JP2690836B2 - Manganese zinc selenide Zinc-based optical 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 II-VI group compound semiconductor useful as an optical semiconductor device in the visible short wavelength region.

[0002]

2. Description of the Related Art Optical semiconductor devices are used for optical communication, optical disks,
It is useful in a wide range of fields such as image processing, and many materials have been proposed.

For example, initially, an optical semiconductor device was developed which was mainly applied to the GaAs system in the infrared region, and thereafter, materials for shortening the wavelength such as AlGaAs system and AlGaInP system were proposed. This is because if the wavelength is shortened, the semiconductor laser can be visualized and full-colored, and at the same time, the recording density of an information processing device such as an optical disk can be improved. For this reason,
For the optical semiconductor device material based on the II-VI wide-gap compound semiconductor (mixed crystal), for example, applied physics 60 volumes (19
(1991) ZnS, ZnS as shown on page 536.
Mainly proposed are e, ZnTe, CdS, CdSe, and mixed crystals combining these.

[0004]

However, when it is applied to an optical semiconductor element such as a laser diode, a material having good crystallinity is required. Therefore, a lattice matching system is used. There was a problem in that it was not possible to obtain a product in the blue to ultraviolet range.

In view of the above points, an object of the present invention is to provide a material which is lattice-matched with a substrate and has excellent crystallinity and which can be applied to an optical semiconductor element in the blue to short wavelength region.

[0006]

In order to achieve the above object, the manganese zinc sulfide selenide-based optical semiconductor of the present invention comprises:
A manganese sulfide zinc selenide-based epitaxial mixed crystal film containing at least zinc, manganese, sulfur, and selenium is formed on a substrate, and the epitaxial mixed crystal film is lattice-matched with the substrate. It is a thing.

In the above structure, the substrate is preferably GaAs or ZnSe.

[0008]

According to the above-mentioned constitution of the present invention, the manganese zinc sulfide selenide-based epitaxial mixed crystal film containing at least zinc, manganese, sulfur and selenium is formed on the substrate, and this film is formed on the substrate. Since they are lattice-matched,
An optical semiconductor that has excellent crystallinity and can be applied to an optical semiconductor element in the blue to short wavelength region due to the size of the band gap can be obtained. That is, when epitaxially grown in a state of being substantially lattice-matched with the substrate, the structure of the substrate is largely affected to form the same structure as the substrate, and a single crystal film with very few crystal structure defects can be obtained.

Further, according to the preferable structure of the present invention in which the substrate is GaAs or ZnSe, the substrate having a lattice constant in the range of the lattice constant that can be taken by the manganese zinc sulfide selenide mixed crystal system is excellent in crystallinity. It can be

[0010]

The present invention will be described more specifically with reference to the following examples. In the present invention, preferably, zinc, manganese, sulfur, and selenium are supplied onto a substrate to form an epitaxial film, and Zn _1-X Mn _X S _Y Se that is lattice-matched to the substrate is used.
_{A 1-Y} (0 <X <1, 0 <Y <1) mixed crystal is obtained. It is generally known that the crystal structure of a mixed crystal is a mixture of binary compounds constituting the mixed crystal. This Zn _1-X M
In the case of n _X S _Y Se _1-Y (0 <X <1, 0 <Y <1) mixed crystal, a sphalerite structure, a wurtzite structure, and a rock salt structure are mixed. However, when epitaxially grown in a state of being substantially lattice-matched to the substrate, there is an effect that a single crystal film having the same structure as that of the substrate is greatly affected by the structure of the substrate crystal and a crystal structure defect is extremely small.

A detailed description will be given below with reference to the drawings. FIG.
Is a molecular beam epitaxial growth apparatus used in one embodiment of the present invention. In the figure, 14a, 15a, 16
Reference numerals a and 17a are metallic zinc 14a, metallic manganese 15a, crystalline sulfur 16a, and metallic selenium 17a, respectively, which are contained in the crucible as a raw material, and are heated and evaporated to produce the zinc molecular beam
c, manganese molecular beam 15c, sulfur molecular beam 16c, and selenium molecular beam 17c are obtained.

As the growth procedure, first, the GaAs substrate 13a whose surface is cleaned is mounted in the vacuum chamber 11 and the
Evacuate to an ultra-high vacuum of about ^-9 Torr. Then substrate 13a
Is heated to about 600 ° C. to remove the surface oxide film. After that, the substrate 13a is cooled to the crystal growth temperature, and the molecular beam shutters 14b, 15b, 16b and 17b are opened to start the growth. Here, the substrate temperature is, eg, 300 ° C., and the temperature of each molecular beam source is adjusted in advance so as to obtain a composition that lattice-matches the substrate. In this case, for example, the temperatures of zinc, manganese, sulfur, and selenium are each set to 4
The temperature is set to 00 ° C, 1100 ° C, 150 ° C, and 350 ° C.

