JPS62230698A - Production of silicon carbide single crystal film - Google Patents

Abstract

PURPOSE:To obtain a silicon carbide single crystal film, capable of accurately sustaining the ratio of Si to C at 1 and having a high quality, by carrying out the growth of the single crystal film in the presence of fluorine active seeds using silicon (Si) molecular beams and carbon (C) molecular beams. CONSTITUTION:A silicon carbide single crystal film is grown in the presence of fluorine active seeds by a molecular beam epitaxial method (MBE) using silicon (Si) molecular beams and carbon (C) molecular beams.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a high quality silicon carbide single crystal film.

(Prior art and its problems) Conventionally, as a method for manufacturing a silicon carbide single crystal film by the molecular beam growth method (MBE method), silicon (Sl) molecular beams and carbon (
C) A method using only molecular beams has been carried out (IEICE technical report 5SD84-24), but since the adhesion coefficients of Si and C are both approximately 1 from L, the molecules during crystal growth are Since changes in the intensity of the lines are immediately reflected in the composition ratio of the crystal, it has been extremely difficult to strictly control the stoichiometric ratio of the grown crystal.

It is an object of the present invention to provide a method for manufacturing a high-quality silicon carbide single crystal film in which the ratio of Si to C can be accurately maintained at 1 by eliminating such conventional drawbacks.

(Means for solving the problems) The present invention grows a silicon carbide single crystal film by a molecular beam growth method using silicon (Si) molecular beams and carbon (C) molecular beams in the presence of fluorine active species. A method of manufacturing a silicon carbide single crystal film is characterized in that:

(Function) In a method of manufacturing a silicon carbide single crystal film by molecular beam growth method (MBE method), a silicon (Si) molecular beam and a carbon (C
) By growing a silicon carbide single crystal film using molecular beams in the presence of fluorine active species, a silicon carbide single crystal film that maintains an accurate stoichiometric ratio (that is, the ratio of 5i:C is strictly 1) is grown. become easily obtainable.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a conceptual diagram showing an example of a crystal growth apparatus to which the present invention is applied. The ultra-high vacuum chamber 1 is equipped with an ultra-high vacuum evacuation system, and the inside of the chamber 1 is traversed from the exhaust system 12 to I
It has a structure that can exhaust air up to Torr. The substrate crystal 4 is inserted into the tantalum susceptor 3 and placed with its growth surface facing down.

The substrate crystal 4 was heated by directly applying electricity through the susceptor 3. A crystal resonator film thickness meter 2 is installed in the ultra-high vacuum chamber 1 near the substrate crystal 4, so that the film thickness can be measured. An E-type electron gun 6 is provided for heating the Si and C sources, and the outside thereof is covered with a liquid nitrogen shroud 5.The evaporation rates of Sz and C are measured by a crystal resonator film thickness meter 2, Prior to growth, the relationship between the intensity of the 5i and C molecular beams to the substrate surface and the control conditions of the E-type electron gun 6 was measured. High purity (9N) polycrystalline Si was used for the Si source 7, and high purity (5N) graphite was used for the C source 8.

Further, the ultra-high vacuum chamber 1 is provided with a plasma generation chamber 9, and active chemical species within the plasma generation chamber 9 can be drawn out into the ultra-high vacuum chamber 1 through an aperture 10. The plasma flows inside the plasma generation chamber 9.
The high frequency coil 11 is maintained in a Torr fluorine atmosphere.
It was generated by applying a high frequency to.

A 6H type silicon carbide single crystal made by the Acheson method was used as the substrate crystal 4, and the (0001) plane was used as the plane orientation of the substrate. After the silicon carbide single crystal substrate 4 was surface-treated with an HF-HNO3 solution, it was placed in the susceptor 3 so that the surface on which crystal growth was to be made faced down. After that, the inside of the ultra-high vacuum chamber 1 is passed through the exhaust port 12 to 3.
After evacuation, the substrate powder &4 was heated to 1400°C in an ultra-high vacuum to clean the surface, and the temperature of the substrate crystal 4 was maintained at 1150°C.

