JP3096073B2 - Vapor phase growth apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

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

[0003]

2. Description of the Related Art In a vapor phase growth apparatus for supplying a gas (a raw material gas, a carrier gas, etc.) into a reaction furnace and vapor-growing a thin film on a substrate arranged in the reaction furnace, conventionally, a gas phase growth apparatus has When trying to change the vapor phase growth rate or the film composition of a thin film, it is generally performed by adjusting the supply amount of only the source gas.

Further, in the conventional vapor phase growth apparatus, when the temperature of the substrate is raised and lowered, the rotation speed of the substrate, the pressure in the reactor, and the supply amount of gas supplied to the reactor are generally constant. Remains.

[0005]

As described above, in the conventional vapor-phase growth apparatus, the control of the film composition and the vapor-phase growth rate of the thin film is performed by changing the supply amount of the source gas alone. With the control of the supply amount of the source gas alone, it is difficult to easily and delicately change the film composition, and it is also difficult to increase the change range of the vapor phase growth rate.

Also, as described above, since the rotation speed of the substrate, the pressure in the reaction furnace, and the supply amount of the gas supplied into the reaction furnace are generally kept constant while the substrate temperature is raised and lowered, the substrate temperature is raised and lowered. It takes time (because the amount of heat radiation from the substrate during the temperature rise or the temperature decrease is not controlled), and it is not possible to improve the throughput (processing capacity per unit time).

Further, when the temperature of the substrate is raised, the heating of the substrate and the substrate holder tends to be uneven, and the substrate and the substrate holder are liable to be deformed such as warping. At this time, if the number of rotations of the substrate is high to some extent, the substrate placed on the substrate holder may be displaced from a predetermined position by a centrifugal force, or may fly out in the worst case.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to easily change a film composition and a vapor growth rate of a thin film during vapor growth, and to shorten a time for raising and lowering a substrate temperature. It is another object of the present invention to provide a vapor phase growth apparatus and a method thereof in which a substrate does not fly out even under growth conditions in which the rotation speed of the substrate is high.

[Structure of the Invention]

[0010]

According to a first aspect of the present invention, there is provided a vapor growth apparatus for supplying a raw material gas into a reaction furnace and vapor-growing a thin film on a substrate disposed in the reaction furnace. Alternatively, in any one or more steps of raising or lowering the temperature of the substrate, a rotation control device that controls the rotation speed of the substrate to an arbitrary rotation speed, and controls the pressure in the reaction furnace to an arbitrary pressure. A pressure control device, a gas supply control device for controlling the total supply amount of the source gas and the carrier gas supplied from the upstream side of the substrate into the reaction furnace to an arbitrary supply amount; It is characterized by having.

According to a second aspect of the present invention, there is provided a vapor phase growth method for supplying a source gas into a reaction furnace and vapor-phase growing a thin film on a substrate disposed in the reaction furnace. During one or more steps of raising or lowering the temperature, one or more of the number of rotations of the substrate, the pressure in the reaction furnace, and the supply amount of gas supplied to the reaction furnace It is characterized in that the vapor growth conditions are changed.

[0012]

When the vapor phase growth is diffusion-controlled, the vapor phase growth rate GR
(Growth rate) is shown below between the source gas supply amount f, the reactor pressure (gas phase growth pressure) P, the substrate rotation speed ω, and the total gas (source gas, carrier gas, etc.) supply amount F. There is a relationship such as Equation 1.

[0013]

(Equation 1)

By satisfying the relationship of Equation 1, by changing the substrate rotation speed ω, the reactor pressure P, and the total gas supply amount F in addition to the source gas supply amount f, the vapor phase growth rate can be reduced as in the prior art. It can be changed more than the case where only the raw material gas supply amount is changed (it can be increased within a range of several times).

When the substrate rotation speed ω, the reaction furnace pressure P, and the total gas supply amount F satisfy predetermined conditions, the substrate rotation speed ω, the reaction furnace pressure P, and the thin film to be vapor-phase grown on the substrate. And the thickness δ of the concentration boundary layer of the following equation (2).

