JPH0431392A - Device for growing molecular beam crystal - Google Patents

Abstract

PURPOSE:To simultaneously grow a large amount of crystal having uniform thickness of film, etc., by constituting a substrate attached face of a manipulator consisting of an inside substrate attached face vertical to a revolving shaft and an inclined outside substrate attached face and making isointensity line of molecular beam move approximately along the outside substrate attached face. CONSTITUTION:A manipulator 11 consists of an inside substrate attached face 14 formed in a face approximately vertical to a central line 11a, a revolving shaft and an inclined outside substrate attached face 15 made in the periphery of the inside substrate attached face and substrate heaters 13a and 13b are fixed at the back of the faces. A line 12a in the molecular beam direction, passing through the center of a molecular beam source 12, crosses the inside substrate attached face by angle alphaat the middle point (crossing point) 14a of the center and an end of the inside substrate attached face 14 and an inclination angle of the outside substrate attached face 15 against the line 12a of the molecular beam direction is made approximately at a right angle. Consequently, the outside substrate attached face 15 is inclined approximately along the isointensity line 12b of molecular beam and a large amount of crystal having uniform film thickness similar to the inside substrate attached face 14 is simultaneously grown.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a method for attaching a plurality of substrates to the substrate mounting surface of a manipulator, and irradiating the substrates with molecular beams from a molecular beam source to grow crystals. This invention relates to a line crystal growth apparatus.

[Prior Art] FIG. 3 is a schematic cross-sectional view showing a conventional molecular beam crystal growth apparatus. Referring to FIG. 3, a substrate heater 3 is provided inside the manipulator 1, and a plurality of substrates are mounted on the substrate mounting surface 4 of the manipulator 1. The molecular beam source is provided so as to irradiate the molecular beam approximately at the center of the substrate mounting surface 4 .

FIG. 4 is a schematic cross-sectional view showing isointensity lines of molecular beams in the conventional apparatus shown in FIG. 3. As shown in FIG. 2, the equal intensity lines 2b are non-uniform with respect to the board mounting surface 4, but since the manipulator 1 is rotating around its center line 1a, the intensity distribution in the radial direction is canceled out. It becomes uniform.

[Problem to be solved by the invention] However, when trying to grow crystals by arranging many substrates on the substrate mounting surface in order to achieve mass production using a conventional molecular beam crystal growth apparatus, it is difficult to arrange many substrates on the substrate mounting surface. In order to achieve this, it is necessary to increase the area of the substrate mounting surface 4 and also to increase the diameter of the molecular beam source 2. therefore,
The problem with conventional devices is that they are quite large.

Furthermore, as the substrate mounting surface and the diameter of the molecular beam source become larger,
Problems arise in that the substrate temperature becomes non-uniform or the intensity of the molecular beam from the molecular beam source becomes unstable, resulting in a problem in that the film thickness of the crystal becomes non-uniform.

The purpose of this invention is to avoid increasing the size as in the past.
It is an object of the present invention to provide a molecular beam crystal growth apparatus capable of growing a large number of crystals at once while making the film thickness uniform.

[Means for Solving the Problems] In the molecular beam crystal growth apparatus of the present invention, a plurality of substrates are mounted on the substrate mounting surface of a manipulator, and the relative positions of the substrates are rotationally moved by rotating the manipulator. This is a molecular beam crystal growth device that irradiates a substrate with molecular beams from a radiation source to grow crystals on the substrate. The outer substrate mounting surface has an inner substrate mounting surface formed from a surface and an outer substrate mounting surface formed around the inner substrate mounting surface and inclined toward the molecular beam source, and the outer substrate mounting surface receives the molecular beam from the molecular beam source. It is characterized by being sloped almost along the isointensity line.

