JPS6190426A - Method for gas-phase epitaxal growth of organic metal - Google Patents

Abstract

PURPOSE:To enable the formation of an epitaxial layer with a flat surface by a thin film thickness of epitaxial layer by effecting the crystal growth on a substrate having a groove at a growing speed of 8mum/h or over, and with a supply molar ratio of V-element to III-element of 10 or more. CONSTITUTION:On a substrate having a groove, crystal growth of III-V compound semiconductor is made at a growing speed of 8 mum/h or over and a supply molar ratio of V-element to III-element of 10 or over. For example, an N type GaAa substrate is used as a substrate 1 and a V-groove of 3 mum depth is formed by photolithography and crystal growth is effected on that. By the method for gas-phase epitaxial growth of organic metal, undoped GaAa is grown. The growing conditions at this time are; a growing temperature of 750 deg.C, a total gas flow of 5l/min, a supply molar ratio of V-element to III- element (V/III supply molar ratio) of 50, and a growing speed of 10mum/h. The groove on the substrate influences on a cross-sectional shape of the epitaxial layer right above it and the epitaxial layer reduces the V-shaped groove according to the passage of a growing time and fills the V-groove on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an organometallic vapor phase epitaxial growth method that can be used for manufacturing various semiconductor devices.

Conventional configurations and their problems In recent years, organometallic vapor phase epitaxial growth methods have improved controllability of film thickness during thin film growth1, uniformity of film thickness, electrical and optical properties within the wafer plane, and uniform crystallization. Because of its excellent wafer-to-wafer reproducibility under growth conditions, it is often used as a method for epitaxial growth of compound semiconductor materials.

In particular, in the production of high-speed devices and planar semiconductor lasers using compound semiconductors, a flat stacked structure is usually formed on a flat substrate, so it is necessary to take full advantage of the above-mentioned features of the metal-organic vapor phase epitaxial growth method. I can do it.

However, the above configuration is not sufficient for manufacturing single mode semiconductor lasers, optical waveguides, and optical integrated circuit elements. One way to reduce the number of steps and obtain good electrical and optical characteristics for these devices is to grow them on a substrate having grooves.

Furthermore, if the final shrimp layer is a flat surface, it can be used in a wide variety of devices.

However, the crystal growth conditions used in conventional metal-organic vapor phase epitaxial growth have the drawback that in order to flatten the surface of the shrimp layer grown on the grooves, a considerably thick layer must be formed. .

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention provides an organic metal vapor phase epitaxial growth method that can flatten the surface of the epitaxial layer with a small thickness of the epitaxial layer.

Structure of the Invention To achieve this object, the organometallic vapor phase epitaxial growth method of the present invention provides crystal growth of an m-v group compound semiconductor on a substrate having a groove at a growth rate of 8 μm/[I or more, and It consists of crystal growth performed under crystal growth conditions in which the molar ratio of supply of V element to Group Ⅰ element is 10 or more, and with this configuration, it is possible to form a flat shrimp layer surface with a small shrimp layer thickness. becomes possible.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the cross-sectional shape of the shrimp layer grown by the organometallic vapor phase epitaxial growth method in the first embodiment of the present invention.

In FIG. 1, 1 is a substrate having a groove, and 2 is an epitaxially grown layer. - As an example, an n-type GaAs substrate is used as the substrate 1. The first photolithography
As shown in the figure, a V-shaped groove with a depth of 3 μm is made, and crystal growth is performed on this groove. Undoped GaAs is grown by metal organic vapor phase epitaxial growth. The growth conditions at this time were: growth temperature: 760°C, total gas flow rate: F5115
+, supply molar ratio of group V element to group ■ element (hereinafter referred to as V/
III supply molar ratio) is 60. Growth rate is 10μm
/It's time. At this time, when a 3 μm shrimp layer was grown,
FIG. 1 shows the cross-sectional shape of a shrimp layer grown on a substrate with grooves depending on the growth time. The time axis advances in the order of a-+b 4 C. The groove on the substrate influences the cross-sectional shape of the shrimp layer directly above it, and as the growth time passes, the shrimp layer fills the V-shaped groove on the substrate while reducing the shape of the figure 7 groove. Under the above growth conditions, when a shrimp layer of about 2.6 μm was formed, its surface became flat.

As described above, according to this embodiment, a flat surface can be obtained even if a thin shrimp layer is deposited on a substrate having grooves.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the cross-sectional shape of the shrimp layer grown by the organometallic vapor phase epitaxial growth method in the second embodiment of the present invention.

In the figure, a substrate 4 having a groove portion 3 is an epitaxially grown layer, and the structure described above is the same as that in FIG. 1.

The difference from the configuration shown in FIG. 1 is that the groove is provided as a U-shaped groove instead of a V-shaped groove.

Figure 2 (→, (11, (→ means (→, (11,
It is shown that the tendency of trench filling when the growth time elapses with the same structure as in (C) is also the same.

By the way, as a result of numerous experiments and measurements, the growth conditions under which the shrimp layer thickness t1 when the shrimp layer surface becomes flat in Figure 1 satisfies t1≦h1 are found to be in the area shown by diagonal lines in Figure 3. Understood. That is, the growth rate is 8 μm/hour or more and the V/Ill supply molar ratio is 10 or more. The correlation with other growth conditions is weak. If it is within the above range shown in Figure 3,
Organic total vapor phase epitaxial growth similar to this example is possible.

In this example, only GaAs was described, but G
It is also possible to apply to the crystal growth of aAlAs-based materials, and also to the crystal growth of doped shrimp layers.

Effects of the Invention As described above, the present invention is capable of filling grooves with a small thickness on a substrate having grooves and making the grooves flat, and also because it uses an organic metal vapor phase epitaxial growth method with good controllability of film thickness, etc. It can be used as a means for producing effective force in various devices, and its practical effects are great.

[Brief explanation of the drawing]

1 and 2 are diagrams showing the cross-sectional shape of a crystal grown by the metal organic vapor phase epitaxial growth method in the first and second embodiments of the present invention, respectively, and FIG. 3 is a diagram showing a crystal to which the present invention can be applied. It is a figure showing the range of growth conditions. 1.3...Substrate, 2,4...Epitaxial growth layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure (a-n (I)) (Fig. 2 (a-n (b) (C)

Claims (1)

[Claims] On a substrate having a groove, a growth rate of 8 μm/hour or more and a supply molar ratio of group V elements to group III elements of 10
An organometallic vapor phase epitaxial growth method characterized in that crystal growth of a III-V compound semiconductor is performed as described above.