JPS6065791A - Apparatus for liquid-phase epitaxial crystal growth - Google Patents

Abstract

PURPOSE:To form a plurality of uniform multi-layered epitaxial layers on plural substrates at the same time, by boring a hole for holding substrate crystals to a slider, placing plural substrates in the hole, and introducing and discharging plural kinds of melt sources successively to the hole. CONSTITUTION:The slider 32 is provided with the hole 34 for holding substrate crystals, and a plurality of substrate crystals 3 are put into the hole 34. The melt sources 1-1', 1-2', etc. are melted completely by heating the growth boat as a whole. The molten melt sources are cooled to a proper temperature, the hole 34 is shifted by operating the handle 14 to transfer the melt source 1-1' to the hole 34, and the epitaxial growth on the substrate crystal 3 is carried out. The hole 34 for holding substrate crystal is shifted again by operating the handle 34 to discharge the melt source 1-1' through the discharging port 37 to the waste liquid reservior 36. The above operations are repeated to form multi-layered epitaxial layers on a plurality of substrates 3 at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for growing epitaxial crystals using a liquid phase method in the field of epitaxial crystal growth on substrate crystals.

Structure of conventional examples and their problems As one of the techniques for growing epitaxial crystals of the same or different type on substrate crystals, the epitaxial crystal growth technique by liquid phase method has traditionally been widely used, and is the most important growth technique. 1. Especially recently, in relation to optical technology, the liquid-phase method V-based compound semiconductors have become popular with Rebus-Zeko, a leading man in the field of photodetectors and high-speed operation electric circuit elements, who have used compound semiconductors. Epitaxial crystal growth technology is one of the essential fundamental technologies.

An epitaxial crystal growth boat is a basic jig used in growing an epitaxial crystal by a liquid phase method, and a conventional example of this growth boat will be described below.

FIG. 1 is a schematic diagram of a growth boat used for growing epitaxial crystals by a liquid phase method. The entire growth boat is made of high-purity carbon, and has multiple melt reservoirs 1-1.1-2.1-3. as shown in the figure. . . . a melt holding section 11, a slider portion 12 provided with a substrate installation section 2 for epitaxial growth, and a lower base section 1.
It consists of 3. In order to simplify the explanation of how to actually grow epitaxial crystals by the liquid phase method using such a growth boat, we will use the basic structure of a 1 μm device as shown in Figure 2 below. 4 onto InP substrate
An example of a layered epitaxial crystal will be shown. The figure shows InP
InP buffer layer 22 continuously grown on the substrate 3
, InGaAsP active layer 23. InP cladding layer 24
This is an example in which an epitaxial crystal consisting of an InGaAsP cap layer 25 is grown.

When such epitaxial crystal growth is carried out using the growth boat shown in Fig. 1, first the InP substrate 3 and the melt reservoir 1-2 are placed in the growth boat as shown in the cross-sectional view of Fig. 3. In is used for meltback to melt the substrate surface layer to remove contaminants and processing scratches on the substrate surface, and a small amount of InF3. (Put in the added melt bag sauce 21. Next, melt reservoirs 1-3 and 1-4
, 1-5.

1-6 respectively (Figure 2) InP buffer 7 f? '−+
2" rInGaAsP active layer 23. 1nP cladding layer 24. Each source material 1-3', 1-4' for forming InGaAsP cap layer 25. A specified amount is added together with In for the whole melt, and the substrate 1nP3 After covering the top of the growth boat with another layer of InPA to prevent thermal damage on the InP substrate surface under the crystal mud, the entire growth boat is placed in an electric furnace and heated to a temperature usually above 650°C in a hydrogen atmosphere. to fully melt each source paulownia wood in the melt reservoir.

Next, the temperature of the electric furnace is not completely slowly cooled (usually 0.5 to 1
10), move the slider 12 using the pull-out rod 14 provided at one end of the slider 12 so that the InP substrate 3 is located below the melt reservoir 1-2. Here, the surface of the substrate 3 is cleaned by combing only a few micrometers of the surface with the meltback solution, and then the melt reservoir 1 is further removed using the pull-out rod 14.
The solution 1-3' for forming a single layer of InP buffer contained in 1-3 is moved below, and a single layer of InP buffer as shown in FIG. 2 is formed.

