JP3050970B2 - Vapor growth method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth method using a vapor phase growth apparatus used for manufacturing semiconductors and the like.

[0002]

2. Description of the Related Art A gas (raw material gas, carrier gas, etc.) is supplied into a reaction furnace, and is placed on a substrate holder disposed in the reaction furnace, heated by a heating means, and rotated by a rotating means. In a vapor phase growth apparatus for growing a thin film in a vapor phase, in general, when the substrate has a small diameter (for example, a diameter of 2 to 3 inches or less), the in-plane temperature distribution of the substrate becomes almost uniform, so that a slip or the like occurs. I never did.

In recent years, substrates having a large diameter (for example, 5 inches or more) have been generally used in order to improve work efficiency and reduce costs.

[0004]

However, as the diameter of the substrate increases, the in-plane temperature distribution of the substrate tends to become non-uniform due to a change in the gas flow rate or a change in the heating state by the heating means.

When the in-plane temperature distribution of the substrate becomes non-uniform,
Dislocation such as slip occurs in a single crystal substrate (such as a Si substrate), and a phenomenon that degrades device characteristics occurs.

[0006] The slip is in a high temperature state (for example, 1000 ° C).
The above-mentioned phenomenon is a phenomenon in which non-uniformity of the in-plane temperature distribution occurs in the substrate, so that a stress exceeding the yield value is generated and slip deformation occurs along the crystal lattice.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an object to eliminate the non-uniformity of heat transfer due to a fluid which is essentially present in CVD, thereby making the temperature distribution in the plane of the substrate uniform and suppressing the occurrence of slip and the like. It is an object of the present invention to provide a vapor phase growth method capable of preventing a high quality thin film from being vapor phase grown.

[0008]

In order to solve the above-mentioned problems, a vapor phase growth method according to the present invention supplies a source gas by a gas flow rate control means into a reactor whose growth pressure is adjusted by a pressure adjustment means. And, while being mounted on a substrate holder placed in the reaction furnace and heated by a heating means, in a vapor phase growth apparatus for vapor phase growth of a thin film on a substrate rotated by a rotary drive means, during the vapor phase growth,

[0009]

(Equation 2)

Here, Q: volume flow rate of supply gas per substrate holder area, r: substrate holder radius (rotation maximum radius),
P: reaction furnace pressure, ω: substrate rotation angular velocity, T: reaction furnace temperature, M: average molecular weight of gas, R: gas constant, μ: viscosity of supply gas at temperature T. It is characterized in that a thin film is vapor-phase grown thereon.

[0011]

By setting the flow rate of the gas supplied into the reaction furnace to be substantially close to the flow rate generated by the rotating substrate holder, the amount of heat taken by the fluid from the substrate can be made uniform within the substrate surface (ie, The in-plane temperature distribution of the substrate becomes uniform).

The present inventors have conducted intensive studies for uniforming the in-plane temperature distribution of the substrate. As a result, it has been found that the occurrence of slip is suppressed when the following conditions are satisfied during the vapor phase growth. did.

[0013]

(Equation 3)

Here, Q is the volume flow rate of the supplied gas per substrate holder area, r is the radius of the substrate holder (the maximum radius of rotation),
P: reaction furnace pressure, ω: substrate rotation angular velocity, T: reaction furnace temperature, M: average molecular weight of gas, R: gas constant, μ: viscosity of supply gas at temperature T This formula means the denominator Is the ratio between the flow rate induced in the rotating body and the flow rate of the supply gas as the molecule. If this is 1, both are equal.

Therefore, in the present invention, by performing the vapor phase growth so as to satisfy the above conditions, the in-plane temperature distribution of the substrate can be made uniform and the occurrence of slip can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on one embodiment shown in the drawings.

FIG. 1 is a schematic diagram showing a vapor phase growth apparatus according to this embodiment. As shown in this figure, a gas flow rate control for supplying gas (raw material, carrier gas, etc.) into the reactor 1 via a gas supply pipe 3 is provided above the reactor 1 in a disk-shaped current plate 2. An apparatus 4 is provided, and a substrate holder (6 inches in diameter in this embodiment) 6 on which a substrate (a silicon substrate having a diameter of 5 inches in this embodiment) 5 is placed at a lower portion in the reaction furnace 1. And a rotating shaft 7 for detachably supporting the substrate holder 6 and a heater 8 for heating the substrate holder 6 and the substrate 5.

A plurality of small-diameter holes 2a are formed in the current plate 2, and the aperture ratio is set to, for example, 0.1. In addition, the rectifying plate 2 is disposed sufficiently separated from the substrate 5 (for example, 5 cm or more). The gas supply pipe 3 is arranged on the upper side surface of the reactor 1 above the current plate 2.

A rotating shaft 7 is provided at a lower portion of the outside of the reactor 1.
Drive device 9 for rotating the drive, a rotation drive control device 10 for controlling the rotation drive of the rotation drive device 9, and an exhaust pipe 11
An exhaust device 12 for adjusting the pressure in the reaction furnace 1 and exhausting unreacted gas and the like through the air, and a filter 13 for collecting powder and the like generated in the reaction furnace 1 are provided.

