Eg (W) / [eV] = 2.635−1.235 W + 0.30 W ² − (1.07 + W) (0.04 + W) / (7.22−W) / (14.89 + W) (2) The value of Eg is set equal to the energy of the laser oscillation wavelength. Equation (2) assumes that the thickness of the ZnCdSe thin film is 5 nm or more, and does not consider the blue shift of laser oscillation due to the quantum effect. The composition W depends on the intensity ratio between the Cd-related molecular beam and the ZnSe compound molecular beam as shown in FIG. In this embodiment, the molecular beam intensity of ZnSe is set to P (ZnSe) =
The growth was performed by fixing the substrate temperature to 1.75 × 10 ⁻⁶ Torr and the substrate temperature to 280 ° C., respectively.

When metal Cd and a ZnSe compound are used, the molecular beam intensity ratio is P (Cd) / (P (Cd) + P (Z
In the region of nSe)) ≦ 0.2, the composition W changes linearly. However, in the region where the molecular beam intensity ratio is 0.2 or more, II
Composition W shows a tendency to saturate because competition for positioning at group sites occurs between Cd and Zn. Therefore, W = 0.
When a ZnCdSe thin film having a composition of about 2 is obtained, according to the method of this embodiment, a ZnCdSe thin film having good composition reproducibility can be obtained even if the molecular beam intensity of each heating evaporation source varies.

When a CdSe compound and a ZnSe compound are used, an arbitrary molecular beam intensity ratio P (CdSe) / (P (C
dSe) + P (ZnSe)), the composition W changes linearly. Since Se is sufficiently supplied by the CdSe raw material, no competition occurs between Cd and Zn,
Composition W does not show a tendency to saturate. By using the method of the present embodiment, the composition W of the ZnCdSe thin film can be freely controlled by the molecular beam intensity ratio. Further, as shown in FIG. 6, the intensity of the molecular beam from the CdSe compound is such that the burst generated by opening and closing the cell shutter is as small as about 1% of the stable intensity and is stabilized within one minute. Therefore, ZnCdS of the same composition
It is suitable for producing a multiple quantum well (MQW) structure in which a plurality of e thin films are introduced into an active layer.

Further, Zn _{1 -W ′} Cd _{W ′} Se (0 <W ′ <1)
When a mixed crystal is used as a raw material, a substrate temperature of 100.degree.
A single crystal thin film of Zn _1-W Cd _W Se (0 <W <1) was formed in the range of 00 ° C. The composition W showed a value substantially equal to the value of the composition W ′.

FIG. 7 shows metal Zn, metal Se and ZnS
N-type ZnS _x Se _1-x (0.
05 <X <0.08) Single crystal thin film, metal Zn, metal Se,
Mg metal and n-type ZnS compound was prepared in the raw material _{Zn 1-Y Mg Y S Z} Se 1-Z (0.05 <Y <0.08 and 0.1
3 <Z <0.20) This shows the doping condition dependence of the carrier density in the single crystal thin film. Here, the doping condition means the temperature (T _Cl ) of the evaporation source filled with ZnCl _2.
Means

FIG. 8 shows a ZnSe compound and a ZnSe compound.
N-type ZnS _X Se prepared from S compound
_1-X (0.05 <X <0.08) single crystal thin film and ZnSe crystal, metallic Mg and nS fabricated using ZnS crystal as raw materials
Type Zn _1-Y Mg _Y S _Z Se _1-Z (0.05 <Y <0.08 and 0.1
15 <Z <0.18) This shows the doping condition dependence of the carrier density in the single crystal thin film.

It can be seen that the carrier density of the thin film of FIG. 8 is smaller than that of the thin film of FIG. 7, and the reproducibility is higher.

Further, in the case of the thin film of FIG.
Whereas the lattice mismatch was in the range of -0.12% to + 0.12% for the thin film of FIG. 8, although it was in the range of 2% to + 0.2%. A small variation in the lattice constant indicates a small variation in the composition. According to the crystal growth method of the present invention, it was found that the reproducibility of the lattice constant and the carrier density was extremely high because the variation in the composition could be reduced. However, the width of the composition deviation due to the fluctuation of the molecular beam intensity differs depending on the MBE apparatus. Therefore, although the degree of the improvement cannot be specified, the reproducibility can be expected to be improved by using the crystal growth method of the present invention as compared with the conventional method if the same apparatus is used.