[0016]

(Equation 2)

When either or both of the pressure P in the reactor and the substrate rotation speed ω are changed when the relationship of Expression 2 is established, a delicate composition due to a difference in reaction and diffusion in the boundary layer of the source gas is obtained. Experiments by the inventor have shown that control is possible.

Further, even if the total gas supply amount F is changed, the thickness δ of the concentration boundary layer changes, so that even if the total gas supply amount F is changed, a delicate composition change is possible.

The amount of heat radiated from the substrate during vapor phase growth q
Assuming that the amount of heat radiation by gas heat transfer is q ₁ and the amount of heat radiation by lateral radiation is q ₂ , there is a relationship of q = q ₁ + q ₂ (3).

The amount of heat released by the gas heat transfer is q
₁ has a relationship between the pressure P in the reactor and the number of rotations ω of the substrate as shown in the following Expression 3.

[0021]

(Equation 3)

Further, the amount of heat obtained by the gas depends on the gas supply amount F
The larger is the larger. By satisfying these relationships, the pressure P in the reaction furnace and the rotation of the substrate are adjusted so that the amount of heat radiation from the substrate is reduced when the substrate temperature rises and the amount of heat radiation from the substrate is increased when the substrate temperature is decreased. Number ω,
By changing the total gas supply amount F, the time required for raising and lowering the substrate temperature can be reduced.

That is, when the substrate temperature rises, the substrate rotation speed ω
, Or the pressure P in the reactor, or the total gas supply amount, or two or more methods. Also, when the temperature is lowered, the substrate rotation speed ω
Is increased, the pressure P in the reactor is increased, or the gas supply amount is increased, or two or more methods are performed.

[0024]

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 one embodiment of the present invention. As shown in this figure,
A substrate holder 3 on which a substrate 2 is placed is provided in the reaction furnace 1, and a motor 5 is mounted on the substrate holder 3 via a rotating shaft 4.
And a rotation control device 6 for controlling the number of rotations of the motor 5 are connected. The rotation control device 6 can arbitrarily change the rotation speed during the vapor phase growth of the substrate holder 3 (substrate 2) and during the temperature rise and fall of the substrate temperature by controlling the rotation speed of the motor 5.

At the upper part of the reactor 1, raw material gases (for example, TMG, TMI, AsH ₃ , PH ₃ )
A gas supply control device 8 for supplying a carrier gas (for example, H ₂ ) and a purge gas (for example, H ₂ ) to the inside of the reactor 1 via a pipe 7b is connected. An exhaust control device (reactor internal pressure control device) 11 is connected via a pipe 10 provided with 9.
The gas supply control device 8 controls the reaction furnace 1 of the source gas, the carrier gas, and the purge gas during the vapor phase growth and during the temperature rise and fall of the substrate temperature.
The gas supply into the reactor can be arbitrarily controlled, and the exhaust controller 11 can arbitrarily control the pressure in the reactor 1 during the vapor phase growth and during the temperature rise and fall of the substrate temperature.

A temperature controller 13 for controlling the temperature of the substrate 2 heated by the heater 12 is connected to the reaction furnace 1.

These control devices may be independent of each other, or may be interlocked by control from another control device.

The vapor phase growth apparatus according to the present embodiment is configured as described above. The exhaust control device 11 evacuates the reactor 1 to adjust the pressure in the reactor, and the substrate 12 is heated by the heater 12. Is raised to a predetermined temperature, the rotation control device 6 rotates the motor 5 to rotate the substrate holder 3 (substrate 2), and the gas supply control device 8 converts the raw material gas, carrier gas, purge gas and the like into the reaction furnace 1. In this case, a multi-element semiconductor thin film is vapor-phase grown on the substrate 2.

At this time, for example, in this embodiment, the supply amount of the total gas (source gas, carrier gas, purge gas, etc.) during the vapor phase growth, the pressure in the reaction furnace 1 and the temperature of the substrate 2 are respectively controlled by the gas supply control device 8. , And is controlled to be constant by the exhaust control device 11 and the temperature control device 13. Then, the number of rotations of the motor 5 that drives the substrate 2 to rotate is changed by the rotation control device 6.