In one of the preferred embodiments according to the present invention, a line in the direction of the molecular beam passing through the center of the molecular beam source is between the center of the inner substrate mounting surface and the inner substrate mounting surface on the opposite side to the side where the molecular beam source is provided. The outer board mounting surface is inclined at an angle of approximately 90-.alpha. to the inner board mounting surface at an angle .alpha.

[Function] In the molecular beam crystal growth apparatus according to the present invention, the outer substrate mounting surface formed around the inner substrate mounting surface is inclined toward the molecular beam source, and the isointensity line of the molecular beam from the molecular beam source is It is sloped almost along the

Therefore, the substrate mounted on the outer substrate mounting surface is irradiated with molecular beams of approximately equal intensity, and crystals with uniform thickness etc. grow.

The outer substrate mounting surface is formed to be inclined toward the molecular beam source with respect to the inner substrate mounting surface. Therefore, even if the board mounting surface has the same area as before, it is not within one plane.
It can be made smaller than before.

FIG. 1 is a schematic sectional view showing one embodiment of the present invention. Referring to FIG. 1, the manipulator 11 has an inner board mounting surface 14 formed from a surface substantially perpendicular to a center line 11a, which is a rotation axis, and an outer board mounting surface 15 formed around the inner board mounting surface. are doing. A substrate heater 13a for heating the substrate is provided on the back side of the inner substrate mounting surface 14, and a substrate heater 13b is similarly provided on the back side of the outer substrate mounting surface 15.

In the molecular beam source 12, a line 12a in the molecular beam direction passing through the center of the molecular beam source 12 intersects the inner substrate mounting surface 14 at an angle α at a midpoint 14a between the center and the end of the inner substrate mounting surface 14. It is set up to do so.

The angle of inclination of the outer substrate mounting surface 15 is approximately perpendicular to the line 12a of the molecular beam direction of the molecular beam source 12. Therefore, the outer board mounting surface 15 is inclined at an angle of approximately 90°-α with respect to the inner board mounting surface.

In this embodiment, by configuring the inner substrate mounting surface 14 and the outer substrate mounting surface 15 as described above, the outer substrate mounting surface 15 can be attached to the molecular beam, as shown in a schematic cross-sectional view in FIG. It almost follows the intensity line 12b.

This example shows a boat fishing example, and it is of course possible to make the outer substrate mounting surface almost follow the isointensity line of the molecular beam from the molecular beam source under conditions other than the above. It is.

As shown in FIG. 2, since the structure is such that the intensity of the molecular beam on the outer substrate mounting surface 15 is almost uniform, the film thickness etc. of the substrate mounted on the outer substrate mounting surface 15 is approximately the same. It is possible to grow crystals uniformly. Further, for the substrate mounted on the inner substrate mounting surface 14, the intensity of the molecular beam is made uniform by rotating the manipulator as in the conventional method, and crystal growth can be performed with uniform film thickness.

Crystals were grown on a substrate using an apparatus as shown in FIG. A molecular beam source with a crucible diameter of 22 mm was used. The angle θ at which the line 12a in the molecular beam direction intersects with the inner substrate mounting surface 14 was 49°. The distance between the intersection 14a with the inner substrate mounting surface 14 and the molecular beam source 12 was 150 mm. The inner substrate mounting surface 14 had a disk shape with a diameter of 120 mm, and three substrates each having a diameter of 2 inches were mounted thereon.

The outer board mounting surface 15 has a width of 5Qmm and a diameter of 2
Five inch boards were installed.

The substrate is heated by substrate heaters 13a and 13b,
The substrate temperature was 630°C. The manipulator 11 was rotated at a rotational speed of 8 revolutions/minute around the central axis 11a. The growth conditions were a growth rate of 1 μm/hr,
A GaAs crystal was grown to a thickness of 5 μm.

When we measured the radial thickness distribution of the grown crystals obtained, the uniformity was ±0.6%, and there was almost no difference between the substrate mounted on the inner substrate mounting surface and the substrate mounted on the outer substrate mounting surface. There was no.

