JP3479542B2 - Method for manufacturing II-VI compound semiconductor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a compound semiconductor layer in vapor phase growth of a II-VI group compound semiconductor thin film, and particularly to suppressing flattening of the growth layer and deposition on a protective film for selective growth. The present invention relates to a method for producing a compound semiconductor suitable for

[0002]

2. Description of the Related Art II-VI group compound semiconductors can cover a short wavelength region from ultraviolet to green and a long wavelength region of infrared. Recently, a blue laser has been successfully oscillated using a II-VI group compound semiconductor lattice-matched to a GaAs substrate. This blue laser oscillation has been achieved by forming a quantum well active layer and improving the p-type doping technique.
However, in order to control the transverse mode, AlGa
A current constriction structure as used in an As-based semiconductor laser is required. The formation of the block layer for constricting the current requires application of the selective growth technique.

[0003]

In order to fabricate the above quantum well structure, it is necessary to precisely control the growth rate, and usually the molecular beam epitaxial growth (MBE) method or the metal organic chemical vapor deposition (MOVPE) method is used. Is used. actually,
By using these growth methods, a steep hetero interface is formed at the atomic layer level. When these structures are applied to a device, the flatness of the hetero interface has a great influence on the device characteristics. At the II-VI group compound interface, the migration distance of the compound molecules is short, so there is a problem such as poor flatness. Recently, selective growth has been used for further optimizing the device structure. However, since selective growth is very difficult by the ordinary MBE method, the selective growth is conventionally performed by the MOVPE method or the MOMBE method. . The advantage of selective growth is that it is a damage-less process at a relatively low temperature, so that a high-quality selective growth region can be obtained and a high-performance element can be obtained.

However, in order to prevent poly (polycrystal) from being deposited on the protective film during the selective growth, the growth conditions, mixed crystal ratio, mask width, etc. are greatly restricted. Particularly, in the case of a II-VI group compound containing Zn, the larger the mask width, the more easily poly is deposited on the protective film, and there is a problem that the desired device structure cannot be obtained.

[0005]

Therefore, as a result of intensive studies to solve the above problems, the present inventors have found that when forming a heterostructure of a compound semiconductor or selectively growing a crystal, a halide gas and / or Further, they have found that by adding a halogen gas, the growth layer surface can be flattened, and high-quality crystal growth can be performed without depositing a polycrystal on a mask over a wide range, and the present invention has been reached. That is, an object of the present invention is to provide a method for manufacturing a semiconductor having improved flatness of a hetero interface and excellent device characteristics, and such an object is to provide a Group II element organic metal and a Group VI element hydride. In the method of vapor-depositing a II-VI group compound semiconductor thin film using the method, when growing a II-VI group compound semiconductor thin film with a growth gas, polycrystals on a mask in a growth gas.
It is easily achieved by a method for producing a II-VI group compound semiconductor, which is characterized by adding a halide gas and / or a halogen gas in an amount that does not cause the deposition of helium.

The present invention will be described in more detail below. As the compound semiconductor raw material used in the production method of the present invention,
There is no particular limitation as long as it is a commonly used one, but one containing no halogen element is preferable. In general, VI
Hydrogen selenide (H ₂ Se), hydrogen sulfide (H ₂ S) and the like are used as the group element hydride, and dimethyl zinc (DMZ), biscyclopentenyl magnesium (Cp ₂ Mg) as the group II element organic metal. ), Dimethyl selenium (D
MSe) or the like is used.

The halide gas and / or halogen gas is not particularly limited, but specifically, the halide gas is HBr, HI, HF, HCl, CCl ₂ F ₂
Examples of the halogen gas include Cl ₂ , I ₂ , and F.
₂ , Br _{2 and the} like and a mixture thereof are mentioned, and preferably Cl _{2 in the} low temperature region or HCl in the high temperature region. The amount of the halide gas and / or the halogen gas used largely varies depending on the size of the growth chamber, the growth temperature, etc., but is usually smaller than the amounts of the hydride containing no halogen element and the organic metal containing no halogen element. The quantitative relationship between the two is that the growth is stopped but the deposition mode area where polycrystal (poly) is deposited on the mask is avoided, but poly is deposited on the mask. Perform so that it enters the selective mode area where no accumulation occurs. This state is shown in FIG. 1 using the flow rates of DMZ and HCl. As described above, since the specific numerical value varies depending on the size of the growth chamber, the growth temperature, and the raw material used, those skilled in the art can appropriately determine the apparatus used by the person skilled in the art. Further, since the etching rate decreases as the temperature decreases, it is preferable to increase the amount of halide gas and / or halogen gas used when the temperature is low.

Further, the total pressure of the flowing gas is preferably atmospheric pressure or less. Regarding the growth temperature, the conditions generally used for vapor phase growth of II-VI group compounds can be applied. The manufacturing method of the present invention is effective for growing a general II-VI group compound semiconductor thin film, but is particularly suitable for growing a II-VI group compound semiconductor thin film containing zinc. As a raw material containing zinc, various known materials can be used depending on the growth method, but dialkylzinc is preferable in the MOCVD method. Also in this case, the halide gas and / or the halogen gas is HCl or C.
l ₂ is preferred.

