JPS6350395A - Production of compound semiconductor crystal substrate - Google Patents

Abstract

PURPOSE:To economically produce the title high-quality compd. semiconductor substrate on a substrate having a large area by forming the intermediate layer of a compd. semiconductor crystal on a supporting crystal substrate of a different kind of material by the MBE method, and growing a compd. semiconductor crystal on the intermediate layer by the VPE method. CONSTITUTION:The intermediate layer 2 of the compd. semiconductor crystal consisting of group III and V elements is formed on the supporting crystal substrate 1 consisting of a silicon or germanium signal crystal by the molecular beam epitaxy (MBE). The same compd. semiconductor crystal 3 is further formed on the intermediate layer 2 by the vapor phase epitaxy (VPE). One method among the chloride VPE method, the high chloride VPE method, and the org. metal vapor phase epitaxy (MO-VPE) or a combination of the two methods is used as the VPE method. As a result, the quality of the semiconductor crystal can be improved to the extent where the crystal can be applied to a device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method for manufacturing a compound semiconductor crystal substrate in which a compound semiconductor crystal is formed on a supporting crystal substrate made of a different material.

[Conventional technology]

Compound semiconductor crystal substrates have traditionally been used in optical devices such as lasers, light emitting diodes (LEDs), and solar cells, and electronic devices such as junction transistors and field effect transistors, and more recently, they have been used to integrate optical devices and electronic devices. It has also been used in so-called opto-electronic devices.

These devices were fabricated on a compound semiconductor substrate manufactured by the horizontal Bridgman method or the Czochralski pulling method, in which a compound semiconductor crystal ingot was cut and cored onto a compound semiconductor crystal support substrate and homoepitaxially formed. However, compound semiconductor crystal substrates manufactured by this method are expensive and have a large surface with few defects.
Currently, it is difficult to obtain multi-crystalline substrates. In order to solve these problems and take advantage of the advantages of compound semiconductor crystals and to obtain large-area, economical compound semiconductor crystal substrates, inexpensive, large-area, mass-production technology has been established. Attempts have been made to form compound semiconductor crystals on silicon or germanium crystals to produce compound semiconductor crystal substrates that can be applied to inexpensive, high-performance, and multifunctional devices.

Production methods that have been tried so far include the chloride VPG method, the hydride VPE method, the MBB method, and the M.

-VPE methods, each of which was used independently.

The chloride VPE method or the hydride VPE method has been applied to the production of practical optical devices such as lasers and LEDs, and has a track record of producing high-quality homoepitaxial compound semiconductor crystal substrates. However, a method for manufacturing a so-called heteroepitaxial compound semiconductor crystal substrate in which a compound semiconductor crystal is formed on a support crystal substrate made of different materials has not yet been developed. The cause is chloride V
The quartz reaction tube wall is etched by the ICt gas, which is very small in the oxygen component contained in the growth source gas used in the PE method or the hydride VPE method, and the supporting crystal substrate surface is oxidized by the oxygen component released from the tube wall. , compound semiconductor crystals are not deposited on the supporting crystal substrate.

MBE method is chloride VPE method or hydride VP
Compared to the E method, a compound semiconductor crystal is deposited on the supporting crystal substrate because an atmosphere with a very low oxygen component is achieved. However, a compound semiconductor crystal on a heterocrystalline substrate formed by the MBE method has poor crystallinity and cannot be applied to devices. Furthermore, MBE equipment generally uses chloride VP.
It is very expensive and has inferior production capacity compared to E equipment or hydride VPE equipment. In the Mo-VPE method, compound semiconductor crystals can be deposited on a supporting crystal substrate made of a different material, but the carbon component contained in the organometallic raw material gas has an adverse effect on the surface of the supporting crystal substrate made of a different material. , MO-VI'E method alone cannot provide a high-quality compound semiconductor crystal substrate that can be applied to devices.

[Problem that the invention seeks to solve]

As described above, the conventional method for manufacturing a compound semiconductor crystal substrate has the drawback that it is difficult to obtain a large-area crystal substrate with few defects at a low cost.