FIG. 2 is a graph showing the relationship between the lattice mismatch (for example, In / Ga), the substrate rotation speed (ω), and the reactor pressure (P) during the vapor phase growth. In this case, the pressure inside the reaction furnace is controlled to be constant by the exhaust control device 11 and the rotation speed of the substrate is changed by the rotation control device 6. In FIG. 2, the vertical axis represents the lattice mismatch ratio (In / Ga), and the horizontal axis represents the square root of the reactor internal pressure (P) / substrate rotation speed (ω).

FIG. 3 is a diagram showing the distribution of the lattice mismatch (for example, In / Ga) in the substrate plane in this embodiment. In this figure, for example, a GaInAs layer and a GaInA
When each sP layer is vapor-phase grown on the substrate 2, the rotation control device 6 controls the number of rotations of the substrate 2 to 2500 rpm.
And the in-plane distribution of the substrate when it is changed to 40 rpm. In FIG. 3, the vertical axis represents the lattice mismatch (In / Ga), and the horizontal axis represents the radial distance from the center (0) of the substrate 2.

As is apparent from FIGS. 2 and 3, the composition of the thin film grown on the substrate 2 can be easily and finely adjusted by changing the rotation speed of the substrate during the vapor growth. It was confirmed that it was possible.

FIG. 4 shows a gas phase growth rate (GR), a reactor pressure (P), a substrate rotation speed (ω), a total gas (a source gas, a carrier gas, a purge gas, etc.) during the vapor phase growth in this embodiment. FIG. 4 is a diagram showing a relationship between a supply amount (F) and a source gas supply amount (f). As shown in this figure, in this embodiment, only the source gas supply amount (f) is changed by changing the substrate rotation speed during the vapor phase growth as in the conventional vapor phase growth method (FIG. 4). The growth rate can be changed in a range several times as large as that in the case of (a). In FIG. 4, the vertical axis is the vapor phase growth rate (GR), and the horizontal axis is Equation 4 shown below.

[0035]

(Equation 4)

In the above-described embodiment, the pressure inside the reaction furnace and the total gas supply amount are controlled to be constant during the vapor phase growth, and only the number of rotations of the substrate is changed. Quantity, one of substrate rotation speed,
Alternatively, any two or all of them may be changed.

Next, the control of the pressure inside the reaction furnace and the number of rotations of the substrate when the substrate temperature is raised and lowered in the above-described embodiment will be described with reference to FIG.

In the present invention, the period during which the temperature of the substrate rises and falls is defined as follows. In other words, the heating period is a period from when the substrate temperature is increased to the start of the vapor phase growth step, and includes a constant temperature period until the substrate temperature becomes substantially constant and the vapor phase growth is performed. Further, the heating period is a period after the end of the vapor phase growth step. The substrate 2 is placed on the substrate holder 3 provided in the reaction furnace 1 of the above-described vapor phase growth apparatus, and the heater 12 is energized to heat the substrate 2 to a predetermined temperature (temperature rising period). At this time, the amount of heat radiation from the substrate 2 can be reduced by controlling the rotation speed of the substrate 2 to a low rotation by the rotation control device 4 as shown in the above equation (4). The time for heating (heating) can be shortened.

Further, by reducing the number of rotations of the substrate at the time of raising the temperature, it is possible to prevent the substrate 2 from jumping out of the substrate holder 3 due to centrifugal force when the substrate 2 is warped and deformed due to the temperature rise.

When the temperature of the substrate 2 is raised and controlled to a predetermined temperature by the temperature controller 13, vapor phase growth is performed by the above-described method (vapor phase growth period).

When the temperature of the substrate is lowered after the vapor phase growth, the rotation speed of the substrate 2 is controlled to a high speed by the rotation control device 6 so that the rotation speed of the substrate 2 from the substrate 2 is increased as shown in the above equation (4). Since the amount of heat radiation can be increased, the temperature lowering (cooling) time of the substrate 2 can be shortened (temperature lowering period).

In the above embodiment, when the substrate temperature is raised, only the substrate rotation speed is reduced. However, the pressure in the reactor is increased, the total gas supply amount is reduced, or The combination can also reduce the time for raising the temperature of the substrate 2.

