JPH01194319A - Vapor growth method and device for semiconductor - Google Patents

Abstract

PURPOSE:To obtain a heterojunction semiconductor crystal having a sharp and good hetero-interface and crystallinity and good characteristics, by adjusting a temperature which is appropriate for growth of a semiconductor using auxiliary heating means and by changing a substrate temperature abruptly. CONSTITUTION:There are provided a high frequency coil 2 heating a susceptor 3 in a reactor 1 by induction heating to heat a substrate on the susceptor around outer periphery of the reactor 1 and an infrared lamp 5 heating the substrate at high speed. With this apparatus, a GaAs semiconductor crystal and AlGaAs are epitaxially grown on a GaAs semiconductor substrate by an organic metal vapor growth method. At this time, a temperature of the susceptor 3 is adjusted for the GaAs semiconductor crystal whose optimal temperature during crystalline growth is the lowest. This susceptor temperature is kept constant with the substrate temperature adjusted by a lamp 5 only. First, GaAs semiconductor crystal is grown, the substrate 4 is heated by the lamp 5 and then the AlGaAs semiconductor crystal is grown. Then, heating by the lamp is stopped and the substrate 4 temperature is lowered and then the GaAs semiconductor crystal is grown again.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for vapor phase growth of semiconductors. More specifically, the present invention relates to a method and apparatus for vapor phase growth of a heterojunction of two or more types of semiconductor crystals having a steep slope and good crystallinity.

BACKGROUND OF THE INVENTION Semiconductor devices such as light emitting diodes and petrojunction bipolar transistors are fabricated by forming two or more types of semiconductors into petrojunctions.

When the above-mentioned semiconductor device is manufactured by the organic gold air one-layer growth method, the optimum substrate temperature for growing each semiconductor is different.

Therefore, conventionally, to fabricate the above-mentioned devices using the vapor phase growth method, there were two methods: (1) growing all semiconductor crystals at a constant substrate temperature that allowed each semiconductor to grow to some extent, or (2) growing each semiconductor crystal at a constant substrate temperature. Semiconductors are grown after adjusting the substrate temperature to an appropriate temperature for each semiconductor, but when changing the substrate temperature, one of the methods used is to temporarily interrupt the growth of semiconductor crystals.

Problems to be Solved by the Invention Conventionally, the above-mentioned semiconductor devices have been manufactured using either of the above two methods, but it is now possible to grow two or more types of semiconductors with different substrate temperatures suitable for crystal growth at the same substrate temperature. However, there was a problem that the characteristics of the semiconductor crystal were not improved.

By adjusting the substrate temperature to suit each semiconductor, the characteristics of semiconductor crystals can be improved, but if crystal growth is interrupted for a long time and the substrate temperature is changed, the crystallinity of the surface may be disturbed during that time, or Phenomena such as the incorporation of impurities occurred, making it impossible to create a steep Peter interface.

Means for Solving the Problems According to the present invention, in a method for epitaxially growing two or more types of semiconductor crystals on a semiconductor substrate by metal organic vapor phase epitaxy, an auxiliary heating means that can be controlled independently of the main heating means for the substrate is used. A semiconductor vapor phase growth method characterized by rapidly changing the temperature of at least the substrate surface using a heating means and growing at a substrate temperature suitable for each semiconductor, and an airtight method for realizing this method. A reactor that is sealed and can change the internal pressure and atmosphere, a gas supply means for supplying a raw material gas and an atmosphere gas into the reactor, an exhaust means for exhausting the gas inside the reactor, and a reactor located inside the reactor, A semiconductor vapor phase epitaxy apparatus comprising a susceptor on which a semiconductor substrate is mounted, and a heating means for heating the semiconductor substrate on the susceptor,
The heating means has two systems: a main heating means that can heat the entire substrate, and an auxiliary heating means that can rapidly heat at least the surface of the substrate, and that each can be independently controlled. A semiconductor vapor phase epitaxy apparatus with features is provided.

For example, when a GaAs semiconductor crystal and an AlGaAs semiconductor crystal are epitaxially grown on a GaAs semiconductor substrate, the method and apparatus of the present invention can be used to grow an InP semiconductor crystal and/or a GaInAs semiconductor crystal and an A11nAs semiconductor crystal on an InP semiconductor substrate. It is preferable to apply this method when epitaxially growing.

In these cases, AlGaAs5A11nAs
During semiconductor crystal growth, both the main heating means and the auxiliary heating means are used to raise the substrate temperature, and also to increase the substrate temperature when growing GaAs, I
nP.