Zn _1-X Mn formed by the above method
_{The X} S _Y Se _1-Y mixed crystal had a composition ratio of X = 0.2 and Y = 0.2. As a result of X-ray diffraction, the lattice constant was 5.653 angstrom, which was almost the same as that of the GaAs substrate, and no diffraction peak other than the peak of the cubic crystal was found in the diffraction spectrum. Furthermore, when the results of transmission electron microscope observation were combined, this mixed crystal had a perfect sphalerite structure. When the substrate of this sample was peeled off and the transmission spectrum was measured, the forbidden band width at room temperature was 2.9 eV.

On the other hand, for a film having a lattice constant different from that of the substrate by 0.1% or more, a hexagonal diffraction peak is observed in the X-ray diffraction spectrum when the film having a thickness of 1 μm or more is formed. , Was not a perfect single crystal. This can be said that the lattice matching has a great influence on the crystallinity. In the photoluminescence spectrum of the lattice-matched film, light emission from a deep level was extremely small as compared with the film not lattice-matched.

FIG. 2 shows the relationship between the lattice constant of this mixed crystal system and the forbidden band width. When a GaAs substrate is used, the mixed crystal composition that lattice-matches the substrate is as shown by the dotted line, and the forbidden band width can be 2.7 to 3.6 eV at room temperature.

Here, GaAs was used as the substrate, but in addition to this, a substrate having a lattice constant in the range of the lattice constant that this mixed crystal system can have and having excellent crystallinity is preferable.
The same effect was obtained using a ZnSe single crystal substrate.

Although metallic zinc was used as the raw material of the molecular beam of zinc in the above-mentioned examples, the same effect was observed by using an organometallic gas containing a constituent element such as dimethyl zinc or diethyl zinc. . Although using a metal manganese as a raw material of a manganese molecular beam, the addition dicyclopentadienyl manganese _{[Mn (C 5 H 5)} 2], tricarbonyl methylcyclopentadienyl manganese [C ₆ H ₈
The same effect was observed when an organometallic gas containing a constituent element such as Mn (CO) ₃ ] was used. Although crystalline sulfur was used as a raw material for the molecular beam of sulfur, the similar effect was also obtained by using organic sulfur gas or hydrogen sulfide gas containing constituent elements such as dimethyl sulfur, diethyl sulfur, and dimethyldisulfur. Similarly, although metal selenium was used as the raw material of the selenium molecular beam, the same effect was also obtained by using organic selenium gas or hydrogen selenide gas containing constituent elements such as dimethyl selenium and diethyl selenium.

Although the molecular beam epitaxial growth method was used as the crystal growth method in the above-mentioned embodiment, the same effect was observed with the metal organic chemical vapor deposition method.

[0019]

As described above, according to the present invention,
Since a manganese zinc sulfide selenide-based epitaxial mixed crystal film containing at least zinc, manganese, sulfur and selenium is formed on the substrate, and this film is lattice-matched with the substrate, the lattice-matched with the substrate. And has excellent crystallinity, and can be applied to optical semiconductor elements in the blue to ultraviolet range.

[Brief description of the drawings]

FIG. 1 is a Zn _1-X Mn _X S _Y in one embodiment of the present invention.
It is a schematic diagram showing a molecular beam epitaxial growth device which produces a Se1 _-Y (0 <X <1,0 <Y <1) mixed crystal.

FIG. 2 Zn _1-X Mn _X S _Y Se _1-Y (0 <X <1,0
<Y <1) It is a figure showing the relationship between the lattice constant of a mixed crystal and a forbidden band width. The region indicated by the dotted line is the range in which lattice matching with the GaAs substrate is performed.

[Explanation of symbols]

 11 Vacuum Container 12 Ultra High Vacuum Evacuation Device 13a GaAs Substrate 13b Substrate Holder 14a Metal Zinc in Crucible 14b Shutter 14c Zinc Molecular Beam 15a Metal Manganese in Crucible 15b Shutter 15c Manganese Molecular Beam 16a Crystalline Sulfur in Crucible 16b Shutter 16c Sulfur molecular beam 17a Metal selenium in crucible 17b Shutter 17c Selenium molecular beam

 ─────────────────────────────────────────────────── ─── Continued Front Page (56) References JPN. J. APPL. PHYS. , VOL. 30, NO. 9B, (1991), PP. L1620-L1623 JPN. J. APPL. PHYS. , VOL. 32, PART 2, NO. 11 B, (1993), PP. L1657-L1659

Claims (2)

(57) [Claims] 1. An epitaxial mixed crystal film of manganese zinc sulfide selenide containing at least zinc, manganese, sulfur and selenium is formed on a substrate, and the epitaxial mixed crystal film is lattice-matched with the substrate. Zinc sulfide selenide zinc-based optical semiconductor. 2. The manganese zinc sulfide selenide-based optical semiconductor according to claim 1, wherein the substrate is GaAs or ZnSe.