In this embodiment, only the n-type semiconductor doped with Cl has been described, but Ga, In, Al, Br, I
It is clear that the reproducibility of the carrier density is also improved for other donor impurities such as. It is also apparent that the reproducibility of carrier density is improved in a p-type semiconductor by adding an acceptor impurity by N, As, and P.

(Embodiment 10) Next, a method of manufacturing a semiconductor laser using the crystal growth method according to the present invention will be described with reference to FIG. FIG. 11 shows a ZnMgSSe single crystal thin film, a ZnSSe single crystal thin film,
An nCdSe single crystal thin film is used.

In this embodiment, an MBE device similar to the MBE device shown in FIG. 2 was used. According to the conventional method, the raw materials used are metal Zn, metal Se, metal Cd, metal M
g, metal Te, ZnS crystal, nitrogen gas, zinc chloride (ZnC
l ₂ ) (for example, S. Itoh et al. Japanese
Journal of Applied Physics Vol.32, pp.L1
530-L1532, 1993.). Thus, the conventional method requires eight kinds of raw materials. However, according to the method of the present embodiment, as shown in FIG. 2, only seven types of raw materials are required. The n-type and p-type carrier densities are controlled by Cl doping with ZnCl ₂ and N doping with nitrogen plasma, respectively.

First, on an n-type GaAs substrate 11, an n-type G
aAs: Si buffer layer (film thickness 0.45 μm, N _d -N _a = 2 ×
10 ¹⁸ cm ^-3 ) 12, n-type ZnSe: Cl contact layer (thickness 30 nm, N _d -N _a = 6 × 10 ¹⁷ cm ^-3 ) 13, n-type Zn
MgSSe: Cl cladding layer (0.8 μm thickness, N _d -N _a = 4x
10 ¹⁷ cm ⁻³ ) 14, n-type ZnSSe: Cl optical guide layer (85 nm in thickness, N _d −N _a = 1 × 10 ¹⁷ cm ⁻³ ) 15, quantum well active layer (Zn _0.65 Cd _0.35 Se quantum well layer (well) Width 2.
4 nm, 4 layers), ZnSSe barrier layer (width 3.4 nm, 3
Layer)) 16, p-type ZnSSe: N light guide layer (film thickness 85n)
m, N _a -N _d = 1 × 10 ¹⁷ cm ⁻³ ) 17, p-type ZnMgSSe: N
Cladding layer (thickness _{0.8μm, N a -N d = 3x10} 17 cm -3) 1
8, p-type ZnSe: N contact layer (thickness 40nm, N _a -N _d =
7x10 ¹⁷ cm ^-3) 19, p-type ZnSe: N / ZnTe: N super lattice contact layer (each film thickness 2 nm, 20 cycles, N _a -N _d = 1x1
^{0 18 cm - 3) 20,} p -type ZnTe: N contact layer (thickness 37
nm, N _a −N _d = 2 × 10 ¹⁹ cm ⁻³ ) 21 are sequentially epitaxially grown. Preferably, these epitaxial growths are performed continuously in a system in which an MBE apparatus for growing a GaAs buffy layer and an MBE apparatus for growing a II-VI semiconductor layer are connected by a vacuum tube.

In this example, the following materials were used as the materials for each semiconductor layer. That is, the raw material of the ZnSe layer is a ZnSe polycrystalline compound. The raw materials of the ZnMgSSe layer are a ZnSe polycrystalline compound, a ZnS polycrystalline compound, and metallic Mg. The raw materials of the ZnSSe layer are a ZnSe polycrystalline compound and a ZnS polycrystalline compound. ZnCdS
The raw materials for the e-layer are a ZnSe polycrystalline compound and a CdSe polycrystalline compound.

The thus formed ZnMgSSe thin film and ZnSSe thin film are lattice-matched to the GaAs substrate 1. The band gap of the ZnMgSSe thin film is 2.
83 eV.

Next, by photolithography, p
The mold contact layers 19 to 21 are etched in a stripe shape. After filling the recess formed by etching with an insulator. An Au electrode 22 is deposited. On the back surface of the substrate 21, I
An n-electrode 23 is formed. Thus, a semiconductor laser of an electrode stripe type is obtained. The resonator of the semiconductor laser is formed by cleavage.