The purpose of the present invention is to solve the drawbacks of the conventional compound semiconductor crystal substrate manufacturing methods described above, and to provide a manufacturing method for economically and high-quality compound semiconductor crystal substrates on a large-area support crystal substrate made of different materials. It is about providing.

[Means for solving problems]

In order to achieve the above object, the present invention forms a compound semiconductor crystal intermediate layer on a supporting crystal substrate of silicon or germanium by the MBE method, and further coats a high quality compound semiconductor crystal thereon by using the chloride VPE method or the hydride method. V.P.E.
The main feature is that the growth can be performed by one method or a combination of two or more methods among the method and the Mo-VPE method. N on the supporting crystal substrate as in the conventional manufacturing method.
This is different from growing a compound semiconductor crystal using only the IBE method or only the VPE method.

[For production]

Reasons for the crystallinity improvement effect of the VPE method In the MBE method, the pressure of the raw material gas is lo-4~/
Since growth is carried out in a high vacuum of about 0-7 torr, it is not possible to raise the substrate temperature too high because if the substrate temperature is high, the group II thorns with high vapor pressure will re-evaporate from the substrate and the crystal will no longer grow. . Furthermore, in the MBE method, the chemical reaction is not sufficient because the vapor deposition method uses thermal decomposition of the raw material. For these reasons, the m-v group compound semiconductor grown on Si by the MBE method has poor crystallinity. However, V
The PE method uses normal pressure to slightly reduced pressure (/ 00 torr -/
(torr), the substrate temperature can be increased without re-evaporation of the group (1) raw material. When an m-v group semiconductor is present on the substrate surface, if the substrate temperature is high, the reaction of the group II and group III that have arrived on the substrate will proceed sufficiently and the m-v group will grow on the substrate.
Group V compound semiconductors have improved crystallinity. Also, M.B.
On the E intermediate layer: - When grown using the VPE method, by raising the substrate temperature higher than the temperature at which the MBE intermediate layer was grown, a solid phase reaction occurs due to the annealing effect, and the lattice distortion is restored, resulting in MBE. The crystallinity of the intermediate layer is also improved, and a crystal with good crystallinity can be grown on it by the VI'E method.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings, citing a compound semiconductor crystal substrate in which a silicon crystal substrate is used as a supporting substrate and GaP is used as a compound semiconductor crystal.

FIG. 1 shows the main steps in one embodiment of the present invention, where l is a silicon supporting crystal substrate, 2 is C) an aP compound semiconductor crystal intermediate layer formed by the MBE method, and 3 is Vl) an aP compound semiconductor crystal intermediate layer formed by the E method. This is a GaP compound semiconductor crystal layer.

A GaP compound semiconductor crystal intermediate layer (as shown in FIG. 1) is formed on the surface of the silicon supported crystal substrate by the MBE method. E After the dust was charged into the equipment and evacuated to a high vacuum with a vacuum level of 10-7 to 0-10'porr, it was treated at a high temperature of 00°C or higher, and the substrate surface was further cleaned, and then the GaP compound semiconductor crystal intermediate was removed. Further, as shown in FIG.
A GaP compound semiconductor crystal is grown by the VPE method on the GaP compound semiconductor crystal intermediate layer formed by the BE method.
A P compound semiconductor crystal substrate is obtained.

Table 1 shows the plane orientation (10O) and U (///) of the silicon supporting crystal substrate /, using hydride VP as the VPE method.
A typical example of evaluating crystal quality when using the E method is to measure the half-width of the X-ray diffraction spectrum by the X-ray double crystal method and the surface condition examined with an optical microscope using a silicon-supported crystal.
The film thicknesses of the GaP intermediate layer formed by the MBE method and the GaP layer grown thereon by the VPE method are shown.