In the above embodiment, when the temperature of the substrate 2 is lowered, only the number of rotations of the substrate is increased. However, the pressure in the reaction furnace may be reduced, or the gas supply amount may be increased.
Alternatively, the temperature drop time of the substrate 2 can be reduced by combining them.

As described above, the time for raising and lowering the temperature of the substrate 2 can be shortened, so that the throughput can be improved.

[0045]

As described above, according to the present invention, according to the present invention, during one of the steps of vapor phase growth or raising or lowering the substrate temperature, the substrate rotation speed is reduced. Any one of the following: reactor internal pressure, gas supply amount
By changing one or more vapor growth conditions, the composition of a film to be vapor-grown on a substrate can be easily and finely changed, and the range of change of the vapor growth rate can be increased. . Further, since the number of rotations of the substrate can be reduced when the temperature of the substrate is increased, it is possible to prevent the substrate from flying out due to the centrifugal force generated during the rotation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a vapor phase growth apparatus according to one embodiment of the present invention.

FIG. 2 shows a lattice mismatch rate (In / G) during vapor phase growth.
FIG. 3A is a diagram showing a relationship among a reaction internal pressure (P) and a substrate rotation speed (ω).

FIG. 3 shows a lattice mismatch ratio (In / G) during vapor phase growth.
FIG. 3A is a diagram illustrating a distribution in a substrate surface of FIG.

FIG. 4 shows a gas phase growth rate (GR) and a reactor pressure (P),
FIG. 3 is a diagram showing a relationship among a substrate rotation speed (ω), a reactor internal pressure (P), a total gas supply amount (F), and a source gas supply amount (f).

FIG. 5 is a diagram showing the relationship between the substrate rotation speed (ω) and the reactor internal pressure (P) from when the temperature of the substrate is increased until the temperature is decreased.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reaction furnace 2 substrate 3 substrate holder 5 motor 6 rotation control device 8 gas supply control device 11 exhaust control device (reactor pressure control device) 12 heater 13 temperature control device

Claims (8)

(57) [Claims] 1. A vapor phase growth apparatus for supplying a source gas into a reaction furnace and vapor-growing a thin film on a substrate disposed in the reaction furnace, comprising: a temperature control means for controlling a temperature of the substrate; Rotation control means for controlling the number of rotations of the substrate in accordance with the temperature of the substrate controlled by the temperature control means. A vapor phase growth apparatus characterized in that the number of rotations is controlled to be lower than the number of rotations during growth. 2. The vapor phase growth apparatus according to claim 1, wherein said rotation control means changes a rotation speed during vapor phase growth. 3. A gas supply control for controlling supply amounts of said source gas and carrier gas supplied from an upstream side of said substrate into said reaction furnace according to a temperature of said substrate controlled by said temperature control means. The vapor phase growth apparatus according to claim 1, further comprising a unit. 4. The apparatus according to claim 1, wherein, when lowering the temperature of the substrate, the rotation control means makes the rotation speed different from the rotation speed during vapor phase growth. Vapor phase growth equipment. 5. A vapor phase growth method for supplying a source gas into a reaction furnace and vapor-phase growing a thin film on a substrate disposed in the reaction furnace, wherein: a temperature control step of controlling a temperature of the substrate; A rotation control step of controlling the number of rotations of the substrate according to the temperature of the substrate set by temperature control means, wherein the number of rotations during vapor phase growth is increased when the substrate is heated. A vapor phase growth method, wherein the rotation speed is controlled to be lower. 6. The vapor phase growth method according to claim 5, wherein the number of revolutions is changed during the vapor phase growth. 7. A gas supply control for controlling supply amounts of the source gas and the carrier gas supplied from an upstream side of the substrate into the reaction furnace according to the temperature of the substrate controlled by the temperature control step. 7. The vapor phase growth method according to claim 5, comprising a step. 8. The vapor phase growth method according to claim 5, wherein, when the temperature of the substrate is lowered, the number of revolutions is made different from the number of revolutions during vapor phase growth.