JPS61287221A - Liquid-phase epitaxial growth method and equipment therefor - Google Patents

Abstract

PURPOSE:To enable the formation of a thin epitaxial layer by sealing a melted layer material solution charging chamber, holding it at the prescribed temperature, then forming a space at the top of the chamber, and cooling while adjusting the volume of the space. CONSTITUTION:A substrate 23 is fixed to the recess 24 of a substrate holder 21, and laminated layer forming materials are charged in 4 melted solution charging chambers 30 of a substrate holder 22. A large-sized cover 28' is mounted in the chambers 30 which contains a material 31 for forming a laminated layer. A boat 20 is held at the prescribed temperature for the prescribed time, and the materials in the chambers 30 are uniformly mixed. Then, an atmosphere is started cooling, the holder 22 is slid to place the chambers 30 on the substrate 23, and an epitaxial layer is grown on the substrate 23. Simultaneously, a wedge-shaped jig 35 is pressed to the lower portion of the cover 28', a space is formed at the top of the chamber 30 to reduce the thermal capacity, thereby quickly cooling. Thus, a material component is precipitated in a source crystal 32 disposed near the liquid surface to reduce the oversaturation in the chamber. The chamber 30 is moved to form a thin layer on the substrate 23. Similarly, epitaxial layers are sequentially formed on the substrate 23.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a liquid phase epitaxial growth method, more specifically,
The present invention relates to controlling the layer thickness when epitaxially growing a layer on a substrate such as a semiconductor, and in particular to a method and apparatus for controlling the layer thickness of a thin layer.

Technical Background When manufacturing a semiconductor electronic device, for example, a semiconductor laser device I or D as shown in FIG. 1 and FIG. Liquid phase epitaxial growth is used to form multiple layers such as layer 5, second cladding layer 6, and cap layer 7. By the way, the active layer 5 in the semiconductor laser device 1 or 1' usually needs to be a thin and uniform layer of 0.1 μm or less, and various proposals have been made regarding liquid phase epitaxial growth methods and devices for this purpose.

The methods proposed above include, for example, reducing the supersaturation degree ΔT of the growing melt, shortening the growth time to about a few seconds, reducing the amount of melt 4'1 at the carbon port of this device, or reducing the growth rate of crystallization. The property that depends on the surface orientation is fl
For example, a substrate on which a layer is to be grown is subjected to a predetermined process.

However, the above-mentioned proposed method specifically
When a plurality of layers are grown, a thinning effect occurs in some unspecified layers, and it is very difficult to grow only a specific layer, for example, the active layer 5, thinly. difficult to implement.

This invention was made in view of the above-mentioned problems, and when epitaxially growing a layer on the substrate-1, the required volume in the upper part of the melt loading chamber of the layer material is A method and apparatus for liquid phase Evitakinoyal growth in which a layer of precise thickness, particularly a thin layer, can be obtained by forming a space of The purpose is to provide

In order to achieve the above object, the liquid phase epitaxial growth method of the present invention basically includes the steps of: sealing a melt loading chamber for epitaxial growth material and maintaining the inside of the melt loading chamber at a predetermined temperature; 1. Forming a space at the top of the melt loading chamber and cooling the melt loading chamber while adjusting the volume of the space; The internal cooling rate is adjusted to reduce the supersaturation of the growth material in the melt as desired, thereby growing a thin layer of precise thickness on the substrate.

Furthermore, the apparatus of the present invention is provided with a means for forming a space of a desired volume at the top of the layer material melt loading chamber in the layer growth port, and the melt is loaded by controlling the volume of the space. The heat capacity inside the chamber is adjusted to control the cooling rate inside the melt loading chamber, and thus precisely adjust the degree of supersaturation of the layer material in the melt.

g-zhang! [This invention will be explained below with reference to FIG. 3 which shows a furnace which is suitable for the Evita epitaxial growth apparatus according to the embodiment. FIG. 3 shows the main components of the furnace which is suitable for the horizontal liquid phase epitaxial growth apparatus according to the present invention.