Next, fluorine plasma was generated by applying high frequency waves to the high frequency filter 11 while maintaining a fluorine atmosphere of 1 Torr in the plasma generation chamber 9, and fluorine active species were drawn into the ultrahigh vacuum chamber 1. Thereafter, Si source 7 and C source 8 were heated and evaporated using E-type electron gun 6 to grow a silicon carbide single crystal film.

Next, we will discuss the difference in the controllability of the stoichiometric ratio of a crystal-grown silicon carbide single crystal film when only silicon (Si) molecular beams and carbon (C) molecular beams are used and when grown by this method. .

Figure 2 shows the Si molecular beam intensity of 5% when the fluorine active species is drawn out into the vacuum chamber 1 as described above.
The evaporation rate of Si was controlled to be X10"i atoms/cm"・sec, and the molecular beam intensity of C was also 5
The deviation from the stoichiometric ratio of the silicon carbide single crystal film determined by x-ray analysis was It is shown based on the atomic ratio of Si and C (Si/C). Also shown are the results when crystals were grown at the same Si and C molecular beam intensities in the absence of fluorine active species.

From this figure, the Si of the silicon carbide single crystal film created by this method
It can be seen that the atomic ratio of Si and C(7) (Si/, C) is strictly 1. In contrast, the atomic ratio of Si to C (Si
/C) deviates considerably from 1.

Also, the reproducibility of stoichiometric ratios is not good.

Figure 3 shows the Si molecular beam intensity 5× with the fluorine active species drawn into the ultra-high vacuum chamber 1 as described above.
The evaporation rate of Si was controlled to be 101'atoms/cm"・See, and the molecular beam intensity of C was set to 4X10" atoms/cm.
The deviation from the stoichiometric ratio of the silicon carbide single crystal film determined by The results are shown based on the atomic ratio of Si and C (Si/C).The results are also shown when crystals are grown at the same molecular beam intensities of Si and C in the absence of fluorine active species. From this figure, it can be seen that the atomic ratio of Si to C (Si/C) in the silicon carbide single crystal film created by this method is strictly 1. In contrast, the silicon carbide single crystal film grown in the absence of fluorine active species The atomic ratio of Si to C (Si/C) of the silicon single crystal film deviates considerably from 1, resulting in a film containing excessive Si.Furthermore, the reproducibility of the stoichiometric ratio is not good.

Further, as a result of measurement of the silicon carbide single crystal films grown by the method of the present invention by reflection type high-speed electron diffraction (R)IEED), 3C type silicon carbide single crystals were obtained in all cases.

(Effects of the Invention) As described in detail above, according to the present invention, silicon (Si
) By growing a silicon carbide single crystal film using molecular beams and carbon (C) molecular beams in the presence of fluorine active species, the stoichiometric ratio was maintained accurately over a wide range of molecular beam intensity ratios (i.e. Si:C). A silicon carbide single crystal film in which the ratio of

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an example of a crystal growth apparatus to which the present invention is applied. FIGS. 2 and 3 are diagrams showing the deviation from the stoichiometric ratio of a silicon carbide single crystal film based on the atomic ratio of Si and C (Si/C) G. In the figure, 1 is an ultra-high vacuum chamber, 2 is a crystal resonator film thickness gauge, 3 is a susceptor, 4 is a substrate crystal, 5 is a liquid nitrogen shroud, 6 is an E-type electron gun, 7 is polycrystalline Si, 8 is graphite, 9 is a plasma generation chamber, 10 is an aperture, 11
is a high frequency filter, and 12 is an exhaust port.

Claims (1)

[Claims] In the presence of fluorine active species, silicon (Si) molecular beams and carbon (
C) A method for producing a silicon carbide single crystal film, which comprises growing a silicon carbide single crystal film by a molecular beam growth method using molecular beams.