JPH0437908Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a molecular beam epitaxial growth apparatus (MBE) used for creating thin films of compound semiconductors, etc.
It is related to.

(Prior Art) In a molecular beam epitaxial growth apparatus, a molecular beam source is opposed to a substrate in an ultra-high vacuum in a chamber, and a film-forming material is evaporated from the molecular beam source to grow crystals on the substrate.

Conventionally, a film-forming material was continuously evaporated and deposited from a molecular beam source until a thin film of a required thickness was grown on a substrate.

(Problems to be Solved by the Invention) In order to grow a crystal on a substrate, atoms that reach the substrate must move on the surface of the substrate or crystal and be arranged in an orderly direction to eliminate unevenness. If the atoms are not sufficiently moved on the surface of the substrate or crystal and atoms fly one after another and are stacked, the irregularities become fixed and the grown crystal becomes incomplete. Put it away.

The object of the present invention is to grow more perfect crystals by promoting the surface movement of atoms that have reached a substrate in a molecular beam epitaxial growth apparatus.

(Means for solving the problem) In the molecular beam epitaxial growth apparatus of the present invention,
A shutter is provided between a substrate on which a thin film is to be grown and a molecular beam source, a light excitation irradiation means for irradiating the substrate is provided, a shutter is also provided between the irradiation means and the substrate, and the shutter for the molecular beam source and A thin film is grown on the substrate while alternately opening and closing the shutter for the irradiation means.

(Function) As shown in FIG. 3, the film-forming material is continuously evaporated or released from the molecular beam source. After the molecular beam source shutter is opened for a predetermined time to deposit a film on the substrate, the molecular beam source shutter is closed, and after a predetermined time, the molecular beam source shutter is opened again for a predetermined time.
While the molecular beam source shutter is closed, the shutter of the optical excitation irradiation means is opened to irradiate the substrate surface with light. This light irradiation promotes diffusion and movement of atoms on the substrate surface or crystal surface.

In this way, there is a step of opening the shutter for the molecular beam source and closing the shutter for the irradiation means to deposit the film-forming material, and a step of opening the shutter for the irradiation means and closing the shutter for the molecular beam source to promote surface movement of attached atoms. By repeating the process, a more perfect crystal thin film is grown.

(Example) FIG. 1 schematically represents an embodiment of the invention.

2 is a chamber, and the inside of the chamber is evacuated to an ultra-high vacuum by a vacuum evacuation system 4. Inside the chamber 2, a substrate 6 is attached to a substrate heating holder 8 and heated. Reference numerals 10 and 12 indicate evaporation sources as molecular beam sources, and the evaporation sources 10 and 12 are of a type that evaporates solid film-forming materials by heating them. Molecular beams 14 from evaporation sources 10, 12,
16 reaches the surface of the substrate 6 and forms a thin film 20.

Shutters 22 and 24 are provided within the chamber 2 between the evaporation sources 10 and 12 and the substrate 6, respectively. By continuously evaporating the film-forming material from the evaporation sources 10 and 12 and opening and closing the shutters 22 and 24, the molecular beams 14 and 16 are flown or blocked from the evaporation sources 10 and 12 to the substrate 6. or

A light source 28 as a light excitation irradiation means is provided outside the light transmission window 26 of the chamber 2.
The light is irradiated onto the surface of the substrate 6 through the light transmission window 26. As the light source 28, a mercury lamp, a laser, or the like is used. A shutter 30 is provided on the optical path from the light source 28 to the substrate 8 within the chamber 2 and is capable of blocking light irradiation from the light source 28 to the substrate 8 .

The shutter 22 includes a rotation introducing machine 32 attached to the chamber 2, as shown in FIG.
By attaching it to the rotating shaft 34 of the chamber 2, it is possible to open and close the chamber 2 from outside. The shutters 24 and 30 also have the same structure.

In this embodiment, the substrate 6 is heated by the substrate heating holder 8 with the shutters 22 and 24 closed, and the evaporation sources 10 and 12 are energized to perform evaporation. For example, it is assumed that the evaporation source 10 evaporates group elements, and the evaporation source 12 evaporates group elements.

Evaporation from the evaporation sources 10 and 12 is stabilized, and the substrate 8
When the temperature of the substrate 8 becomes constant, the shutters 22, 24 and the shutter 30 are alternately opened and closed as shown in FIG. are repeated alternately.

The opening and closing operations of the shutters 22, 24, and 30 are automatically performed by driving the rotation introduction device 32 by a motor via a controller.

During the period when the shutters 22 and 24 are opened to deposit the film-forming material on the substrate 8, the shutter 30 is closed to block light irradiation because the film-forming material is optically excited in the space inside the chamber 2. This is to avoid causing a reaction.

In the above embodiment, the evaporation sources 10 and 12 using solid raw materials are used as the molecular beam source, but the present invention can be applied in exactly the same way even when using a molecular beam source using a gas source. .

(Effect of the invention) In the molecular beam epitaxial growth apparatus of the invention,
A shutter is provided between the substrate on which a thin film is grown and the molecular beam source, an irradiation means for optical excitation is provided to irradiate the substrate, a shutter is also provided between the irradiation means and the substrate, and the shutter for the molecular beam source and the irradiation are provided. Since the means shutters are opened and closed alternately, the movement of atoms attached to the substrate, that is, the diffusion movement on the surface of the substrate or crystal is promoted, and the unevenness of the atomic layer is eliminated and the crystal grows while gradually forming a flat surface. will be carried out. Therefore, the epitaxial growth layer formed has perfect crystallinity.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a schematic sectional view showing the shutter mechanism, and FIG. 3 is a waveform chart showing the operation of the same embodiment. 2... Chamber, 6... Substrate, 8... Substrate heating holder, 10, 12... Evaporation source, 20... Thin film, 22, 24... Shutter for evaporation source, 28...
Light source for optical excitation, 30...Shutter for light source.

Claims (1)

[Scope of utility model registration request] A shutter is provided between a substrate on which a thin film is to be grown and a molecular beam source, a light excitation irradiation means for irradiating the substrate is provided, a shutter is also provided between the irradiation means and the substrate, and the shutter for the molecular beam source and A molecular beam epitaxial growth apparatus that alternately opens and closes the shutter for the irradiation means.