JPS6121994A - Vapor growth device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor phase growth apparatus for obtaining multi-layered growth layers using a thermal decomposition reaction.

Conventional Structures and Problems There is a vapor phase growth method that utilizes thermal decomposition of raw material gas as an epitaxial growth technique for semiconductor crystals necessary for manufacturing semiconductor devices. Examples include a Si vapor phase epitaxy method using S s H4 (monosynthene), and an organic gold vapor phase epitaxy method (MOCVD method) for growing a compound semiconductor crystal using organic gold Jli (alkylated compound). In these vapor phase growth apparatuses, a susceptor on which a substrate is placed is generally heated and maintained at a growth temperature. Then, the source gas undergoes a thermal decomposition reaction on the substrate surface to grow crystals.

On the other hand, as semiconductor devices become more complex, and in the production of optical devices such as semiconductor lasers, the process of epitaxially growing multiple layers of crystal layers with different electrolytic patterns, and crystal layers with different characteristics such as energy gap and bending M[ is required. It has become necessary. For example, India.

In a laser with an AsP quaternary mixed crystal active layer, an InP layer with a wider energy gap and lower refractive index than InGaAsP is used as the cladding layer.
A stack of a P layer and an InGaAtzP layer is required.

In addition, superlattice structure devices, which have recently attracted attention,
Multilayer epitaxial growth with a thickness of several tens to hundreds of layers is essential. For example, when manufacturing a GaAs-based multilayer quantum well laser using the MOqVD method, the GaAs layer and I'
In order to stack the J and GaAs layers alternately, conventionally the growth layers were switched by opening and closing the supply pulp of triethylaluminum (TMA), which is the raw material for M. However, due to the distance from the supply nozzle to the gas inlet, it takes time for the gas to remain or for the supply amount to stabilize after switching the gas, making it difficult to obtain a steep interface between different growing crystal layers. No. For superlattice structure devices,
Since the thickness of one layer is several tens to hundreds of layers, the steepness of the interface must be several tens of angstroms or less.

Therefore, a vapor phase growth apparatus (Japanese Unexamined Patent Publication No. 57-27016) having two growth chambers as shown in FIG. 1 was devised.

That is, in each growth chamber 100.2oO, a raw material gas is constantly flowed so that different crystals grow, and the substrate 3oo is rotated to move back and forth between the two growth chambers 100, 200. This method performs multilayer epitaxial growth.

However, in this vapor phase growth apparatus, a growth chamber is required depending on the number of types of crystals to be grown, so the reactor becomes complicated and large. Furthermore, most of the raw material gases used in the vapor phase growth of the rod conductor crystal are poisonous and highly dangerous, which increases the complexity and size of the reactor and increases the degree of danger.

Purpose of the Invention The present invention provides a method for supplying different raw material gases for crystal growth to a reactor while being shifted in the gas flow direction of the reactor, and to supply gas inlet ports near each gas inlet that supplies the raw material gases to the reactor while shifting the raw material gases to the reactor. By moving the substrate, the raw material gas can be constantly and stably supplied to the reactor, and the purpose is to obtain an epitaxially grown crystal with a multilayer structure with steep interfaces.

Structure of the Invention The present invention provides gas inlet ports of a plurality of gas inlet pipes for supplying raw material gas for crystal growth into a reactor so as to be shifted in the gas flow direction in the reactor, and also provides a substrate in the gas flow direction. This is a vapor phase growth apparatus in which a raw material gas is supplied near each gas inlet and is supplied from a gas inlet downstream of the gas inlet.

DESCRIPTION OF EMBODIMENTS MOCVD which is an embodiment of the present invention as shown in FIG.
The present invention will be described in detail with reference to a case where an InP-InGaAsP multilayer quantum well laser is manufactured using the apparatus.

