JP3752895B2 - Method for manufacturing silicon carbide thin film wafer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silicon carbide thin film wafer and a method for manufacturing the same.
[0002]
[Prior art]
Epitaxial growth of silicon carbide is performed by a CVD method, using hydrogen as a carrier gas and mixing a source gas such as SiH ₄ or C ₃ H ₈ with a carrier gas, and this mixed gas is formed in a reaction furnace (usually made of high-purity quartz. And a silicon carbide or silicon single crystal substrate disposed on a graphite susceptor disposed in a reaction furnace is heated from 1400 ° C. to 1500 ° C. to form a silicon carbide single crystal thin film Is epitaxially grown.
[0003]
[Problems to be solved by the invention]
By the way, the deterioration of the graphite susceptor has been a problem. Also, the graphite susceptor coated with silicon carbide has a problem of deterioration. Here, the deterioration refers to a phenomenon in which carbon and silicon carbide evaporate and the susceptor becomes shabby and thin.
[0004]
This deterioration deteriorates the reproducibility of epitaxial growth. This is because consumption of the susceptor causes changes in the temperature of the substrate, instability, and deterioration of the temperature distribution. In addition, there is a problem in that the material evaporated from the susceptor adheres to the inner wall of the reactor and accumulates, and this deposit causes a change in gas flow path and impurity contamination.
[0005]
Accordingly, an object of the present invention is to solve the above-mentioned problems and provide a method for producing a high-quality silicon carbide thin film wafer and a silicon carbide thin film wafer that does not consume susceptors.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a silicon carbide thin film wafer according to the present invention comprises placing a silicon carbide single crystal substrate on a susceptor made of graphite or SiC-coated graphite placed in a CVD reactor, Oite silicon carbide thin film and more the silicon carbide single crystal substrate in.) except for the CVD method to the method for manufacturing the silicon carbide film wafer epitaxially grown, with use of the vertical type normal pressure reaction furnace as the CVD reactor, the In order to prevent deterioration of the susceptor from a carrier gas introduction pipe provided at the bottom of the atmospheric pressure reactor, a susceptor on which a silicon carbide single crystal substrate is placed is vertically suspended in the atmospheric pressure reactor. In addition, the bottom of the atmospheric pressure reactor is also maintained while flowing the carrier gas not containing oxygen and maintaining the atmosphere inside the atmospheric reactor without hydrogen and oxygen. Flowing by adding a raw material gas from the raw material gas introduction pipe provided at the one in which the epitaxial growth of silicon carbide thin film on the silicon carbide single crystal substrate.
[0018]
Here, this inventor considered the cause of deterioration of a susceptor for forming a silicon carbide thin film wafer.
[0019]
When hydrogen gas is used as a carrier gas, graphite is consumed when hydrogen gas is reduced with carbon of the graphite susceptor to generate methane. It was also found that oxygen contained as an impurity in the reaction atmosphere reacts with carbon to generate carbon dioxide and the like, which consumes graphite.
[0020]
In addition, silicon carbide of the silicon carbide coated susceptor reacts with hydrogen to form a hydride of silicon or carbon and vaporizes. If oxygen is present in the atmosphere as an impurity, an oxidation reaction is added to the above-described reduction reaction, and the deterioration of silicon carbide is further accelerated.
[0021]
For this reason, it turned out that hydrogen should not be used for carrier gas. It has also been found necessary to grow a silicon carbide thin film on the substrate in an oxygen-free atmosphere.
[0022]
Therefore, when an inert gas such as argon is used as the carrier gas, the above-described deterioration is suppressed. In addition, when an inert gas such as argon is used as the carrier gas, the temperature distribution of the atmospheric gas on the substrate becomes steep, and consumption of the raw material in the gas can be prevented.
[0023]
When the temperature distribution becomes steep, the temperature of the substrate facing surface of the reactor becomes lower, so that the deposition on the facing surface is reduced, the utilization efficiency of the raw material is improved, and the stability and reproducibility of growth are improved. Since the gas flow is not disturbed by the deposit, high-quality epitaxial growth can be performed.
[0024]
According to the present invention, by growing a silicon carbide thin film on a substrate in an atmosphere containing no hydrogen, it is possible to prevent silicon carbide from causing a reversible reaction with hydrogen and vaporizing into a hydride of silicon or carbon. The As a result, it is possible to provide a method for manufacturing a high-quality silicon carbide thin film wafer and a silicon carbide thin film wafer that does not consume the susceptor. In addition, when the silicon carbide thin film is grown on the substrate in an atmosphere not containing oxygen, there is no oxidation reaction, so that the deterioration of the silicon carbide thin film is prevented.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for producing a silicon carbide thin film wafer of the present invention will be described.
[0026]