When growing a GaInAs semiconductor crystal, it is preferable to keep the substrate temperature low by using only the main heating means.

Various types of semiconductors using functional heterojunctions require both that each semiconductor crystal has good crystallinity and excellent characteristics, and that the semiconductors have good junctions and that the heterojunction is steep. be done.

When a semiconductor crystal having a heterojunction is manufactured by metal organic vapor phase epitaxy, the substrate temperature suitable for growing each semiconductor crystal usually differs depending on the semiconductor.

However, the conventional methods are to grow all semiconductor crystals while keeping the substrate temperature constant, or to change the substrate temperature for each semiconductor, but when changing the substrate temperature, the growth of semiconductor crystals is interrupted. Either method was used.

In the former method, the substrate temperature is constant and is not the optimum substrate temperature for crystal growth of each semiconductor, resulting in poor crystallinity of the semiconductor crystal and problems with properties. In addition, in the latter method, the crystallinity of the semiconductor crystal,
Although the characteristics are improved, since crystal growth is interrupted for a long time and the substrate temperature is changed, the crystallinity of the surface is disturbed and impurities are incorporated during that time, resulting in poor heterojunction conditions.
Additionally, the interface was no longer steep.

In the method of the present invention, by using auxiliary heating means, the substrate temperature is rapidly changed to a temperature suitable for growing the respective semiconductor crystal without interrupting the crystal growth for a long time.

Therefore, the petrojunction semiconductor crystal obtained by the method of the present invention not only has good crystallinity of each semiconductor crystal and excellent properties, but also has good heterojunction state and interface state, and is a high-performance product. becomes.

In the method of the present invention, AlGaA
When producing a heterojunction semiconductor by epitaxially growing an s semiconductor crystal and a GaAs semiconductor crystal,
It is preferable to apply this method to the case where a heterojunction semiconductor is manufactured by epitaxially growing an InP semiconductor crystal and/or a GaInAs semiconductor crystal and an Al[nAs semiconductor crystal on an InP semiconductor substrate.

Further, the present invention provides a semiconductor vapor phase epitaxy apparatus for implementing the above method. In the vapor phase epitaxy apparatus of the present invention, the substrate heating means consists of two independent systems: a main heating means that heats the entire substrate, and an auxiliary heating means that can rapidly heat at least the surface of the substrate. Herein lies its main characteristic.

As the heating means for the vapor phase epitaxy apparatus of the present invention, it is preferable to use, for example, a high frequency induction heating device as the main heating means and an infrared lamp as the auxiliary heating means. It is also preferable to sandwich a heat insulating material such as a quartz plate between the susceptor on which the substrate is mounted and the substrate to reduce the heat capacity around the substrate so that the temperature change by the auxiliary heating means becomes more rapid.

Embodiment FIGS. 1 and 2 show a structural diagram of an example of the device of the present invention and an enlarged view of the vicinity of the substrate. The device of the present invention shown in FIG. 1 is hermetically sealed or placed around the outer periphery of an actor 1, and heats a substrate 4 on the susceptor 3 by induction heating a carbon susceptor 3 inside the reactor 1. a high-frequency coil 2 for rapidly heating the substrate 4, an infrared lamp 5 for rapidly heating the substrate 4, a supply means (not shown) for accurately supplying raw material gas,
It mainly consists of an evacuation means (not shown) that evacuates the inside of the reactor 1 to a high vacuum and can freely set the pressure inside the reactor 1. Further, as shown in FIG. 2, the substrate 4 is placed on the susceptor 3 via a quartz plate 6 having a heat insulating effect, and thermocouples 8. 9 is installed to monitor the temperatures of the susceptor 3 and the substrate 4.

Using the above-described apparatus of the present invention, a GaAs semiconductor crystal and an AlGaAs semiconductor crystal are formed on a GaAs semiconductor substrate by the method of the present invention, and an InP semiconductor crystal, a GafnAs semiconductor crystal, and an AlInAs semiconductor crystal are formed on an InP semiconductor substrate. All were grown epitaxially by metal organic vapor phase epitaxy.

When producing a GaAs-based semiconductor, the susceptor temperature was set to 700° C. in accordance with the GaAs semiconductor crystal, which has the lowest optimum temperature for crystal growth. Note that this susceptor temperature remained constant during semiconductor fabrication, and the substrate temperature was adjusted only by an infrared lamp. First, a GaAs semiconductor crystal was grown to a thickness of 1 μm, and after heating the substrate temperature to 775° C. with an infrared lamp, an AlGaAs semiconductor crystal was grown to a thickness of 0.5 μm.