In the drawing, 20 is a ball for liquid phase epitaxial growth.
- in which, for example, a carbon port may be used. This carbon port 20 consists of a band-shaped substrate holder 21 and two band plate bodies 22-- which are slidably placed on the substrate boulder 21''.
The melt boulder 22 is formed by stacking 1.22-2. This melt boulder 22 is moved to the substrate holder 2 via a known pushing or pulling rod (not shown).
It is possible to move left and right relative to 1.

A plurality of through holes 26 of a predetermined size are provided in the melt boulder 22.
is provided. A fluid support step 2 is provided at the upper end of each through hole 26.
7 is formed, and a lid body 28 having a flange 29 at one end is attached to the through hole 26 by insertion. In this case, the top surface 28a of the lid body 28 and the top surface 22a-1 of the strip body 22-1
is considered to be a plane-state. In this way, each 11 through hole 2
6 forms a sealed chamber 30 with the lid 28 and two surfaces 21a of the substrate holder 21. As shown in FIG. Each chamber 30 contains a material 3 of the layer to be grown on the substrate 23.
1. For example, a melt of semiconductor material is loaded. This room 3
0 is hereinafter referred to as the melt loading chamber. A source crystal 32 having the same quality as the growth material is placed near the melt surface in each melt loading chamber 30 .

Of the melt loading chamber 30, a fluid 28' having a large Franz 29' is installed in the through hole 26 which is loaded with a material for epitaxially growing a thin layer. This lid body 28' is adapted to be hung on the opening edge of the through hole 26, that is, on the upper surface 22a-1 of the strip body 22-1. A wedge-shaped jig 35 having an inclined surface at its tip is slidably mounted on the band plates 22 to 1 of the melt boulder 22. By inserting the tip of this wedge-shaped jig 35 into the lower part of the flange 29' of the lid 28', the lid 28' is moved to one side, so that a space is formed in the melt loading chamber 30. It has become. The volume of this space is determined in accordance with the lifting distance of the fluid 28' commensurate with the cooling rate inside the melt loading chamber 30, as will be described in detail later.

A heater (not shown) such as an electric resistance heating element is installed around the carbon port 20.

Next, the operation of the liquid phase epitaxial growth apparatus having the structure described in item 1 will be explained according to the manufacturing process of the semiconductor laser device 1 shown in FIG.

Substrate boulder 21 at port 20 of the device shown in FIG.
A substrate 23 corresponding to the substrate 2 of the semiconductor laser element I is fixed in the recess 24 . Note that the layer 3 has already been formed on this wall plate 23 by liquid phase epitaxial growth. On the other hand, the four melt loading chambers 30 of the melt holder 22 are sequentially loaded with materials for forming the layers 4, 5, 6 and 7, and source crystals 32 corresponding to the materials, starting from the leftmost chamber. The melt loading chamber 30, in which the material 31 forming the active layer 5 is accommodated, is fitted with a fluid 28' having a large flange 29'.

The two-legged carbon boat 20 is heated by a known method via a heater (not shown), and the ambient temperature of the carbon boat 20 is maintained at a constant temperature of about 850° C. for a predetermined period of time. This situation is shown in period t in FIG. -1, indicates. In this way, it is ensured that the melt components of the material enclosed within each melt loading chamber 30 are uniformly mixed.

Next, at time L1, the cooling of the two-legged atmosphere is started, and a pusher (not shown) moves the melt holder 22 and the substrate holder 21 in the direction shown by the white arrow in FIG. Slide it so that the melt loading chamber 30 for forming the internal current confinement layer 3 is located directly north of the weir plate 23. In this way, the internal current confinement layer 3 of about several μm is epitaxially grown on the dam plate 23.