An AlGaAs crystal was grown to a thickness of 2 μm on a GaAs substrate using the same apparatus as in the above example. When the radial film thickness distribution of the obtained grown crystal was measured, the uniformity was ±0.6%.

Further, when the composition distribution within the substrate plane was investigated by photoluminescence method (PL method), it was found to be ±0.6%. Also P
Strong light emission with a narrow half-value width of the spectrum of L was observed, and it was confirmed that the crystal was good as a crystal.

For comparison, a GaAs crystal was grown on a GaAs substrate in the same manner as in the above example using a conventional device in which the substrate mounting surface was enlarged in the same plane as shown in FIG. When we measured the film thickness distribution in the system direction of the crystal, we found that
Uniformity was ±0.9%. From this, it has become clear that the molecular beam crystal growth apparatus according to the present invention can grow crystals with a more uniform thickness.

E. Effects of the Invention As explained above, the molecular beam crystal growth apparatus of the present invention is provided with an inner substrate mounting surface and an outer substrate mounting surface, and the outer substrate mounting surface receives the molecular beam from the molecular beam source. Since it is inclined so as to substantially follow the intensity line, the intensity of the molecular beam on the outer substrate mounting surface can be made substantially uniform. Therefore, it is possible to simultaneously grow a large amount of crystals with uniform thickness on the outer substrate mounting surface as well as on the inner substrate mounting surface.

Furthermore, since the outer substrate mounting surface is formed at an angle with respect to the inner substrate mounting surface, the device can be made smaller than conventional devices.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the isointensity lines of molecular beams in the embodiment of FIG. 1. FIG. 3 is a schematic sectional view showing a conventional device. FIG. 4 is a schematic cross-sectional view showing isointensity lines of molecular beams of the conventional apparatus shown in FIG. In the figure, 11 is a manipulator, 11a is a center line,
12 is a molecular beam source, 12a is a line in the direction of the molecular beam passing through the center of the molecular beam source, 12b is an isointensity line of the molecular beam, 13a, 13b
1 is a substrate heater, 14 is an inner substrate mounting surface, and 15 is an outer substrate mounting surface. (Idiot 2ru) Figure 2 City-1/Ku

Claims (2)

[Claims] (1) Mount multiple substrates on the substrate mounting surface of the manipulator, rotate the manipulator to rotate the relative positions of the substrates, and irradiate the substrates with molecular beams from a molecular beam source to form crystals on the substrates. A molecular beam crystal growth apparatus for growing crystals, wherein the substrate mounting surface of the manipulator includes an inner substrate mounting surface formed from a plane centered on the rotation axis of the manipulator and substantially perpendicular to the rotation axis; an outer substrate mounting surface formed around the substrate mounting surface and inclined toward the molecular beam source, such that the outer substrate mounting surface substantially follows the isointensity line of the molecular beam from the molecular beam source. A tilted molecular beam crystal growth device. (2) Mount multiple substrates on the substrate mounting surface of the manipulator, rotate the manipulator to rotate the relative positions of the substrates, and irradiate the substrates with molecular beams from a molecular beam source to form crystals on the substrates. A molecular beam crystal growth apparatus for growing crystals, wherein the substrate mounting surface of the manipulator includes an inner substrate mounting surface formed from a plane centered on the rotation axis of the manipulator and substantially perpendicular to the rotation axis; an outer substrate mounting surface formed around the substrate mounting surface and inclined toward the molecular beam source, such that a line in the molecular beam direction passing through the center of the molecular beam source is aligned with the center of the inner substrate mounting surface. The outer substrate mounting surface intersects with the inner substrate mounting surface at an angle α at approximately the midpoint between the end of the inner substrate mounting surface on the opposite side and the side where the molecular beam source is provided, and the outer substrate mounting surface intersects with the inner substrate mounting surface at an angle α. A molecular beam crystal growth apparatus that is inclined at an angle of approximately 90°-α to the mounting surface.