JP2003081695A - SiC SEMICONDUCTOR AND METHOD OF EPITAXIALLY GROWING SiC - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress miss-fit dislocations caused by the difference in the lattice constants, and to provide a high quality SiC semiconductor and a method of epitaxially growing SiC. SOLUTION: The SiC semiconductor is characterized in that 3C-SiC is formed by an epitaxial growth method on the surface of a Si wafer interposing a buffer layer of BP being a sphalerite-type single crystal between the 3C-SiC and the Si wafer. The epitaxial growth method comprises interposing BP being the sphalerite-type single crystal as the buffer layer when the 3C-SiC is epitaxially grown on the surface of the Si wafer being the substrate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a SiC semiconductor and a SiC epitaxial growth method.

[0002]

2. Description of the Related Art There is a lattice mismatch between silicon that becomes a substrate and SiC that is epitaxially grown on the silicon substrate. As a result, many crystal defects are generated due to misfit dislocations, which is a problem during device fabrication.

Therefore, it is important to introduce a technique for suppressing crystal defects due to the difference in lattice constant.

A method is known in which the surface of a silicon substrate is carbonized with a hydrocarbon gas and SiC is grown using this as a buffer layer.

[0005]

According to this conventional method, the phenomenon that Si atoms in the silicon substrate are carried away to the substrate surface by the carbonization treatment and voids are formed in the silicon substrate, and the silicon substrate is roughened, is found. To be

An object of the present invention is to provide a high-quality SiC semiconductor and a SiC epitaxial growth method that suppresses misfit dislocations due to a difference in lattice constant.

[0007]

The solution means of the present invention is exemplified as follows.

(1) A SiC semiconductor characterized in that 3C-SiC is formed by epitaxial growth on the surface of a Si wafer via a BP buffer layer.

(2) The aforementioned SiC semiconductor in which BP is a zinc blende type single crystal.

(3) A SiC wafer in which a single crystal SiC film is formed on a silicon substrate via a buffer layer.

(4) The buffer layer is B of zinc blende type crystal
The aforementioned SiC wafer which is P.

(5) 3C on the Si wafer to be the substrate
-A SiC epitaxial growth method characterized in that when epitaxially growing SiC, BP is interposed as a buffer layer.

(6) The above-mentioned SiC epitaxial growth method in which BP is a zinc blende type single crystal.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides an SiC semiconductor having an excellent performance as a semiconductor function as compared with Si and an epitaxial growth method.

SiC semiconductors, especially 3C-SiC semiconductors, are manufactured mainly by epitaxially growing 3C-SiC on a Si (silicon) substrate.

In such epitaxial growth, the film formation layer inherits the crystallinity of the silicon substrate. Therefore, the roughening of the substrate should be avoided in order to obtain a good quality crystal.

Therefore, it is preferable to provide a buffer layer of an appropriate substance so as not to cause the roughness of the substrate.

For example, 3 is formed on a Si wafer which is a substrate.
When C-SiC is epitaxially grown, zinc blende type single crystal BP (boron phosphide) is used as a buffer layer. Thereby, crystal defects are reduced.

The lattice constant of BP (boron phosphide), which is a zinc blende type crystal, is 4.538 angstroms, which is almost the same as 4.358 angstroms of 3C-SiC, and misfit dislocations due to lattice mismatching occur. Can be suppressed. Also, the coefficient of thermal expansion is almost the same.

BP has a lattice constant of 1 with Si.
BP can be heteroepitaxially grown on Si with a difference of 6.4%.

First, by epitaxially growing BP on a Si substrate and then growing 3C-SiC, a crystal in which misfit dislocations are suppressed can be obtained.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the preferred embodiments will be described below.

(1) Substrate Si (100) or (1
By heating 11) above 1000 ° C. in a hydrogen atmosphere, the native oxide film on the substrate is removed.

[0024] As hydrogen (2) carrier gas, flowing BCl ₃ and PCl ₃ in P raw material B material in the reaction tube, for about 30 minutes at about 200 to 500 ° C. The low temperature growth.

(3) At the end of the low temperature growth, the supply of the BP raw material is stopped and the temperature is raised to 900 to 1200 ° C. which is the BP crystal growth temperature.

(4) When the growth temperature reaches 900 to 1200 ° C., the supply of the BP raw material is started and maintained for 30 minutes or longer to form a BP layer of about 1 to 5 μm.

(5) After completing the predetermined crystal growth time,
The supply of the BP raw material is stopped and the temperature is maintained for about 30 minutes.

(6) Next, the low temperature growth temperature of SiC is set to 200 to 500 ° C., the supply of methylsilane as a raw material is started, and the temperature is maintained for about 10 minutes.

(7) The crystal growth temperature of 3C-SiC is set to about 800 to 1200 ° C. and kept for 30 minutes or longer to form a SiC layer of 10 to 30 μm.

(8) The methylsilane raw material supply is stopped at the time when the 3C-SiC crystal growth time ends, and the temperature is maintained for about 30 minutes.

3 produced by the above steps (1) to (8)
For comparison with a C-SiC semiconductor (particularly its crystal), a 3C-SiC crystal was grown on a Si substrate without a BP layer, that is, under the conditions in which the step (2) to (5) were excluded. An attempt was made to manufacture a 3C-SiC semiconductor. Comparing these, the 3C-SiC semiconductor crystal prepared by providing the BP buffer layer had high quality crystals in which misfit dislocations due to the difference in lattice defects were satisfactorily suppressed. The one manufactured without the buffer layer only forms polycrystalline SiC,
Could not be manufactured.

The present invention is not limited to the embodiments. For example, as the source gas, various substances such as hydride, organic metal source material, etc. can be used in addition to chloride.

[Brief description of drawings]

FIG. 1A is a schematic view showing a state where SiC is directly grown on a Si wafer. FIG. 3B is a schematic diagram showing growth of a 3C-SiC single crystal according to a preferred embodiment of the present invention.

Continued front page    (72) Inventor Hideo Nakanishi             30 Soya, Hadano City, Kanagawa Prefecture             Kusu Co., Ltd. Development Laboratory (72) Inventor Kazutaka Terashima             206-3 Nakano, Ebina City, Kanagawa Prefecture F-term (reference) 4G077 AA03 BE08 DB05 DB09 ED06                       EF02 HA06 TK01                 5F045 AA03 AB06 AB09 AC03 AD06                       AD07 AD08 AD09 AD12 AD13                       AD14 AD15 AD16 AF03 BB12                       DA53 EB15

Claims (6)

[Claims] 1. A SiC semiconductor, wherein 3C-SiC is formed by epitaxial growth on the surface of a Si wafer via a BP buffer layer. 2. The SiC semiconductor according to claim 1, wherein BP is a zinc blende type single crystal. 3. A single crystal SiC film is formed on a silicon substrate via a buffer layer.
C wafer. 4. The SiC wafer according to claim 3, wherein the buffer layer is BP of zinc blende type crystal. 5. A 3C-S film is formed on a Si wafer as a substrate.
A SiC epitaxial growth method characterized by interposing BP as a buffer layer when epitaxially growing iC. 6. The SiC epitaxial growth method according to claim 5, wherein BP is a zinc blende type single crystal.