[0009]

[Example 1] [Example 1] Cr-doped GaAs {100}
As shown in FIG. 2, ZnSSe was used as a barrier layer on the substrate, and well widths 10Å, 20Å, 30Å, 60Å, 80Å,
A heterostructure having 100 Å 6 ZnSe quantum wells was prepared by MOVPE method. At this time, dimethylzinc (DMZ), hydrogen selenide (H ₂ Se) and hydrogen sulfide (H ₂ S) were used as source gases. The total flow rate is 7.7.
The SLM, the growth temperature was 550 ° C., the pressure was 35 Torr, and the growth rate was about 1 μm / h. Under the above growth conditions, Zn
HCl during the growth of the Se quantum well layer and the ZnSSe barrier layer.
Samples (A) to which 0.25 sccm was added and samples (B) to which HCl was not added (conventional growth method) were prepared. The decrease in growth rate due to the addition of 0.25 sccm of HCl under the above growth conditions was only 5%.
Photoluminescence (PL) measurement was performed on these samples at 4.2 K, and light emission from the quantum well was observed.
The PL intensities of the samples (A) and (B) were almost the same, but the PL half-width of the sample (A) was greatly reduced. The PL half-width has a close relationship with the flatness of the hetero-interface at both ends of the quantum well, and the flatter the hetero-interface is, the smaller the half-width is. From this, it is considered that the addition of HCl promoted the migration of the compound containing Zn and formed a flat hetero interface.

Example 2 100 μm as shown in FIG.
SiN with different width (5 to 200 μm) _XOf membrane
MO on a GaAs substrate with a stripe pattern
A ZnSe layer having a thickness of about 1 μm was grown by the VPE method. This
At this time, dimethyl zinc (DMZ) and
Hydrogen selenide (H₂Se), DMZ, H₂Se's
The number of moles supplied is 2 x 10 each^-Fivemol / min, 4x
10^-FiveIt was set to mol / min. The total flow rate is 7.7S.
LM, growth temperature is 650 ° C, pressure is 76 Torr, growth
The speed was about 2 μm / h. HCl for 0.5 s during growth
Sample (A) added with ccm and HCl were not added
Sample (B) (conventional growth method)
Partial optical micrographs of the wafer surface are shown in FIGS. 4 and 5, respectively.
Shown in. In the figure, the part that looks white is ZnS on GaAs.
The part where e has grown and the part that looks black is SiN
_XMembrane, and SiN_XThe white dots on the film indicate the ZnSe
It is Li. In the sample (B) shown in FIG. 5, the ZnSe layer
When grown, wide SiN_XMembrane (width 100μ
m) SiN even on the stripe_XMany on the whole surface of the membrane
Poly has accumulated. In the normal MOVPE method, Z
migration of compounds containing n is quite slow and
Due to high reactivity with the protective film, decompression of several tens Torr
Even if it grows, selective growth of ZnSe becomes quite difficult.
It is reported that the conventional growth method is similar in this case as well.
I got a result. On the other hand, the sample shown in FIG.
In (A), when the ZnSe layer is grown, the width is 200 μm.
m of SiN_XPoly deposition on the film stripe
I couldn't do it. From this, Zn was added by adding HCl.
Selective growth promoted migration of contained compounds
It is thought that the above was successfully performed.

[0011]

As described above in detail, according to the present invention, a hetero interface is flattened or masked over a wide range by adding a halide gas such as HCl and / or a halogen gas during the growth of a compound semiconductor. High quality crystal growth is possible without depositing polycrystals on the surface. In the present invention, the growth rate is slightly reduced by the addition of a slight amount of HCl, but the reproducibility and controllability of the conventional thin film growth remain sufficiently, which is a practically effective method. Although MOVPE has been described in the embodiment, it is not particularly limited to MOVPE, and other vapor phase growth methods such as MBE method are also effective.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a selective mode of the present invention.

FIG. 2 is an explanatory diagram of a hetero structure used in Example 1.

FIG. 3 is an explanatory diagram of a stripe pattern used in Example 2.

FIG. 4 is an electron micrograph of a metal crystal showing a surface state of the sample (A) of Example 2.

FIG. 5 is an electron micrograph of a metal crystal showing a surface state of the sample (B) of Example 2.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Goto               1000, Higashi-Huiana-cho, Ushiku-shi, Ibaraki Mitsubishi               Sei Co., Ltd. Tsukuba factory                (56) References Japanese Patent Laid-Open No. 63-17293 (JP, A)                 JP-A-3-197382 (JP, A)                 JP-A-4-37691 (JP, A)                 JP-A-2-152191 (JP, A)

Claims (5)

(57) [Claims] 1. A method of vapor-depositing a II-VI group compound semiconductor thin film using a Group II element organic metal and a VI group element hydride, wherein the II-VI group compound semiconductor thin film is grown with a growth gas, Polycrystalline deposition on mask in growth gas
A method for producing a II-VI group compound semiconductor, which comprises adding an amount of a halide gas and / or a halogen gas which is not allowed . 2. The method for producing a semiconductor according to claim 1, wherein a hydride containing no halogen element and an organic metal containing no halogen element are used as growth raw materials. 3. The growth method is area selective growth.
Or the method of manufacturing a semiconductor according to 2. 4. The method for producing a semiconductor according to claim 1, wherein the flow rates of the halide gas and / or the halogen gas are maintained in the selective mode. 5. A Zn containing raw material is used to contain Zn containing II.
The method for producing a semiconductor according to claim 1, wherein a group VI compound is grown.