The method for manufacturing the silicon carbide film wafer of the present invention, all SANYO growing a silicon carbide thin film on a substrate in an atmosphere not containing hydrogen and oxygen, consisting of graphite and graphite or SiC coated was placed into the CVD reactor A silicon carbide single crystal substrate is placed on a susceptor, and a silicon carbide thin film is epitaxially grown on the silicon carbide single crystal substrate by a CVD method (excluding a plasma CVD method). At this time, a vertical atmospheric reactor is used as the CVD reactor, and a susceptor on which a silicon carbide single crystal substrate is placed is suspended in the atmospheric pressure reactor in the vertical direction. Further, in order to prevent deterioration of the susceptor from the carrier gas introduction pipe provided at the bottom of the atmospheric pressure reactor, a carrier gas not containing hydrogen and oxygen is flowed to maintain the atmosphere in the atmospheric pressure reactor not containing hydrogen and oxygen. Similarly, a source gas is additionally flowed from a source gas introduction pipe provided at the bottom of the atmospheric pressure reactor to epitaxially grow a silicon carbide thin film on the silicon carbide single crystal substrate.
[0027]
According to the present invention, by growing a silicon carbide thin film on a substrate in an atmosphere containing no hydrogen, it is possible to prevent silicon carbide from causing a reversible reaction with hydrogen and vaporizing into a hydride of silicon or carbon. The As a result, a high-quality silicon carbide thin film wafer is obtained, and it is possible to provide a method for manufacturing a silicon carbide thin film wafer without susceptor consumption.
[0028]
【Example】
FIG. 1 is a conceptual diagram of a reactor to which the method for producing a silicon carbide thin film wafer of the present invention is applied.
[0029]
A vertical atmospheric reactor was used as a CVD furnace as the reaction furnace. This reactor is made of high-purity quartz and is cooled by a water cooling mechanism (not shown).
[0030]
The reaction furnace has a substantially funnel-shaped and closed-bottomed quartz reaction tube 1 and a susceptor rotation mechanism that is provided on the lid of the quartz reaction tube 1 and suspends and rotates a disk-shaped susceptor 4 in the vertical direction in the reaction tube 1. 9 and a high-frequency heating mechanism 2 disposed on the outer periphery of the quartz reaction tube 1, and a carrier gas introduction pipe 6, a source gas introduction pipe 7 and a dopant gas introduction pipe 8 are provided at the bottom of the quartz reaction tube 1. Yes. Reference numeral 3 denotes an exhaust port for exhausting excess gas.
[0031]
The silicon carbide single crystal substrate is placed on a susceptor 4 made of graphite, high purity argon as a carrier gas is supplied at 9 liters per minute, and the silicon carbide single crystal substrate 5 is heated to 1500 ° C. by heating with the high-frequency heating mechanism 2. When the temperature of the silicon carbide single crystal substrate 5 reaches 1500 ° C., 1 cc of SiH ₄ is flowed as a source gas per minute, and 0.6 cc of C ₃ H ₈ is flowed per minute, and carbonized on the silicon carbide single crystal substrate 5. A silicon film was epitaxially grown to a thickness of 10 μm. Grow several tens of times while flowing a dopant gas that controls conductivity, such as p-type, n-type, and i-type, if necessary, and changing the carrier gas flow rate, SiH ₄ , C ₃ H ₈ flow rate, and growth thickness I let you.
[0032]
As a result, the conventional susceptor using hydrogen gas was not consumed or deteriorated. As the susceptor 4, it may be used Si C coated graphite.
[0033]
【The invention's effect】
In short, according to the present invention, the following excellent effects are exhibited.
[0034]
It is possible to provide a method for manufacturing a high-quality silicon carbide thin film wafer and a silicon carbide thin film wafer that does not consume the susceptor.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a reactor to which a method for producing a silicon carbide thin film wafer of the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Quartz reaction tube 2 High frequency heating mechanism 3 Exhaust port 4 Susceptor 5 Silicon carbide single crystal substrate 6 Carrier gas introduction pipe 7 Raw material gas introduction pipe 8 Dopant gas introduction pipe 9 Susceptor rotation mechanism

Claims (1)

The susceptor silicon carbide single-crystal substrate made of the graphite or SiC coated was placed into the CVD reactor graphite is placed, a CVD method (excluding a plasma CVD method.) Silicon carbide thin film more silicon carbide single-crystal substrate Oite a method of manufacturing a silicon carbide thin film wafer is epitaxially grown, with using a vertical atmospheric pressure reactor as the CVD reactor, vertical susceptor placing the silicon carbide single crystal substrate by the atmospheric pressure reactor In order to prevent deterioration of the susceptor, a carrier gas containing no hydrogen and oxygen is flowed from the carrier gas introduction pipe provided at the bottom of the atmospheric pressure reactor to suspend the hydrogen and oxygen inside the atmospheric pressure reactor. While maintaining an atmosphere that does not contain any of the above, the source gas is additionally flowed from the source gas introduction pipe provided at the bottom of the atmospheric reactor, and the silicon carbide A method of manufacturing a silicon carbide thin film wafer, comprising epitaxially growing a silicon carbide thin film on a single crystal substrate .

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