JPH0714787A - Production of ii-vi compound semiconductor - Google Patents

Abstract

PURPOSE:To provide a method for producing a semiconductor excellent in element characteristics and the flatness of heterointerface is improved by repeating the step for introducing an organic metal of group II element and halide gas and/or halogen gas alternately into a growth chamber thereby forming a thin film. CONSTITUTION:In the CVD method for forming a thin film of II-VI compound semiconductor using an organic metal of group II element and a hydrogenated group 1 element as material, a step for introducing an organic metal of group II element and halide gas and/or halogen gas alternately into a growth chamber is repeated to grow a thin film. Duration of group II element supply is preferably set at 1min or less and more preferably set at 30sec or less. This method flattens the heterointerface, improves the flatness of surface morphology or facet surface, and allows high quality crystal growth because polycrystal is not deposited over a wide range on a mask.

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 by growing a II-VI group compound semiconductor thin film, and more particularly to flattening the growth layer and suppressing deposition on the 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 that is normally 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.

In order to manufacture 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 (M
OVPE) method is used. In fact, a steep hetero interface is formed at the atomic layer level by using these growth methods. When these structures are applied to a device, the flatness of the hetero interface has a great influence on the device characteristics. II-VI
At the 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 the selective growth is very difficult in the ordinary MBE method, the conventional MOVPE method or MONBE method has been used.
Selective growth is being done by law. 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.

[0004]

However, in order to prevent poly from being deposited on the protective film during 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 easier it is to deposit on the protective film,
There has been a problem that the desired device structure cannot be obtained.

[0005]

The inventors of the present invention have, as a result of diligent studies to solve the above problems, form a heterostructure of a compound semiconductor or a matrix of a compound to be grown when selectively growing crystals. It has been found that by adding a halide gas and / or a halogen gas containing no element, the growth layer surface is flattened, and high-quality crystal growth is possible without depositing polycrystals on a mask over a wide range. The invention was reached. That is, the object of the present invention is to
An object of the present invention is to provide a method for manufacturing a semiconductor having improved hetero interface flatness and excellent device characteristics, and an object thereof is to use an organic metal of Group II element and a hydride of Group VI element as a raw material II- A method for producing a Group VI compound semiconductor thin film by vapor phase growth, characterized in that the thin film is grown by repeatedly introducing an organometallic group II element and a halide gas and / or a halogen gas into the growth chamber alternately. -VI
This is easily achieved by the method for producing a group compound semiconductor.

The present invention will be described in more detail below. As the hydride of the Group VI element used in the production method of the present invention, those containing no halogen element are preferable, and hydrogen selenide (H ₂ Se), hydrogen sulfide (H ₂ S) and the like are used. As the organic metal of the Group II element, those containing no halogen element are preferable, and dimethyl zinc (DMZ), biscyclopentenyl magnesium (Cp ₂ Mg), dimethyl selenium (DMSe) and the like are used. The halide gas and / or the halogen gas is not particularly limited,
Specifically, as the halide gas, HBr, HI, H
F, HCl, CCl ₂ F _{2 and the} like can be mentioned, and as the halogen gas, Cl ₂ , I ₂ , F ₂ , Br _{2 and the} like and a mixture thereof can be mentioned. Cl ₂ at low temperature and HCl at high temperature
Is preferably used.

The amount of the halide gas and / or the halogen gas used is preferably an amount smaller than that for etching the surface of a semiconductor thin film, but is not particularly limited. These conditions are set in consideration of the size of the growth chamber, the growth temperature, and the like. Further, the total pressure of the flowing gas is preferably normal pressure or lower. The growth temperature may be any temperature condition generally used for vapor phase growth of II-VI compounds.

In the present invention, the group II raw material and the halide gas and / or the halogen gas are alternately introduced into the growth chamber, but the supply duration of the group II raw material once is preferably 1 minute or less, more preferably. It is 30 seconds or less. If the duration exceeds 1 minute, it becomes difficult to obtain the effects of the present invention such as flattening the growth surface. Then, the supply of the Group II raw material is stopped, and this time, the halide gas and / or the halogen gas is supplied. The supply time of the halide gas and / or halogen gas is also preferably 1 minute or less, particularly preferably 30 seconds or less. The time when neither the group II raw material nor the halide gas and / or the halogen gas is flowing when switching the supply of the both is not particularly limited, but it is necessary to prevent the group II raw material and the halide gas and / or the halogen gas from mixing on the growth surface. It is preferable. Practically, the gas switching time becomes worse when the time is long, so 10 seconds or less is preferable.
1 to 10 seconds is preferable.