Following the same procedure, 1nGaA is obtained at the point of melt reservoir 1-6'.
After the InGaAsP cap layer 25 shown in FIG. 2 is formed by the sP cap As forming melt 1-6', the substrate 2 on the slider 12 is pulled out to the outside of the melt reservoir and rapidly cooled to form the InGaAsP cap layer 25 shown in FIG. The four epitaxial crystal layers shown will be formed on the substrate InF3.

At this time, the thickness of each epitaxial crystal 22 to 25 shown in FIG. 2 can be determined by the temperature at the time of formation, growth time, source material, etc.

By the way, in the growth of epitaxial crystals by the liquid phase method using the above-mentioned growth hole, epitaxial crystals are only grown on one substrate in one growth process, and the melt reservoir is filled in each growth process. There is an extremely high possibility that variations in the composition and characteristics of the obtained epitaxial crystal itself will occur due to factors such as variations in the weight of the source material, variations in the growth time, and slight errors in the growth temperature. Therefore, from the standpoint of mass production of devices with uniform characteristics, such as laser devices, the above-mentioned epitaxial crystal growth method is considered to be an extremely inefficient method.

Purpose of the Invention The present invention solves the above-mentioned conventional problems and improves the mass productivity of epitaxial crystal growth by liquid phase method by simultaneously forming corbitaxial crystals with uniform characteristics on a large number of drawing plates in one epitaxial growth process. The object of the present invention is to provide an epitaxial crystal growth boat having a novel structure that makes it possible to significantly improve uniformity.

Composition of the Invention The present invention includes a melt holding section having a plurality of melt reservoirs arranged in a row for liquid-phase epitaxial crystal, and a drainage reservoir combined to be integrated with the melt holding section. A growth boat consisting of a base part and a part of a slider that fits between the melt holding part and the base part and is configured to slide along the melt reservoir.The slider part has multiple sheets for epitaxial growth. In addition to the substrate installation hole for installing the substrate crystal, the lower part of the substrate installation hole is provided with a discharge hole for melt drainage that penetrates to the bottom of the slider.

Further, in the base part, there is a drain introduction hole for guiding all the drain liquid flowing out from the discharge hole of a part of the slider to a drain liquid reservoir provided in the base part. It is installed directly under the wall of the reservoir. The walls between the plurality of melt reservoirs provided in the melt holding section are designed to be thicker than the length in the sliding direction of the substrate crystal installation hole provided in at least a portion of the slider.

In addition, if the lower part of the substrate crystal installation hole in a part of the slider is sloped so that the whole part descends toward the melt discharge hole provided in that part, the melt can be easily discharged. It is possible to guide the discharged melt to a reservoir in the base.

DESCRIPTION OF EMBODIMENTS FIG. 4 shows a diagram of a boat according to an embodiment of the present invention. In the figure, 31 is a melt holding part, 32 is a part of a slider,
33 is a base portion equipped with a drainage reservoir, and the melt holding portion 3
1 has three melt reservoirs 1-1.1-2.1-3f.

Further, the slider portion 32 has a substrate crystal installation hole 34 in which a plurality of substrate crystals can be installed. The bottom of the substrate crystal installation hole 34 formed in the slider part 32 and the melt reservoir provided in the base, which cannot be seen in the perspective view as shown in FIG. 4, are shown in the cross-sectional structure diagram of this growth boat. (Figure 6).

In FIG. 5, the same parts as in FIG. 4 are indicated by the same numbers as in FIG. In Figure 6, 35Vi slider part 3
2, a drainage outflow hole provided at the bottom of the substrate crystal installation hole 34; 36, a drainage reservoir provided at the base; and 37, the drainage from the drainage outflow hole 36 is led to the liquid reservoir 36. This is a drainage inlet hole for

The figure also shows the substrate crystal 3.0 installed in the substrate crystal installation hole 34 in order to explain the growth process of epitaxial crystal using the growth boat of the present invention. and melt reservoir 1-1.1-2
．． 1-3 has melt sauce 1', 1-2', 1-
3' is shown loaded.

