JPH04214639A - Method and apparatus for manufacture of chalcogen compound - Google Patents

Abstract

PURPOSE:To manufacture a chalcogen compound on a substrate at a low temperature by using a group II organometallic gas and a group VI organometallic gas by an organometallic vapor growth method. CONSTITUTION:Pipes 2, 3 which introduce a group II organometallic gas and a group VI organometallic gas individually into a reaction furnace 1 are installed. A substrate 5 on which a chalcogen compound is deposited by an organometallic vapor growth method by a reaction on the substrate is installed on the downstream side of the air current of the organometallic gases which are introduced from the pipes 2, 3. A thermofilament 6 which heats and decomposes the organometallic gases is installed between the substrate 5 and the pipes 2, 3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to metal organic vapor phase epitaxy (M
chalcogen compounds, such as zinc sulfide (Z
The present invention relates to a method and apparatus for manufacturing nS).

0002

BACKGROUND OF THE INVENTION Chalcogen compounds have a wide band gap and are promising as optoelectronic materials such as light emitting devices and photoconductive devices.

[0003] Vapor deposition, sputtering, and molecular beam epitaxy have been used to produce chalcogen compounds, but in recent years, MOCVD has attracted attention because it can produce uniform thin films over a large area at low cost. Physics Vol. 55 No. 11 (1986) No. 1027 (5) - 1028
The production of ZnS is reported on page (6).

0004

[Problems to be Solved by the Invention] However, in the conventional MOCVD method, the substrate temperature is set to a high temperature (over 500°C).
It is stated in the above report that the material that can be used as a substrate is limited, and the crystallinity of the ZnS thin film is affected by the fact that the optimum temperature for deposition (nearly 300°C) is not reached. There was a problem with the decline.

[0005] The present invention makes it possible to produce a chalcogen compound at a lower substrate temperature than before when producing a chalcogen compound by depositing Group II and VI organometallic gases on a substrate by MOCVD using an on-substrate reaction. The present invention provides a method and apparatus for producing a chalcogen compound.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a method for depositing group II and group VI organometallic gases onto a substrate using an organometallic vapor phase epitaxy method based on an on-substrate reaction in a reactor. In producing a chalcogen compound by deposition, the organometallic gas is thermally decomposed in the reaction furnace immediately before being deposited on the substrate, and then deposited on the substrate, and in order to realize this, Into the reactor I
A tube is provided for introducing group I and group VI organometallic gases individually, and the organometallic gas is applied to the downstream side of the airflow of the organometallic gas introduced from the tube by an organometallic vapor phase growth method using an on-substrate reaction. The present invention is characterized in that a substrate for depositing a chalcogen compound is provided, and a hot filament for thermally decomposing the organometallic gas is provided between the substrate and the tube.

[0007]

[Operation] According to the present invention, by thermally decomposing the group II and group VI organometallic gases immediately before they are deposited on the substrate,
It is no longer necessary to rely solely on the substrate temperature, and chalcogen compounds can be produced at lower substrate temperatures than in the past.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows the structure of a film forming apparatus by the MOCVD method used to produce ZnS as an example of the present invention, in which 1 is a quartz tube reactor, 2 is a DMZ gas (I
3 is a stainless steel tube for introducing DMS gas (group VI organometallic gas) into the reactor 1; 4 is inside the reactor 1; A stainless steel holder is provided perpendicularly to the gas flow downstream of the gas flow introduced from the tubes 2 and 3, 5 is a substrate attached to the holder 4, and 6 is a stainless steel holder installed between the substrate 5 and the tubes 2 and 3. A red-hot tungsten filament is provided 10 mm apart from the substrate 5 and is housed in the chamber 7 . Note that 8 is a power source for driving the filament 6.

[0009] Specific conditions for producing ZnS were determined as follows. That is, the DMZ gas flow rate in tube 2 was 16.4 μmol.
/min, DMS gas flow rate of tube 3: 33.4 μmol/min, substrate 5: (100) gallium arsenide (GaAs), temperature of filament 6 (Tf): 880°C, filament 6
The temperature of the substrate 5 due to radiant heat was 340° C., the degree of vacuum in the chamber 7 was 0.1 Torr, and the film forming time was 2 hours.

