JPS6217370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor vapor phase growth apparatus for growing semiconductor crystals on a substrate by a vapor phase method.

Methods for growing semiconductor crystals on a substrate include a vapor phase method, a liquid phase method, and a molecular beam method. Among them, the gas phase method is generally used in the field where Si is used as the matrix. FIG. 1 schematically shows a cross-sectional example of a conventional Si vapor phase epitaxial growth apparatus. In FIG. 1, a Si substrate 1 is placed on an inclined substrate setting plate 2 and set inside a high purity quartz tube 3. In order to grow crystals, the temperature of the substrate setting plate 2 is increased using high frequency, and the temperature of the substrate 1 is controlled to a desired temperature. Only the parts necessary for explanation are shown in the figure, that is, 4 is a coil that heats the board setting plate 2, and a high frequency power source and the like are omitted. Although not shown, the raw material gas for growth, such as SiCl ₄ or SiH ₄ , is used on the left side of Figure 1 (arrow 5) using high-purity hydrogen as a carrier gas.
is supplied onto the Si substrate 1 from. Since the Si substrate 1 is heated to a desired temperature, Si is deposited on the Si substrate 1. In order to control the electrical conductivity and conductivity type of the grown layer, it is necessary to inject impurity gas at a predetermined concentration in advance, for example.
This is carried out by mixing PH ₃ , B ₂ H ₆ , etc. with SiCl ₄ or SiH ₄ , and then supplying the mixed gas onto the Si substrate 1. In this method, by switching and supplying different types of raw material gases, Si growth layers 7 and 8 with desired electrical conductivity are grown on the Si substrate 6, as shown in the cross section of the growth layer in FIG. be able to.

In such a case, if the impurity concentration in the substrate 6 is high and the impurity concentration in the growth layer is low, this may be due to the well-known autodoping of impurities or the presence of a stop layer that contributes to its effects. ,
It is difficult to obtain crystals with a steep concentration profile at the interface between the substrate 6 and the growth layer 7. Furthermore, when growth layers 7 and 8 are grown with different conductivity types, since the volume from the source gas switching point to the substrate is large, it takes time to replace the gas, and a steep rise occurs near the interface between the growth layers. It has the disadvantage that crystals with changed conductivity types cannot be obtained.

In the present invention, a growth gas supply member is disposed so that its opposing surface is parallel to and close to the substrate, and a scavenging gas introduction pipe having a scavenging port opening approximately in the center of the opposing surface is provided. This drawback can be eliminated by configuring the system so that the gas can be quickly switched and supplied onto the substrate, and it can also be effectively applied to - group compound semiconductor crystals and their mixed crystals, which have recently become rapidly needed. The present invention provides a semiconductor vapor phase growth apparatus constructed as described above.

An embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view of the vapor phase growth apparatus,
A gas supply system, a power source for heating the substrate, etc. are not shown. Here, it is one of - group compound semiconductor crystals. In _x Ga _1-x As _1-y P _y on InP substrate
An example will be described by taking as an example a case where InP is grown sequentially. Therefore, in this case, in the cross-sectional view of the grown crystal in FIG. 2, 6 corresponds to the InP substrate, 7 corresponds to the In _x Ga _1-x As _1-y P _y growth layer, and 8 corresponds to the InP growth layer. In Fig. 3, 11 is a plurality of InP substrates, 12 is a substrate setting heating plate, which can be rotated around an axis 12a, 14 is a heating high frequency coil housing part, and 15 is connected to the heating power source. This is a thermocouple that controls the substrate temperature at a constant level. Reference numeral 16 denotes a gas supply member for uniformly supplying the raw material gas to be grown onto the substrate 11, and the surface of the gas supply member facing the substrate in close proximity to the substrate is installed parallel to the substrate, and the opposite surface is arranged in parallel with the substrate. It has an area covering a plurality of substrates 11, and is provided with many pores 16a on the opposing surface, and feed gas is introduced onto the substrates 11 from an inlet 17 through the pores 16a. A gas introduction pipe 18 is provided at the center of the gas supply member 16 to allow scavenging gas to be introduced onto the substrate 11 independently of the growth supply gas. This gas introduction pipe is an inlet 19 through which gas is introduced.
It has an opening on the substrate 11. The gas supplied from the inlet 20 is used to discharge other unnecessary gases from the outlet 21 to keep the inside of the growth apparatus 13 clean. When actually growing a crystal, it is done as follows. The InP substrate 11, which has been pretreated to a desired state, is set as shown in FIG. The temperature is raised to a predetermined temperature in a desired atmospheric gas.
Next, in order to grow a quaternary compound crystal that is InGaAsP, In(C ₂ H ₅ ) ₃ , Ga(C ₂ H ₅ ) ₃ , AsH ₃ ,
A gas mixed with PH ₃ at a desired partial pressure is supplied to the gas supply member 16 through the inlet 17 in FIG. 3 using a carrier gas.
It flows onto the InP substrate 11 through the pores 16a. At this time, In(C ₂ H ₅ ) ₃ , Ga(C ₂ H ₅ ) ₃ , AsH ₃ , and PH ₃ undergo a chemical reaction to form a desired composition on the InP substrate 11.
InGaAsP grows. The thickness at which InGaAsP grows is determined by the substrate temperature, the amount of mixed gas supplied, and other factors. When the desired growth layer has been obtained, a scavenging gas consisting of high purity hydrogen or an inert gas is introduced onto the substrate 11 from the gas introduction pipe 18 to remove any residual gas.
In( _{C2H5 ) 3} , Ga _{( C2H5} ) ₃ , etc. are removed. next
In order to grow InP, a mixed gas of In(C ₂ H ₅ ) ₃ and PH ₃ at a desired partial pressure is introduced onto the substrate 11 through the gas supply member 16 and the pores 16a, and the gas introduction pipe 1
Stop the gas introduced from 8. After the desired InP has grown, the introduction of the mixed gas from the gas supply member 16 is stopped, and a desired atmospheric gas is quickly introduced from the gas introduction pipe 18 to stop the growth on the substrate 11. The surface of the substrate 11 and the gas supply member 16
Since the surface facing the substrate 11 is placed parallel to the substrate 11, the amount of growth gas supplied onto the substrate 11 is kept uniform, and the temperature distribution within the upper surface of the substrate 11 is also maintained. kept uniform. Therefore, the thickness of the film grown on the substrate 11 can be controlled uniformly. Furthermore, it is also possible to grow while rotating the substrate 11. The material for the gas supply member 16 is preferably high-purity quartz or boron nitride, but metals such as molybdenum and tungsten may also be used. Further, as the growth raw material, a growth element or a composition material consisting of a growth element can be used. Furthermore, it is obvious that in order to perform impurity doping with this apparatus, a compound gas containing an impurity element may be added to the growth mixed gas at a predetermined partial pressure. Zn as a source of impurities
( _C2H5 ) ₂ , _H2Se , _H2Te , _H2S , _SnCl2 , _{GeH4 ,}
SiH ₄ or the like can be used as appropriate.

As described above, the present invention provides a growth gas supply member having a large number of pores on the surface facing the substrate, and an exhaust gas introduction pipe for controlling the atmospheric gas on the substrate, so that the bonding changes rapidly. This has the effect of making it possible to obtain crystals with planes.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional Si vapor phase growth apparatus, Figure 2
The figure is a cross-sectional view of a grown crystal, and FIG. 3 is a cross-sectional view of a vapor phase growth apparatus according to an embodiment of the present invention. 11
16 is a substrate, 16 is a growth gas supply member, 16a is a pore, and 18 is an exhaust gas introduction pipe.

Claims (1)

[Claims] 1. A heating plate for heating a plurality of substrates placed on its upper surface, and an opposing surface that covers all of the substrates and has a large number of pores formed therein, which is parallel to and close to the substrates on the heating plate. a growth gas supply member which supplies a growth element, a composition comprising the growth element, or a mixed gas thereof onto the substrate through the pores using a carrier gas; and a scavenging gas opening approximately in the center of the opposing surface. A scavenging gas introduction pipe having a gas scavenging port and introducing a scavenging gas onto the substrate from the scavenging port and discharging the growth gas remaining on the substrate to the outside. Phase growth device.