The X-ray half-width in Table 1 is a (≠00) plane reflection when a silicon <, 1oo) substrate is used, and a C333' single plane reflection when a silicon (/I/) substrate is used. As is clear from Table 1, Ga formed by MBE on a silicon support substrate
The X-ray half-width of the P intermediate layer is large, indicating poor crystal quality, but the X-ray half-width of the Gat' crystal grown on the MBE intermediate layer by the VPE method is small, indicating that the crystal quality is poor. Silicon accounts for 6%, which has a large quality improvement effect (//
/) In the case of the support substrate, the half-width of the MBE intermediate layer is infinite,
The quality of the crystals cannot be evaluated using the so-called X-ray double crystal method.
This indicates that the crystal quality is poor, but even in that case, MBE
GaP grown by VPE method on the intermediate layer (7)
The half width of the line is small, indicating that the VPE method has a significant effect of improving crystal quality. Furthermore, in order to examine the effects of the present invention, an LED device shown in FIG. 2 was fabricated using the compound semiconductor crystal substrate according to the above example.

In the figure, / indicates a silicon supported crystal substrate 1.21"!: GaI' compound semiconductor crystal intermediate layer formed by MBE method, 3/ indicates a mouth-shaped GaP layer, and 32 indicates a P-type G formed by zinc diffusion.
The aP layer is shown, Hiroshi indicates a P-type electrode, and Yu indicates an N-type electrode. The GaP LED device fabricated on the GaP compound semiconductor crystal substrate in this way has a center wavelength! 73-, which demonstrated the effect of the present invention, that is, that high-quality P-type and N-type GaP crystals were obtained.

In the above embodiments, a silicon crystal substrate is used as a supporting crystal substrate.
In the case where GaP is used as the compound semiconductor crystal,
Even when a germanium crystal substrate is used as the supporting crystal substrate, the same effect as described above can be obtained, and even when the compound semiconductor crystal is made of group II and group V elements other than GaP, the same effect as above can be obtained, and the MBE method This is also the case when only the hydride VPE method is used, but the same result can be obtained even if other VPE methods such as chloride VEP method, MO-VPE method, etc. are used individually, or when two or more VPE methods are combined. You can expect good results.

〔Effect of the invention〕

As explained above, in a method for manufacturing a compound semiconductor crystal substrate by forming a compound semiconductor crystal on a supporting crystal substrate made of a different material, M B is formed on the supporting crystal substrate.
By forming a compound semiconductor intermediate layer using the E method and growing a compound semiconductor crystal on top of it using the VPE method,
The quality of compound semiconductor crystals can be improved to a level that can be applied to devices, making it possible to economically manufacture multifunctional optical devices, electronic devices, and opto-electronic devices that are integrated over a large area.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main steps in an embodiment of the present invention, and FIG. 2 is a sectional view of the present invention applied to an LED device. /...Silicon supporting crystal substrate, 2...GaP compound semiconductor crystal intermediate layer by MBE method, 3...VlJ
GaP compound semiconductor crystal layer by E method, ≠...P-type electrode,! ...n-type electrode, 3/...n-type GaP layer, 32
...P-type GaP layer. Part 1 Anti-Y2 diagram

Claims (1)

[Claims] 1. In manufacturing a compound semiconductor crystal substrate by forming a compound semiconductor crystal on a supporting crystal substrate of a different material, a compound semiconductor crystal is formed on the supporting crystal substrate by molecular beam epitaxy (MBE). A method for manufacturing a compound semiconductor crystal substrate, comprising forming an intermediate layer and growing a compound semiconductor crystal thereon by vapor phase epitaxy (VPE). 2. The method for manufacturing a compound semiconductor crystal substrate according to claim 1, wherein the supporting crystal substrate is made of silicon or germanium single crystal, and the compound semiconductor crystal is made of a group III and group V element. 3. The vapor phase epitaxy (VPE) method uses chloride VP
The compound according to claim 1, which is a method of one method or a combination of two or more of the E method, hydride VPE method, and metal organic vapor phase epitaxy (MO-VPE) method. A method for manufacturing a semiconductor crystal substrate.