Next, a method for growing epitaxial crystals using a growth boat according to the present invention will be explained. To simplify the explanation, after performing a melt-back process on an InP substrate crystal 3 as shown in FIG. 2 as an epitaxial crystal, one InP buffer layer 22. It is assumed that two layers including the InGaAsP active layer 23 and the InGaAsP active layer 23 are grown. In this case, melt reservoir 1 in Figure 6
-1.1-2, melt sauce 1.1-2' contained in 1-3.

1-3' are respectively In, In+InP, In+InP+
It is a mixed melt of InAs+GaA. First, as shown in FIG. 5(a), a plurality of substrate crystals 3 are installed in the substrate crystal installation hole 34, and then the entire growth boat is placed in an electric furnace and heated in a hydrogen gas atmosphere to form each melt 1. −
1', 1-2', and 1-3' are sufficiently dissolved.

It is better to carry out this melt melting process while moving the substrate crystal installation hole 34 by operating the pull-out rod 14 of the slider as shown in 5th fV (b), as it may cause surface damage to the substrate crystal 3 (- Less is desirable.

Next, the electric furnace is gradually cooled (o, 5-b, etc.) When the appropriate temperature is reached, the pull-out rod 14 is operated again as shown in FIG.
The melt 1-1' moves to the substrate crystal installation hole 34 and melts back the substrate crystal InP3. After the melt bank is completed, the pull-out rod 14 is further operated to move the substrate crystal installation hole 34 to the position shown in FIG. 5(d).

The In melt 1-1' in the substrate crystal installation hole 34 is drained through the drain outflow hole 35. The drained liquid 6iU flows into the drained liquid reservoir 36 through the inlet hole 37. Thereafter, the same operation was repeated one after another until melt sauces 2' and 1-3' were obtained, as shown in Fig. 2.
An InP layer 22°, 1nGa86P active layer 23 is formed on the nP substrate 3.

The example of growing two layers of epitaxial crystal on the InP substrate 3 has been described above.
．． It goes without saying that any number of layers can be formed by digging a number of holes.

Effects of the Invention The liquid phase method epitaxial crystal growth boat of the present invention has a drain outflow hole at the bottom of the substrate crystal installation hole in a part of the slider, as well as a drain reservoir and a drain introduction hole in the base. It becomes possible to form a multilayer epitaxial layer on a substrate crystal using operations that are completely unchanged from conventional methods, and it becomes easy to fabricate an epitaxial crystal with extremely uniform properties. This is an extremely effective means for producing a large number of devices with high yield and uniform characteristics when manufacturing devices using the present epitaxial crystal.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional liquid-phase epitaxial crystal growth boat, Figure 2 is a cross-sectional view of the structure of the epitaxial crystal formed in the growth boat of Figure 1, and Figure 3 is the epitaxial crystal of Figure 2. Cross-sectional view of the growth boat during formation, No. 4
The figure is an exploded perspective view of a growth boat for liquid-phase epitaxial crystal of the present invention, and FIGS. 6(a) to 6(d) are cross-sectional views of the growth boat for explaining the growth process of epitaxial crystal using the boat of the present invention. be. 31...Mel! - Holding part, 32... Part of slider, 33... Base part, 34... Substrate crystal installation hole, 3
5...Drainage outflow hole, 36...Drainage reservoir, 37-
... Drainage hole.

Claims (1)

[Claims] (1) A melt holding section having a plurality of melt reservoirs arranged in a row for liquid-phase epitaxial crystal, a base section having a drainage reservoir integrally combined with the melt holding section, and the melt holding section. A slider part is fitted between the part and the base part and configured to be able to slide along the melt reservoirs arranged in a row, and a plurality of substrate crystals can be installed in the slider part. A penetrating melt discharge hole for melt outflow is provided at the bottom of the substrate crystal hole together with the substrate crystal installation hole, and the base portion is provided for guiding the drain liquid flowing out from the melt discharge hole of a part of the slider to a drain liquid reservoir. A liquid phase epitaxial crystal growth apparatus, characterized in that a drainage inlet hole is provided below the surface of the wall of the twinkling melt reservoir of the melt holding section. (Low force due to the substrate crystal film N of the slider blind;
The liquid phase epitaxial device according to claim 1, characterized in that the melt provided in a part of the lower part of the substrate crystal installation hole is inclined in the −F direction toward the J1 exit hole. Crystal growth equipment.