The production method of the present invention is effective for the growth of ordinary II-VI group compound semiconductor thin films, but especially II-VI containing zinc is used.
Suitable for growing Group VI compound semiconductor thin films. 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, HCl or Cl ₂ is preferable as the halide gas and / or the halogen gas.

When doping a II-VI group compound semiconductor thin film, halogen is usually used as an n-type dopant which enters a VI group site. Therefore, the method of introducing the group II raw material and the halide gas and / or the halogen gas alternately into the growth chamber of the present invention is to prevent the mixing of the halogen entering the group VI site with the group II raw material, the halide gas and / or the halogen gas. Alternatively, the effect of the present invention is more significant than in the case where halogen gas is simultaneously supplied.

[0011]

[Function] In the growth of II-VI group compound semiconductor thin film, II
By introducing the group source gas and the halide gas and / or the halogen gas alternately into the growth chamber at least once, the hetero interface is flattened by growing under the growth conditions which are almost the same as those of the conventional MOVPE method. The surface morphology and facet surface are improved to be flat, and high-quality crystal growth is possible over a wide area without depositing polycrystals on the mask.

[0012]

[Examples] Examples of the present invention will be described below.
The present invention is not limited to the examples as long as the gist thereof is not exceeded. As shown in FIG. 1, a ZnSe layer having a thickness of about 1 μm was grown by the MOVPE method on a GaAs substrate on which a stripe pattern of a SiN _x film having a width changed every 100 μm (5 μm to 200 μm) was formed. At this time, dimethylzinc (DMZ) and hydrogen selenide (H ₂ Se) were used as source gases, and the supply mole numbers of DMZ and H ₂ Se were 2 × 10 ⁻⁵ mol / min and 4 × 10 ⁻⁵ mol, respectively.
/ Min. The total flow rate is 7.7 SLM, the growth temperature is 650 ° C., the pressure is 76 Torr, and the growth rate is about 2 μm.
m / h. FIGS. 2 and 3 show optical microscope photographs of the wafer surface after growth for the sample (A) to which HCl was added at 0.5 sccm during growth and the sample (B) to which HCl was not added (conventional growth method). H under the above growth conditions
The decrease in growth rate due to the addition of 1 sccm of Cl was 5%. In the sample (B) in FIG. 3, when growing the ZnSe layer, thick poly (polycrystalline) on one side on the SiN _X film even in a narrow SiN _X film (width 3 [mu] m) on the stripe width is had deposited. In the figure, the black part is S
It is an iN _X film, and many white spots (poly) are visible on its surface. The part that looks like a white band is ZnSe, but its width is 100 μm. In the portion where the width of the SiN _x film is narrower, poly is generated on one surface, and it is difficult to distinguish between the ZnSe portion and the photograph. In the ordinary MOVPE method, the migration of the compound containing Zn is considerably slow and the reactivity with the protective film is high. Therefore, ZnS is grown even under reduced pressure of several tens Torr.
It has been reported that the selective growth of e becomes considerably difficult, and in this case, the same result was obtained by the conventional growth method. On the other hand, in the sample (A) of FIG. 2, when the ZnSe layer was grown, poly deposition was not observed even on the SiN _x film stripe having a width of 200 μm. From this, it is considered that the addition of HCl promoted the migration of the compound containing Zn, and the selective growth was successfully performed.

[0013]

As described above in detail, according to the present invention, a hetero interface is flattened or masked over a wide range by adding a minute amount of 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 top. 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. Also, in the embodiment, MOVP
Although E has been described, 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 stripe pattern used in an example of the present invention.

FIG. 2 is an electron micrograph of a crystal structure obtained as a result of an example of the present invention.

FIG. 3 is an electron micrograph of a crystal structure obtained as a result of a conventional method.

Claims (5)

[Claims] 1. A method for vapor phase growth of a Group II element organometal and a II-VI group compound semiconductor thin film using a Group VI element hydride as a raw material, wherein the Group II element organometal, a halide gas and / or Characterized by repeatedly introducing alternating halogen gas into the growth chamber to grow a thin film
II-VI Group Compound Semiconductor Manufacturing Method. 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.
A method for manufacturing the semiconductor described. 4. The method for producing a semiconductor according to claim 1, wherein the supply time of the growth material once is 1 minute or less. 5. A Zn containing raw material is used to contain Zn containing II.
The method for manufacturing a semiconductor according to claim 1, wherein the group VI compound is grown.