First, a graphite susceptor 2 on which an InP substrate 1 is placed
, triethyl indium (TE
I ), and bosfin (PH3
) is placed at the position (c) in the figure on the upstream side of the gas inlet 5 of the gas inlet pipe 4 that supplies the reactor 3, and the InP substrate 1 is heated together with the graphite susceptor 2 by the high frequency heating coil 6. Heat to raise the temperature to crystal growth temperature and keep warm.

Next, the InP substrate 1 and the susceptor 2 are moved to the position (B) in the figure near the gas inlet 5 using the substrate handling tool 7, and the inlet pipe 9 is installed. Gallium (TEG) and arsine (As H3), which is a raw material gas for As, are supplied to the reactor 3. In order that the gases supplied from these gas inlet ports 8 do not affect the InP growth at the position shown in the middle of the figure, the gap between the gas inlet ports 5 and 8 (several (7) or more) is spaced apart, and Sufficient carrier gas (mainly hydrogen containing inert gas) is supplied to gas inlet pipe 1 so that the supplied raw material gas does not flow back inside reactor a.
It is necessary to supply from 0.

Now, after growing the InP layer, use the substrate handling tool 7 to move the substrate 1 together with the susceptor 2 to the position (q) in the figure near the gas inlet 8, and grow a total of about 300 InGaAsP layers. Return the substrate 1 to the position (B) using the substrate handling tool 7 again and grow about 200 InP layers. Next, move the substrate 1 again to the position (q) and grow an InGaAsP layer.
Grow N.・Repeat the above steps to obtain InP
- Form a superlattice structure of the InGaAsP layer.

If the positions (B) and (q) of the substrate 1 are moved at high speed, a laminated layer with a steeper interface can be obtained.The exhaust gas after the reaction is exhausted through the exhaust pipe 11.

Using such a vapor phase growth apparatus which is an embodiment of the present invention, different crystal growth gases are supplied to the reactor while being shifted in the gas flow direction in the reactor, and the substrate is connected to the gas inlet of each raw material gas. By repeating the process of moving the crystal nearby and growing the crystal at high speed, multilayer growth with a steep interface can be performed using relatively small equipment.

Furthermore, FIG. 3 shows an MOCVD apparatus having a vertical reactor as another embodiment of the present invention. Each number in the figure has exactly the same function as in FIG. 1.

In addition, although the invention has been explained by multilayer growth for an InP-InGaAsP superlattice structure, there are also other GaAsP superlattice structures.
The present invention can also be applied to a superlattice structure such as As-AQGaAs or a vapor phase growth apparatus that performs stacked growth. Further, the substrate heating method may be a resistance heating method or a lamp heating method.

Effects of the Invention The vapor phase growth apparatus according to the present invention can supply the crystal growth gas to the reactor while being shifted in the gas flow direction of the reactor, and can perform crystal growth by moving the substrate near the gas inlet of each raw material gas. Therefore, by moving the substrate at high speed, laminated growth with a steep interface can be performed using relatively compact equipment.

It can also be applied to the fabrication of superlattice structures by repeatedly moving the substrate. Therefore, the present invention can be used for crystal growth of devices such as semiconductor lasers that require lamination, and devices with a superlattice structure, such as multilayer quantum wells.
Effective in improving characteristics.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the reactor section of a conventional MOCVD apparatus having two growth chambers, and FIG. 2 is a schematic cross-sectional view of the horizontal reactor section of an MOCVD apparatus according to an embodiment of the present invention. Figure 3 shows M with a vertical reactor, which is another embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of the reactor section of the OCVD apparatus.

Claims (1)

[Claims] Gas inlets of a plurality of gas inlet pipes for supplying raw material gas for crystal growth into the reactor are provided to be shifted in the gas flow direction in the reactor, and the substrate is freely moved in the gas flow direction. and can be stopped near each of the gas inlets at a position where crystal growth is possible without being affected by raw material gas supplied from a gas inlet downstream of the gas inlet. A vapor phase growth apparatus characterized by being provided with.