Also, at time t, the tip of the wedge-shaped jig 35 is connected to the Franz 29 of the fluid 28', as shown in FIG.
is pushed into the lower part of the active layer forming material melt loading chamber 30.
A space of the required volume is formed at the top of the . By forming this space, the heat capacity inside the melt loading chamber 30 is made smaller than in other melt loading chambers 30 having no space, and therefore the temperature inside the chamber 30 is rapidly reduced. Therefore, the material components in the melt in the chamber 30 rapidly reach the source crystal 32 located near the liquid surface.
The degree of supersaturation of the semiconductor material in the melt of the active layer material decreases rapidly compared to that in the other chamber 30. As a result, a very thin active layer of about 0,605 μm can be epitaxially grown on the substrate 23. The volume of the space thus formed should be appropriately determined depending on the thickness of the layer to be epitaxially grown, the material of the layer, the volume and weight of the melt loading chamber 30, etc. Note that the volume of the space may be changed at an appropriate rate of change during epitaxial growth, instead of being held constant during epitaxial growth in the embodiments described above. In this way, the layer thickness of the grown layer can be adjusted more precisely.

Thereafter, the melt holder 22 is moved as shown in FIG.
At predetermined timings tt, C3, .
5.6 is epitaxially grown. These evitaginal growth operations are well known in the technical field, and their explanation will be omitted.

Incidentally, in the above embodiment, the case of manufacturing a semiconductor laser device 1 has been described, but it goes without saying that the present invention can be used to manufacture other semiconductor electronic devices by the liquid phase epitaxial growth method.

According to the present invention, a space is formed at the top of the melt loading chamber for the epitaxially grown filter layer material, and the melt loading is performed by adjusting the volume of the space. The heat capacity inside the chamber is prevented from decreasing at a desired rate of change, and the degree of supersaturation of the growth material in the melt is adjusted to the desired degree, allowing for precise control of the layer thickness of the growth layer within the cylinder. be able to. In particular, when forming a diagonal semiconductor layer on a dam plate, such as in the manufacture of semiconductor laser devices, it is difficult to form a very thin active layer of approximately 0.1 μm or less using conventional liquid phase epitaxial growth equipment. By simply adding means for forming a space of a required volume in the lower part of the material melt loading chamber, only a predetermined layer among a plurality of semiconductor layers can be epitaxially grown to a desired thin thickness.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional VSIS type semiconductor laser device.
FIG. 2 is a cross-sectional view of a conventional TR8 type semiconductor laser device, FIG. 3 is a diagram showing the main components of a liquid phase epitaxial growth apparatus according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a conventional TR8 type semiconductor laser device. 3 is a graph showing an operating characteristic diagram when manufacturing the semiconductor laser device 1. FIG. I. Semiconductor laser element, 2. Substrate, 3. Internal current confinement layer, 4. First crat layer, 5. Active layer, 6. Second crat layer, 7. Cap layer, 8.・V-shaped i
! L20...Epitaxial growth boat (carbon boat), 2 tons・Weir plate holder, 22・Melt boulder, 22=
1.22-2... Band plate body, 23... Substrate, 24 ・
Recess, 26... Through hole, 27... Lid support step, 2
3.28' - Lid, 29.29' - Franz, 30 - Growth material melt loading chamber, 31 32 - Source crystal, 35 - Wedge-shaped jig.

Claims (2)

[Claims] (1) In epitaxially growing a layer on a substrate, there is a step of sealing the layer material melt loading chamber and maintaining the inside of the melt loading chamber at a predetermined temperature, and forming a space at the top of the melt loading chamber. A liquid phase epitaxial growth method comprising the steps of cooling the melt loading chamber while adjusting the volume of the space. (2) In an apparatus for growing a layer on a substrate by a liquid phase epitaxial growth method, a means for forming a space of a desired volume is provided at the top of a layer material melt loading chamber in a layer growth boat, and the volume of the space is controlled. A liquid phase epitaxial growth apparatus characterized in that the heat capacity in the melt loading chamber is adjusted by adjusting the heat capacity in the melt loading chamber.