The Au electrode 2 of the semiconductor laser shown in FIG.
When a voltage of about 13 V was applied in a pulse form between the In 2 and the In electrode 2, a current of about 88 mA flowed, and laser light with a wavelength of about 518 nm could be obtained. The measurement temperature is room temperature.
The light output exceeded 100 mW at one end face as shown in FIG. For laser oscillation, ZnMgSSe clad layer and ZnSS
It is required that the e-light guide layer and the ZnCdSe active layer have sufficient crystallinity, and it can be seen that the crystallinity is obtained in the method of the present invention. Although several similar structures were produced, the threshold currents showed almost the same value, confirming that the reproducibility was high. The Cd of the active layer
The composition is W = 0.35. The laser oscillates at 518 nm, which is shorter than the wavelength 555 nm expected from the equation (2). The reason for this is that the thickness of the well layer is extremely thin, 2.4 nm, and a blue shift due to the quantum effect has occurred.

In this example, ZnSe compounds, ZnTe compounds, ZnS compounds, CdSe compounds, and metallic Mg were used as main raw materials, but the present invention is not limited to these raw materials. That is, the ZnMgSSe single crystal thin film is made of either one of MgS compound or MgSe compound and three kinds of ZnSe compound and ZnS compound, or two kinds of metal Mg or MgS compound or one of MgSe compound and ZnSSe mixed crystal. The growth can be performed with good reproducibility even when the raw material or only the ZnMgSSe mixed crystal is used as the raw material. A ZnSSe single crystal thin film can be grown with good reproducibility even when a ZnSSe compound is used as a raw material. The ZnCdSe single crystal thin film is formed by using metal Cd and a ZnSe compound as raw materials, or
Even if only the nCdSe compound is used as a raw material, growth can be performed with good reproducibility.

[0091]

As described above, the present invention provides a ZnMgSSe
A single crystal thin film, a ZnSSe single crystal thin film, and a ZnCdSe single crystal thin film that can realize crystal growth with high composition reproducibility, high carrier density reproducibility, and low cost. Is supplied with good reproducibility and at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of the structure of a conventional MBE apparatus.

FIG. 2 is a schematic sectional view of a structure of an MBE apparatus used in the present invention.

FIG. 3 is a graph showing a PL spectrum of a Cl-doped ZnMgSSe thin film at 12K.

FIG. 4 is a graph showing a PL spectrum of a ZnSSe-free thin film at 12K.

FIG. 5 shows the composition W of the Zn _1-W Cd _W Se thin film and the molecular beam intensity ratio (P (Cd) / (P (Cd) + P (ZnSe));
The graph which shows the relationship of (CdSe) / (P (CdSe) + P (ZnSe)).

FIG. 6 is a diagram showing a change in CdSe molecular beam intensity due to opening and closing of a shutter.

FIG. 7 is a graph showing the doping condition dependence of the carrier density of an n-type ZnSSe thin film (open circle) and an n-type ZnMgSSe thin film (black circle) manufactured by a conventional method.

FIG. 8 is a graph showing the doping condition dependence of the carrier density of the n-type ZnSSe thin film (open circle) and the n-type ZnMgSSe thin film (black circle) manufactured by the method of the present invention.

FIG. 9 is a graph showing the dependence of the RHEED pattern obtained from the surface of a ZnSe thin film growing by a conventional method on the molecular beam intensity ratio (J _Se / J _Zn ) and the substrate temperature.

FIG. 10 is a diagram showing the substrate temperature dependence of an RHEED pattern obtained from the surface of a ZnSe thin film growing by the method of the present invention.

FIG. 11 is a structural sectional view of a semiconductor laser manufactured by using the method of the present invention.

FIG. 12 is a graph showing light output-current characteristics of the semiconductor laser of FIG. 11;

[Explanation of symbols]

 1-6 Heat evaporation source 8 Plasma cell 9 Substrate heating mechanism 10 Substrate 11 n-type GaAs substrate 12 n-type GaAs: Si buffer layer 13 n-type ZnSe: Cl contact layer 14 n-type ZnMgSSe: Cl cladding layer 15 n-type ZnSSe: Cl Optical guide layer 16 Quantum well active layer 17 p-type ZnSSe: N optical guide layer 18 p-type ZnMgSSe: N cladding layer 19 p-type ZnSe: N contact layer 20 p-type ZnSe: N / ZnTe: N superlattice contact layer 21 p-type ZnTe: N contact layer 81 Nitrogen gas

