JPH0543109Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a compound semiconductor crystal growth apparatus.

[Prior Art] In the liquid phase epitaxial growth process of compound semiconductors, a slide boat consisting of a raw material solution reservoir jig and a slide plate is usually used. A method is used in which a substrate is placed and the substrate is brought into contact with a solution to grow crystals, but as the number of epitaxial layers increases or the size of the substrate increases, slide boats are also used. It becomes necessary to use a large one.

[Problems to be solved by the invention] As mentioned above, as the number of epitaxial layers increases and the size of the substrate increases, a larger slide boat becomes necessary. In this case, due to the anisotropy of the constituent material, such as graphite, the thermal uniformity deteriorates, making it difficult to perform stable multilayer epitaxial growth, resulting in nonuniform impurity concentrations within the plane of the epitaxial layer, and The variation in thickness becomes large.

An object of the present invention is to provide a compound semiconductor crystal growth apparatus having a slide boat with good thermal uniformity that can improve the uniformity of the in-plane impurity concentration and film thickness of the epitaxial layer.

[Means for Solving the Problems] The present invention provides a compound semiconductor crystal growth apparatus in which a raw material solution and a substrate are placed in a slide boat, and the substrate is moved and brought into contact with the solution to grow a compound crystal thin film. The slide boat is characterized in that it is made of graphite in which the direction of the layered lattice matches the direction of movement of the substrate, and the objective is achieved by making the slide boat uniform in thermal characteristics.

[Function] As shown in FIG. 3, graphite is composed of a plurality of stacked microlayers.

In the compound semiconductor crystal growth apparatus of the present invention, when manufacturing a slide boat made of graphite used for epitaxial growth, the direction Y of the so-called layered lattice of graphite is aligned with the direction in which the substrate moves, that is, within the epitaxial growth furnace. The heat conduction characteristics of the slide boat are improved and the thermal characteristics within the slide boat are uniform, and the impurity concentration during crystal growth is made uniform, resulting in a constant film thickness. High quality compound semiconductor crystals can be obtained.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of an embodiment of the compound semiconductor crystal growth apparatus of the present invention.

In the figure, 2 is a slide plate, 3 is a slide plate 2
For example, the boards 4A, 4B, and 4C attached to
The raw material melts are made by dissolving GaAs crystals in a Ga solution, and each has a different composition. 1 is a raw material solution reservoir into which raw material solutions 4A to 4C are placed. 5 is a support.

In this example, the substrate 3 is moved together with the slide plate 2 in the arrow
By successively contacting B and 4C, it is possible to grow multiple layers of single crystals with different properties on the substrate 3.

The raw material solution reservoir jig 1, the slide plate 2, and the support body 5 are made of graphite, and the direction of the stratified lattice of graphite that makes each of these parts is the direction of the arrow x in the figure, i.e. Since the direction of movement of the substrate 3 coincides with that of the substrate 3, the thermal conductivity of the growth apparatus is improved, the thermal uniformity is significantly improved, and a high-quality multilayer epitaxially grown layer can be obtained.

Although FIG. 1 shows the case where three types of solutions, 4A, 4B, and 4C, are used as the raw material solution, the same can be applied to the case where two or less or four or more types are used.

In addition, in a slide boat of the type in which the substrate 3 is installed vertically as shown in FIG. The thermal conductivity and soaking properties of the device are improved, and high quality crystals can be grown.

Example 1 A 20 μm thick GaAs layer was deposited on a GaAs substrate with a target Si concentration of 1×10 ¹⁸ cm ^-3 using the slide boat shown in FIG. Made it grow. obtained
The uniformity of the impurity concentration in the GaAs layer is ±8%.
The variation in film thickness was ±2 μm or less.

Comparative Example 1 When a GaAs layer was grown under the same conditions as in Example 1 using a slide boat made of non-oriented graphite, the uniform impurity concentration variation in the resulting GaAs layer was ±15% or more. The variation in film thickness was ±5 μm or more.

As described above, according to each embodiment of the present invention, the following effects can be obtained.

(1) Even if the growth device is large and there is a risk of deterioration of thermal characteristics, by aligning the direction of the layered lattice of the material graphite with the direction of movement of the substrate, the thermal conductivity characteristics and uniform temperature of the growth device itself can be improved. Characteristics can be improved.

(2) By creating each part of the growth device in consideration of the direction of the stratified lattice of graphite, the thermal conductivity has been improved by 100 to 1000 compared to the case where the growth device was created with the direction of the stratified lattice irregular. It can be doubled.

[Effects of the invention] As explained in detail above, according to the invention, a compound having a slide boat with good thermal uniformity that can improve the in-plane impurity concentration and uniformity of the film thickness of the epitaxial layer can be obtained. A semiconductor crystal growth apparatus can be provided.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the compound semiconductor crystal growth apparatus of the present invention, FIG. 2 is an explanatory diagram of another embodiment, and FIG. 3 is an explanatory diagram showing the layered structure of graphite. 1, 6... Raw material solution reservoir jig, 2... Slide plate, 3... Substrate, 4A, 4B, 4C... Raw material solution, 5... Support.

Claims (1)

[Scope of utility model registration request] A raw material solution reservoir jig for accommodating a raw material solution and a slide plate for setting a substrate are provided, and the raw material solution reservoir jig and the slide plate are relatively moved to bring the raw material solution and the substrate into contact with each other, and the substrate is brought into contact with the raw material solution and the substrate. A compound semiconductor crystal growth apparatus for epitaxially growing a compound crystal thin film thereon, wherein the raw material solution reservoir jig and the slide plate are made of graphite whose layered lattice direction coincides with the moving direction of the substrate. Compound semiconductor crystal growth equipment.