The pitch 8 is connected to a heater power supply 14, a temperature control device 15, and a thermometer 16 such as a radiation thermometer for measuring the temperature of the substrate 5. The thermometer 16 is connected to the reaction furnace 1.
It is disposed outside a quartz window 17 formed below the current plate 2 on the upper side surface of the plate.

The vapor phase growth apparatus according to this embodiment is configured as described above. The inside of the reactor 1 is evacuated by the exhaust unit 12 to adjust the pressure in the reactor to a predetermined pressure (for example, 38 Torr). The substrate holder 6 is heated by the heater 8 to raise the temperature of the substrate 5 to a predetermined temperature (for example, 1000 ° C.), and the substrate 5 is rotated at a predetermined rotation speed (for example, 800 rpm) by the rotational drive of the rotary drive device 9 to supply gas. Control device 4
Into the reactor 1 through the gas supply pipe 3, by feeding with raw material gas through the small diameter hole 2a of the current plate 2 (e.g. SiH ₂ Cl ₂₎ carrier gas (e.g., H _2), a semiconductor on a substrate 5 The thin film grows in vapor phase.

In the present invention, the following conditions are satisfied when performing the vapor phase growth using the above-described vapor phase growth apparatus.

[0023]

(Equation 4)

Here, Q: volume flow rate of supply gas per substrate holder area, r: substrate holder radius (maximum rotation radius),
P: pressure in the reactor, ω: substrate rotational angular velocity, T: average temperature of gas inlet temperature and substrate temperature (Κ), M: average molecular weight of gas, R: gas constant, μ: viscosity of supply gas at temperature T When the operating conditions are set to satisfy the conditions
The thickness of the temperature boundary layer in the plane of the substrate becomes substantially uniform,
The temperature distribution in the substrate surface was made uniform.

FIG. 2 is an experimental result showing the amount of slip generated on the substrate 5 under the above conditions. At this time, the substrate 5
Is 5 inches and the diameter of the substrate holder 6 on which the substrate 5 is placed is 6 inches, but the calculated radius r is 2.5 inches (6.3 cm). The average molecular weight M and the gas constant R of the gas (SiH ₂ Cl ₂ ) and the hydrogen gas are 2 ×
10 ⁻³ kg / mol and 8.31 J / mol · k, and T is 8
00 ° C (1073K).

As is clear from the experimental results shown in FIG.

[0027]

(Equation 5)

Is from 0.3 to 1.7, preferably from 0.5 to 1.7
If it is in the range of 1.5, the amount of slip generation is greatly reduced,
At about 0.8, the amount of slip was almost zero.

The experimental results shown in FIG. 2 indicate that the substrate temperature was kept at a constant temperature (1000 ° C.) and that at each measurement point, any one of the supply gas volume flow rate Q, the reactor pressure P, and the substrate rotation angular velocity ω was used. Is arbitrarily changed. For example, at a position where the slip generation amount becomes almost zero (the lowest measurement point in the figure), the supply gas volume flow rate Q is 9 × 10 ⁻³ m.
³ / sec, the pressure P in the reactor is 1 × 10 ⁴ Pa (0.1 at
m), and the substrate rotational angular velocity ω is 84 rad / s (800 rpm). this is,

[0030]

(Equation 6)

In other combinations of the pressure, the flow rate and the number of revolutions having the same value, the slip generation amount becomes almost minimal.

Further, in the case where the same experiment as described above was performed on a substrate having a diameter of 2 inches (the diameter of the substrate holder was about 3 inches), the in-plane temperature distribution of the substrate was almost uniform. But it hardly occurred.

Further, if the substrate has a diameter larger than about 4 inches (the diameter of the substrate holder is about 5 inches), by satisfying the above-mentioned conditions, the amount of slip can be greatly reduced. Was.

[0034]

As described above, according to the present invention, even when vapor phase growth is performed on a substrate having a large diameter, the in-plane temperature distribution of the substrate can be made uniform. Therefore, occurrence of slip or the like on the substrate can be prevented, and a high-quality thin film can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a vapor phase growth apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in the amount of slip generated on a substrate by a vapor phase growth method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction furnace 2 Rectifier plate 4 Gas flow control device 5 Substrate 6 Substrate holder 8 Heater 9 Rotation drive device 10 Rotation drive control device 12 Exhaust device 15 Temperature control device

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 H01L 21/31 H01L 21/365 C23C 16/00-16/56

Claims (2)

(57) [Claims] 1. A source gas is supplied by a gas flow rate control means into a reaction furnace whose growth pressure is adjusted by a pressure adjustment means, placed on a substrate holder arranged in the reaction furnace, and heated by a heating means. At the same time, in a vapor phase growth apparatus for vapor phase growth of a thin film on a substrate rotated by a rotation driving means, Here, Q is the supply gas volume flow rate per substrate holder area,
r: substrate holder radius (rotation maximum radius), P: reaction furnace pressure, ω: substrate rotation angular velocity, T: reaction furnace temperature (average of inlet gas and substrate temperature), M: average molecular weight of gas, R: gas A constant, μ: vapor phase growth of a thin film on the substrate so as to satisfy a condition of viscosity of supply gas at temperature T. 2. The vapor phase growth method according to claim 1, wherein the diameter of the substrate holder is 4 inches or more.