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/363 H01L 21/203

Claims (12)

(57) [Claims] 1. A material selected from the group consisting of metallic Mg, MgS compound and MgSe compound,
filling the nSe compound and the ZnS compound into separate heating evaporation sources, and controlling the temperature and the molecular beam intensity of the heating evaporation source to form a Zn _1-Y Mg _Y S _Z Se on the heated substrate. _1-Z (0 <Y
<1 and 0 <Z <1) a step of growing a single crystal thin film,
A crystal growth method comprising: 2. A material selected from the group consisting of metallic Mg, MgS compound and MgSe compound,
a step of filling nS _{X ′} Se _{1−X ′} (0 <X ′ <1) mixed crystal into separate heating evaporation sources, and heating by controlling the temperature and molecular beam intensity of the heating evaporation sources. On the substrate, Zn _1-Y Mg _Y S _Z Se _1-Z (0 <Y
<1 and 0 <Z <1) a step of growing a single crystal thin film,
A crystal growth method comprising: 3. The method according to claim 1, wherein Zn _{1-Y ′} Mg _{Y ′} S _{Z ′} Se _{1-Z ′} (0 <Y ′ <1
And 0 <Z '<1) and filling a mixed crystal heating evaporation source, by controlling the temperature and the molecular beam intensity of the heating evaporation sources, the heated substrate _{Zn 1-Y Mg Y S Z} Se _1-Z (0 <Y
<1 and 0 <Z <1) a step of growing a single crystal thin film,
A crystal growth method comprising: 4. Zn _{1-Y ′} Mg _{Y ′} S _{Z ′} Se _{1-Z ′} (0.02
The mixed crystal of ≦ Y '≦ 0.08 and 0.30 ≦ Z' ≦ 0.60 was charged into the heating evaporation _{source, Zn 1-Y Mg Y S} Z Se 1-Z (0.0
5 ≦ Y ≦ 0.15 and 0.10 ≦ Z ≦ 0.25) The crystal growth method according to claim 3, wherein the single crystal thin film is grown. 5. A step of filling a ZnSe compound and a ZnS compound into separate heating evaporation sources, and controlling the temperature and molecular beam intensity of the heating evaporation sources to form ZnS _x Se _1-x ( 0 <X <1) a step of crystal growing a single crystal thin film. 6. A step of filling a mixed crystal of ZnS _{X ′} Se _{1-X ′} (0 <X ′ <1) into a heating evaporation source, and controlling the temperature and molecular beam intensity of the heating evaporation source to heat the mixture. Crystal growing a ZnS _x Se _1-x (0 <x <1) single crystal thin film on the substrate obtained. 7. ZnS _{X ′} Se _{1-X ′} (0.08 ≦ X ′ ≦ 0.4
0) The mixed crystal was filled in a heating evaporation source, and Zn was placed on the heated substrate.
_{S X Se 1-X (0.03} ≦ X ≦ 0.10) crystal growth method according to claim 6, a single crystal thin film is grown. 8. A step of filling any one of a material selected from the group consisting of metallic Cd and CdSe compounds and a ZnSe compound into separate heating evaporation sources, respectively; By controlling, Zn _1-W Cd _W Se (0 <W <1)
A crystal growth method for growing a single crystal thin film. 9. A step of filling a mixed crystal of Zn _{1-W ′} Cd _{W ′} Se (0 <W ′ <1) into a heating evaporation source, and controlling the temperature and molecular beam intensity of the heating evaporation source. Zn _1-W Cd _W Se (0 <W <1) on the heated substrate
Crystal growing a single crystal thin film. 10. The crystal growth method according to claim 1, wherein the temperature of the heated substrate is set in a range from 100 ° C. to 400 ° C. 11. A method for manufacturing a semiconductor device, comprising a step of forming a single-crystal thin film using the crystal growth method according to claim 1. 12. A quantum well layer comprising a Zn _{1- W} Cd _W Se (0 <W <1) single crystal thin film is formed by using the crystal growth method according to claim 8 or 9. 6, ZnS _x Se _1-x (0 <X <1)
A method of manufacturing a semiconductor device in which a barrier layer made of a single crystal thin film is formed, and thereby a quantum well active layer is formed.