Furthermore, we stopped heating the infrared lamp and lowered the substrate temperature to 7.
The temperature was lowered to 00° C., and GaAs semiconductor crystal was grown again to a thickness of 1 μm. The time during which crystal growth was interrupted was 10 seconds in each case, which was significantly shortened compared to conventional methods.

When manufacturing InP-based semiconductors, the susceptor temperature should be
I
After growing an nP semiconductor crystal to a thickness of 1 μm, heating was performed using an infrared lamp to raise the substrate temperature to 670° C., and an AlInAs semiconductor crystal was grown to a thickness of 0.1 μm. Furthermore, heating with an infrared lamp was stopped, and when the substrate temperature had fallen to 620° C., GaInAs semiconductor crystal was grown again to a thickness of 0.3 μm.

As described above, G
Both the aAs-based heterojunction semiconductor crystal and the InP-based heterojunction semiconductor crystal had a heterointerface of 6 Å or less, which was extremely steep. In addition, each semiconductor had good crystallinity and excellent properties.

Effects of the Invention As detailed above, according to the present invention, a heterojunction semiconductor crystal having a steeper and better heterojunction interface and crystallinity and having excellent characteristics can be obtained compared to the conventional method. This is achieved by utilizing an auxiliary heating means unique to the apparatus of the present invention, adjusting the temperature to the optimum temperature for the growth of each semiconductor, and rapidly changing the substrate temperature, which is a feature of the method of the present invention. This was made possible by making the interruption time extremely short.

The present invention is effective when used to fabricate HEMTs that use two-dimensional electrons at heterointerfaces, laser diodes that use quantum well structures, and the like.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of an example of the device of the present invention, and FIG. 2 is an enlarged view of the vicinity of the substrate of the device shown in FIG. [Main reference numbers] 1...Reactor, 2...High frequency coil, 3...
... Susceptor, 4... Substrate, 5... Infrared lamp, 6... Quartz plate, 7... Dummy substrate, 8.9
...Thermocouple patent applicant Sumitomo Electric Industries, Ltd.

Claims (6)

[Claims] (1) In a method of epitaxially growing two or more types of semiconductor crystals on a semiconductor substrate by metal organic vapor phase epitaxy, at least the surface of the substrate is A method for vapor phase growth of semiconductors characterized by rapidly changing the temperature of the semiconductor and growing at a substrate temperature suitable for each semiconductor. (2) In a method of epitaxially growing a GaAs semiconductor crystal and an AlGaA semiconductor crystal on a GaAs semiconductor substrate, when growing the AlGaAs semiconductor crystal, the substrate is heated using both the above-mentioned main heating means and the above-mentioned auxiliary heating means. Raising the temperature and heating the substrate using only the above-mentioned main heating means during GaAs semiconductor crystal growth,
The method according to claim 1, characterized in that the substrate temperature is lowered. (3) In a method of epitaxially growing an InP semiconductor crystal and/or a GaInAs semiconductor crystal and an AlInAs semiconductor crystal on an InP semiconductor substrate, A
During the growth of the lInAs semiconductor crystal, the substrate temperature is raised by heating using both the above-mentioned main heating means and the above-mentioned auxiliary heating means, and the InP semiconductor crystal and GaInA
s. The method according to claim 1, wherein during semiconductor crystal growth, the substrate is heated only by the main heating means to lower the substrate temperature. (4) A reactor that is hermetically sealed and can change the internal pressure and atmosphere, a gas supply means for supplying raw material gas and atmospheric gas into the reactor, an exhaust means for exhausting the gas inside the reactor, and a reactor. In a semiconductor vapor phase epitaxy apparatus comprising a susceptor on which a semiconductor substrate is mounted, and a heating means for heating the semiconductor substrate on the susceptor, the heating means is a main heating device capable of heating the entire substrate. 1. A semiconductor vapor phase epitaxy apparatus comprising two systems: a heating means and an auxiliary heating means capable of rapidly heating at least the surface of a substrate, each of which can be controlled independently. (5) The semiconductor vapor phase epitaxy apparatus according to claim 4, wherein the main heating means is a high-frequency coil, and the auxiliary heating means is an infrared lamp. (6) The semiconductor vapor phase epitaxy apparatus according to claim (4) or (5), wherein the semiconductor vapor phase epitaxy apparatus is used for metal organic vapor phase epitaxy.