[0010] In order to evaluate the crystal structure and morphology of ZnS produced in this manner, X-ray diffraction and RHEED were performed. For comparison, the temperature of filament 6 is 82
Zn when manufactured at 0°C (substrate 5 temperature 310°C) and 930°C (370°C) under the same conditions.
At the same time, we also investigated S.

FIG. 2 is a diagram showing changes in the X-ray diffraction spectrum. Regardless of the temperature of the filament 6, the main peaks are identified as GaAs and cubic ZnS. In addition, since the reflection of ZnS is only the h00 reflection, ZnS has a (100)
It was found that plane-preferential orientation growth occurs. It should be noted that these peaks increase as the temperature of the filament 6 increases, but this seems to be mainly due to the effect of the film thickness.

FIG. 3 is a photograph showing changes in the RHEED pattern corresponding to changes in the temperature of the filament 6. It can be seen that when the temperature of the filament 6 is 880° C. or lower, it is spot-like, and although the ZnS surface is rough, it has high crystallinity. On the other hand, the temperature of filament 6 is 9
At 30° C., ring-shaped diffraction reflections and cubic crystal spot-shaped reflections identified as wurtzite ZnS were confirmed.

From the above, it was found that according to the above embodiment, cubic ZnS could be obtained even when the temperature of the substrate 5 was 400° C. or lower. However, the temperature of filament 6 9
At 30°C (temperature of substrate 5: 370°C), the peak of the spectrum is high, but the crystallinity is slightly poor; conversely, at the temperature of filament 6, 820°C (temperature of substrate 5: 310°C), although the peak of the spectrum is good, the peak of the spectrum is low. It will be slightly lower. The former is thought to be caused by the high temperature of the substrate 5, which is a problem in the conventional MOCVD method, and the latter is caused by the fact that a sufficient film thickness cannot be obtained due to the low temperature of the substrate 5. Therefore, when manufacturing ZnS, the temperature of the filament 6 is 880°C (the temperature of the substrate 5 is 340°C).
It was found that the vicinity is suitable from the viewpoint of crystal structure and morphology.

In the above embodiment, the hot filament 6
Although a device for heating the substrate 5 using radiant heat has been shown, other heating means may be provided on the opposite side of the substrate 5 from the hot filament 6 to heat the substrate 5 together with the hot filament 6.

In addition to ZnS, DMZ gas and dimethyl selenium (DMSe) gas can be used to produce zinc selenide, dimethyl cadmium (DMCd) gas and DMSe gas can be used to produce cadmium selenide, etc. It can also be applied to the production of other chalcogen compounds using Group and VI organometallic gases.

[0016]

[Effects of the Invention] As described above, according to the present invention, MOC
By the VD method, chalcogen compounds using Group II and Group VI organometallic gases can be produced at lower temperatures and more favorably than conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the structure of a reactor of a film forming apparatus used to carry out the present invention.

FIG. 2 is a characteristic diagram showing the X-ray diffraction spectrum of ZnS produced according to the present invention.

FIG. 3 is a photograph showing the RHEED pattern of ZnS as above.

[Explanation of symbols]

1 Reactor 2 Pipe (for DMZ gas) 3 Tube (for DMS gas) 5　Substrate 6 Heat filament

Claims (2)

[Claims] 1. In producing a chalcogen compound by depositing group II and group VI organometallic gases on the substrate by an organometallic vapor phase epitaxy method based on an on-substrate reaction in the reactor, A method for producing a chalcogen compound, characterized in that the organometallic gas is thermally decomposed immediately before being deposited on the substrate, and then deposited on the substrate. 2. A tube for individually introducing group II and group VI organometallic gases into the reactor is provided, and the organometallic gas is placed on the substrate on the downstream side of the flow of the organometallic gas introduced from the tube. An apparatus for producing a chalcogen compound, characterized in that a substrate is provided on which a chalcogen compound is deposited by an organometallic vapor phase growth method using a reaction, and a hot filament is provided between the substrate and the tube to thermally decompose the organometallic gas. .